RATIONAL USE OF FIRED CLAY BRICKS
COMPARATIVE STUDY BETWEEN
LOAD-BEARING & CONCRETE SKELETON
STRUCTURES
A DISSERTATION SUBMITTED IN PARTIAL
FULFILLMENT FOR THE DEGREE
OF MASTER OF SCIENCE IN
BUILDING TECHNOLOGY
BY
ABDEL HALIM ABDEL RAZIG AWAD ALLA
EL NOUR
BUILDING AND ROAD RESEARCH INSTITUTE
UNIVERSITY OF KHARTOUM
NOVEMBER 2003
Dedicated to
My Parents , Brothers and Sisters
My Wife Nagwa and My Children Mohamed,
Samah , Samar , Ethar and Israa.
Those who are in the operation holes to those
who are holding the gun lock in all sites.
To the Martyr who sacrifice themselves for the
sake of the Religion and the Homeland.
ACKNOWLEDGEMENT
I wish to express my sincere gratitude and appreciation to my Supervisors
Dr. Ahmed Mustafa Mohammed , Dr. Abdullahi Ibrahim Fadl and Dr.
Mohammed Hussein Hamid for their help and guidance which
contributed immeasurably to this work.
I am indebited to the Director of the Building and Road Research Institute
(BRRI) and the Staff for their encouragement and rewarding discussions.
Special thanks are due to the Technical Staff of BRRI for their help in
carrying out the laboratory work.
The skill and patience of Mrs. Rafaa Ramzi who typed this dissertation is
greatly appreciated.
Finally I wish to express my gratitude and thanks to the Director of Soba
University Hospital, and the Staff of Maintenance Department for
unfailing support and moral encouragement throughout the period of this
work.
ABSTRACT
Most buildings in Northern Sudan have been constructed as loadbearing structures. In
recent years reinforced concrete skeleton is widely used in big towns and cities.
Machine made fired clay bricks are mainly used as facing skin for aesthetic and
maintenance free purposes. Can machine made bricks, when used as loadbearing
structures, be an alternative to reinforced concrete skeletons? The answer to this
question, is the main objective of this study. This dissertation attempted to cover the
following aspects:
(i)
Collection of information and data about brickwork design,
including techniques used in the existing loadbearing structures
in Sudan, advantage and disadvantage of brickwork, physical
and mechanical properties of brickwork materials such as
bricks (ordinary and machine) and mortars.
(ii)
Determination of the characteristic compressive strength of
brickwork using prism tests and some other methods according
to some of the codes of practice together with factors affecting
the compressive strength of brickwork and loadbearing
capacity of brickwork.
(iii)
Experimental works, which included tests on the BRRI bricks,
mortars, prisms and the results were used in the calculations of
the characteristic compressive strength of brickwork used in the
design of the loadbearing structures.
(iv)
Adoption of an existing apartment building and determination
of the number of floors, which can be supported using BRRI
Soba Factory Bricks.
(v)
Design the adopted building as a loadbearing structure, and
redesign it as a reinforced concrete skeleton.
(vi)
Estimation of the costs of the two types of structures applying a
suitable costing method and comparing the results for the two
structures with respect to the total values, types and quantities
of materials used, and the savings in the strategic material such
as steel reinforcement and cement. The significance of the
conclusions from these results were discussed.
(vii)
The study showed clearly that machine made brick of Soba
plant can be used as loadbearing up to five storey building and
its cost is less than that for reinforced concrete frame building
systems.
‫ﻤﻠﺨﺹ‬
‫ﺃﻏﻠﺏ ﺍﻟﻤﺒﺎﻨﻰ ﻓﻰ ﺸﻤﺎل ﺍﻟﺴﻭﺩﺍﻥ ﺒﻨﻴﺕ ﻋﻠﻰ ﺃﺴﺎﺱ ﺍﻟﺤﻭﺍﺌﻁ ﺍﻟﺤﺎﻤﻠﺔ‪ .‬ﻭ ﻓﻰ ﺍﻟﺴﻨﻭﺍﺕ ﺍﻷﺨﻴﺭﺓ‬
‫ﺃﺴﺘﻌﻤﻠﺕ ﻤﺒﺎﻨﻰ ﺍﻟﻬﻴﺎﻜل ﺍﻟﺨﺭﺴﺎﻨﻴﺔ ﺒﺼﻭﺭﺓ ﻭﺍﺴﻌﺔ ﻓﻰ ﺍﻟﻤﺩﻥ ﺍﻟﻜﺒﻴﺭﺓ ﻭ ﺍﻟﺼﻐﻴﺭﺓ ‪ ،‬ﻭ ﺇﻗﺘﺼﺭ‬
‫ﺇﺴﺘﻌﻤﺎل ﺍﻟﻁﻭﺏ ﺍﻵﻟﻰ ﺒﺼﻭﺭﺓ ﻤﺤﺩﺩﺓ ﻓﻰ ﺍﻟﻭﺍﺠﻬﺎﺕ ﻷﻏﺭﺍﺽ ﺍﻟﺠﻤﺎﻟﻴﺎﺕ ﻭ ﺨﻔﺽ ﺘﻜﺎﻟﻴﻑ‬
‫ﺍﻟﺼﻴﺎﻨﺔ‪ .‬ﻫل ﻴﻤﻜﻥ ﺃﻥ ﻴﻜﻭﻥ ﺍﻟﻁﻭﺏ ﺍﻷﻟﻰ ﺒﺩﻴل ﻟﻠﻬﻴﺎﻜل ﺍﻟﺨﺭﺴﺎﻨﻴﺔ ﻟﻭ ﺘﻡ ﺍﻟﺘﺼﻤﻴﻡ ﺒﻨﻅﺎﻡ‬
‫ﺍﻟﺤﻭﺍﺌﻁ ﺍﻟﺤﺎﻤﻠﺔ – ﺍﻹﺠﺎﺒﺔ ﻋﻠﻰ ﻫﺫﺍ ﺍﻟﺴﺅﺍل ﻫﻭ ﺍﻟﻤﺠﺎل ﻭ ﺍﻟﻬﺩﻑ ﺍﻟﺭﺌﻴﺴﻰ ﻤﻥ ﻫﺫﻩ ﺍﻟﺩﺭﺍﺴﺔ‪.‬‬
‫ﻫﺫﻩ ﺍﻟﺭﺴﺎﻟﺔ ﺤﺎﻭﻟﺕ ﺃﻥ ﺘﻐﻁﻰ ﺍﻟﺠﻭﺍﻨﺏ ﺍﻟﺘﺎﻟﻴﺔ‪-:‬‬
‫)‪ (1‬ﺠﻤﻊ ﺍﻟﻤﻌﻠﻭﻤﺎﺕ ﻭ ﺍﻟﺤﻘﺎﺌﻕ ﻋﻥ ﺘﻨﻔﻴﺫ ﻭ ﺘﺼﻤﻴﻡ ﺍﻟﻤﺒﺎﻨﻰ ﻋﻠﻰ ﺃﺴﺎﺱ ﺍﻟﺤﻭﺍﺌﻁ ﺍﻟﺤﺎﻤﻠﺔ‬
‫ﻭﺸﻤل ﺫﻟﻙ ﺨﻠﻔﻴﺔ ﻋﻥ ﺍﻟﻤﺒﺎﻨﻰ ﺍﻟﻤﻭﺠﻭﺩﺓ ﻓﻰ ﺍﻟﺴﻭﺩﺍﻥ‪ ،‬ﺍﻹﻴﺠﺎﺒﻴﺎﺕ ﻭ ﺍﻟﺴﻠﺒﻴﺎﺕ ‪،‬‬
‫ﺍﻟﺨﺼﺎﺌﺹ ﺍﻟﻔﻴﺯﻴﺎﺌﻴﺔ ﻭ ﺍﻟﻤﻴﻜﺎﻨﻴﻜﻴﺔ ﻋﻥ ﺍﻟﻤﻭﺍﺩ ﺍﻟﻤﺴﺘﻌﻤﻠﺔ ﻓﻰ ﺍﻟﻤﺒﺎﻨﻰ ﻭ ﺘﺄﺜﻴﺭﻫﺎ ﻋﻠﻰ‬
‫ﻗﻭﺓ ﺘﺤﻤل ﺍﻟﻤﺒﺎﻨﻰ‪.‬‬
‫)‪ (2‬ﺘﺤﺩﻴﺩ ﻗﻭﺓ ﺍﻟﻀﻐﻁ ﺍﻟﻤﻤﻴﺯ ﻟﻤﺒﺎﻨﻰ ﺍﻟﻁﻭﺏ ﺒﺈﺴﺘﻌﻤﺎل ﺍﺨﺘﺒﺎﺭ ﺍﻟﻤﻨﺸﻭﺭ ﻭ ﺒﻌﺽ ﺍﻟﻁﺭﻕ‬
‫ﺍﻷﺨﺭﻯ ﺇﺴﺘﻨﺎﺩﹰﺍ ﻋﻠﻰ ﺒﻌﺽ ﺍﻟﻤﺭﺍﺠﻊ ﻤﻊ ﺍﻟﺘﻌﺭﺽ ﻟﻠﻌﻭﺍﻤل ﺍﻟﻤﺅﺜﺭﺓ ﻋﻠﻴﻪ ﻭ ﻋﻠﻰ ﻗﻭﺓ‬
‫ﺘﺤﻤل ﺍﻟﺤﻭﺍﺌﻁ ﺍﻟﺤﺎﻤﻠﺔ ﻟﻤﺒﺎﻨﻰ ﺍﻟﻁﻭﺏ‪.‬‬
‫)‪ (3‬ﺒﻌﺽ ﺍﻟﺘﺠﺎﺭﺏ ﺍﻟﻤﻌﻤﻠﻴﺔ ﻋﻠﻰ ﻁﻭﺏ ﻤﻌﻬﺩ ﺒﺤﻭﺙ ﺍﻟﺒﻨﺎﺀ ﻭ ﺍﻟﻁﺭﻕ )ﻤﺼﻨﻊ ﺴﻭﺒﺎ(‬
‫ﻭﺃﻨﻭﺍﻉ ﺍﻟﻤﻭﻨﺔ ﻭ ﺇﺨﺘﺒﺎﺭ ﺍﻟﻤﻨﺸﻭﺭ ﻟﻺﺴﺘﻔﺎﺩﺓ ﻤﻥ ﺍﻟﻨﺘﺎﺌﺞ ﻓﻰ ﺘﺤﺴﻴﺏ ﻗﻭﺓ ﺍﻟﻀﻐﻁ‬
‫ﺍﻟﻤﻤﻴﺯ ﻟﻤﺒﺎﻨﻰ ﺍﻟﻁﻭﺏ ﻭ ﺍﻟﺫﻯ ﺒﻤﻭﺠﺒﻪ ﻴﺘﻡ ﺘﺼﻤﻴﻡ ﺍﻟﺤﻭﺍﺌﻁ ﺍﻟﺤﺎﻤﻠﺔ‪.‬‬
‫)‪ (4‬ﺇﺨﺘﺒﺎﺭ ﺘﺼﻤﻴﻡ ﻤﻨﺎﺴﺏ ﻟﻤﺒﺎﻨﻰ ﺍﻟﺸﻘﻕ ﺍﻟﺴﻜﻨﻴﺔ ﻭ ﻤﻥ ﺜﻡ ﺤﺴﺎﺏ ﻋﺩﺩ ﺍﻟﻁﻭﺍﺒﻕ ﺍﻟﺘﻰ‬
‫ﻴﻤﻜﻥ ﺃﻥ ﻴﺘﺤﻤﻠﻬﺎ ﻫﺫﺍ ﺍﻟﻨﻭﻉ ﻤﻥ ﺍﻟﻁﻭﺏ‪.‬‬
‫)‪ (5‬ﺘﺼﻤﻴﻡ ﺍﻟﻤﺒﻨﻰ ﺍﻟﻤﺨﺘﺎﺭﺓ ﻋﻠﻰ ﺃﺴﺎﺱ ﺍﻟﺤﻭﺍﺌﻁ ﺍﻟﺤﺎﻤﻠﺔ ﻭ ﺃﻴﻀﹰﺎ ﻋﻠﻰ ﺃﺴﺎﺱ ﺍﻟﻬﻴﻜل‬
‫ﺍﻟﺨﺭﺴﺎﻨﻰ‪.‬‬
‫)‪ (6‬ﺘﻘﺩﻴﺭ ﺘﻜﻠﻔﺔ ﻜل ﻤﺒﻨﻰ – ﻤﻊ ﻋﻤل ﻤﻘﺎﺭﻨﺔ ﺒﻴﻨﻬﺎ ﻓﻰ ﺍﻟﺘﻜﻠﻔﺔ ﺍﻟﻜﻠﻴﺔ – ﻭﺃﻨﻭﺍﻉ ﻭ ﻜﻤﻴﺎﺕ‬
‫ﺍﻟﻤﻭﺍﺩ ﺍﻟﻤﺴﺘﻌﻤﻠﺔ – ﻭ ﺍﻟﻭﻓﺭﺓ ﻓﻰ ﺇﺴﺘﻌﻤﺎل ﺍﻟﻤﻭﺍﺩ ﺍﻹﺴﺘﺭﺍﺘﻴﺠﻴﺔ ﻤﺜل ﺤﺩﻴﺩ ﺍﻟﺘﺴﻠﻴﺢ‬
‫ﻭﺍﻷﺴﻤﻨﺕ‪ .‬ﻭ ﻨﺎﻗﺸﺕ ﺍﻟﺭﺴﺎﻟﺔ ﺃﻫﻤﻴﺔ ﺘﻠﻙ ﺍﻟﻨﺘﺎﺌﺞ ﺍﻟﻤﺴﺘﺨﻠﺼﺔ‪.‬‬
‫)‪ (7‬ﺃﻭﻀﺤﺕ ﻫﺫﻩ ﺍﻟﺩﺭﺍﺴﺔ ﺃﻥ ﺍﻟﻁﻭﺏ ﺍﻷﻟﻰ ﻤﻥ ﻤﺼﻨﻊ ﺴﻭﺒﺎ ﻴﻤﻜﻥ ﺃﻥ ﻴﺴﺘﻌﻤل ﻟﺤﺎﺌﻁ‬
‫ﺤﺎﻤل ﻟﺨﻤﺱ ﻁﻭﺍﺒﻕ ﺒﺘﻜﻠﻔﺔ ﺃﻗل ﻤﻥ ﺍﻟﻤﺒﺎﻨﻰ ﺒﻨﻅﺎﻡ ﺍﻟﻬﻴﻜل ﺍﻟﺨﺭﺴﺎﻨﻰ‪.‬‬
Table of Contents
Page
Abstract
Acknowledgement
Table of Contents
List of Tables
List of Plates
List of Drawings
List of Appendices
Notations
1 Introduction
1.1
General
1.2
Objective
1.3
Scope
2
Brickwork Overview
2.1
2.2
2.3
2.5
2.6
5
General
Traditional Techniques of Earth Construction
2.2.1 Cob Techniques
2.2.2 Adobe Technique
2.2.3 Gishra Technique
Traditional Fired Clay Bricks Walling
2.3.1
5
7
7
7
8
8
8
2.3.2 Walls Built in Cement Sand Mortar
2.3.3 Walls Built in Lime Mortar
Advantage and disadvantage of Brickwork
2.4.1 General
2.4.2 Advantage
2.4.3 Disadvantage
Fired Clay Bricks (Technical Specification)
2.5.1 General
2.5.2 Types of Bricks
2.5.3 General Situation of bricks Production
2.5.4 Methods of Production
2.5.5 Properties of Bricks
Mortars
2.6.1 General
2.6.2 General Types of Mortars
2.6.3 Factor Affecting Mortars Strength
8
9
10
10
10
14
16
16
16
17
18
23
26
26
27
28
Walls Built in Safaya Mortar
2.4
i
v
vi
x
xii
xiii
xiv
xv
1
1
2
2
2.6.4 General Properties of Mortars and Their Effect 29
on Brickwork
2.7
2.8
2.9
Strength of Brickwork
2.7.1 General
2.7.2 Effect of Brick and Mortar Strengths
2.7.3 Effect of Brick Shape
2.7.4 Effect of Thickness of the Mortar and
Brick Height
2.7.5 Effect of initial rate of Absorption of Bricks
and Water Retentivity of Mortar
2.7.6 Effect of Ageing
2.7.7 Effect of Patterns and Method of Bonding
2.7.8 Effect of Variation in Dimensions of Bricks
2.7.9 Effect of Eccentricity of Loading and
Slenderness Ratio.
2.7.10 Effect of Small Cross-Sectional Area
2.7.11 Effect of Workmanship
Assessment of Characteristic Strength of Brickwork
2.8.1 Prisms Tests as a Measure of Brickwork
Strength
2.8.2 Assessment of Characteristics Strength of
Brickwork Units and Prisms
2.8.3 Calculation of Characteristic Compressive
Strength of Brickwork
2.8.4 Permissible Compressive Strength of Brickwork
2.8.5 Permissible Compressive Force or
Loadbearing Capacity of Brickwork
2.8.6 Increase in permissible Stress in Members
Subjected to Concentrated Loads
2.8.7 Stress in Brickwork Subjected to lateral
Supports
2.8.8 Permissible Compressive Force in columns
(Peirs)
2.8.9 Column Formed by Openings
Previous Research Work and Studies on the Use of
Fired Clay Bricks in Loadbearing Walls
2.9.1 Comparative Study on the Rational Use of Fired
Clay Brick in Building in Khartoum
31
31
31
32
32
33
33
34
34
34
35
35
39
39
42
44
45
49
51
53
53
56
58
58
2.9.2 Comparative Study Between Loadbearing
and Reinforced Concrete Skeleton Buildings
(Egypt 1975)
3.
4.
Experimental Work
3.1 Introduction
3.2 Characterization of Bricks
3.3 Mortar Tests
3.4 Characteristic Compressive Strength of Prisms
and Brickwork
3.4.1
Compressive strength of prisms
3.4.2
Calculation of characteristic compressive strength
of prisms and brickwork
3.5 Compressive Strength of Short Peirs
3.5.1
The Loadbearing Capacity of the Peirs
3.6 Discussion of the Results
3.6.1
Bricks
3.6.2
Mortar
3.6.3
Brickwork, Prism and Peirs
3.7 Conclusions
Loadbearing Design
4.1 Introduction
4.2 Design Information
4.3 Loading
4.3.1 Section Loads
4.3.2 Bending Moment and Shear Forces
4.4 Design of Slabs
4.5 Design of Beams
4.6 Design of Stair Case
4.7 Design of Load Bearing Walls
4.8 Construction Detail Consideration
5
Reinforced Concrete Skeleton Design
5.1 Introduction
5.2 Design Information
5.3 Loading
5.3.1 Section Loads
5.3.2 Bending Moment and Shear Forces
5.4 Design of Slabs
62
64
64
64
65
65
65
65
67
67
69
69
69
70
71
73
73
76
77
79
79
79
79
80
80
81
84
84
85
85
86
88
88
5.5
5.6
5.7
5.8
6
Design of Beams
Design of Columns
Design of Stair Case
Design of Concrete Wall
The Comparison of Costs
6.1
6.2
6.3
6.4
6.5
Introduction
The Accounting ٍSystems
6.2.1 Conceptual and Preliminary Estimates
6.2.2 Detailed Estimates
6.2.3 Choice of Accounting System
Types of Detailed Estimate
6.3.1 Fair Cost Estimate
6.3.2 Contractors Bid Estimate
6.3.3 Definitive Estimates
Choice of Estimating Method
Estimates of the Construction Costs
6.5.1
6.5.2
92
92
92
94
94
94
95
95
95
96
97
97
Components of the Structures for Cost Estimating 98
99
Breakdown of Unit Rate Estimate
6.6 Total Estimated Costs
6.6.1 Results
6.6.2 Analysis of the Results
6.6.3 Discussion of the Analysis of Results
7
88
89
90
91
Conclusions and Recommendations
7.1 Conclusions
7.2 Recommendations
100
100
100
101
102
102
103
References
105
Tables
107
Plates
126
Drawings
130
Appendices
137
List of Tables
Page
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
2.10
2.11
2.12
2.13
2.14
2.15
2.16
2.17
3.1
3.2
3.3
3.4
3.5
3.6
Annual brick production in Northern Sudan 1994
Dimensional Tolerance (Bricks) According to BS
3921/65
Dimensional Tolerance (Bricks) According to
MSS/No/6/1990
Compressive Strength and Absorption of bricks to both
B3921/65 and MSS/No/6/1990
Mortar Designation. According to BS/5628-1978
Aspect ratio (H/T) Correction Factors for Compressive
Strength in accordance with AS/1640-1974
Sample size Factor for Characteristic Strength.
According to BS 5628-1978
Characteristic Compressive Strength of Brickwork
According to BS 5628- 1978.
Partial Factors of Safety on Materials as Specified by BS
5628 –1978.
Effective Height in Accordance with BS 5628-1978
Effective Length in Accordance with BS 5628-1978
The Appropriate Stiffness Factor “k” . According to
BS5628-1978.
Capacity reduction Factor β According to BS5628-1978
Reduction Factor (Ka,Ke) for Slenderness Ratio and a
uniform eccentricity of Force as Prescribed by AS 16401974.
Design Local Compressive Stress According to BS56281978.
The Effective Height of Column in Accordance with BS
5628/1978.
Quantities and Their Cost of the Reinforced Concrete
Skeleton and the Loadbearing Walls Structures , Egypt
1975.
Dimensions of Machine Bricks in Relation to
MSS/No/6/1990
Water Absorption of Machine Bricks
Compressive Strength of Machine Bricks
Efflorescence of Machine Bricks
Sieve Analysis of Sand Used for Mortar Preparation
Grades of Sand. According to BS 882-1973
107
107
107
108
108
109
109
109
109
109
109
110
111
111
112
112
112
113
113
113
114
115
115
3.7
3.8
3.9
Physical Properties of Cement. According to BS 12/1978 116
Compressive Strength of Mortar Cubes
116
Compressive Strength of Prisms
117
Page
3.10
3.11
3.12
3.13
4.1
6.1
6.2
6.3
6.4
6.5
6.6
Compressive Strength of Peirs (1.0m high)
Compressive Strength of Peirs (1.5m high)
Design Loads. According to BS 5628-1978
Comparison between the Loadbearing Capacity
Calculated Using Different Methods
Design and parameter informations
Bill of Quantities of Loadbearing
Bill of Quantities of Reinforced Concrete Skeleton
Quantities and Their Costs of Reinforced Concrete
Skeleton and the loadbearing Walls Structures.
Quantities of main materials
Saving in Materials for the loadbearing Structure
Saving in Materials for the Reinforced Concrete
Skeleton.
117
118
119
120
121
122
123
124
125
125
125
List of Plates
Page
3.1
Constructed Piers covered with polythin sheets as a curing.
126
3.2
BRRI crushing machine and the piers after failure.
127
3.3
Piers after release of loads and the cracking on both sides.
128
3.4
Splitting failure of Piers.
129
List of Drawings
Page
4.1
Plan arrangement showing the grid notation and selected
sections for loadbearing structure.
130
4.2
Arrangement of Reinforced steel for the whole slab of loadbearing structure.
131
4.3
Plan of designed walls of load-bearing structure.
132
5.1
Plan arrangement showing the grid notation and selected
sections for reinforced concrete skeleton
133
5.2
Arrangement of reinforced steel for the whole slab of
reinforced concrete skeleton.
134
5.3
Beams detail
135
5.4
Columns detail
136
Appendix
(i)
Load Bearing Structure
Appendix (A)
Bending moments and Shear Forces Calculation
137
Appendix (B)
Design of Selected Slabs
Design of Beams
Design of Stair Case
145
154
155
Appendix (C)
Design of Selected Walls and Piers
157
(ii)
Concrete Skeleton Structure
Appendix (D)
Bending Moments and Shear Forces Calculation
169
Appendix (E)
Design of Selected Slabs
177
Appendix (F)
Design of Beams
186
Appendix (G)
Design of Selected Columns
Design of Reinforced Concrete Wall
209
225
(iii) Calculations
Appendix (H)
Calculations of Reinforcements Bars
Breakdown of Rate Estimates
Abstract and Calculation of Quantities
226
228
231
Notations
A
Ag
As
Asc
b
C
DL
d
e
ea
eI
et
ex
f
fcu
concrete
fk,fm
fp
fy
fy1
fyv
GK
GQ
H
hb
Kci
k
ka
ke
L
LL
Lx
Ly
N
n
nw
PL
R
S
SR
Cross-sectional area
Gross-sectional area
Area of Tensile Reinforcement
Area of Compressive Reinforcement
Major axis of column
Mean of Sample
Dead Load
Effective depth to tensile reinforcement
Eccentricity
Additional Eccentricity due to deflection in wall.
Eccentricity at bottom of wall
Total design eccentricity at approx. mid-height
Eccentricity at top of wall
Reduction Factor
Characteristic compressive strength of reinforced
Characteristic compressive strength of masonry
Characteristic compressive strength of prism
Characteristic tensile strength of steel
Characteristic Strength of Mild Steel
Characteristic Strength of Shear Reinforcement
Characteristic DL
Characteristic LL
Average height of prisms
Height of bearing relative to the lower support
Aspect ratio correction factor
Sample Size Factor
Capacity Reduction Factor
Capacity Reduction Factor
Length
Live Load
Length of span in short direction
Length of Span in long direction
Design vertical axial load
Axial Load Per unit length of wall
Design vertical load per unit length of wall
Point Load
Group Range
Standard Deviation of Sample
Slenderness ratio
Su
Spacing of link reinforcement
T
Tw
t
tef
UDL
V
Wm
Wt
w
wx
wy
x
β
γf
γm
Average thickness of prisms
Standard thickness of wall
Thickness of wall, minor axis of column
Effective thickness of wall
Uniformly distributed load
Shear Force
Unit weight of machine brick wall
Unit weight of traditional brick wall
Total unfactered load
Load in short span
Load in long span
Mean of Sample
Capacity Reduction Factor
Partial Safety Factor For Load
Partial Safety Factor for Material
CHAPTER ONE
INTRODUCTION
1.1
General:-
Brick is a universal building material however, there is a tendency to use
brick masonry more as cladding and in-fill material rather than as
structural material. A large proportion of brickwork buildings for
residential and other purposes is satisfactorily designed and built in
accordance with empirical rules and practices without the need for special
structural consideration . However, the limits of this approach can not be
extended much beyond the scale of two storey houses of conventional
construction without having to resort to very thick walls, which in turn
result in waste of materials and other disadvantages. However in old
conventional practice, the thickness of brickwork is decided on the basis
of storey height without relating it to the load it has to withstand. The
economic success of brickwork construction has been achieved not only
by the rationalization of structural design, but also because it is possible
for the walls which comprise a brick building structure to perform several
functions, such as thermal and a accaustic insulation, fire and weather
protection as well as sub-division of space. As a building material it is
relatively cheap and durable, can provide virtually infinite flexibility in
plan form and offer an attractive external appearance.
Furthermore
brickwork buildings can be constructed without heavy capital expenditure
on the part of the builder.
Recent studies have established brick as structural material. It has been
established that brick masonry can be designed as a loadbearing structural
element in conjunction with other structural parts of the building such as
floors, beams and columns. To make the best use of the inherent
advantages of brickwork, it is necessary to apply its construction in cases
where the accommodation gives rise to moderate or small floor spans,
and where it is possible to continue the loadbearing walls uninterrupted
from foundation to roof.
In the Sudan it is now generally accepted that brickwork forms an
attractive, durable cladding with good thermal and accaustic insulation,
excellent fire resistance, etc; but it is not so widely appreciated as an
economical structural material that can often be built faster more simple
than its main rivals steel and concrete, for multi-storey structures.
1.2
Objective of the Dissertation:-
The overall objective of this study is to work out the loadbearing capacity
of brickwork built from locally produced machine made bricks and then
to prove that it can be used in multi-storey apartment buildings by
determining the number of floors it can carry.
It is also attempted to compare the cost of such type of construction with
concrete frame structure apartment buildings of the same plan form and
number of storey high.
1.3
Scope of the Work
Broadly the scope is of three folds:a) Establish the loadbearing capacity of brickwork built of
machine made bricks of Soba Brick Factory of the Building
and Road Research Institute – University of Khartoum
(BRRI- U. of Kh.)
b) Design a suitable apartment building based on the
parameters resulted from (a) above as a loadbearing
structure.
c) Design the same a apartment building as a concrete frame
structure of the same storey high. .
d) Compare the cost of the two types of construction method in
relation to the overall cost of the buildings and their
component cost of the various materials, labour etc.
The methodology of the study is as follows:(i)
Characterization of BRRI bricks in order to study their
physical
and
dimensions,
mechanical
compressive
properties
strength,
such
as
absorption,
efflorescence, etc.
(ii)
Study of compatible mortar to be used, which include
study of materials such as sand, cement, and its cube
compressive strength.
(iii)
Determination of characteristic compressive strength
of brickwork by means of crushing test carried out on
prisms of bricks. The prisms are constructed, cured,
and tested as specified by Australian Standard
AS/1640/1974.
(iv)
Calculation of the loadbearing capacity of brickwork
using the above obtained characteristic strength.
(v)
Construction of two types of short piers in order to
verify the
results obtained by prism tests, namely
compressive strength, loadbearing capacity and the
mode of failure.
(vi)
Determination of plan arrangement of walls in
accordance with the function of the building and to
provide lateral strength and rigidity and to ensure that
the building is generally robust.
(vii) Determination of number of floors that such type of
bricks can carry according to the results of strength
obtained
from
brickwork
tests,
the
loading
characteristic of an apartment loadbearing building,
logical thickness of walls and environment considered
(viii) Redesign of the same building with the number of
floors but as a reinforced concrete frame building.
(ix)
Calculation and comparison of the two types of
construction in relation to overall cost, materials,
labour construction time…etc.
CHAPTER TWO
BRICKWORK OVERVIEW
2.1 General
The use of earth as a building material is an old practice in Sudan. For wall
construction, the people use different traditional techniques such as cob (jalous),
adobe blocks, wattle and daub and gishra. Mud house is one of the earliest types of
construction known in Sudan. Traditional earth building techniques were developed in
various regions of the country to suit the available materials and the climatic
conditions. In Southern Sudan, Wattle and daub methods of construction are
promoted by the availability of timber and also by the continuous rain almost
throughout the year. In northern Sudan, the weather is dry hence cob and adobe
blocks are extensively used. Traditional buildings are noted for their simplicity,
utilization of local materials and good thermal insulation. However, they deteriorate
easily and require periodic maintenance. The annual expenditure on maintenance
sometimes outweighs all the economy achieved in the initial cost of the building.
Fired clay bricks are an important development of earth construction. The produced
bricks are more durable, since they withstand action of rain, and still have the good
properties of earth building of good thermal insulation, good fire resistance etc.
Fired clay bricks are extensively used in Sudan. The annual consumption of fired clay
bricks is estimated to be about 2.8 billion bricks per annum(1). Such extensive use
necessitate scientific exploration of the great potential that brickwork and other earth
building could offer to ever-growing building industry.
This chapter attempts to cover the following aspects:a)
Brief information about the traditional techniques of earth
construction (Cob, adope, gishra) and the traditional fired clay brick
walling in Sudan.
b)
Advantage and disadvantage of brickwork.
c)
Technical specification of rational fired clay bricks and machine
made bricks such as general situation of production in Sudan,
method of production, physical and mechanical properties of bricks
as reported in previous studies.
d)
General information about mortars, which includes, general types,
factors affecting mortar strength, general properties of mortar and
their effect on brickwork.
e)
Strength of brickwork, which includes effect of brick and mortar
strengths on brickwork strength , assessment of characteristic
strength using prism tests as a measure of brickwork strength and
factor affecting the prism tests.
f) Calculation of characteristic strength and permissible compressive
strength of brickwork and units using formulae and equations
according to BS 5628/1978 and AS 1640-1974.
g)
Factors affecting the permissible stress such as eccentricity, small
cross-sectional area and slenderness ratio.
h)
The loadbearing capacity of brickwork calculations according to AS
1640-1974 and BS 5628-1978.
i)
Permissible compressive force in columns, the effect of slenderness
ratio, eccentricity on them.
j)
Previous research work and studies on the use of fired clay bricks in
loadbearing walls which include comparative study on the rational
use of fired clay bricks in building, comparative study between
loadbearing and reinforced concrete skeleton buildings.
2.2 Traditional Techniques of Earth Construction
2.2.1 Cob Technique
Most of the soils used are light, grey, sandy clay soil having an average
liquid limit of 32% and average plastic limit of 18%. In about 50% of
the buildings, the soil is usually used without any additive while in
30% of the buildings, mud is to be added to the soil. In other cases
13% Safaya (Silty loam) is added to the soil. The consistency of soil to
be used is usually determined by the builder based on his experience
and on types of soils available near the site.
Shrinkage cracks, which are likely to occur in the cob techniques, are
repaired with more mud, Animal dung (Zibala) is generally used as
external rendering in 75% of the buildings. In 90% of the building,
sand plus gum Arabic is used for the internal rendering. In few cases
no rendering was applied to either face of the wall (2).
2.2.2
Adobe Technique
Adobe bricks or blocks rank second as construction technique for earth
building. A soil (similar to that used in the cob technique) is molded in
a single-cavity wood mould. Enough water is added to the soil mixture
to produce a plastic and workable consistency that allows the material
to be formed in the mould. Usually the mortar joint for adobe block
wall is made of pure soil, and in about 50% of the cases the soil used
for the mortar is the same soil as that used in making the adobe
blocks.(2)
2.2.3 Gishra Technique
This technique, is an improvement of cob and adobe techniques. The
walls are built in two leaves. The internal face of the wall is of adobe
bricks or cob, and the external face is built of burnt clay bricks. The
idea is to protect the external face of the wall by burnt clay bricks,
which are more durable. This technique also improves the appearance
of the finished house. The two leaves of the gishra wall are either built
simultaneously or the burnt clay bricks are built after the adobe or cob
has already been built. The later case occurs when the owner can
afford to improve his adobe or cob house without demolishing the
existing walls.
These traditional techniques are relatively easy to produce and cheap
but the earth buildings are susceptible to continuous deterioration
caused by weathering factors such as rain and wind. When properly
applied improved construction techniques of earth buildings, such as
rammed earth and stabilized soil blocks, proved to be durable and
resistant to weathering factors. Results of experimental studies showed
that adding adequate stabilizer to the soil improves the engineering
properties of the soil.(2)
2.3 Traditional Fired Clay Brick Walling
This type of walling is more durable requires less maintenance cost and nice in
appearance over the earth buildings.
This type of walling may be classified as follows:2.3.1 Walls built in safaya mortars
This type of walling is usually of thickness 1, 1.5 brick, and withstands light roof
loadings like, corrugated iron sheets, timber boarding.
Cement sand mortar usually used for internal plastering and some times for
external rendering.
2.3.2 Walls built in cement sand mortar
This type of walling may be classified according to the wall thickness
as:a) Walls of one brick thick
Capable to withstand light roof loading and has a
compressive strength more than walling built in Safaya.
Cement sand plastering is usually used internally, but
some times for external renderings as well and some
few houses have Dahara as external finishings.
b) Walls of more than one brick thick
Usually for building of two or more stories high, with
reinforced concrete cover slabs, internal and external
finishings like in (a), above .
2.3.3 Walls built in lime mortars
Usually built in different thickness according to the number of
floors and types of roofing, found in old building in Khartoum.
Historically the use of masonry in walls and columns both
internal and external to carry the weight of floors and roofs was
the normal practice until steel and reinforcement concrete
frames came into use towards the end of the nineteenth century.
2.4 Advantage and Disadvantage of Brick work
2.4.1 General
The durability of brickwork when used properly is excellent. However
as with other materials, the proper use of brickwork requires an
understanding of its physical characteristics, its strength and weakness,
the method of construction and the availability of various shapes and
textures of bricks.
2.4.2 Advantages
(a) Cost
It is difficult to obtain accurate and comprehensive costs for
building elements. Cost reflect the current state of the
building market, and nearly always provide only the cost of
erecting the building and the long term cost of the building
over its life span. Experience and practice showed when a
brickwork structure is appropriate, it is cheaper than the
other structural alternatives for the following reasons:- (3)
(i)
In steel and concrete frame structures,
brickwork or other materials are used to
form the external envelope, partitions,
and the like if these partitions and other
walls are designed as load bearing
brickwork they can be made to carry
loads and thus can do without the
skeleton.
(ii)
Experience has shown that generally the
less the amount of work put out to subcontractors,
the
construction
costs.
lower
With
are
the
brickwork
structures not only is the number of subcontractor reduced, but there is also
reduction
in
the
number
of
site
operations, trades and materials.
(iii) Brickwork buildings tend to be quick to
erect, resulting in lower site overhead
costs.
(iv) The maintenance costs are reasonable.
(v)
A high degree of fire resistance, thermal
and
sound
insulation,
exposure
protection, are automatically provided
within the structural requirements of
brickwork buildings making them to be
relatively economical.
(b) Speed of Erection
A brickwork wall can easily be built in few days, and can
support a floor or roof load after few days. While concrete
frame will require more than few weeks to erect shuttering, fix
reinforcement , cast concrete, cure, prop and then strike the
formwork.(3)
(c)
Repair and Maintenance
Properly designed brickwork requires little or no
maintenance and is extremely economical in terms of
maintenance costs. A well-designed building will contain
the majority of damage within the mortar and movement
joints, and repointing the brickwork will make good most of
the defects.(3)
(d) Availability of Materials and Manpower
The normal module size of bricks and the generally readily
available of their raw materials means that they can be mass
produced in many locations and stocked in standard sizes.
Modern transportation and packing enable speedy delivery
of bulk supplies of bricks, and reduce the number damage
in transit to the minimum. Similarly, the materials used in
mortar are available in many locations and are easily
transported.
Being a well-established trade, skilled bricklayers are
normally available in most areas. Early discussions with the
tradesmen on the site regarding the constructional
requirements will result is a proper understanding of the
job.
(e) Durability
The excellent durability of brickwork is one of its greatest
advantages. It varies accordingly to the nature of units, the
composition of the mortar and the degree of exposure to the
weather, atmospheric pollution and aggressive condition.
For example, in severe exposure such as that below dampproof course particular attention should be paid to the
choice of brick and mortar. (3)
(f) Fire Resistance and Accidental Damage
Brick structures suffer less damage than steel or concrete
buildings – which fact provides evidence of not only the
high fire resistance of brickwork structures, but also of their
inherent capacity to resist accidental damage.
Brickwork is incombustible and do not start or spread a fire.
Brickwork is rarely seriously damaged by fire, it does not
buckle like steel or spell like reinforced concrete or burn
like timber and only melt under very high temperature.
The thickness of walls is taken such that the materials and
methods of construction will provide the necessary period
of fire resistance under the conditions of loading. (3)
(g)
Thermal Insulation
To provide for acceptable thermal conditions inside
buildings, brick wall envelopes can provide insulation
against excessive loss or gain in heat and have adequate
thermal capacity if properly designed.
The loss or gain in heat through the wall depends on
temperature difference between the air on both sides of the
wall. The good thermal properties of cavity walls have long
been recognized. (3)
(h) Sound Insulation
The major noise intrusion is considered to be caused by
airborne sound and the best defense against this is by
material insulation. The more dense a partition the less is
the noise transmitted through it. Brickwork provides the
dense partition without too much rigidity. (3)
(i) Resistance to Movements
It is essential that the strength of mortar should be less than
that of brick, because any cracking resulting from any
movement will occur at mortar joints. These movements are
usually due to chemical reactions, foundation settlement,
differences or changes in temperature and moisture. The
mortar joint should always be the weak link, in order to
retain any cracking within horizontal and perpendicular
joints between the bricks. A correct relationship between
the mortar and the brick strength will result in the total
effect of the movement being distributed amongst
numerous fine cracks. Such cracks are largely concealed
and can be easily pointed without becoming unsightly. (3)
(j) Aesthetics
The aesthetic appeal of a building is a result of many
factors: form, massing, scale, elevation treatment, colour,
texture, etc. Brickwork is of human scale, available in a
vast range of colours and texture, and due to the small
module size of bricks is extremely flexible in application in
that it can be used to form a great variety of shapes and
sizes of walls, piers, arches, domes etc. (3)
2.4.3 Disadvantage
(a) Lack of knowledge
Unfortunately, education has been lagging behind the
development, and this has left the construction industry in a
situation where it can not fully exploit brickwork
capabilities unless geared to the new techniques and
applications.
It is the experienced designer who construct a suitable wall
which will service its intended function without troubles.
The durability of the brickwork depends on the quality of
design and construction, and these, in turn, depend upon
suitably educated and experienced designers and
construction operatives. (3)
(b) Increase in Obstructed Area Over Steel and
Reinforced Concrete
Although brickwork units can be obtained with extremely
high crushing strength, the design compressive strength of
brickwork walls are generally lower than for steel or
reinforced concrete. It follows, therefore that for a
particular loading condition, brickwork will require a
greater cross-sectional area. In location where large
unobstructed areas are required, brickwork may prove
unacceptable.(3)
(c) Large Openings
In situations where large openings are to be formed and a
level soffit is required, reinforced concrete or steel beam are
generally found to be the most economical means of
support. They can be combined with the composite action
of any brickwork above and, unless fair faced brickwork is
a particular requirement for the soffit of the support , they
will usually provide a more economical solution than the
brickwork alternative. It must be pointed out, however, that
where the soffit can be in the form of an arch, and where
the horizontal reactions from such a form can be
accommodated, brickwork may prove more economical. (3)
(d) Control Joints
In some forms of brickwork construction the need for
relatively close spacing of the control joints necessary to
prevent cracking from the effect of shrinkage and/or
expansion can be difficult to accommodate, due to
structural, visual and other constraints. (3)
2.5 Fired Clay Bricks : Technical Specification
2.5.1
General
BS 3921-1965 describes a brick as a walling unit laid in mortar,
and being not more than 337.5mm long x 225mm wide x 112.5mm
high.
Brick is defined as small building unit, solid or cored not in excess
of 25%, commonly in the form of rectangular prism formed from
clay and hardened by heat. (4)
In general, good clay bricks have a compact texture, are reasonably
free from cracks, lime, stones and pebbles and the harder varieties
give a metallic ring when struck with a trowel. Good bricks are
well burnt, i.e. they have achieved a good ceramic bond.
Strength and durability should be sufficient for the conditions in
which the brick is to be used. Where necessary, bricks should be of
good appearance or provide a good base for rendering, plastering
or decoration. The size and shape of bricks should be regular to
facilitate bonding. In its most common form a brick can be held in
one hand and its length is equal to twice its width plus a 10mm
joint.
2.5.2 Types of Bricks
According to methods of manufacturing and production bricks in
Sudan can be classified into two categories:(i)
Traditional fired clay bricks.
(ii)
Mechanized fired clay bricks.
2.5.3 General Situation of Brick Production In Sudan
(i) Traditional fired clay bricks
Brick production in Sudan is concentrated in Central Sudan
which include Khartoum, Central State, and Southern part of
Northern State. This area i.e. Central Sudan produces most of
Northern Sudan brick production. Traditional brickmaking in
this area depends upon river sediments which are deposited
annually on the Nile banks during the flood season. This
explains the scattering of traditional bricks production units
along the Blue Nile and River Nile.
In Eastern State brick production units are found along the
banks of El Gash seasonal water course in Kassala area, along
River Atbara banks at Khashim El Girba and El Showak areas.
Brick production in these areas also depends on river sediments
which are deposited annually during the flood season.
Fired clay bricks production in Western Sudan depends on
sediments of seasonal streams (Khors) and Valleys which are
deposited during the rainy season. Brick production exist in
Kordofan state at El Obied area, Rahad, Um Ruwaba, and in
Darfor State around Niyala and Zalinga areas. (1)
The annual production of each state in thousand, and as percent
of total annual production in Sudan are illustrated in Table
(2.1).
(ii) Mechanized fired clay bricks
•
Soba Brick Factory “Khartoum”
•
Atbara Brick Factory “Northern State”
•
El Bagair Brick Factory “Central State”
The production of the above three modern brick factories
does not exceed 2% of the traditionally produced bricks as
of 1994. (1)
2.5.4 Methods of Production
(i)
Traditional Fired Clay Bricks
Essentially bricks are produced by mixing finely
ground clay with water, moulding or forming it
into desired shapes, then drying and burning.
(a) Shaping (Forming)
Fired clay bricks in Sudan are entirely
produced by traditional brickmaking mud
process. The soft mud process consists of
mixing clays with 20-30% or even more of
water and then forming the units in wooden
or steel mould. It is the oldest method used
for producing bricks in Sudan.
Usually the clay and an organic matter
additive are mixed together and then water
added. The most widely used additive is
animal dung, because it is dominating in all
parts of the Sudan. Other additives like
bagasse in eastern state, ground nut shells in
western Sudan and wheat waste in Central
State.
The mix is then thoroughly worked by hoes
and spades, and left about 12 hours for
ageing. The most commonly used moulds
are steel moulds open at top and bottom and
having two compartments. Usually
allowance is made in size moulds for drying
and firing shrinkage so as to produce bricks
of required prescribed dimensions.
There are two types of moulding tables, the
first type is the one built with red bricks
above the ground level, the second type is
not a table as its name implies but is a flat
surface area just above the ground and
situated very close to clay pit.
A mass from the prepared mix is cut off,
rolled into a clot, slightly exceeding the
volume of the mould. The clot is then
thrown with some force into the mould, the
surplus is cut off by hand removed away,
and the mould is demoulded on the drying
yard.(1)
(b) Drying
Drying of bricks is carried out under sun
rays. This entails leaving the freshly
moulded bricks for about 24 hours exposed
to the sun, then turned over on edge and left
for another 1-2 days. Bricks are then taken
aside and stacked in honey comb
arrangement to allow air circulation for
further drying.
Total drying period depends on the capacity
of the kiln and the daily output of green
bricks. It is a common practice that the first
moulded batch undergoes a drying period of
18-25days wile last batch 2-4 days. (1)
(c) Firing
Firing of traditionally produced bricks is
carried out in stove kiln where wood is used
as a fuel. Once wood is set on fire, the fire
progresses until it reaches the other end of
the tunnel without any control on the rate of
heating.
When the fire reaches the other end of the
tunnel, it is then closed by green bricks and
thus the fire is directed upwards. During this
process of firing, feeding of kiln with wood
logs is continuous. As the fire reaches the
top of the kiln and bricks inside are seen to
be red hot, firing is stopped, and all the
openings are closed with green bricks and
plastered with mud. Firing lasts 24 hours
only and about two days later, tunnels are
opened for cooling. The maximum
temperature attained in local stove kilns is
about 850oC. Finally the bricks are taken out
of the kiln and sorted into first class, second
class, over-fired and under-fired, groups of
bricks. (1)
(ii) Mechanized Fired Clay Bricks
a-
Shaping
The method used for shaping production is an
extrusion process. In this process the clay is
mixed with only sufficient water to produce
plasticity from 15-30% by weight as follows:-.
Clay and a suitable additive and water are added
together and mixed thoroughly by loader and
left for ageing, then remixed and fed to the box
feeder. The mix moved by
a slat conveyer to
the wet pan mill, in which the grounded of wet
and plastic clay is usually carried out. After that
the grounded mix is moved by a belt conveyer to
the fine differential mill through a rough
differential mill in order to have a suitable
fineness and homogeneous mix. Then the mix is
moved by a belt conveyer to the extruder, in
which the mix is de-aired and extruded through
a die producing a clay column, solid or cored.
The column is moved by a belt conveyer to a
cutting table. (1) This is the case of Soba Brick
Plant.
b- Drying
After the brick units are formed they are dried
before burning. Wet clay units come from
extruding and cutting machines containing
appreciable amount of water between 15-30%.
In the formed bricks water occurs in three forms,
free water which fills the pores, water which
clings to the pore walls after free water is
removed, and chemically combined water. Free
and pore water are removed in the drying stage,
while chemically combined water is removed at
firing stage.
There are different types of dryers such as hot
floor dryers, chamber dryers, tunnel dryers, etc.
Total drying period depends on the capacity of
the kiln and the dryer and the daily output of the
green bricks. (1)
c- Firing
Essentially firing consists of subjecting the clay
units to gradually increasing temperatures up to
a maximum of 900 to 1300oC depending on the
fusing characteristic of the clay.
Firing Comprises the Following Stages:(i)
Drying or smoking stage, in
which the clay units are heated
to a temperature not exceeding
150oC.
(ii)
Preheating stage: It cover the
temperature range up to 800oC.
In this period the clay is
partially decomposed.
(iii)
Full fire stage: It covers the
temperature range of 800 up to
the
maximum
temperature
required depending on the clay
and unit types. In this stage the
kiln is heated to the maximum
rating.
(iv)
The soaking period or the
finishing stage;-
It represents the period
during which the
maximum temperature of
heating is maintained with
the purpose of ensuring
all parts of the unit
attaining the maximum
temperature. (1)
d- Cooling
It is the period of time during which the
burnt bricks temperature is reduced from the
maximum to a point at which it is safe and
convenient to remove them from the kiln. (1)
2.5.5 Properties of Bricks
(i) Traditional Fired Clay Bricks
a)
Dimensions
The dimensions of the moulds differ
from one production unit to another.
Sometimes in one production unit
different moulds are used. This results in
production of bricks of variable sizes.
Traditional fired clay bricks as tested are
not in compliance with the
MSS/No/5/1990 (5) nor with BS
3921/1965 (4). (Table 2.2 and 2.3).
Furthermore they are irregular in shape
and corners. This has adverse effect on
the strength of brickwork, the quantity of
mortar used and the output of bricklayers
since a lot of time is spent in adjustment
and alignment of bricks. In many cases
the requirement of length equal twice the
width plus 10mm is not applied. (6)
b- Absorption
The water absorption of the traditional
fired clay bricks varies from 20 to 40%.
This absorption is not in compliance
with any of the accepted standards. (6)
The high percentages of absorption is
due to the type and amount of additive
used, the cracks and voids on the surface
and the method used in shaping of
bricks.
Bricks of high absorption will absorb
some water from the mortar, and hence
lead to weak bond strength of brickwork.
That implies that bricks must be wetted
for a reasonable time before using them
in building operations. (6)
c- Compressive Strength
The compressive strength of the
traditional fired clay bricks varies from 2
to 6 N/mm2. This compressive strength is
very low but it is in compliance with
MSS/No/5/1990, but not with BS
3921:1965, table (2.4). These variations
are due to the type of clay, type and
amount of additive used, methods and
duration of drying and firing , and before
that the method of forming. These wide
variations of the compressive strength of
the unit brick leads to decrease in
compressive strength of brickwork.
Some codes of practice limits these
variations to some percentage more than
it the compressive strength will be
reduced by reduction factor, in other
codes the wide variation will increase the
safety factor which decrease the
compressive strength of brickwork..
This low compressive strength of bricks
limits the use of the bricks as infill,
partitions, and loadbearing for not more
than two floors.
d) Efflorescence
The efflorescence of traditional fired
clay bricks varies from slight to
moderate.
The efflorescence of traditional fired
clay bricks is in compliance with
MSS/No/5/1990 during the early life of
the building. But later on the bricks may
be affected by the environmental
condition due to type of exposure or due
to acids and salts which may be found in
the cementituous materials in the mortar.
(ii) Mechanized Fired Clay Bricks
a- Dimensions
Due to the manufacturing process and
the standard mould used all the
mechanized fired clay bricks in Sudan
are in compliance with MSS/No/6/1990
(8)
and BS3921/1965. (Table 2.2, and 2.3)
Further more they have regular shapes
and corners, and in compliance with the
prerequisite that length is twice the width
plus 10mm.
b- Absorption
The water absorption of mechanized
fired clay brick varies between 1115%.(6)
According to BS 3921/1965 and
MSS/No/6/1990, there is no specific
requirements of absorption for
loadbearing brick.
The same remarks about bricks of high
absorption stated in section 2.5.5 (i) b
for traditional fired clay bricks apply.
c) Efflorescence
The liability of mechanized fired clay
bricks to efflorescence is found to be not
significant. (6)
The efflorescence of mechanized fired
clay bricks is in compliance with
MSS/No/6/1990 and BS 3921/1965.
d) Compressive Strength
The compressive strength of unit
brick vary from 20N/mm2 to
30N/mm2. (6)
According to MSS/No/6/1990 and
BS 3921/1965 the compressive
strength of mechanized fired clay
bricks is classified as loadbearing.
(Table 2.4).
2.6 Mortar
2.6.1
General
The term mortar is taken to mean mixes used for joining of bricks,
stones, blocks, etc. The Primary function of brickwork mortar is to
develop a complete strong and durable bond between brick units in
brickwork. The behaviour of mortar between bricks, blocks, etc.
used in structural elements as a binding material is a very important
and complex. There are certain requirements to be met by mortar in
freshly made and hardened states.
During construction it has :(i)
To be workable.
(ii)
To remain plastic long enough to enable lining and
leveling of bricks.
(iii) To retain water so that it does not dry out and stiffen
too quickly with absorbent bricks.
(iv) To harden in a reasonable time to prevent squeezing
out under the weight of the bricks laid above.
When hardened in the finished structure, the mortar has
to transfer compressive, tensile, and shear stresses
between adjacent bricks and to be sufficiently durable to
continue to do so. (6)
2.6.2 General Types of Mortars
(i) According to BS 5628-1978 and AS 1640-1974
mortars are classified as:(a)
Cement,
lime,
sand
cement,
sand
sand
with
mortars.
(b)
Masonry
mortars.
(c)
Cement,
plasticiser, mortars.
Each type has been graded as illustrated in
Table (2.5).
(ii)
For practical purposes mortar can be classified as
(i) Straight cement mortars.
(ii) Cement lime mortars.
(iii)Straight lime mortars.
(iv)Lime possolana mortars.
2.6.3 Factor affecting mortar strength
(i)
Water cement ratio
It is well known that compressive strength of mortar
is affected greatly by W/C ratio. As the ratio
increases the strength of mortar decreases. (6)
(ii)
Sand cement ratio
For both straight cement mortar and cement lime
mortar as sand cement ratio increases the
compressive strength of mortar decreases. (6)
(iii)Cement lime ratio
It is well known that pure lime mortars are very
weak, while straight cement mortars are much
stronger. Therefore in composite mortars (cement
lime mortars) which are more commonly used, the
strength depends mainly on cement to lime ratio. As
this ratio increases the strength increases. (6)
(iv)Effect of Lime
As lime content increases the consistence
retentivity, water retentivity and workability of
mortar increases but the compressive strength
decreases . (6)
(v) Lime Possolana Mortars
Lime possolana mortars yields reasonable strength
with high workability. The use of lime possolana
and sand without cement will undoubtedly
contribute to the economy of building, since
possolanas are comparatively cheep materials. (6)
2.6.4 General Properties of Mortars and Their Effect on
Brickwork
(i) Strength
The strength of brickwork mortars depends to a large
extent on the amount of cement which they contain and
upon the water cement ratio. The strength of brickwork
depend upon, both the mortar and the brick unit, it is
useless to use a very strong mortar if the brick units are
themselves weak. Strong cement mortar are most likely
to lead to shrinkage cracking and therefore should be
avoided except where high strength is an essential
requirements. (7)
(ii) Resistance to Rain Penetration
This is a very important aspect of walling, rain
penetration is more likely to occur through shrinkage
cracks rather than directly through bricks or through the
mortar, so it is an essential requirements to reduce
shrinkage, as cracks tend to occur first at the junction of
mortar joint and building unit. Good adhesion of the
mortar is an important property.
In all cases shrinkage is ineitable, the magnitude
depends upon the width of mortar joint such as the
wider the joint the greater the shrinkage. (7)
(iii) Workability
Workability is an essential property of any mortar for
brickwork construction, since it is only through this
property that the mortar can be brought into intimate
and complete contact with the brick units.
A mortar is workable if its consistency is such that it
can be placed and spread with little effort, and if it has
the property sometimes referred to as stickability or
stickiness which causes it to adhere to vertical surfaces
of the brickwork units immediately after placing.
Requirements for water retentivity and aggregate
grading are relied upon to insure satisfactory
workability. For instances mortars of low water
retentivity, will as a rule be judged harsh, while mortars
of high water retentivity will usually be considered
workable. (7)
(iv)
Water Retentivity
Water retentivity is a major and important property of
mortar, it is defined as the ability of mortar to retain its
mix water to a reasonable time after mixing. The bond
strength developed between brick and mortar depends
on the balance achieved between the absorption
characteristics of brick on one hand and the water
retentivity of the mortar on the other hand. If bricks
with very weak absorption are combined with mortar
with strong water retention, the brick will tend to float
on the mortar bed, and this leads to poor bond between
bricks and mortar. If bricks with strong absorption are
combined with a mortar of poor water retention, the
mortar stiffens too rapidly, once again the bond between
bricks and mortar is weak. (7)
2.7 Strength of Brickwork
2.7.1
The
General
most
thoroughly
studied
property
of
brickwork
experimentally and theoretically is its strength under a load
perpendicular to the bed joints. This section deals with the
influences of the different factors on load carrying capacity of
brickwork under axial compression. The strength of brickwork is
influenced by the following factors:•
Properties of brick units such as strength, shape, height,
initial rate of absorption and variations in dimensions of
brick units.
•
Properties of mortars such as strength, water retentively,
age of mortar.
•
Workmanship and building patterns including thickness of
mortar joints.
•
Size of brickwork including effect of slenderness ratio and
small cross-sections of brickwork element.
2.7.2 Effect of Brick and Mortar Strengths
Due to numerous possible combinations of bricks and mortars,
the range of obtainable strength is very broad. The strength of the
brickwork, generally increases with increased brick and mortar
strength and it is said to be about 25-50% of brick strength; the
lower values are associated with low mortar strength and the
higher values with high mortar strength. This ratio tends to
decrease with increasing brick strength. In any case the use of
stronger mortar does not necessarily produce stronger brickwork,
because the mortar strength is not directly related to the strength
of brick units. There is an upper optimum mortar strength above
which no increase in the strength of brickwork can be attained.
It is expedient to make the strength of mortar less than that of
bricks as any cracking from thermal or other movements will
occur at mortar joints. When the mortar is stronger than the brick
unit such cracking will develop in the brick units. Cracks in
mortar tend to be smaller and easier to repair than cracks in brick
units.
Many attempts have been made to formulate the relationship
between the strength of brickwork and the unit and mortar
strength. For example it has been found by some earlier
researchers that the strength of brickwork is proportional to the
square root of brick strength, and that it may vary as ⅓ power or
the ⅔ power of mortar strength. (6,7)
2.7.3 Effect of Brick Shape
It has been found experimentally that for a given material
strength, the larger the individual units, the higher the strength of
brickwork. In fact, the larger the units the fewer the number of
mortar joints which are the weakest points in such systems of
construction. (6)
2.7.4 Effect of Thickness of the Mortar Joints and Brick Height
The main structural role of the mortar in brickwork is to provide
bonding between the units to ensure uniform transfer of stresses.
Since it is well known that the mortar joint is the weakest element
of brickwork construction, the highest strength are obtained with
thin bed joints and as well with a low ratio of bed joint thickness
to brick unit height. This fact has been confirmed by many
investigators. (6)
2.7.5
Effect of Initial Rate of Absorption of Bricks and Water
Retentivity of Mortar
The tensile and bond strengths of mortars are just as important as
compressive strength, in relation to the strength and durability of
brickwork. The shear resistance of brickwork infill panels in tall
framed buildings is obviously dependant on the bond between the
brick units. Even in walls loaded in compression, failure usually
occurs by tensile splitting of the brickwork. The bond strength is
important not only in relation to compressive strength or shear
strength of brickwork, but also in relation to the passage of
moisture. Rain usually penetrates a wall through the fine cracks
between the units and mortar, and only rarely through the body of
the bricks or the mortar. When the tensile strength of the bond is
greater the possibility of leakage is reduced. The bond strength
developed between brick and mortar depends on the balance
achieved between the absorption characteristics of the brick on
one hand and the water retentivity of the mortar on the other
hand.
It is reported that the prewetting of bricks of high absorption
characteristics, increase the strength of brickwork. (6)
2.7.6
Effect of Ageing
The curing time of the mortar in the joints affects brickwork wall
strength in the same way as it affects the strength of concrete.
Investigations showed that mortar strength increases with time
and the brickwork continuous to gain strength long after it had
been built. (6)
2.7.7
Effect of Patterns and Method of Bonding
All structural brickwork and all normal brickwork shall be bond
together, with some exception of reinforced brickwork. Once one
of the established bond patterns is adopted (Flemish or English)
variation in bond have little effect on the compressive strength of
the wall. Some investigations showed that there is no significant
difference in strength between different types of bonds. (6)
2.7.8
Effect of Variation in Dimensions of Bricks
If the dimensions of brick unit vary, the dimensions of the mortar
joints will also vary and the result is non uniform thickness of
joints, creating bending moments and stress concentration in the
bricks. In order to obtain a high brickwork strength it is advisable
to use units of well controlled dimensions. However the use of
units with small dimensional variation speeds up the work. (6)
2.7.9
Effect of Eccentricity of Loading and Slenderness
Slenderness ratio is a measure of the tendency of a wall or a
member to fall by buckling under compression loading before
failure by crushing occurs. The grater the slenderness ratio the
greater the tendency for the member to fail by buckling and thus
the lower the load bearing capacity of the member.
The slenderness ratio is defined as the effective height or the
effective length divided by effective thickness whichever is the
lesser. The effective height or length is determined from the
actual length or height which is then modified depending on the
bases of the restraint conditions, (i.e. the manner in which the
member is restrain from buckling by adjacent members). These
adjacent members generally provides supports at right angles to
the members. Such supports are termed lateral supports which
may either be horizontal in case of effective height or vertically
in case of effective length.
The design strength or the load carrying capacity of a wall is
further reduced by eccentric loading which will further increase
the tendency of the member to buckle. The load carrying capacity
of a member of known slenderness ratio and eccentricity of
loading can be computed using a factor, known as capacity
reduction factor. (6)
2.7.10
Effect of Small Cross-Sectional Area
The characteristic compressive strength of a wall of small crosssectional area should be multiplied by a reduction factor which
varies from one code of practice to another. (6)
2.7.11
Effect of Workmanship
The strength of brickwork is affected by the standard of site
workmanship. The concern here is with the identification of
various defects in site work and with assessment of their effect on
the performance of brickwork. The most obvious workmanship
factors are:(i) In correct Proportioning and Mixing of Mortar
Generally the mortar strength, as defined by cube crushing
strength, is not a very critical factor in brickwork strength. A
halving of the mortar cube strength from 14 to 7 N/mm2 may be
expected to reduce the compressive strength of the brickwork
from 16 to 14 N/mm2. This corresponds roughly to a change of
mortar mix from 1:3 to 1:4 ½, A similar reduction in mortar
strength could of course be brought about by an excess of water.
The effect on brickwork compressive strength is proportionately
much less, at any rate when the units are of low to medium
strength. In the case of high strength units, however, the effect
of variations of mortar strength is likely to be more
significant.(9)
(ii) Incorrect Adjustment of Suction Rate
The water absorbed by the bricks leaves cavities in the mortar,
which result in a weakened material on setting. On the other
hand brickwork built with saturated bricks develops poor
adhesion between bricks and mortar and is of course susceptible
to frost damage and other troubles. Some specifications
recommend a limiting suction rate, or alternatively the use of
high retentivity mortar to control the extraction of water from
mortar. In so far as water extraction affects the final strength of
mortar, one would not expect it to result in a serious weakening
of brickwork in compression.
It is clear therefore that suction rate is a factor to be taken very
seriously, especially in the case of slender walls built in
relatively low-strength bricks. If the bricks being used have a
high initial rate of absorption, it is essential to adjust this by
wetting them before laying.(9)
(iii)
In Correct Jointing Procedures
A variety of defects can arise from incomplete filling of joints
and some evidence is available on the structural effects. The
tests showed that unfilled vertical joints had no significant
effect on the strength of the wall. But careless filling of vertical
joints may be indicative of poor workmanship in other respect,
and would certainly reduce non-structural performance in terms
of sound insulation and resistance to rain penetration to a
serious extent.
Incomplete filling of bed joints is from the structural point of
view, much more serious and has been investigated, and
resulted in a reduction of strength of about 33%, it may be
assumed that the most reduction arose from the furrowed bed
joints.
Another factor in brickwork jointing is that of thickness, it has
been shown that thick bed joint say 16-19mm may be expected
to reduce the strength of brickwork about 30%, as compared to
normal 10mm thick joints. Another laying defect arise from the
practice of spreading too long a bed of mortar. Only sufficient
mortar should be spread as to permit bricks to be set in plastic
mortar. (9)
(iv)
Disturbance of Bricks After Laying
Any disturbance of bricks after they have been placed will
result in breaking the bond between bricks and mortar and this
has adverse effect on strength and resistance to moisture
penetration. This commonly happens at corners, when the
bricklayer attempts to correct plumbing errors by hammering
bricks into a true plumb position, but there is no quantitative
data available on the effect of the disturbance on the strength of
brickwork. (9)
(v) Failure to build Wall Plumb and True to Line and
Level
This type of defect can give rise to eccentric loading in a wall
under compression and thus reduce strength. Comparing the
strength of two walls one with load applied eccentric with
respect to axis of the wall and other with load applied axially a
reduction in strength of the order of 15% is noticed. Comparing
the strength of two walls one of them built 20mm off-plumb
indicates a reduction in the strength similar to the above one.
The following levels of accuracy may be attained in brickwork
construction:- (9)
* Wall plumb over a storey height + 13mm.
* Vertical alignment between top and bottom of walls of
successive storey + 20mm..
(vi) Failure to Protect Work From the Weather
Newly completed brickwork can be adversely affected by
exposure condition to unfavorable weather conditions such as
curing under very hot conditions and rain. A series of tests on
walls built in high temperature (78-100)oF , and cured in the
sun for 5 to 6 days. These walls showed about 10% reduction in
the strength as compared with wall cured in the shade under
polythene. (9)
(vii) Overall Effects of Workmanship on Brickwork
Strength
In the foregoing sections the separate effects of a number of workmanship factors
have been discussed. In any particular case, these defects will be present in varying
degrees and the overall strength of the brickwork will reflect their combined effect.
The assessment of the relative importance of the various defects
in terms of the probable reduction in strength of a wall built
under laboratory conditions is given as follows:- (9)
Outside curing (warm condition)
10%
Furrowed bed
25%
16mm thick bed joints
25%
Perpend joints unfilled
Nill
12mm bow
15%
2.8 Assessment of Characteristic Strength of Brickwork
2.8.1 Prisms tests as a measure of brickwork strength
Tests on prisms are frequently taken as a convenient and
economical means for studying structural properties such as
compressive, shear, tensile and flexural strength. Prism tests are
adopted in some codes of practice as the basis for determining the
design strength of brickwork. Prisms are small specimens of
brickwork, they are either bonded prisms or stack-bonded prisms.
It is suggested that the prism tests are thought to be more reliable
to obtain allowable design compressive stresses than tabulated
values of codes, since prism tests can take account of the
variations in the strength of local materials, mortar, workmanship
etc.. Cubes of brickwork of 230mm in cross-section with height
to the thickness ratio equal to unity, have been suggested as a
suitable specimen for testing by British Ceramic Research
Association. AS 1640-1974 recommends a stack-bonded prism
for determination of both compressive and flexural strength of
brickwork, four courses high for the former and nine course high
for the later.
The prism behaviour should reflect as far as possible the
behaviour of masonry to be used in building and hence the prism
should be built with similar workmanship, joint thickness, bond
pattern and should be subjected to similar type of curing and
failure mode. The major factors influencing the prism
compressive strength are:(i)
Height to Thickness Ratio
As prisms are normally tested between plates which are much
stiffer than masonry, the lateral expansion at the ends of the
prisms are restrained by friction. Due to this end restraint the
specimen will fail by shear rather than tensile splitting. This
restraint significantly increases in the capacity of the specimen to
resist the load and a higher apparent compressive strength will
result. This effect diminishes as the ratio of the height to the
thickness, termed aspects ratio or slenderness ratio, increases and
eventually becomes insignificant for tall specimens. Shorter
prisms are desirable due to height limitations in the test machines
and handling difficulties. Thus correction or reduction factors
should be applied in case of prisms shorter than specified aspect
ratios(6)
Table (2.6 ) shows : Aspect ratio H/T correction factors for
compressive strength in accordance with AS 1640 – 1974.
(ii)
Number of Courses
There shall be enough courses to allow adequate representation of
interaction between mortar and bricks. Prism made of varied
number of courses of bricks, ranging from 2 – 6 were used, the
strength of prism continued to decrease as the number of bricks
increase. From the results of the experimental investigation
carried, it is found that the compressive strength do not vary
significantly between 4 to 6 courses. Hence they recommend and
prefer the use of four course prism as a control prism in practice
for simplicity in casting and testing. (6)
(iii)
Capping
Capping material between the prism and steel plates can also
affect the prism strength. Capping ensures uniform distribution of
the load on the prism and reduces plate restraint. Example of
common capping materials are mortar, sulphar, dental plaster,
plywood, fiber-board, etc. Soft materials such dental plaster,
sulpher, or suitable mortar are used for capping, together with
fibre board or plywood or alone. (6)
(iv)
Test Age
The standard test age specified by most of the codes is 28 days. In
many cases, however, shorter periods would be convenient if the
prisms are to be used for site quality control or in research. Some
relationship between these shorter periods and the standard test
age of 28 days has been found. In particular 7 days age gave
about 90% of strength obtained at the age of 28 days. (6)
(v) Rate of Loading
Loading rate, usually specified in terms of load as opposed to
strain, ranges from 2.5 N/mm2 to 28 N/mm2 per minute. This
range of loading has not shown to have significant effect on the
ultimate strength. The method of load control may cause
differences in the ultimate strength. Some standards require that
the rate of loading control should not be altered near failure even
though the loading rate is reduced. (6)
(vi) Number of Test Samples
Most codes specify a minimum of 5 or 6 samples. A minimum number of 10
is recommended to compute the mean strength and its variations.(6)
2.8.2 Assessment of Characteristics Strength of Brickwork Units
and Prisms
The characteristic strength of a larger population can be inferred
from the characteristic strength of a representative sample. A
definition of characteristic strength more frequently used by BS
5628-1978 is as follows:95% characteristic strength = X- 1.64 S
where x = mean of sample
S = standard deviation of the sample
This definition assumes normal distribution and makes no
allowance for the size of the sample. A characteristic strength
calculated this way will not necessarily be representative of the
total population. For the purpose of design this variation must be
taken into account with consideration being given to the size of
the sample. For normal distribution it can be calculated as
follows:95% characteristic strength = X-KS
where X, S, as defined before
K= a sample size factor (Table 2.7 ).
AS1653-1974 defines the characteristic compressive strength of
brickwork units as follows :(6)
85% characteristic compressive strength = C-0.43R
where C= mean of the sample
R = The group range which is defined as the difference
between the average of the two highest strength and the average
of the two lowest strengths in the group.
AS 1640-1974 defines the characteristic compressive strength of
brickwork prism as follows:- (6)
85% characteristic compressive strength = C-0.38R
where C = mean of the sample
R = the group range, which is defined as the difference
between the strongest and the weakest specimens.
2.8.3 Calculation of Characteristic Compressive Strength of
Brickwork
(A) Minimum ultimate compressive strength of brickwork F(m)
as determined in accordance with AS 1640-1974 “Using prism
tests”.
According to AS 1640-1974 the ultimate compressive strength of
the four high prisms, below which only 5% of the value expected
to fail is found by the expression (X-0.38R)
AS 1653-1974 “Standard Association of Australia: Australian
Standard for Calcium Silicate Brick”
AS 1640-1974 Australian Standard SAA Brickwork Code, metric
units.
Comparative study for prisms and storey height walls have
indicated that the strength of the wallettes and wall corrected for
slenderness ratio is on the average equal to 75% of that of prisms.
(6)
The value of F(m), the 85% characteristic compressive strength
of brickwork is determined as follows:- (6)
F(m) = 0.75 (X-0.38R) Kc1 where
Where X,R, are defined as before
Kc1 = Aspect ratio correction factor defined by AS 1640-1974,
Table
( 2.6).
If 0.75 (X-0.38R) is more than X min, X min is taken as F(m)
after correction by appropriate aspect ratio correction factor.
X min is the compressive strength of the weakest prism.
(B)Characteristic
compressive
strength
of
brickwork
in
accordance with BS 5628-1978 :- fk
It is determined by using compressive strength of brick units and
type of mortar (Table 2.8 ).
2.8.4 Permissible Compressive Strength of Brickwork
As stated previously, the permissible compressive strength in
brickwork depends on the following factors:(i)
Slenderness ratio of brickwork.
(ii)
Eccentricity of loading.
(iii)
Minimum ultimate compressive strength of brickwork or
characteristic compressive strength of brickwork.
(iv)
Cross sectional area of the brickwork.
(v)
Nature of the load combination.
The permissible stress in brickwork member is determined by
dividing the characteristic compressive strength of brickwork (Fm,
fk) by the appropriate safety factor.
According to AS 1640-1974 permissible stress shall not exceed
0.2Fm or 0.25Fm, i.e. the safety factor is taken as 4 or 5 where
appropriate. (6)
According to BS 5628-1978 the safety factor is taken to range from
2.5 to 3.5 depending on the degree of quality control on both
manufacture of the brickwork units and construction (Table 2.9). (3)
The permissible stress is further modified by appropriate reduction factor for e.g. slenderness ratio, eccentricity, and
small cross-sectional area.
(i) Slenderness Ratio
Slender brickwork walls and columns under compressive loading
are likely to buckle in the same way as concrete, steel or timber
columns in compression. It is therefore, necessary to determine the
brickwork wall or column slenderness ratio in order to relate
failure in building to the compressive load carrying capacity of a
wall or column .
The slenderness ratio SR of brickwork walls or column is defined
in the codes as
SR = effective height (or length) = hef or Lef
Effective thickness
tef
The effective length should be used where this gives the lesser SR
The slenderness ratio is a measure of the tendency of a member
under compressive loading to fail by buckling before failure by
crushing occurs. The greater the slenderness ratio, the greater the
tendency for the member to fail by buckling, and thus the lower the
load bearing capacity of the member.
The effective height or length used in the determination of the slenderness ratio of an element, is based on the actual
height or length which is then modified depending on the restraint condition Tables (2.10) and (2.11). For a solid wall
not stiffened by intersecting or return walls, the effective thickness is equal to the actual thickness. Where a solid wall
is stiffened by piers, the effective thickness tef is increased by an amount depending on the stiffening effect of the
piers i.e. their size and spacing.
tef = t.k where:
t = the actual thickness of the solid wall.
K= the appropriate stiffness factor as given in table (2.12 ).
Where a solid wall is stiffened by intersecting walls, the stiffening
coefficient as obtained from table (2.12) may be used to calculate
the effective thickness, in the same way as for a wall stiffened by
piers.
For the purpose of calculating the effective thickness, the
intersecting walls are assumed to be equivalent to piers whose
width are equal to the thickness of the intersecting walls, and of the
thickness equal to three times the thickness of the stiffened wall(3,6).
(ii) Eccentricity
When considering a member subjected to compressive loading, it is
unlikely that the loading will ever be truly applied concentrically.
In most instances, the load will be applied at some eccentricity to
the centroid of the member , whether due to construction
tolerances, varying imposed loads on adjacent floor spans or other
cases.
Generally, in the absence of evidence to the contrary, it is assumed
that the load transmitted to a wall by a single floor or roof acts at
one-third of the length of the bearing area.
BS 5628-1978 states that eccentricity has maximum values ex just
under the applied load and the member must be designed to resist
the extra stresses incurred due to this eccentricity. But the effect of
the eccentricity may be assumed to decrease down the height of the
member, until its effect is zero at the bottom of the member. Thus
the vertical load on a member may be considered as being axial
(concentric) immediately above a lateral support. In the case of
walls it is not necessary to consider the effect of eccentricity where
ex is less than 0.05t.(3)
(iii) Combined Effect of Slenderness and Eccentricity of Loads
It was seen that the load bearing capacity of a member was reduced
due to the effects of slenderness on the tendency of the member to
buckle. The application of an eccentric load will further increase
the tendency of the wall to buckle, and thus reduce the load
carrying capacity of the member.
This reduction is catered for by factor β (named the capacity reduction factor), depending on the ratio of the
eccentricity ex to the member thickness. (Tables 2.13, 2.14 )(3,6).
(iv) Column or Wall of Small Plan Area
In a member whose plan area is relatively small, the number of
individual units available to support the loading is less than in the
case of a wall. It is necessary therefore to adjust the design strength
of a column or a wall of small area, to ensure that the probability of
failure is similar to that of normal wall.
The recommendation given in AS 1640-1974 applies to walls or
columns whose horizontal cross-sectional area is less than
1300cm2, and states that the characteristic compressive strength
should be multiplied by a factor “f” given by the following
formula:-
f=0.75+A/5200 where A is a horizontal cross-sectional area of the
column or wall in cm2.(6)
The recommendation given in BS 5628-1978 applies to walls or
columns whose horizontal cross-sectional area is less than 0.2m2,
and states that the characteristic compressive strength should be
multiplied by a factor given by the following formula:(3)
f = 0.7+1.5A where
A is a horizontal cross-sectional area of the column or wall in m2.
2.8.5 Permissible Compressive Force or Load Bearing Capacity
of Brickwork “P”
(i) According to AS 1640-1974 the load bearing capacity P is
determined as follows: (6,15)
Effective eccentricity of vertical forces:In a wall or isolated pier subjected to compression and bending, the
vertical and bending forces shall be combined at the top and bottom of
the member by regarding the vertical force as acting at statically
equivalent effective eccentricity ex at each end. Permissible compressive
force, where the effective eccentricity ex is the same at both ends of the
member and less than (tw)/24, the permissible compressive force shall be
determined by the equation:-
P(a)=ka(0.2Fm)Ag
Where:ka, =capacity reduction factor ( Table 2.14 )
Ag = gross sectional area of wall or peir
tw = standard thickness of the wall.
2.1
When the effective eccentricity is the same at both ends of
the member and is equal to or greater than tw/24, the
permissible compressive force Pe shall be determined by
Pe=ke(0.25Fm)Ag
2.2
Where :Ke = Capacity reduction factor (table 2.14)
When the effective eccentricity e is not the same at both
ends of the member, the permissible compressive force
P 'e =
Pe
e1 Pa
0.6e
e1
(1 + ) +
(1 −
)(1 − )
2
e
2
tw
e
2.3
Where:
e1=eccentricity at the other end
In this equation e1 is negative when eccentricity e1 and e are
on the opposite sides of the axis of the member.
(ii) According to BS 5628-1978 the load bearing capacity is
determined as follows:P = β t fk/γm where
β = capacity reduction factor
fk = characteristic strength of brickwork
t = effective thickness of the wall.
γm = revalent partial safety factor on materials.
2.8.6
Increase in Permissible Stress in Members Subjected to
Concentrated Loads
(i) As in AS 1640-1974
Additional stresses of a purely local nature, as girder
bearing, column bases, lintols or other position where
concentrated loads occur shall be calculated, and the
maximum stress resulting from a combination of these
stresses allowed before and in case of walls or isolated pier
of small cross-sectional area shall not exceed the permissible
stress obtained from equations, 2.1, 2.2, and 2.3 by more
than 50%.
When loading is transmitted through brickwork, the angle of
dispersion of the loading shall be taken as not more than 45o
from the direction of such loading.(6,14)
(ii) BS 5628-1978 clause 34, considers that in general, the
concentrated load may be assumed to be uniformly
distributed over the area of bearing and dispersed in two
planes within a zone contained by lines extending
downwards at 45o from the edges of the loaded area.
The design local compressive stresses recommended in the
code vary according to the type of bearing considered. Three
types are being designated as type 1,2 and 3. The appropriate
design local compressive stresses for all three types are
given in table (2.15).
Also the stresses at a distance of 0.4 hb below the bearing
must be checked, where hb is the height of the bearing
relative to the lower support.
(a)
Total stress just below the reaction:= design reaction at end of beam
“bearing area”
+design load from floor and brick below reaction
“area of wall”
i.e. local concentrated stress +uniformly distributed
stress
(b) The total applied stress at a distance of 0.4hb below the
bearing:=
design reaction at end of beams
(bearing width+0.8hb)(wall thickness)
+ design load from floor and brickwork
“area of the wall”
must be less or equal to = β t fk/ γm
Spreaders and bearer plates shall be used at points of
concentrated bearing to distribute forces which would
otherwise cause high local stresses which may excess the
allowable stress.
2.8.7 Stress in Brickwork Subjected to Lateral Supports
Reduction factor for slenderness ratio need not be used for sections
within one-eight of the height of the member above or below
positions of adequate lateral support. For such sections the
slenderness ratio may be taken as 6 (BS 5628 and AS 16401974).(3,6)
2.8.8 Permissible Compressive Force in Columns (Piers)
In terms of load bearing brickwork subjected to axial compressive
loading, a column is only a special case of the design of walls. A
column is defined in BS 5628-1978 is an isolated vertical load
bearing member whose width is not more than four times its
thickness. The following factors needs to be considered:- (3)
(i) Slenderness Ratio:As an isolated member, a column does not gain from the lateral
support provided at the longitudinal direction by the adjacent
elements of a wall. The slenderness ratio of a column must,
therefore, be checked in two directions, and the worst case used
to determine the design strength. The effective height of a
column is defined as the distance between lateral supports or
twice the actual height in respect of a direction in which lateral
support is not provided. (Table 2.16 ). The effective thickness
of a solid column is equal to the actual thickness (t) relative to
the direction being considered. As in the case of walls, the
slenderness ratio of column about either axis is restricted to not
more than 27.(3)
(ii) Eccentricity
The application of loading to a column may be eccentric
relative to two axis, as compared to a wall where the
eccentricity is generally related only to an axis in the plane
parallel to the center line. The code defines eccentricity as
relative to the major axis or minor axis of the column. The
major axis being defined as the principle axis, about which the
member has the larger moment of inertia. The minor axis being
perpendicular to the major axis. The dimensions of the section
are then taken as being ‘b’ for the side perpendicular to the
major axis and “t” perpendicular to minor axis. The values of
the capacity reduction factor are determined in accordance with
BS 5628-1978 as follows:- (3)
(a)
Case 1 : Nominal Eccentricity at Both Axis
When eccentricities about major and minor axes at the top
of the column are less than 0.05b and 0.05 t respectively, β
is taken from the range of values given in table (2.13) for
ex up to 0.05t, with the slenderness ratio based on the value
of tef appropriate to the minor axis.
SR = effective height (relative to minor axis)
Effective thickness (based on t)
(b) Case 2: Nominal Eccentricity – Major Axes Eccentric
About Minor Axis
When the eccentricities about the major and minor axes are
less than 0.05 b but greater than 0.05 t respectively, β, is
taken from table (2.13), using the values of eccentricity and
slenderness ratio appropriate to the minor axis.
SR = effective height (minor axis)
Effective thickness (minor axis)
(c) Case 3 : Nominal Eccentricity – Minor Axis
Eccentric About Major Axis
When the eccentricities about the major and minor axis are
greater than 0.05 b but less than 0.05t respectively β is
taken from Table
(2.13) using the value of electricity
appropriate to the major axis and the value of slenderness
ratio appropriate to the minor axis .
SR = effective height (minor axis)
effective thickness (minor axis)
(d) Case 4 : Eccentricity About Both Axis Greater
Than Nominal
When the eccentricities about major and minor axis are
greater than 0.05b and 0.05 t respectively, β is calculated
by deriving additional eccentricities and substituting in
the appropriate formula as follows:The eccentricity of applied loading is assumed to vary
from ex at the point of application to zero above the
lateral support, and an additional eccentricity considered
to allow for slenderness effect, i.e., the tendency of the
member to buckle. This additional eccentricity “ea” is
considered to vary linearly from zero at the lateral
supports to a value over the central fifth of the member
height given by the formula:⎛
⎜ 1 ⎛⎜ hef
ea = t ⎜
⎜ 2400 ⎜⎝ tef
⎝
2
⎞
⎞
⎟ − 0.015 ⎟
⎟⎟
⎟
⎠
⎠
The total design eccentricity, et, for calculation of the
capacity
reduction factor is given by the sum of ex and ea
at the point being considered. When considering the midheight section, where ea is maximum.
et = 0.6ex + ea (at mid height)
When considering the top of the member, ea will be zero
and ex at a maximum
et = ex at the top of the member.
Thus for columns in case 4, the value of β may be
calculated for each axis and the minimum design capacity
calculated.
2e
β = 1.1 ⎛⎜1 − t ⎞⎟
⎝
t ⎠
This method has a more general application and may be used
to determine β for any member at any position. The values
given in the table are strictly only appropriate for the midheight region of a member.
2.8.9 Column Formed by Openings
Most walls contain door, window or some other form of
opening and these are often close together so that a section
of the wall between the adjacent openings becomes very
narrow. In case where this section of walling is by definition
a column, i.e. width not more than four times its thickness,
the effective height relative to an axis perpendicular to the
wall will, due to reduced restraint offered by the remaining
section of the wall, be less than that of a completely isolated
member but greater than that of a continuous wall.
The assessment of the effective height will vary depending
on the size of the column.
BS 5628-1978 gives two general recommendations for the
assessment of the effective height as follows: (3)
(i)
Where simple resistance to lateral movement of the
wall containing the column is provided, the effective
height should be taken as the distance between
supports.
(ii)
Where enhanced resistance to lateral movement of the
wall containing the column is provided, the effective
height should be taken as 0.75 times the distance
between the support plus 0.25 times the height of the
taller of the two openings.
* A section of a wall between adjacent openings becomes
very narrow, this section of walling is by definition a
column, the effective height should be taken as twice the
height of the highest opening or the values from table if less.
2.9
Previous Research Work and Studies on Use of Fired Clay
Bricks in Loadbering Walls:
2.9.1 Comparative Study on the Rational Use of Fired Clay
Brick in Building in Khartoum
In this section remarks and Conclusion are mainly drawn from a
Thesis submitted for the degree of doctor of philosophy presented
by Mohamed Hussein Hamid of the Building and Road Research
Institute in 1987 (6)
In this study investigation is carried out on three main categories.
(i) Physical and chemical properties of several types of bricks:a- Local traditional fired clay brick.
b- Trial standard traditional fired clay brick (BRRI brick)
c- Atbara Brick Factory (mechanized fired clay brick (ABF).
The following remarks can be passed on some of the properties
of the bricks:- Local bricks in general fails to satisfy Sudanese Standard
(S.S.) 1974.
- Both BRRI and ABF bricks satisfy S.S. 1974, moreover
ABF bricks comply with specification of class 2 of load
bearing brickwork specified by BS 3921/65.
- Both local and BRRI bricks fail to satisfy minimum
BS3921/65 and BS 5628-1978 requirements of compressive
strength 7N/mm2 for loadbearing bricks. ABF satisfy this
requirement.
- Both local and BRRI bricks have very high absorption while
ABF give comparatively lower water absorption but higher
when compared with BS 3921/1965 requirement.
- Initial Rate of Absorption (IRA) given by both local and
BRRI is high.
- Compressive strength and dimensions of local bricks vary in
the course of production depending on the type of clay used.
- Compressive strength of local bricks varies from one site to
another and from one area to another.
ii) Mortar made from indigenous material available in
Khartoum Area:The following remarks can be passed on some of the mortar
properties:- Natural sand can produce mortar of satisfactory strength.
- The general belief that fine sand always gives mortars of less
strength is not always true, it appears however to depend on
many complicated factors which may relate to the packing
property and void content of sand and water cement ratio,
etc.
- Studies on mortars have revealed useful information on the
degree of extent experienced by different factors on the
strength. The factor considered:•
Water cement ratio.
•
Sand cement ratio.
•
Cement and lime content in mortars.
•
Lime pozzolana mortars.
Water retentivity and consistence retentivity of mortars
increases with increasing lime content in mortar.
Addition of lime to mortar increase workability and water
retentivity of mortar and may decrease its compressive strength.
Addition of lime to pozzolana gives mortars of good
workability and water retentivity and reasonable strength.
iii) Determination of Brickwork Strength Using the Above Data on Bricks and
Mortar:-
- Applying direct calculation based on standard formula and
equation using the compressive strength of stack bond
prisms.
- Rational graphical presentation for the prediction of
characteristic compressive strength of brickwork, applying
known properties of brickwork constituents. In this
connection the presentation is given as :(a)
From known characteristic compressive strength of
brick and mortar type.
(b)
From known mortar compressive strength and brick
type.
The predicted values are found to be matching with codal
values of some international standards .
The graphical representation, show the effect of various
brick production techniques on brick and brickwork strength,
thus enabling a technologist to adjust appropriate production
technique to produce bricks of required strength to build a
brickwork of predetermined strength.
Studies on brick and brickwork strength have provided
guidance for calculating the design strength and loadbearing
capacity of brickwork members made from available bricks
and mortar types. Calculated values are found to be
comparable with codal values of some international
standard. Lean cement mixes and also lime pozzolana mix
which are of moderate strength appear to be most suitable
mortars for laying traditionally produced bricks. Strong
cement mortar mixes appear to suit machine made bricks of
Atbara brick factory. Cement lime mortars have the ability to
better distribute the load throughout the mortar bed having a
degree of internal stresses. For instance straight cement
mortars, though stronger than cement lime, yet yields weaker
brickwork.
Production of standard size bricks in compliance with
provisional Sudanese Standards gives brickwork with
increased compressive and flexural strength. For example
BRRI trial bricks showed an increase amounting to about 24 and 1.5-2.5 times greater in compression to now produced
local
bricks
for
compressive
and
flexural
strength
respectively.
Further increase has also been achieved by the ABF machine
product. The compressive strength has an increase of about
8-12 times greater compared to the traditional bricks.
The outcome of these studies is considered to furnish
grounds for setting up local guidelines for brickwork design
purpose.
2.9.2 Comparative Study Between Load Bearing and Reinforced
Concrete Skeleton Buildings:- Egypt 1975(10)
A building was designed for comparison between the load bearing
and reinforced concrete skeleton . The building comprises ground
floor and three typical floors, ( built area 374m2 per floor). Each
floor contains 4 flats.
The quantities of work and their costs are illustrated in Table
(2.17).
The cost based on one metre cube of concrete, 100kg steel was 35
pounds (Egyptian pounds).
The foundation to depth 1.5m, and the permissible stresses of
concrete was 1kg/cm2.
The difference between the two buildings in cost was found to be
515 Egyptian pounds.
The difference between the two buildings in cost when using
facing bricks (No plastering renders for the external walls) was
found to be 915 Egyptian pounds, in the rate of 61 Egyptian
pounds for every 100m2.
(a) Saving in cement of load bearing building was 11.60 ton :
(775kg/100m2) when using: plain concrete of 200kg/m3.
Reinforced concrete of 350kg/m3. Mortar in load bearing
walls of 400 kg/m3 cement .The mortar in concrete skeleton
of 250kg/m3.
(b) Saving in reinforcement steel was 6.7ton (488 kg/100m2.
(c ) Saving in formwork was 1310m2 (88m 2 /100m2) and
(d) Saving in the total cost when using load bearing building was
5.8%.
CHAPTER THREE
EXPERIMENTAL WORK
3.1 Introduction
Materials used in the construction of the load bearing walls (brick,
mortar) and their constituents are characterized to find their physical,
mechanical and chemical properties and their effect on the loadbearing
capacity of the walls is also studied. The characteristic compressive
strength of brickwork is then determined using prism test as outlined by
AS 1960-1974. The obtained results are used in designing the required
loadbearing walls.
The tests include the following:(i)
Characterization of machine made bricks of Soba
Brick Plant designated as BRRI Bricks.
(ii)
Test on mortar and its components.
(iii)
Construction and testing of prisms.
3.2 Characterization of BRRI Bricks
The following physical and mechanical properties were determined in
accordance with MSS/No./6/1990 and BS 3921/65.
(i) Dimensions
(ii) Water Absorption
(iii) Compressive Strength
(iv) Efflorescence
Tables 3.1 to 3.4 show the results of these investigations. The following
two findings need to be highlighted:(a) It was found that BRRI Bricks in relation to
dimensions comply with MSS/No.6/1990 and
also with the formula length = 2xwidth +
10mm.
(b) The compressive strength was found to be of
24N/mm2 and the BRRI bricks can be
classified a loadbearing bricks of class 3.6
according
to
MSS/No6/1990
and
BS
3821/1965.
3.3 Mortar Tests
3.3.1 Mortar Constituents
(i) Sieve analysis of sand carried out as specified by BS
812-1975,(11) Sand used in mortar preparation is
analyzed.
Table (3.5) shows its sieve analysis.
(ii) Cement tested in accordance with BS 12-1978(12)
Ordinary
Portland
Cement
used
in
mortar
preparation is tested in accordance with BS121978. The results obtained are shown in Table
(3.7).
3.3.2 Mortar Compressive Strength
Mortar mix of 1:6 cement sand is selected as previous study
showed its suitability to BRRI bricks (6). The mortar
prepared and tested according to BS 4551-1980 table 3.8
shows the test result.
3.4 Characteristic Compressive Strength of Prisms and Brickwork
3.4.1 Compressive Strength of Prisms
In this investigation stack-bonded prisms four courses high
are used to determine the compressive strength of brickwork.
In this respect five prism specimens are constructed, cured,
and tested as specified by AS 1640-1974. (6,15)
Bricks used in this investigation are BRRI Bricks with
mortar 1:6 cement sand. Table (3.9) shows the Prisms test
results.
3.4.2
Calculation of Characteristic Compressive
Strength of Prisms and Brickwork
From
data
obtained
from
prism
tests,
characteristic
compressive Strength of prism and that of brickwork are
calculated as follows, According to AS-1640-1974. (6,15)
(i)
Characteristic Compressive Strength of
Prism “fp”
fp=
C – 0.38R where
C = mean compressive strength of prisms
R = The group range which
is defined as the
difference between the
strongest
and
the
weakest specimens.
From Table 3.9
C = 8.47 N/mm2
compressive strength of strongest specimen =
9.136N/mm2
compressive strength of weakest specimen
7.383N/mm2
=
.. R = (9.38 - 7.58) 0.974 = 1.7532N/mm2
where 0.974 is a machine factor
.. fp = 8.47 – 0.38 x 1.7532 = 7.81 N/mm2
(ii) Characteristic Compressive Strength of brickwork, Fm
Fm = 0.75fp Kc
From the calculation of the compressive strength of the prism
Average height of prisms H
= 150.2/5
Average thickness of prisms T = 52.3/5
.. H/T = 150.2/52.3
From Table (2.6 ),
= 2.87
kci
= 0.98
Fp = characteristic compressive strength of the prism
=
7.81
.. Fm = 0.75x7.81x0.98
=
5.74N/mm2
3.5 Compressive Strength of Short Piers:
In order to verify the results obtained by prism tests two types of piers were
constructed. The two types were identical in materials (brick and mortar), length
and width , but they are only differ in height. Piers of 1.0m and 1.5m high were
constructed and tested as shown in plates.
The construction and curing of piers was carried out in the same way as for prisms.
Tables 3.10 and 3.11 shows the compressive strength of the two types of piers.
3.5.1 Loadbearing Capacity of the Piers
(i)
According to AS 1640-1974
Height of peir (H) = 1.50m
Thickness of peir (T)= 0.225m
Width or length of peir (B) = 0.5m
Characteristic strength of brickwork fm = 5.74N/mm2
Cross-Section area (A) = T.B = 500x225=112500mm2
Loadbearing capacity “Pa”
Factor of safety “ γm”
Pa = ka Fm A/ γm
H/T = 1.50/0.225
=
6.66
From table (2.14) ka =
0.982
γm = 5
.. Pa = 0.982x5.74x500x225/5x103 = 126.83KN
Since the area A = 112500 < 130000
.. The loadbearing capacity must be modified by a reduction factor “f”
f = 0.75 + A/520000
.. f = 0.75 + 112500/520000 = 0.97
.. The loadbearing capacity = 126.83 x 0.97
= 123KN
When using a factor of safety
γm = 4
.. The loadbearing capacity = 123 x5/4 =
154KN
(ii)
The loadbearing capacity according to
BS 5628-1978 :Mean compressive strength of
brick =24N/mm2
Mortar designation = (IV)
Wall thickness
= 210mm
Factor of safety γm = 3.5
Effective height of peir = 1.5m
From table (3.12) the loadbearing capacity =
342KN
For peir 225x500, the loadbearing capacity =
(342/2)x225/210 = 183 KN
Reduction factor for small cross-section area “f’
f = 0.7 + 1.5A
f = 0.7+1.5x0.5x0.225 = 0.86875
.. The loadbearing capacity = 183x0.86875 =
159KN
(iii)
Crushing Load of Peirs when tested
From table (3.11)
Average
crushing
load
=
(20.2+20+21.6)/3=20.6Ton
=20.6x1000x0.974x9.81/1000
=196.8KN
.. The crushing load 196.8> Design
Load according to
AS 16401974 (154KN)
> Design
Load according to
BS
5628-1978 (159KN)
These values are illustrated in
Table (3.13)
3.6 Discussion of Results
3.6.1 Bricks
(i) The average dimensions of brick are found to
be 227.4 x 109.4 x 63.4mm, i.e. they comply
with specification stated by MSS/No/6/1990
Standard.
(ii) Average Water absorption of bricks is found to
be 15.51%. Although there is no specification
for water absorption for such type of bricks but
it is much less than the 35% specified for
traditional bricks.
(iii) The mean compressive strength of bricks is
found to comply with class 3.6 of loadbearing
bricks of BS3921/65 and MSS/No/6/1990, but
with some variation. It varies between 20.155 to
30.528N/mm2, with standard deviation of
2.9N/mm2 and coefficient of variation equal to
(12.08%).
(iv) Efflorescence tests revealed that bricks show no
efflorescence.
3.6.2 Mortar
(i)
Sand used in mortar is found to fall in zone
(3) and matching with specified gradation of
sand for mortar according to BS5628-1978.
(ii)
The Ordinary Portland Cement used in
mortar preparation is found to be of :(a)
Consistency 29.25%
(b)
Initial setting time 1 hr 37
min
(c)
Final
setting
time
3hr
20min.
(d)
Compressive Strength
For 3 days > 235kg/cm2
For 28 days > 418 kg/cm2
and thus complies with BS 121978
(iii)
Mortar cube strength is found to be
5.72N/mm2, and thus complies
with
BS5628-1978.
3.6.3 Brickwork, Prisms & Piers:(i)
The characteristic compressive strength of
prisms is found to be 7.81 N/mm2, while that
of brickwork is found to be 5.74 N/mm2,
also there is some variation in the strength of
prisms due to the variation in brick strength.
(ii)
Brickwork built of such brick and mortar
type
(iii)
and
(iv)
has
characteristic
compressive strength of 6.49N/mm2, and
5.733N/mm2, as specified by BS5628-1978
respectively. But it seems that results from
prism tests are more reliable than that
tabulated in BS, as factors other than bricks
and mortar types have their effect on
brickwork strength (e.g. workmanship).
(iii)
The Loadbearing capacity of the pier
obtained according to
AS 1640-1974 is
found to be match with that obtained
according to BS 5628-1978 and shows a safe
margin when compared to the crushing load
of the prisms.
(iv)
The observation of failure on the short piers
when tested, shows that tension cracks
developed parallel to the axis of loading, as a
result of tensile stresses at right angles to the
primary compression, while splitting failure
as a result of secondary tensile stress caused
by the restrained deformation of the mortar
in the bed joints.
(v)
Generally the strength of brickwork in
compression was much smaller than the
nominal compressive strength of the bricks
from which it is built, on, the other hand,
brickwork strength may exceed the crushing
strength of the mortar used in it, as clearly
shown in tables 3.1 and 3.9. It seems that the
compressive strength of bricks in standard
crushing test is not a direct measure of the
strength of the unit in brickwork, since the
mode of failure is different in the two
situations, and that although mortar is
weaker it is able to withstand higher
compressive stresses in brickwork bed joints
because of the multi-axial nature of the
stressing in this situation
3.7 Conclusion
3.7.1 From the various tests conducted it can be said that:- Machine made bricks are of standard size.
- In terms of strength these bricks comply with
class
3.6
thick
of
BS3921-1965
and
MSS/No/6/1990.
- The gradation of sand is complying within zone
3 of BS 882-1973.
- The ordinary Portland cement used in preparing
the mortar complying with BS 12-1978.
- Mortar cube strength is complying with BS
5628-1978.
- Strength of brickwork determined by prism test
is complying with BS 5628-1978.
- Test on constructed Piers confirms methods of
calculating brickwork strength from prism tests.
3.7.2 These findings will be used in the design of the
loadbearing apartment building.
CHAPTER FOUR
LOAD BEARING DESIGN
4.1 Introduction:
In this chapter five storey apartment building is designed as a
loadbearing structure. Typical plan of the apartment is shown in
drawing 4.3. The same building is resigned as a reinforced
concrete framed structure for comparison, (See Chapter five).
The basic aim of structural design is to ensure that a structure
should fulfill it’s intended function throughout it’s lifetime
without excessive deflection, cracking or collapse, and this aim
must of course be met with due regard to economy.
The first consideration in the design of brickwork building is to
determine the plan arrangement of the walls in accordance with
function of the building. From the structural point of view the
wall arrangement is important, firstly: as a means of providing
lateral strength and rigidity and secondly in order to ensure that
the building is generally robust in the sense that the local
damage to the structure does not result in catastrophic collapse.
Possible wall arrangement are almost unlimited but it may be
helpful to distinguish the following categories. (3)
(a) Cellular arrangement in which both internal and external
walls are loadbearing and form a cellular pattern in plan.
Principally this arrangement is used for tall tower blocks
of flats, which are generally square on plan.
(b) Cross walls which are mainly used for hotel bedroom
blocks, school classrooms, student hostels, town
houses, and other rectangular buildings, with repetitive
floor plans.
(c) Spine Construction which is used where open-plan
interiors are necessary such as in office blocks, hospital
wards, ware-houses and similar structures.
(d) Column Construction, which is an alternative to spine
construction.
Hence , it can be said that the cellular pattern is one of
the options for the wall arrangement of the apartment
building under consideration in this dissertation. This
pattern is claimed to have the following advantages:
(a)Cellular structures are of the multiplicity
of walls. They
are often easier to alter
more than other structural forms.
(b) Since the load is shared by all the walls
the stresses tend to be lower than in other
structural brickwork forms.
(c) The foundation of cellular structures tend
to be cheaper. The loads are spread over
many walls, at closer spacing and contact
pressure, therefore, are generally low.
(d) Of all structural brickwork forms cellular
construction is the most resistant to lateral
loads and accidental damage.
This chapter includes the following:(i) Design Information
The data and information used in the loadbearing design
were :(a) Durability and fire resistance requirements.
(b) General loading conditions
(c) Material data
(d) Design data
(e) Intended use of structure
(f) Other relevant information
(ii) Calculation of Loading
(a) Distribution of the loads by the two directions
of slabs using certain formulae.
(b) Selected sections of the plan arrangement in
order to analyse and calculate bending
moments and shear forces in the slabs for the
purpose of the design of slabs.
(c) Computer Programme for the analysis of the
bending moment and shear forces.
(iii) Design of slabs
Using the data obtained from (i) and the bending
moment and shear forces obtained from (ii) the
selected slabs were designed according to BS81101997. (16)
(iv) Design of Loadbearing Walls and Peirs
Selected walls and piers were designed according to
AS 1640-1974 and Egyptian Code of practice 2001.
(v) Design of Stair Case
Stairs supported on loadbearing walls were designed
according to BS 8110-1997.
(vi) Construction Detail Consideration
4.2 Design Information
Chapter two gives in details the current practice and standard
for the design of brick loadbearing structure.
Table (4.1) gives information and parameter for the design
of the intended apartment building.
4.3
Loading
The deadload (D.L)of slab composed of the self weight of
the slab and the finishing while the life load (L.L.) was taken
from the standard for the residential buildings.
Loading
D.L. from Slab = 0.125x24
=
3.0 KN/m2
Finishing
=
1.5 KN/m2
Characteristic D.L.
=
4.5KN/m2
Characteristic L.L.
=
1.5KN/m2
Distribution of the loads in the two direction of the two-way slabs
wx =
wy =
w
⎞
⎛L
1+ ⎜ x
⎟
⎝ Ly ⎠
4
w
⎛L
⎞
1+ ⎜ y ⎟
⎝ Lx ⎠
4
4.1
4.2
where:
w
=
Total unfactored load
wx
=
Load in the short span (unfactored)
wy
=
Load in the long span (unfactored)
Ly
=
Length of span in the long direction.
Lx
=
Length of span in the short direction
4.3.1 Section Loads
Fig. 4.1 shows the selected sections which are used for the analysis of loads and calculations of the bending moments and
shear forces. The width of section was one metre and the dead and imposed loads were taken from section (4.3), while
equations (4.1), (4.2) were used for the distribution of the loads.
Fig. (4.1)
Sections Loads
(See drawing No. 4.1)
(1) Section 1-1 :
D.L. (KN/m2)
2.25
4.5
2.745
2.745
4.5
Span m
4.25
2.0
4.25
4.25
2.0
L.L. (KN/m2)
0.75
1.50
0.90
0.90
1.5
(2) Section 2-2 :-
D.L. (KN/m2)
4.5
2.25
3.465
2.25
4.5
Span m
2.0
4.25
4.25
4.25
2.0
L.L. (KN/m2)
1.5
0.75
1.155
0.75
1.5
(3) Section 3-3 :
D.L. KN/m2
4.5
2.25
2.25
2.25
2.25
4.5
Span m
2.0.
4.25
4.25
4.25
4.25
2.0
0.75
0.75
0.75
1.5
L.L. (KN/m2)
1.5
0.75
(4) Section 4-4 :-
D.L. KN/m2
1.755
1.035
1.035
1.755
Span m
4.75
5.75
5.75
4.75
L.L. (KN/m2)
0.59
0.345
0.345
0.59
4.3.2
Bending Moments and Shear Forces
After the dead and imposed loads for each section were calculated, the data was
fed as input to a computer programme package for the analysis of beams. The
bending moments and shear forces for each section were establish. (See appendix
A).
4.4 Design of Slabs
The design of slabs was carried according to BS8110-1997(16)for
reinforced concrete solid slabs (See Appendix B)..
Referring to drawing (4.1) the bending moments and shear forces
for each slab was determined from the analysis of the loads of
sections. A suitable arrangement was maintained from the
individual design of slabs. (drawing 4.2).
Results of the design are :(a) Thickness of slab
= 125mm
(b) Reinforcement diameter
= 10mm
(c) Bar spacing both ways
= 150mm
(d) Amount of reinforcing steel per cubic
metre concrete
= 120kg
4.5 Design of Beams
According to BS 8110-1997(16 )
Beams resting on walls below, transfer the loads from above.
The beams were in compression and reinforced with nominal
steel (See Appendix B), and the results of design are :(a) The beam cross section = 225x325mm
(b) The reinforcing steel = 2 Ø 12mm
(c) Links = Ø 8 at 200mm
(d) The amount of steel per cubic meter of concrete =
80kg.
4.6 Stair Slab Design
The usual form of stairs can be classified into two types:(a) Stairs spanning horizontally: may be supported on
both sides or they may be cantilevered.
(b) Stairs slab spanning longitudinally : may span into
landings which span at right angles to the stairs or it
may span between supporting beams.
The stair slab is designed according to BS 8110-1997
(16)
(see
appendix B), and the results of design are:
(a) Riser
=
150mm
(b) Tread
=
300mm
(c) Main reinforced steel diameter = 12mm
(d) Spacing of main bars = 175mm
(e) Transfer steel diameter = 10mm
(f) Spacing of transfer steel = 250mm
(g) Amount of reinforcing steel per cubic metre = 120kg
4.7 Load-bearing Walls Design
The design was carried according to the AS 1640-1974 (15) and Egyptian
Code of practice 2001 (14)of the load bearing walls for the apartments (See
Appendix C ).
The number of floors was determined by the bearing capacity of 1 brick
interior supporting its weight and the load from slabs and roof using the
formula.
Number of floor < bearing capacity of the wall/design
load to be carried by the floor.
The results of design are :
(a) The numbers of the floors = 5
(b) The external loadbearing walls were designed of 1.5 brick thick for the purpose of heat and sound installation.
(c) The intersection of walls were the strongest part or sections of the
walls as they support small loads from the floors.
(d) The slabs were designed resting on walls without beams except
at edges of the slab where beams were introduced to prevent
any sort of deformation.
(e) The design assumed the same type of bricks from ground to roof.
4.8 Construction Detail Consideration
(i) Provision for Services
The horizontal cutting of chases for electrical conducts. etc. decrease the walls
effective thickness and cross-sectional areas, and thus may increase the stress in
the wall and its tendency to buckle. Vertical chases may not appear to be of a
problem, but could form cracks. Detailed drawings of service holes and chases
should be given to the contractor before the commencement of building operations.
(3)
(ii)Concrete roof slab/loadbearing wall connections
In situ concrete roof slabs should not be cast directly on to
brickwork walls. As the roof expands and contracts due to
thermal and other movements, the wall will tend to crack
particularly at the connection. A sliding joint, such as a
layer of d.p.c. should be laid on top of walls before casting
the concrete. (3)
(iii) Choice of Brick and Mortar
Whilst it is quite simple to design every wall in every storey height with a different
structural brickwork unit and mortar, this increases the costs, planning and
supervision of the contract. On the other hand, although the use of only one brick
laid in one class of mortar simplifies planning and supervision enormously, it may
not be most economical solution overall. Thus before making a choice, the cost
implication should be carefully considered . Brick strength should generally be
uniform throughout any one storey, and changes in strength should be limited to
approximately every three storey. (3)
(iv) Movements Joints
Whilst brickwork structures tend to be more resistant to damage due to movement,
it is still necessary to install movements joints. Movement joints should also be
used to break up L and T plan shapes when they are sensitive to movement. The
spacing of movement joints depends on the brickwork unit used, i.e. 12m
spacing is usually adequate for clay burned bricks. (3)
(v) Vertical alignment of loadbearing walls
For simplicity, speed of construction and cost, walls should remain in the same
vertical plane from foundations to roof. However it is expected to limit changes in
vertical alignment to situations where it can not be avoided. (3)
(vi) Thickness of brickwork walls
The selection of the thickness of the brickwork walls is restricted for practical
consideration by the width and length of the brickwork units i.e. ½B, 1B, 1 ½B
etc..
CHAPTER FIVE
REINFORCED CONCRETE DESIGN
5.1 Introduction
In this chapter the structural system for the apartment building
under consideration is treated as a reinforced concrete frame.
The structural configuration of the architectural design in relation
to the column spacing, number of bays in each direction, the type
of building from functional point of view and marginal functional
changes to be expected in such types of building during its life time
seems to make beam and slab system the most economical choice
from cost point of view. The findings of this chapter will be used in
the following chapters to conduct the comparison between the two
structural systems.
The method applied in the R.C. design is the limit state design
given in BS 8110-97(16), which admits that a structure may become
unsatisfactory through a number of ways which all have to be
considered independently against defined limits of satisfactory
behavior. It admits that there is an inherent variability in loads,
materials and method of design and construction which makes it
impossible to achieve complete safety against possible short
comings. The aim of limit state design is to provide an acceptable
probability that the structure will perform satisfactorily during its
intended life.
Limit state can be classified into two main groups.
(i)
The ultimate limit state, which is concerned with the
provision of the adequate safety.
(ii)
The serviceability limit states, which are essentially
concerned with durability.
Calculations alone do not produce safe, serviceable and durable structures.
Equally important are the suitability of the materials, quality control and
supervision of the workmanship.
This chapter will start with the design information necessary for
the design of reinforced concrete skeleton for the residential
buildings, calculation of loading used in the design of slabs and
their distribution in the two direction of the two way slabs, and
selected section for determination of the bending moment and
shear forces using computer programmes.
Also this chapter includes the design of slabs using the data
obtained from above information, the design of beams and columns
using computer programmes, design of staircase, wall and
presentation of results and findings in the form of drawings.
5.2 Design Information
Table (4.1) gives information and parameter for the design of the intended
apartment building.
5.3 Loading
The deadload of slab composed of the self weight of the slab and
the finishings, while the life load was taken from the standard for
the residential building.
D.L. from Slab = 0.125x24
Finishings
Characteristic D.L.
Characteristic L.L.
Distribution of the loads in the two directions
as in (4.3)
=
=
=
=
of the
3.0 KN/m2
1.5KN/m2
4.5KN/m2
1.5KN/m2
two way slab
5.3.1 Section Loads
Fig. 5.1 shows the selected sections which are used for the analysis of
loads and the calculation of the bending moments and shear forces.
The sections are of one metre width and the dead and imposed loads
were taken from section 5.3, while equation 4.1, 4.2 were used for the
distribution of the loads.
Fig. (5.1)
Sectional Loads
(See drawing No. 5.1)
(1) Section 1-1 :
D.L. (KN/m2) 4.5
4.17
8.55
0.67
1.33
4.5
Span (m)
2.0.
2.25
2.0
4.25
4.25
2.0
L.L. (KN/m2) 1.5
1.39
1.5
0.224
0.236
1.5
(2) Section 2-2 :-
D.L. (KN/m2)
4.5
2.25
3.465
2.25
4.5
Span (m)
2.0
4.25
4.25
4.25
2.0
L.L. (KN/m2)
1.5
0.75
1.155
0.75
1.5
(3) Section 3-3:
D.L. (KN/m2)
4.5
0.3
2.3
2.3
0.30
4.5
Span (m)
2
4.25
4.25
4.25
4.25
2.0
1.5
0.1
0.8
0.8
0.1
1.5
L.L. (KN/m2)
(4) Section 4-4 :-
D.L. (KN/m2)
Span (m)
L.L. (KN/m2)
4.5
3.825
1.035
1.035
3.825
4.5
2
2.75
5.75
5.75
2.75
2.0
1.5
1.28
0.345
0.345
1.28
1.50
5.3.2 Bending moment and shear forces
After the dead and imposed loads for each section were
calculated, the data was fed as input to a computer
programme package for the analysis and design of
beams. The bending moments and shear forces for
each section were established (see Appendix D).
5.4 Design of Slabs
The design of slabs was carried according to BS 8110-1997 for
reinforced concrete solid slabs (see Appendix E).
Referring to drawing 5.1, the bending moments and shear forces
for each slab was determined from the analysis of loads of the
sections obtained from the computer programme (Appendix D). A
suitable arrangement of steel was maintained from the individual
design of slabs (Drawing 5.2), the results fo the design are as
follows:(a)Thickness of slab = 125mm
(b)Reinforcement diameter = 10mm
(c)Bar spacing both way = 150mm
(d)Amount of reinforcing steel per cubic metre = 120kg
5.5 Design of Beams
Reinforced concrete beam design consists primarily of producing
member details which will adequately resist the ultimate bending
moments, shear forces and torsional moments. At the same time
serviceability requirements must be considered to ensure that the
member will behave satisfactorily under working loads. It is
difficult to separate these two criteria, hence the design procedure
consists of a series of interrelated steps and checks. These steps
may be considered into three basic design steps:(i)
Preliminary analysis and member sizing.
(ii)
Detailed analysis and design reinforcement.
(iii)
Serviceability calculations.
The loads that to be carried by beams such as dead, imposed from the
slabs, weight of traditional fired clay bricks and the self weight of the
beam, were calculated and applied to a computer programmes prepared
for analysis and design of beams. The results of analysis and design of
beams were reported in (Appendix F). The results of the design are as
follows:(a) Typical Cross-Section of beams = 250x500mm
(b) Amount of reinforcing steel for cubic metre = 125kg
5.6 Design of Column
The column are structural member to carry the loads from the beams and
slabs down to the foundations, and therefore they are primarily
compression members, although they may also have to resist bending
forces due to the continuity of the structure.
Design of columns is governed by the ultimate limit state. Deflections and cracking
during service conditions are not usually a problem, but nevertheless correct detailing
of the reinforcement and adequate cover are important.
In the analysis it was necessary to classify the columns into one of the
following types:-
(a) A braced column: where the lateral loads are resisted by walls or some other form of bracing, and
(b) Unbraced column: where the lateral loads are resisted by the bending action of the columns.
Also the columns are classified as:(a) Short columns if both lex/h and ley/b are less than 15 for
braced columns and less than 10 for unbraced columns.
(b) Slender columns if both lex/h and ley/b are more than 15 for
braced columns and more than 10 for unbraced columns.
Where lex, ley are the effective lengths relative to XX and YY axes, h is
the overall depth of the section in the plane of bending about the XX axis
and b about the YY axis.
The Loads carried by the columns and the bending moments taken for the
design of the columns were taken from the analysis and design of the
beams and tabulated in the first section of the column design.
The loads and moments taken by the columns were fed in a computer
programme for the design of the columns as reported in (Appendix F), the
results of the columns are :(a) Cross-section of columns = 500x250mm
(b) Amount of reinforcing steel for cubic metre = 125kg
5.7 Design of Stair Slab
According to BS 8110-1997
The design is the same as in paragraph 4.6 of this dissertation (See
Appendix B).
5.8 Design of Reinforced Concrete Wall
The design requirements for reinforced concrete walls which are defined
as a vertical loadbearing members with greatest lateral dimension
exceeding four times the least lateral dimension and containing not less
than 0.4% of vertical reinforcement, are similar to these for columns. The
method of design of short or slender concrete walls subjected to axial
load with or without bending corresponds to that previously described for
the corresponding column section.
The design was carried out according to BS 8110-1997 (see Appendix
F). The results of the design of r.c. walls are:(a) The wall thickness = 150mm
(b) The vertical reinforcement diameter = 12mm for inner and outer steel at 200mm center to center.
(c) The horizontal reinforcement diameter = 10mm for inner and outer steel at 250mm center to center.
(d)The amount of reinforcing steel for cubic meter = 120kg
CHAPTER SIX
THE COMPARISON OF COSTS
6.1 Introduction
The comparison of costs of the construction of the loadbearing and the reinforced
concrete apartment buildings is fundamental to this dissertation.
The object of the cost investigation includes among other things the
following:-
Comparison of the cost accounts for the errection of the
two types of construction methods of the same apartment
building.
-
Comparison of the quantities consumed of the strategic
building materials (particularly imported materials e.g.
cements, reinforcement steel) used in the permanent
works.
-
Comparison of building materials used in the temporary
works
(e.g. timber or steel in shuttering).
This chapter is devoted to the selection of the appropriate cost accounting
methodology in relation to the resources, including time, at the disposal
of the author of this dissertation, and the application of the selected cost
accounting system to the two construction method.
6.2 The Accounting Systems
The topical method for ascertaining the costs of the two construction method is to
actually construct the two apartment buildings at a particular location (site) under a
controlled experiment based on work study methods. This method has been ruled out
due to financial and time constraints. Cost account based on historical data seems to
be the only option available for the author of this dissertation. A number of costing
systems are available for such costing investigation. The choice between them
depends on the degree of details of the two construction schemes, the current
available relevant information about the cost parameters, the degree of confidence in
the result to be obtained and the simplicity of applying the system.
However each method has its appropriate applications and limitations, but
it is important to recognize and emphasize that all estimates are
approximations based upon judgment and experience.
These estimates range in scope and detail from educated guesses to
contractor bid estimates. The latter are based on a relatively complete set
of plans and specifications and they involve much more than simply
applying historical unit costs to computed quantities.
To get the costs the estimator must particularly build the project on paper.
He must assess quantities not only of the contract materials reflected in
the drawings but also of the temporary materials such as formwork for
concrete and temporary plant.
The latter estimates, in turn, require that the estimator hypothesize
alternative methods that could be used to build the different components
of the project, determine the resources of labour, equipment, and
materials that would be required by each method, evaluate the
productivity and costs, and select those methods, which taken together
will complete the project on schedule and at the lowest overall cost.
Cost estimate can be broadly grouped under two types that can be used
during evolution of a project under the professional construction
management approach, namely conceptual, preliminary estimates and
detailed estimates.
6.2.1 Conceptual and Preliminary Estimates
As the name implies, are generally made in the early phases of a
project. Initially they tell an owner whether a project of the scope
he has in mind is any where near to being economically feasible.
(17)
6.2.2 Detailed Estimates
After conceptual design has been approved and after most or all of
the detail design work is complete, approximate estimates are
generally supplemented by detailed estimates. Those normally
require a careful tabulation of all the quantities for a project or
portion of a project; this is called quantity takeoff. These quantities
are then multiplied by selected or developed unit costs, and the
resulting sum represents the estimated direct cost of the facility.
The addition of indirect costs, plant and equipment, head-office
overheads, profits, escalation and contingency will develop the
total estimated project cost. (17)
6.2.3
Choice of Accounting System
A detailed estimate base on computed quantities can not be made at
the concept, feasibility study, or preliminary design stage, because
the project itself is not yet defined in terms of plan and
specifications upon which computations of quantities are based.
Furthermore, the estimating process itself becomes increasingly
accurate as more detailed and better technique are applied. Hence a
detailed estimate is to be used in this dissertation.
6.3 Types of Detailed Estimates
6.3.1
Fair Cost Estimate
Fair cost estimates for construction projects are best prepared from
the actual bid documents provided to the bidders, or used by the
constructors. They are best prepared from completed plans and
specifications. They are based upon actual quantity take off which
are multiplied by unit prices developed by the estimator.(17)
Acknowledgeable professional construction manager will prepare
an equally accurate quantity takeoff and will choose the number of
line items to be estimated on the basis of the objectives of the
particular project and the level of detail required to achieve these
objectives. Fair cost estimate is one of the primary tools in
establishing basis for measuring job progress and for the schedule
and cost control. (17)
6.3.2 Contractor’s Bid Estimate
The Contractor’s bid estimate is his foundation for a successful
project. He must bid low enough to obtain the work, yet high
enough to make profit.
Bid estimates are sometimes less detailed than fair-cost estimates.
Contractor bid estimates are based upon similar information (of fair
cost estimate), but may be developed in considerably more detail
depending upon the Contractor’s own procedure. Bid estimate
typically include lump-sum or unit price material and sub contracts
quotations. (17)
6.3.3 Definitive Estimates
As a project involves, initial approximate estimates become more
refined and more accurate as additional information is developed.
Finally, there comes a time when a definitive estimate can be
prepared that will forecast the final project cost.
Project can be separated into four broad categories for purposes of
definitive estimates:(i)Unit-price projects
These projects usually encompass heavy construction jobs such as dams, tunnels,
highways, and airport. Hence the prices have been set constant, while quantities
vary within limits inherent in the nature of the work. (17)
(ii)Traditional Projects
Projects in this category include lump-sum, guaranteed maximum – price and costplus a-fee negotiated contracts. (17)
(iii)Design Construct Projects
Design construct projects can be generally categorised into Lump-sum, guaranteed
maximum-price and cost plus –a- fixed fee similar to traditional approach. (17)
(iv)Professional Construction Management Projects
Professional construction management projects can be accurately prepared about
the same time as the guaranteed-maximum or cost-plus-a fixed fee option under
the traditional or the design – construct approach. (17)
6.4 Choice of Estimating Method
A contractor bid estimate method prepared from completed plans and
specifications based upon actual quantity takeoff, for both reinforced
concrete and loadbearing buildings, was found to be suitable for cost
estimates as far as this dissertation is concerned.
6.5 Estimates of Construction Costs
The estimated cost to a contractor of carrying out the work is known as the
construction cost and is composed of the directs cost of carrying out the
work to which are added the site overheads (on costs).
A direct cost consists of the cost of the resources – materials, labour,
equipment, and sub-contractors – needed to carry out a specific, welldefined item of work.
Site overheads or “on cost” include all of those costs needed to operate the
site work production activities that cannot be attributed to direct costs.
They include site management and supervision, offices, storage sheds, cars
and other transport and services, and general labour not assigned to
production.
The construction cost then forms the basis for determining the net cost
for a contract. (18)
6.5.1 Components of the structures for cost estimating
(a) Load-bearing ٍstructure Components
(a) Roofing
(b) Typical floors
(c) Grade beams
Super
structure
(d) Finishing
(e) Services
(f) Foundations
Sub
structure
(b) Reinforced concrete structure components
(a) Roofing.
(b) Typical floors.
(c) Grade beams.
Super structure
(d) Finishing
(e) Services
(f) Short columns
Sub structure
(g) Foundation
The substructures were not calculated for the two buildings
estimates because they were affected by the type of the soil
on which to be erected.
Also all the services and finishes which were considered
the same in the two buildings were not included in the
estimation, e.g. tiles, doors and windows, electricity, water
supply and drainage systems, etc.) because they have no
effect on the comparison.
6.5 .2 Breakdown of unit rate estimates
A breakdown must be carried out to discover the standards that will
subsequently be used in the standard costing system. Three elements
require extracting from the bills of quantities or quotation rate –
Material, labour and on cost – either gross or net, depending on the
proposed standard cost.
Because a standard cost in an attempt to compare like with like, the
planned profit margin allowed in the estimate must be removed if
standard are being calculated in cash. The same applies to the
allowance for head office overheads, unless these overheads are being
included on the cost side of the standard cost.
Neither an adequate library of standard nor estimator’s calculations are
available. The only remaining source of standards is from one of the
reputable construction firms on estimating backed by individuals
records and knowledge of outputs. (18)
In this dissertation the breakdown was carried for the ground floor. The
unit price estimated in the breakdown was increased (labour and site
overhead) by 10% for each floor above as follows:(1) Ground floor =
Estimated unit price.
(2) 1st floor
=
1.10xground floor (labour+site overhead)
(3) 2nd floor
=
1.10x1st floor(labour+site overhead)
(4) 3rd floor
=
1.10 x 2nd floor (labour + site overhead)
(5) 4th floor
=
1.10x3rd floor (labour+site overhead)
This was illustrated in the breakdown schedules (Appendix H) and the
average of the five floors was taken for the calculation of bill of
quantities Tables 6.1,6.2) .
6.6 Total Estimated Costs
The quantity of each element or activity was calculated, using standard
method of measurements and their unit cost was estimated, then bills
of quantities were prepared, and hence the total estimated costs were
determined for both reinforced concrete and the loadbearing buildings.
6.6.1
Results
Table 6.3 shows the summary of the results of the cutting exercise
for the two types of structure.
Table 6.4 summaries the quotation of the strategic materials used in
each type of construction method.
6.6.2
Analysis of the Results
Table 6.5 computes the saving in the materials when designed as a
loadbearing structure in absolute quantities and as a percentage
taking reinforced concrete skeleton as a base.
Table 6.6 computes the saving in materials of the reinforced
concrete skeleton.
6.6.3
Discussion of the Analysis of the Result
a- There is saving in all materials when
the apartment building is designed as a
loadbearing structure except for the
machine fired bricks.
b- The saving in materials results in
saving in cost which make the
loadbearing structure is economy than
the reinforced concrete skeleton.
c- The
saving
supported
materials
e.g.
which
cement
are
and
reinforcement steel is to be noted.
d- The overall saving is in the range of
7% of total superstructure costs.
CHAPTER SEVEN
CONCLUSIONS AND RECOMMENDATIONS
7.1 Conclusion
7.1.1
Physical and mechanical properties of the mechanized
fired clay bricks of Soba Plant are in complete
compliance with BS 3921/1965 and MSS/No. 6/1990.
7.1.2
Sand used for mortar preparation lies in zone 3 with
small amount of silt and clay content 2.78%, whereas
the ordinary Portland cement used in complete
compliance with B.S. 12/1978.
The mortar cubes which are prepared and tested
according to BS 4551/1980 are of compressive
strength complying with BS 5628/1978.
7.1.3
The characteristic compressive strength of brickwork
obtained from the prism which are constructed and
tested according to AS 1640-1974 was found to match
with BS 5628-1978 for bricks units of the same mean
compressive strength and mortar designation (4).
7.1.4
Five storey loadbearing building can be built from
mechanized fired clay brick of Soba Plant.
7.1.5
There is overall saving in both materials and cost
when using loadbearing structure instead of reinforced
concrete of the same selected apartment building. This
is manifested in :• Saving in steel bars amount to about 27
tons.
• Saving in ordinary Portland cement
amount to 56 tons.
• Saving
in
formwork
amounting
to
1545m2
• Saving in cost found to be SD3,321,850
(12,392 US$) which represent 7% saving.
The total cost of reinforced concrete
structure is found to be SD49,054,100
(US $ 188670), while the cost of
loadbearing structure is SD45,832,250
(US$ 176,278).
7.1.6
Saving steel bars and cement means saving of hard
currency which the country is in bad need of.
7.1.7
Use of loadbearing structure save time and time is
money.
7.2 Recommendation
7.2.1 Encouragement of using machine bricks in loadbearing
walls instead of R.C. structures in addition of using
them as facing bricks. This will save cost and hard
currency.
This could be made feasible by lowering their cost
by subsidizing their manufacturing input materials,
specially energy (fuel oil and electricity).
7.2.2 A pilot study of actual building of the two structures
(Loadbearing and R.C.) will demonstrate their exact
load-carrying capacity and will give the true amount of
work and materials required for each type of
construction.
7.2.3 Improvement the quality of produced bricks and
introduction of other types of clay products (such
hollow blocks, ceiling blocks etc.) may prove
meaningful in cost reduction of multi-storey buildings.
7.2.4 Mortars from indigenous materials must be investigated
and thoroughly studied to find their properties and
establish their grades
7.2.5 Investigate
the
correlation
between
prism
and
brickwork strengths by building walls from local
material (bricks and mortars) of one storey height and
of different thickness. These walls could be tested by
suitable crushing machines. The results obtained can be
compared with the values obtained from prisms, and
codes .
This will help in finding safety factors suitable for
local materials and local workmanship.
7.2.6 Introduce computer programmes for the design of
laodbearing structures.
7.2.7 The encouragement of the loadbearing structure will
result in the establishing number of modern factories for
brick and clay product in the Sudan.
References:[1] Hamid M.H., (1994) “Brickmaking industry in Sudan. Study
prepared for Forestry National Corporation F.N.C. and F.A.O.
Sudan-1994.
[2] ESCAP –RILEM – CIB in corporation with UNIDO UNCHS
and UNESCO, IT, NHA, TISTR., Building Materials for LowIncome Housing - 1987.
[3] Curtain W.G. and Partners, Consulting Structural and Civil
Engineers Structural Masonry Designers Manual, London 1982.
[4] B.S. 3921/1965. British Standard Institution Specification For
Bricks and Blocks of Fired Brickearth clay or shale, England
1985.
[5] M.S.S/No./5/1990 , Military Standard Specification For
Common Burnt Clay Building Bricks- Sudan.
[6] Hamid M.H. (1987) “Comparative Study on the Rational Use
of Fired Clay Bricks in Khartoum , PhD. Thesis 1987.
[7]
Plummer H.C., Brick and Tile Engineering
Second Edition November 1982.
Second Printing November 1967.
[8]
MSS/No/6/1990 , Military Standard Specification For Mechanized
Clay Bricks - Sudan
[9] Hendry A.W., “Structural Brickwork”, London – 1983. .
[10]
Comparative Study Between Loadbearing and Reinforced
Concrete Skeleton, Egypt 1975.
[11]
BS 812-1975 , British Standard Institution
Method for
sampling and testing of mineral aggregates, sands and fillers.
[12] BS 12-1978 , British Standard Institution. Specifications and
Methods for Testing Cement.
[13]
BS 4551-1980, British Standard. Institution Methods of
Testing Mortars, Screeds and Plaster .
[14] ES – 2002 , Egyptian Code of Practice Structural Masonry.
[15] AS 1640-1974 , “ Australian Standard “ SAA Brickwork
Code Metric Units.
[16]
BS 8110-1997, “British Standard Institution”. Structural
Use of Concrete. Code of practice for design and
construction.
[17]
Pitcher R. “ Principles of Construction Management –
Third Edition England - 1992
[18] Barrie D.S. and Other, “Professional Construction
Management, Second Edition, USA – 1984.
[19] Gabourne J., “Cost Control in the Construction Industry”
London – 1973.
Table No. 2.1
Annual Brick Production in Northern Sudan (1994)
State
Annual Production in
(Thousands)
Annual Production as percent of total
annual production in Sudan
Khartoum
1,280,000
46.2
Central
1,172,480
42.3
Northern
90,720
03.3
Eastern
84,000
03.0
Darfor
77,280
02.8
Kordofan
64,960
02.4
2,769,440
100.0
Total
Table 2.2
Dimensional Tolerance (Bricks)
According to BS 3921(1965)
Specified Dimensions
(inches)
Overall Measurement of 24 bricks
(inches)
2⅝
63+ 1¾
4⅛
99 + 1¾
8⅝
207+ 3
Table 2.3
Dimensional Tolerance (Bricks)
According to MSS./No/6/1990
Specified
Dimension (mm)
Overall
Measurement of 24
bricks (mm)
230
5520
Dimension Limit
Max limit
Min limit
5595
5445
110
2640
2685
2595
60
1440
1485
1395
Table 2.4
Compressive Strength and Absorption of Bricks
According to both BS 3521/65 and
MSS/No/6/1990
Min. Average
compressive strength
Max. Average
absorption
Class
(N/mm2)
(% by weight)
Engineering
A
70
4.5
Brick
B
51
7.0
Loadbearing
15
103.5
No specific
brick
10
69
requirement
7
48.5
5
34.5
4
27.5
3
20.5
2
14.0
1
7.0
D.P.C.
As required
Designation
Brick for Damp
4.5
Proof Courses
Table 2.5
Mortar Designation
According to BS 5628-1978
Grade Cement
Lime
Sand
Masonry
cement
Sand
Cement
Sand with
plasticizer
(i)
1
0-¼
3
--
---
---
---
(ii)
1
½
4–
1
2½ -3½
1
3-4
4½
(iii)
1
1
5-6
1
4-5
1
5-6
(iv)
1
2
8-9
1
5½-6½
1
7-8
Table (2.6)
Aspect Ratio H/T Correction Factors for Compressive Strength
According to AS 1640-1974
Standard
Aspect Ratio
H/T
2.0
2.5
3.0
3.5
4.0
4.5
5.00 or more
AS 1640-1974
H= Height of Prism
Aspect Ratio
Concretion factor
0.85
0.92
1.00
1.06
1.10
1.14
1.16
T= Thickenss of Prism
Table (2.7)
Sample Size Factors for Characteristic Strength
According to BS 5628-1978
No. of
specimen
in sample
Sample
size factor
5
10
30
120
>120
2.34
1.93
1.73
1.67
1.65
Table (2.8)
Characteristic Compressive Strength of Brickwork
According to BS 5628-1978
Mortar
Designation
(i)
(ii)
5
2.5
2.5
Compressive Strength of Units (N/mm2)
10
15
20
27.5
35
50
70
4.4
6.0
7.4
9.2
11.4 15.0 19.2
4.2
5.3
6.4
7.9
9.4 12.2 15.1
100
24.0
18.2
(iii)
(iv)
2.5
2.5
4.1
3.5
5.0
4.4
5.8
5.2
7.1
6.2
8.5
7.3
10.6
9.0
13.1
10.8
Table (2.9)
Partial factors of safety on materials as specified by
BS 5628-1978
Category of
manufacturing
control
Special
Normal
Category of construction control
Special
Normal
2.5
3.1
2.8
3.5
15.5
12.7
Table (2.10)
Effective Height
According to BS 5628-1978
Restraint Condition
(a) Horizontal
lateral
supports
provide
resistance
Effective Height hef
0.75 h
which
enhanced
to
lateral
movement
(b) Horizontal
lateral
supports
which
provide
simple
resistance to lateral
movement.
h
h = The clear distance between horizontal lateral supports.
Table (2.11)
Effective Length
According to BS 5628-1978
Resistance condition
Effective Length Lef
(a) Vertical lateral supports which
provide enhanced resistance lateral
0.75L
movement.
(b) Vertical lateral support which
provides enhanced resistance to lateral
2L
movement, and a free edge.
(c) Vertical lateral supports which
provide simple resistance to lateral
L
movement.
(d) Vertical lateral support which
provide simple resistance to lateral
2.5 L
movement and a free edge.
L = The clear distance between vertical lateral supports.
Table (2.12)
The Appropriate Stiffness Factor “k”
According to BS 5628-1978
Ratio of pier
spacing center to
center to pier width
Ratio
1
6
1.0
10
1.0
20
1.0
Linear interpolation is permissible
=
Pier thickness
Wall thickness
2
1.4
1.2
1.0
=
tp
t
3
2.0
1.4
1.0
Table (2.13)
Capacity Reduction Factor β
According to BS 5628-1978
Slenderness
ratio
Hef/tef
0
6
8
10
12
14
16
18
20
22
24
26
27
Eccentricity at top of the wall ex
Up to 0.05t
1.00
1.00
1.00
0.97
0.93
0.89
0.83
0.77
0.76
0.62
0.53
0.45
0.40
0.1t
0.88
0.88
0.88
0.88
0.87
0.83
0.77
0.70
0.64
0.56
0.47
0.38
0.33
0.2t
0.66
0.66
0.66
0.66
0.66
0.66
0.64
0.57
0.51
0.43
0.34
0.3t
0.44
0.44
0.44
0.44
0.44
0.44
0.44
0.44
0.37
0.30
Table (2.14)
Reduction Factor (ka, ke) for Slenderness Ratio and Uniform
Eccentricity of Force as Prescribed by AS 1640 – 1974.
Uniform effective eccentricity ratio of vertical
force e/tw
Slenderness 0
ratio
Ka
6
1.00
8
0.94
10
0.88
0.0417=1/24 0.1
Ke
Ke
0.80
0.63
0.75
0.59
0.70
0.54
0.2
Ke
0.46
0.42
0.38
0.3
Ke
0.30
0.27
0.24
0.4
Ke
0.15
0.14
0.12
0.5
Ke
0
0
0
12
14
16
0.82
0.76
0.70
0.65
0.59
0.54
0.50
0.46
0.41
0.34
0.30
0.26
0.22
0.18
0.16
0.11
0.09
0.08
0
0
0
18
20
22
0.64
0.58
0.52
0.49
0.43
0.38
0.36
0.31
0.27
0.23
0.19
0.15
0.13
0.10
0.07
0.06
0.05
0.05
0
0
0
24
27
0.46
0.37
0.33
0.25
0.22
0.16
0.11
0.06
0.04
0.01
0.02
0.00
0
0
Note:
Linear interpolation between adjacent values is permissible
Table (2.15)
Appropriate Design Local Compressive Stresses
According to BS 5628-1978
Design local compressive stress in
brickwork
Bearing Type
1
2
3
1.25 fk/γm
1.5 fk/γm
2.0 fk/γm
Table (2.16)
Effective Height hef of Column
According to BS 5628-1978
End Condition
Type of Restraint
Column restrained at least Floor or roof of any construction
against lateral movement spanning onto column from both
top and bottom
sides at the same level
Concrete floor or roof irrespective
of direction of span, which has a
bearing of at least 2/3 t but not less
than 90mm
Column restrained against No bearing or bearing less than case above
lateral movement at top Floor or roof of any construction
and bottom by at least two irrespective of direction of span
ties 30x5mm min at not
more than 1.25m centers
Effective Height hef
h in respect of both
axes
h in respect of both
axes
h in respect of minor
axis
2h in respect of major
axis
Table (2.17)
Quantities and their costs of the Reinforced Concrete Skeleton
and the Load Bearing Walls Structures-Egypt 1975
Item
No.
1
2
3
Plain concrete
Reinforced concrete
Wall of ½
Reinforced concrete
Load bearing walls
skeleton
Quantity Unit Cost
Quantity Unit Cost
rate Egyptian
rate Egyptian
pounds
pounds
3
3
111m
8
888
94m
8
752
3
3
377m
30.5
11499
214m
33.5
7169
2
2
650m
1.5
975
486m
2.0
972
Brick
4
Wall of 1 brick
5
Excavation
Total
242m3
374m3
8.5
0.75
548m3
352m3
2057
281
15700
11.0
0.75
Table 3.1
Dimensions of Machine Bricks
In Relation to MSS/No/6/1990
Machine
Standard Brick
Bricks
One brick
24 bricks
Maximum
Minimum
24 bricks
mm
mm
Limit
Limit
mm
Mm
Mm
230
5520
5595
5445
5457
110
2640
2685
2595
2618
60
1440
1485
1395
1522
Table 3.2
Water Absorption of Machine Bricks
Brick
Weight Dry (Wd)
Weight Wet(Ww)
No.
(gm)
gm
1
2119.5
2406.3
13.5
2
2061.2
2378.4
15.4
3
2214.0
2488.5
12.4
4
2137.3
2457.2
15.0
5
2109.7
2409.6
14.2
6
1961.4
2325.1
18.5
Absorption
⎡ ww − Wd ⎤
⎢
⎥ x100%
W
d
⎣
⎦
6028
264
15185
7
2036.3
2374.8
16.6
8
2112.7
2422.7
14.7
9
2039.1
2383.3
16.9
10
1994.1
2350.3
17.9
Sum
Mean absorption = 155.1/10
=
155.1
15.51%
Table 3.3
Compressive Strength of Machine Bricks
Brick
No.
Failure Failure Compressive Compressive
Brick
Dimensions
Length Width Area
Load
Load
Strength
Strength
(Ton)
(Kg)
(Kg/cm2)
N/mm2
(cm)
(cm)
1
22.5
10.5
236.25
62.00
62000
262.434
25.745
2
22.7
10.7
242.89
60.50
60500
249.084
24.435
3
22.7
10.5
238.35
66.50
66500
279.001
27.370
4
22.8
10.5
239.40
74.50
74500
311.195
30.528
5
22.5
10.5
236.25
50.50
50500
213.757
20.970
6
22.5
10.4
234.00
58.50
58500
250.000
24.525
7
22.5
10.6
238.50
57.50
57500
241.090
23.651
8
22.5
10.6
238.50
49.00
49000
205.451
20.155
9
22.6
10.7
241.82
63.00
63000
260.524
25.557
10
22.7
10.6
240.62
58.00
58000
241.044
23.646
(cm)
Sum
Mean compressive strength = 0.974 x 246.582/10 = 24N/mm2,
Table 3.4
Efflorescence of Machine Bricks
According to BS 3921-1965
246.582
MSS/No.6/1990
Brick No.
1
2
3
4
5
6
7
8
9
10
Area Covered
0
0
0
0
0
0
0
0
0
0
%
0
0
0
0
0
0
0
0
0
0
Table 3.5
Sieve Analysis of Sand used for Mortar Preparation
Sieve Size
(mm)
10
Weight Retained
(gm)
0
Weight Passing
(gm)
1000
%
Passing
100
5
0
1000
100
2.38
0
1000
100
1.18
004.1
995.9
99.59
0.60
379.8
616.1
61.61
0.30
408.7
207.4
20.74
0.15
168.6
38.8
3.88
PAN
038.8
0
0
* Silt and clay content = 2.78% < 3%
Table 3.6
Grades Zones of Sand (% passing)
According to BS 882-1973
Sieve Size
(mm)
Zone(1)
Zone(2)
Zone(3)
Zone(4)
9.52
100
100
100
100
4.76
90-100
90-100
90-100
95-100
2.40
60-95
75-100
85-100
95-100
1.20
30-70
55-92
75-100
90-100
0.6
15-34
35-59
60-79
80-100
0.3
5-20
8-30
12-40
15-50
0.15
0-10
0-10
0-10
0-15
Table 3.7
Physical Properties of Cement
According to BS 12/1978
Test
Consistency
Initial Setting
Time
Final Setting
Time
Compressive
Strength
3 days
28 days
29.25%
1hr 37 min.
BS 12-1978
Requirements
26-32
> 45 min
3 hrs 20 min.
<10 hrs
Results
1- 305 kg/cm2
2- 321 kg/ cm2
3- 337 kg/ cm2
> 235 kg/ cm2
1- 474 kg/ cm2
2- 494 kg/cm2
3- 498 kg/ cm2
> 418 kg/ cm2
Table 3.8
Compressive Strength of Mortar Cubes
Cube No.
1
Failure
Load
(Ton)
3
Failure
Load
(Kg)
3000
Compressive Compressive
Strength
Strength
2
(Kg/ cm )
N/mm2
61.22
6.01
2
2.6
2600
53.06
5.21
3
3.2
3200
65.31
6.41
Sum
Cube Area
=
17.63
7x7=49 cm2,
.. Mean compressive strength of mortar
=
0.974x17.63/3
= 5.72 N/ mm2
Table 3.9
Compressive Strength of Prisms
Prism Height Thickness Width
Area
Crushing Compressive Compressive
Load
strength
strength
Cm
Kg
Kg/cm2
N/mm2
22.4
232.96
22000
94.44
9.26
10.5
22.5
236.25
21200
89.74
8.80
30.0
10.4
22.3
231.92
22400
95.59
9.38
4
29.4
10.5
22.2
233.10
18000
77.22
7.58
5
30.5
10.5
22.5
236.25
20400
86.35
8.47
Sum
150.2
52.3
No.
H
T
W
Cm
Cm
Cm
1
30.3
10.4
2
30.0
3
43.49
Mean compressive strength = 0.974x43.49/5 = 8.47N/mm2,
Table 3.10
Compressive Strength of Piers
1.0m Height
Prism Height Length Width
No.
H
L
W
Cm
Cm
Cm
Area
Crushing
Load
Cm
Compressive Compressive
strength
strength
Kg/cm2
N/mm2
Kg
1
101.0
48
22.5
1080
41500
38.43
3.77
2
100.5
47.3
22.0
1040.6
35500
34.11
3.35
3
102.0
49.2
22.2
1092.24
25500
23.35
2.29
Sum
9.41
Mean compressive strength = 9.41x0.974/3 = 3.055N/mm2,
Table 3.11
Compressive Strength of Peirs
1.5m Height
Prism Height Length Width
No.
Area
Crushing Compressive Compressive
Load
strength
strength
Cm
Kg
Kg/cm2
N/mm2
22.5
1057.5
20200
19.10
1.87
48
22.6
1080
20000
18.52
1.82
49
22.4
1097.6
21600
19.68
1.93
H
L
W
Cm
Cm
Cm
1
149
47
2
150.5
3
155
Sum
Mean compressive strength = 5.62x0.974/3 = 1.82N/mm2,
5.62
Table 3.12
Design Loads
According to BS 5628-1978
Wall Thickness
=
210mm
Partial safety factor for material strength
=
3.5
Mortar Designation IV
Effective
Brick Strength N/mm2
height (m)
20
e<0.05t
27.5
35
e=0.2t
e <0.05t
e=0.2t
e<0.05
50
e=0.2t
e<0.05t
E=0.2t
0.90
312
205.9
372.0
245.5
438
289.1
540
356.4
1.20
312
205.9
372.0
245.5
438
289.1
540
356.4
1.50
312
205.9
372.0
245.5
438
289.1
540
356.4
1.80
312
205.9
372.0
245.5
438
289.1
540
356.4
2.10
304.3
205.9
262.8
245.5
427.2
289.1
526.7
356.4
2.40
295.5
205.9
352.4
245.5
414.9
289.1
511.5
356.4
2.70
285.6
205.9
340.6
245.5
401
289.1
494.4
356.4
3.00
274.5
205.9
327.3
245.5
385.4
289.1
475.2
356.4
3.30
262.3
200.5
312.7
239.1
368.2
281.5
435.9
347.0
3.60
248.9
187.1
296.7
223.1
349.4
262.6
430.7
323.8
3.90
234.3
172.5
279.3
205.7
328.9
242.1
405.5
298.5
4.20
218.5
156.7
260.5
186.9
306.7
2.20
378.2
271.3
4.50
201.6
139.8
240.3
166.7
283.0
196.3
348.9
242.0
4.80
183.5
121.7
218.8
145.1
257.6
170.9
317.6
210.6
5.10
164.2
102.4
195.8
1221
230.5
143.8
284.2
177.3
5.40
143.8
82.0
171.4
97.8
201.9
115.1
248.9
142.0
5.67
124.4
62.6
148.3
74.7
174.7
87.9
215.3
108.4
Table 3.13
Comparison between the failing load of brick peirs and
the load bearing capacity calculated according
to AS 1640-1974 & BS 5628-1978
Mean Failure Load
Loadbearing capacity (kN)
(kN)
AS 1640-1974
BS 5628-19
196
154
159
Table 4.1
Design Parameter Informations
Residential flats
Exposure Conditions:Internal
= Mild
External
= Moderate
Fire Resistance = 1 hour
Intended use of structure
Durability and fire resistance
requirements
Loads:Deadload:Roof finish= 2.75KN/m2
Floor finish= 1.50 KN/m2 (20KN/m3)
(Unit Weight of Walls Wm)=18KN/m3
(Unit Weight of Walls WT)=15KN/m3
General Loading Condition
Imposed Load:
Roof (No access) = 0.75KN/m2
Floors
= 1.50KN/m2
Characteristic Strength:=
25N/mm2
Fcu
=
250N/mm2
Fym
=
420N/mm2
Fyt
Fyv
=
250N/mm2
Unit weight of concrete = 24KN/m3
Characteristic strength of
brickwork
(Fm) = 5.74N/mm2
Notes
Exposure Conditions
(i)
Material data
Mild : Concrete surfaces protected against
weather or aggressive conditions
(ii)
Moderate: Concrete surfaces sheltered from severe rain
while wet.
Table 6.1
Bill of Quantities for Load-bearing Structure
Description
Unit
Quantity
Rate
Amount
32
50,000 1,600,000
240
54,000 12,960,000
1395
6,000
8,370,000
1584
9,000
14,256,000
3750
900
3,375,000
1450
1,000
1,450,000
3750
1450
700
825
2,625,000
1.196,250
45,832,250SD
175603US$
(I) Concrete:Rate
includes
all
formwork, reinforcement
bars
(i) Provide all materials and
cost reinforced concrete in M3
1:2:4 (c:s:g) mix for beams
(ii) Ditto, Ditto in R.C. slab
125mm thick
M3
(II) Brickwork
(i) Provide all materials and
build one brickwall built
out of machine fired clay M2
bricks in 1:6 c:s mortar
(ii) Ditto, Ditto in 1 ½brick M2
thick
(III) Plaster:
(i) Provide all materials and
2
plaster walls, internally M
with 1:6 c:s mortar
M2
(ii) Ditto, Ditto
to ceiling
(IV) Painter
(i) Provide all materials and
apply three coats pomastic
paints to walling
M2
(ii) Ditto,Ditto to ceiling
M2
Total
Table 6.2
Bill of Quantities for R.C. Skeleton Structure
Description
Unit Quantity
Rate
Amount
SD
M3
41
55,600 2,279,600
M3
181
55,600 10,063,600
226
54,000 12,960,000
46
54,000 00,972,000
2362
2,650
6,259,300
M2
1245
3,575
4,450,875
(i) Provide all materials and
plaster walls, internally and
2
externally with 1:6 (c:s) mortars M
(ii) Ditto, Ditto to ceiling
M2
5103
1510
1,125
1,000
05,740,875
01,510,000
(IV) Painter
(i) Provide all materials and
apply three coats pomastic
paints to walling
M2
(ii) Ditto, Ditto to ceiling
M2
5103
1510
700
825
3,572,100
1,245,750
(I) Concrete:-
Rate includes all formwork,
reinforcement bars
(i) Provide all materials and cost
reinforced concrete in 1:2:4
(c:s:g) mix for columns
(ii) Ditto, Ditto in r.c. beams
(iii) Ditto, Ditto in r.c. slab
125mm thick
M3
(iv) Ditto, Ditto in r.c. wall
150mm thick (lift wall)
M3
(II) Brickwork
(i) Provide all materials and
build one brick wall with mortar
1:8 c:s mix and ordinary red M2
bricks
(ii) Provide all materials and build
½
brick wall of machine fired clay
bricks fair face externally using
extrernally using ½” bars to
express joint in 1:6 (c:s) mortar
(III) Plaster:
Total
49,054,100SD
187947US$
Table 6-3
Quantities and their costs of the reinforced concrete skeleton and the loadbearing walls structures
Item
No.
1
2
3
Reinforced Concrete Skeleton
Quantity Unit
Unit rate
Type
Reinforced Concrete
(a) Slabs
and
walls
(b) Column
s
and
beams
Brickwork
(a) ½brick
thick
(b) 1
brick
thick
(c) 1½brick
thick
Finishings
(a) Plaster
i-
w
Cost
Sudanese
Dinar
Loadbearing walls
in Quantity
Unit
Unit rate
Cost
in
Sudanese
Dinar
258
222
M3
M3
54,000
55,600
13,932,000
12,343,400
240
32
M3
M3
54.000
50.000
12,960,000
1600,000
1245
2362
---
M2
M2
----
3575
2650
---
04,450,875
06,259,300
---
--1390
1584
--M2
M2
--6.000
9.000
--8,370,000
14,256,000
5103
M2
1125
5,740,875
3750
M2
900
03,375,000
ii-
(b)Painter
i-
ii-
Total Cost
a
l
l
i
n
g
c
e
i
l
i
n
g
1510
M2
1000
1,510,000
1450
M2
5103
1510
M2
M2
700
825
03,572,100
01,245,750
3750
1426
M2
M2
1000
700
825
01,450,000
02,625,000
1,196,250
w
a
l
l
i
n
g
c
e
i
l
i
n
g
49054100
45,832,250
Table 6.4
Quantities of the Main Materials
Description(item)
Unit
Loadbearing
(1)Machine bricks
Thousand
453
75
2) Traditional bricks
Thousand
---
355
3) Concrete
M3
272
480
4) Steel bars
Ton
32
59
5) Cements
Ton
210
266
6) Formwork
M2
375
1920
R.C.
Skeleton
Table 6.5
Saving in Materials for the Loadbearing Structure
Item Type Unit
Unit
R.C.
Loadbearing
Skeleton
Save in
Save
quantities as %
1
Concrete
M3
480
272
208
43.3%
2
Steel bars
Ton
59
32
27
45.8%
3
Cement
Ton
266
210
56
21%
4
Formwork M2
1920
375
1545
80.5%
5
Traditional thousand
355
---
355
100%
bricks
Item
Table 6.6
Saving in Materials for the R.C. Skeleton
Type
Unit
R.C.
Loadbearing Save in
Skeleton
1
Machine Thousands
brick
75
453
Save
quantities
as %
378
83.4%
APPENDIX (A)
LOAD-BEARING
BENDING MOMENTS AND SHEAR FORCES CALCULATION
APPENDIX (B)
LOAD-BEARING
(i)
(ii)
(iii)
DESIGN OF SELECTED SLABS
DESIGN OF BEAMS
DESIGN OF STAIR CASE
Typial Floor slab
Two Way Slab
Slab (C-E)-(4-5)
4.25m
Reference
BS8110
Table 3.3
Table 3.4
Calculation
Durability
Resistance:-
and
Output
Fire
Cover = 20mm
fire resistance is
O.K.
Nominal cover for mild condition of exposure
= 20mm
Maximum fire resistance of 125mm slab with
20mm cover >1h
Loadings:-
Self wt. Of slab =0.125x24= 3.00 KN/m2
Finish
= 1.50KN/ m2
Characteristic dead load = 4.50KN/ m2
Characteristic imposed load= 1.50KN/m2
Design load=1.4x4.5+1.6x1.5=8.70KN/m2
gk = 4.5 KN/ m2
qk= 1.5 KN/ m2
F = 8.7KN/ m2
Ultimate bending Moments:Lx = 4.25m, Ly = 5.75m
Interior panel:Sec.2.2
Negative moment at continuous edges:Sec.4.4
(AppendixA) Mx1 = 9.2 , Mx2 = 9.20 KN/m
My1 = 7.6, My2 = 4.00KN/m
Sec.2.2
Positive moment at mid-span
Sec.4.4
(AppendixA) Mx = 7.63 KN m/m
My = 3.44 KN m/m
Shear forces:-
Sec.2.2
V sx1 = 14.4V sx2 = 14.4KN
Sec.4.4
(AppendixA) V sy1 = 5.7, Vsy 2 = 5.6 KN
Reinforcements:b = 1000mm
d = 125-20-10-10/2 = 90mm
b=1000mm
d = 90mm
At Continuous edge:Mx=9.20KN m/m
k = M/fcu bd2=9.20x106/25x103x90=0.045<0.156
z/d=0.94467
Reference
BS8110
Calculation
Output
..As=9.20x106/0.87x0.9467x250x90=497 mm2
.. Use Ø10 at 150mm (523 mm2)
My = 7.6 KN m/m
K = 0.0375
Z/d = 0.956 > 0.95
Top Ø10 at 150
(523 mm2/m)
.. As = 7.6x106/0.87x0.95x250x90=409mm
Top Ø10 at 175
(449 mm2/m)
.. Use Ø 10 at 175mm (449mm2)
At mid span:Mx = 7.63 KN m/m
k = 0.0374
Bottom Ø10 at
2
Z/d = 0.957>0.95
6
2 175(449 mm )
As = 7.63x10 /0.87 x 0.95x 2.50x90=407mm
.. Use Ø10 175 (449 mm2)
Table 3.8
My = 3.44 KN/m
As=3.44x106/0.87x0.95x250x90=185mm2
Nominal steel = 0.0024bh
= 99,24x1000x125=300mm2
.. Use Ø10 at 250mm (314 mm2)
Nominal steel
Bottom Ø10 at
250(314 mm2 /m)
Shear:-
Shear is O.K.
Vsx = 14.4KN, Vs/bd
υ = 14.4x103/103x90 = 0.16<4 N/mm2
100As/bd = 100x523/103x90 = 0.58
.. υc = 0.70 N/mm2 > 0.16
Table 3.9
Deflection:-
Shear resistance
is O.K.
Table 3.10
Basis span/effective depth ratio = 26
M/bd2 =7.67x106/103x902=0.935
.. Modification factor = 1.97
.. Allowable L/d = 26x1.97 = 51.22
Actual L/d = 4250/90 = 47.22 < 51.22
.. Deflection is O.K.
Deflection
O.K.
is
Reference
BS8110
3.12.11.2.7
Calculation
Cracking:
h = 125 < 250mm
Clear distance between bars:= 175-10 = 165mm
3d = 3x90 = 270> 240>165
No further check required
.. cracking is O.K.
Output
Crack width is
O.K.
Typical Floor Slab Design
Two way slab
Slab (B- D)-(1-3)
4.25m
Reference
BS8110
Calculation
Output
Ultimate bending moments:Lx = Ly = 4.25m
Interior panel
Negative moment at continuous edges
Sec 1.1
Mx= 7.5/m ,
Sec 3.3
(AppendixA) My1 = 6.0 KNm/m , My2 = 7.0KNm/m
Positive moment at mid-span:Sec 1.1
Mx = 7.06KNm/m
Sec 3.3
(AppendixA) My = 4.73 KNm/m
Shear Forces:
Vsx1 = 8.0KN , Vsx2 = 11.30KN
Sec 1.1
Vsy1 = 9,8KN , Vsy2 = 9.8KN
Sec 3.3
(AppendixA)
Reinforcements:b = 1000 ,
d = 90mm
At continuous edges:Mx = 7.5KNm/m
k = 0.037
z/d = 0.957>0.95
.. As = 7.5x106/0.87x0.95x250x90=404mm2
.. Use Ø 10 at 175 (449 mm2)
My2 = 7.0KNm/m
K=0.023457
Z/d = 0.96>0.95
.. As = 7.0x106/0.87x0.95x250x90=377mm2
.. Use Ø 10 at 200 (393mm2)
At mid span:-
Mx = 7.06 KNm/m
.. Use Ø 10 at 200 (393mm2)
My = 4.73KNm/m
b= 1000
d = 90
Top Ø 10 at 175
(445mm2/m)
Top Ø 10 at 200
(393mm2)
Bottom Ø 10 at
200(393mm2/m)
K=0.0234<0.156
Z/d = 0.97>0.95
Reference
BS8110
Calculation
Output
.. As = 4.73x106/0.87x0.95x250x90=254mm2
.. Use Ø 10 at 250 (314mm2)
Bottom Ø 10 at
250(314mm2/m)
Shear:
Shear is O.K.
Vsx2 = 11.30KN
υ = 11.30x103/103x90 = 0.126<4.0N/mm2
100 As/bd = 100x449/103x90 = 0.50
.. υc = 0. 67 N/mm2 > 0.126 N/mm2
Shear resistance is
O.K.
Table 3.8
Table 3.9
Deflection:-
Basic span/effective depth ratio = 26
2
6
3
2
Table 3.10 M/bd = 4.82x10 /10 x90 = 0.87
.. Modification factor
= 1.98
.. Allowable L/d = 1.98x26 = 51.48
Actual L/d = 47.22, 51.48
.. Deflection is O.K.
3.12.11.2.7 Cracking :
h = 125 < 250mm
clear distance between bars = 250-10 = 240mm
3d = 3x90 = 270 > 240
No further check required
.. cracking is O.K.
Deflection is O.K.
Crack
O.K.
width
is
Typial Floor slab
Two Way Slab
Slab (D-E) –(2-4)
4.25m
Reference
BS8110
Calculation
Output
Ultimate bending Moments:Lx = Ly = 4.25m
Interior panel:Section 2.2
Negative moment at continuous edges:Section 3.3
(AppendixA) Mx1 = 5.4 , Mx2 = 9. 0 KN/m
My1 = 70, My2 = 6.6 KN/m
Section 2.2
Positive moment at mid-span
Section 3.3
(AppendixA) Mx = 4.16 KN m/m
My = 4.82 KN m/m
Shear forces:-
Section 2.2
V sx1 = 9.1 V sx2 = 10.2 KN
Section 3.3
(AppendixA)
V sy1 = 9.7, Vsy 2 = 9.5 KN
Reinforcements:b = 1000mm d = 90mm
At Continuous edge:Mx2=9.0KN m/m
k = 0.0444 < 0.15637
z/d=0.948
As=9.0x106/0.87x0.94788x250x90=485mm2
.. Use Ø10 at 150 (523mm2)
My2 = 7.0 KNm/m
k = 0.0345 < 0.156
z/d = 0.96 >0.95
As =7.0x106/0.87x0.95x250x90 = 377mm2
.. Use Ø10 at 150 (523mm2)
At mid span:Mx = 4.16 KN m/m
k = 0.0205 <0.156
b=1000
d= 90
Top Ø 10 at 150
(523mm2)
Top Ø 10 at 200
(393mm2 /m)
Bottom Ø 10 at
250 (314mm2/m)
Reference
BS8110
Table 3.8
Z/d = 0.98 > 0.95
As = 4.16x106/0.87 x 0.95x 2.50x90=224mm2
.. Use Ø10 250 (314 mm2)
Calculation
Shear:-
Vsx2 = 10.2KN,
υ = 10.2x103/103x90 = 0.113 <4.0 N/mm2
100As/bd = 100x523/103x90 = 0.58
.. υc = 0.70 N/mm2 > 0.113 N/mm2
Table 3.9
Table 3.10
3.12.11.2.7
Deflection:Basis span/effective depth ratio = 26
M/bd2 =4.82x106/103x902=0.595
.. Modification factor = 2.0
.. Allowable L/d =2x26 = 52
Actual L/d = 4250/90 = 47.22 < 52
.. Deflection is O.K.
Output
Shear is O.K.
Shear resistance
is O.K.
Deflection
O.K.
is
Cracking:h = 125<250
Clear distance between bars=250-10=240mm
3d = 3x90=270>240
No further check required
.. Cracking is O.K.
Crack width is
O.K.
Typial Floor slab
Two Way Slab
Slab (A-C) –(4-5)
4.25m
Reference
BS8110
Calculation
Output
Ultimate bending Moments:Lx = Ly = 4.25m Ly=4.75m
One edge discontinuous (Long)
Negative moment at continuous edges:Section 1.1
Mx1 = 5.3 , Mx2 = 8.9 KN m/m
Section 4.4
(AppendixA) My = 7.6, KNm/m
Positive moment at mid-span
Section 1.1
Mx = 5.73 KN m/m
Section 4.4
(AppendixA) My = 7.10 KN m/m
Shear forces:-
Section 1.1
Vsx1 = 10.8KN, Vsx2=12.0KN
Section 4.4
(AppendixA)
Vsy1=7.0KN, Vsy2=9.9KN
Reinforcements:b = 1000mm d = 90mm
At Continuous edge:Mx= 8.9KN m/m
k = 0.044 < 0.156
z/d=0.9485
As=8.9x106/0.87x0.9485x250x90=485mm2
.. Use Ø10 at 150 (523mm2)
b= 1000
d = 90
Top Ø10 at 150
(523mm2/m)
My2 = 7.60 KNm/m
k = 0.0375
z/d=0.956>0.95
As=7.6x106/0.87x0.95x250x90=409mm2
.. Use Ø10 at 175 (449mm2)
Top Ø10 at 175
(449mm2 )
At mid span:-
Bottom Ø10 at
200 (393 mm2/m)
Mx = 5.73 KN m/m
k = 0.0283 < 0.156
Reference
BS8110
z/d=0.968 >0.95
As=5.73x106/0.87x0.95x250x90=308mm2
.. Use Ø10 at 200 (393 mm2)
Calculation
My = 7.10 KNm/m
k = 0.035 < 0.156
z/d=0.96 >0.95
As=7.10x106/0.87x0.95x250x90=382mm2
.. Use Ø10 at 175 (449 mm2)
Table 3.8
Table 3.8
Table 3.9
Table 3.10
3.12.11.2.7
Shear:-
Vsx2 = 12.0KN,
υ = 12.0x103/103x90 = 0.133 <4.0 N/mm2
100As/bd = 100x523/103x90 = 0.35
.. υc = 0.70 N/mm2 > 0.133 N/mm2
Vsx1 = 9.9KN,
υ = 9.9x103/103x90 = 0.11 <4.0 N/mm2
100As/bd = 100x523/103x90 = 0.5
.. υc = 0.67 > 0.11N/mm2
Deflection:Basis span/effective depth ratio = 26
M/bd2 =7.1x106/103x902=0.876
.. Modification factor = 1.98
.. Allowable L/d =1.98x26=51.48
Actual L/d = 47.22<51.48
.. Deflection is O.K.
Cracking:h = 125<250mm
Clear distance between bars=200-10=190mm
3d = 3x90=270>190
No further check required
.. Cracking is O.K.
Output
Bottom Ø10 at
175 (449 mm2/m)
Shear is O.K.
Shear Resistance
is O.K.
Shear is O.K.
Shear Resistance
is O.K.
L/D ratio is O.K.
Crack width is
O.K.
Load Bearing Design
Typical floor beams
Reference
BS8110
Calculation
Durability and fire resistance:
As for slab
Reinforcements:
Beams are rested on walls below transfer the
loads from above. The beams are in
compression , and reinforced with nominal
steel
Table 3.25
100xAs/Ac = 0.15
..As = 0.0015x225x325=110mm2
.. Use 2 Ø 12mm (226mm2)
Table 3.7
Links:
Area of shear reinforcement to be provided
Asv > 0.4 bu Su/0.87 fyv
Use 8mm diameter for vertical links
.. 100 > 0.4x225xSv/0.87x250
.. Sv < 241/mm
Use Ø 8 at 200mm Centres
Output
Cover =20mm
Fire Resistance is
OK
Stair Case Design
Stairs Spanning into landings
Riser = 8x0.15 = 1.20m
Tread = 7x0.30 = 2.10
Span = 1.8 + ½ (1.2+1.2)= 3.0m
Waist = 0.125m
Reference
Calculation
BS8110
Table 3.3 Durability and fire resistance
Table 3.4 As for slabs
Loadings:
Waist thick = 125mm , d=90mm
Slope length of stairs = (2.1) 2 + (1.2) 2 = 2.42m
Considering 1m length of stairs
Wt. of waist plus steps:
[0.125x2.42+0.30x1.5/2]24
=11.58KN
Finishing =2x2.42
=4.84
Characteristic D.L.
= 16.42KN
Characteristic L.L.=2.1x3.00
=06.30
Ultimate load F=1.4x16.42+1.6x6.30
=33.07KN
Output
Cover =20mm
fire resistance
is OK
Reference
BS8110
Table 3.5
Calculation
Ultimate bending moment:
M=FL/10
= 33.07x3.2/10
Output
= 10.58KN/m
Reinforcement:
M=10.58KNm
K=M/bd2fcu=10.58x106/103x902x25
Z/d=0.938
,,As=10.58x106/0.87x0.938x90x250
..Use Ø12 at 175(646mm2)
Transfer steel
As=0.24bh/100=0.24x103x125/100
..Use Ø 10 at 250mm centers (3/4mm2)
Table 3.9 Deflection
depth ratio
Table 3.10 Basic span/effective
6
3
M/bd2=10.58x10 /10 x902
.. Modification factor
Allowable L/d = 1.78x26
Actual L/d = 3200/90
=35.6<46.28
=0.052
=576mm2
=300mm2
= 26
=1.30
= 1.78
=46.28
Deflection is O.K.
3.12.11.2.7 Cracking:
H=125mm < 250mm
Clear distance between bars = 240mm
3d = 3x90 = 270>240
No further check is required
Crack
O.K.
width
is
APPENDIX (C)
LOAD BEARING
DESIGN OF SELECTED WALLS AND PIERS
Design of Walls
Load bearing walls design
Wall No. (2-4) –E & (4-5)-E
fm= 5.74N/mm2
H = 3.00m
L = 4.25m
T = 0.225
Reference
Calculation
Output
Fire resistance for fired clay bricks wall of
225mm thick is > 1 hr
Loaded area:
⎛1
⎞
= 9.031m 2
⎜ x 4.25 x 4.25 / 2 ⎟2
⎝2
⎠
Loadings:
Self wt. Of r.c. slab=0.125x24
= 3.0KN/m2
Finishes
= 1.5KN/m2
Characteristic D.L.
=4.5KN/m2
Equivalent D.L.
= 9.56KN/m
Self wt. Of wall:
0.225x3x18+0.04x3.0x20
= 14.55KN/m
Characteristic life load
= 1.5KN/m2
Equivalent L.L.
= 3.19KN/m
.. Design Load per metre length:
1.4(9.56+14.55)5+0.6x1.6x5x3.19
= 184.082KN/m
Fire resistance is
O.K.
ES2001
AS1640-74
A=9.031m2
F=184.082KN/m
Table 7
The flour slab built into the wall provide
enhanced resistance to lateral movements then
the effective height of the wall =0.75h = Hef = 2.25m
0.75x3.00=2.25m
(8,9,a)
The effective thickness = thickness of the wall
Tef = 0.225m
Slenderness ration : - SR
SR=hef/tef = 2.25/0,225 = 10
SR=10
Reference
Calculation
The maximum eccentricity at first floor level:
Output
1
R1 = [1.4 x9.56 + 1.6 x0.7 x3.19] = 8.48 KN / m
2
R2 = 9.56 / 2
= 4.78KN/m
The load in the wall above the first floor level
may be assumed to be axial.
= 4[9.56+14.55] = 96.44KN/m
Taking moment about the face, P let x be the
distance to the resultant of R1, R2 and the axial
load.
96.44x0.1125+8.48x0.0375+4.78x0.1875
= (96.44+8.48+4.78)x
x=0.11m
.. eccentricity at the top of the wall
ex = 0.1125 – 0.11 = 0.0025 < 0.047
ex=0.0025
Reference
Calculation
Output
eccentricity at the bottom of the wall:-
Taking moment about the face p, let x be the
distance of the resultant of 109.7 and 14.55
(109.7+14.55)x = 109.7x0.11+14.55x0.1125
.. x = 0.11
ex at the top of the wall=ex at the
bottom of the wall <0.047
Table 10
Table 2.14
Equ. 3
Equ. 2.1
ka = 0.88
.. The bearing capacity of the wall per metre
length Pa= ka x Fmx t/5
0.88 x 5.74 x 225/5 = 227.3 KN/m
.. The bearing capacity “227.3” > The design
load (184.082)
the design is O.K.
Pa=227.3KN/m
2- Wall No. (4-5) –I & (5-6) – I
fm= 5.74N/mm2
H = 3.00m
L = 4.25m
T = 0.34
Reference
ES 2001
AS1640-74
Calculation
Output
Fire resistance f fired clay bricks wall of 340mm Fire resistance
thick is > 1 hr
is O.K.
Loaded area:
A=4.516m2
½x4.25x4.25/2 = 4.516m2
Loadings:
Self wt. Of r.c. slab=0.125x24
= 3.0KN/m2
Finishes
= 1.5KN/m2
Total
= 4.5KN/m2
EquivalentD.L.
=4.78KN/m2
Self wt. Of wall:
18(0.34x3.00.25x0.25)+0.02x3.0x20=18.435KN/m
Self wt. Of beam=0.25x0.25x24
=1.5KN/m
Parapet:
0.9x0.225x18+1.15x0.02x20
= 4.105KN/m
Characteristic life load
= 1.5KN/m2
Equivalent L.L.
= 1.59KN/m
Design Load:
1.4[5(4.78+18.435+1.5)+4.105]+0.6x1.6x5x1.59=
= 186.384KN/m
Table 7
8,9,a
Effective height =0.75h , hef
Effective thickness = , tef
Slenderness ration : hef/tef=2.25/0.34
= 2.25m
= 0.34m
=6.62m
F=186.384KN/m
hef = 0.225m
tef = 0.34m
SR= 6.62m
Reference
ES 2001
AS1640-74
Calculation
Output
The maximum eccentricity at first floor level:
R1=[1.4x4.78+1.6x0.7x1.59]=8.48KN/m
The load in the wall above the first floor level
may be assumed to be axial.
4[4.78+18.435+1.5]+4.105 = 102.965KN/m
Taking moment about the face p, let x be the
distance to the resultant of R and the axial load.
102.965x0.17+8.48x0.2567=111.445x
x = 0.177
.. Eccentricity at the top of the wall
ex=0.177-0.17=0.000659 =0.007<0.0417
Eccentricity at the bottom of the Wall
ex=0.007
Taking moment about the face p, let x be the
distance of the resultant of 111.445 and 18.435
(111.445+18.435)x=111.445x0.177+18.435x0.17
.. x=0.177
ex at the bottom = ex at the top
Table 10
Table 2.14
Ka
= 0.982
.. The bearing capacity of the wall per metre
length =
0.982x5.74x340/5 = 383.3 KN/m
Design Load = 186.384 < 383.3
Design is OK
Ka
= 0.982
3- Wall No. (F-H) -I
fm= 5.74N/mm2
H = 3.00m
L = 4.25m
T = 0.35
Reference
ES 2001
AS1640-74
Calculation
Output
Loaded area: A
A = ½ x 4.25x4.25/2
= 4.516m2 A=4.516m2
Loadings:
Design Load (Neglecting the opening)
F=186.384
= 186.384KN/m
Total Design Load :
=4.25x186.384
=792.132KN
Self wt. of wall above the lintol
(0.90x0.34-0.25x0.25x2)18+0.02x0.90x20
= 3.62KN/m2
Wt of lintol and beam:
2x0.25x0.25x24
=3.00KN/m
D.L. from slab
= 4.78KN/m
Self wt. of wall under the window lintol of the
above floor:
2.10x0.34x18+0.02z2.10x20
=13.692KN/m
Total D.L.
For 1.8m
Life Load from slab
L.L. for 1.8m = 2.862KN
Total Design Load (for bearing)
1.4x56.974+1.6x2.862
= 31.652KN/m
= 56.974KN
= 1.59KN/m
Bearing Capacity of the Wall:Pa
Pa=0.982x5.74x340x3.05
=1162KN
.. The bearing capacity =1162>792.132
(Design Load)
=83.34KN
Pa=1162KN
Reference
ES 2001
AS1640-74
Calculation
Check of Stresses under the lintol:
Bearing stress=83.34x103/2x300x340 =0.41N/mm2
Compressive stress
=4.25x186.384x103/3050x340=0.76N/mm2
Total Stress = 1.17N/mm2
8.10.4.a
Wall stress=1.5x0.982x5.74/5=1.69N/mm2 > 1.17
.. Design is O.K.
Output
4- Wall No. (A-C) - 5
Reference
ES2001
AS1640-74
Calculation
Loaded area:
[0.5+4.75]x4.25x4.25x2/2x2
Output
= 11.156m2
A=11.156m2
Loadings:
Self wt. of slab=11.156x4.5/4.75=10.57KN/m
Self wt. Of wall=0.34x3x18+0.04x3x20
=20.76KN/m
Life Load =11.156x1.5/4.75
= 3.69KN/m
Design load = 4.75x1.4x5x10.57
+ 1.4x5x3.25x20.76 +0.6x1.6x5x3.69x4.75
F=907.87KN
=907.87KN
Load supported by 2.1m beam (1)
D.L. from slab above = 2.1x70.57
= 22.20KN
Self wt. Of beam = 2.04x2.1
= 4.28KN
Characteristic D.L.
= 26.48KN
Characteristic L.L. = 3.69x2.1
= 7.75KN
Design Load = 1.4x26.48+1.6x7.75
=49.48KN
Load supported by 2.1m beam (2)
Self wt. Of beam = 4.28
D.L. from slab = 2x0.75x2.1x4.5
=14.175KN
Characteristic D.L.
= 18.46KN
Characteristic L.L. =2x0.75x2.1x1.5 =4.725KN
Design Load = 18.46x1.4+1.6x4.725
=33.4KN
Load supported by 2.1m beam (3)
Self wt of beam
D.L. from slab =
= 4.28KN
⎡1.5 + 5.75 ⎤ 4.25 4.5
⎢⎣
⎥⎦ 2 x 4.75 = 6.03KN / m
2
Characteristic D.L.
Characteristic L.L. =12.66x1.5/4.5
Design Load = 1.4x16.94+1.6x4.22
= 12.66KN
= 16.94KN
=4.22KN
=30.47KN
Reference
Calculation
Output
Bearing Capacity of the Wall:
Pa=0.982x5.74x340x3.25/5
= 1245.71KN
Pa=1245.7KN
.. The bearing capacity =1245.71 > Design load
(907.87KN)
(a) Stresses check : 1.5m wall
Bearing stress:
4.9.48x103/2x340x300
Compressive stress:
907.87x103/3250x340
Total
8.10.4.a
Wall stress:1.5x0.982x5.74/5
= 0.24N/mm2
= 0.82N/mm2
= 106N/mm2
=1.69N/mm2>1.06
(b) 1.75m wall
From cross-wall:
33.4x103/2x340x340 = 0.14N/mm2
From right wall:
30.47x103/2x300x340 = 0.15N/mm2
Additional stress due to two reactions
(30.47+33.4)=(31.94KN)
Additional stress =31.94x103/340x1750=0.054
Total stress =0.87+0.14+0.15=1.16N/mm2<1.69
Total load on 1.75m wall
=907.87x1.75/3.25+31.94=520.8KN
Equ. 3
Equ.4.1
The bearing capacity of 1.75m
=0.974x5.74x1.75x340/5=665.3KN>
The design load (520.8)
.. Design is O.K.
½
F=520.8KN
Pa=665.3KN
5- Peir No. C-7
Reference
ES2001
AS1640-74
Table 7
8,9,a
Calculation
Output
Loadings:
Equivalent D.L. from slab = 4.5x2.55
=11.48KN
Self wt of peir = 0.81x0.34x3x18
=14.87
Wt of balcony = 7.75x0.9x18x0.225
+1.75x0.90x0.02x20
=7.01
Self wt. of beam:
2.55x0.25x0.25x24+0.25x2.55x0.02x20
=4.08
Characteristic D.L.
=37.44KN
Characteristic L.L.=2.55x1.5
=3.825KN
Design Load
1.4x37.44x5+0.6x1.6x5x3.825
=280.44KN F=280.44KN
Effective height
= 3.000m
Effective thickness
= 0.34m
Slenderness ratio=3.00/0.34
=8.82
The maximum eccentricity at first floor level:
Reference
ES2001
AS1640-74
Calculation
The load from above:37.44x4
The reaction R1=
R1=37.44x1.4/2+0.7x1.6x3.825/2
R2=37.44/2=18.72
The resultant of the forces acting at x
Distance from the face P
Taking moment at face P
150x0.4+18.72x0.133+28.35x0.667
x=81.4/197
.. ex=0.413-0.400=0.013<0.047
Table 10
Table
2.14
Equ. 3
Equ. 4.1
Output
=150KN
=28.352KN
=197x
=0.413m
Ka =0.916
..The bearing capacity of the peir Pa
= 2.89.6KN Pa=289.6KN
Pa=0.976x5.74x0.34x0.81/5
..The design load
=280.44<289.6
..The design if O.K.
=============================================
Reference
Calculation
Output
Durability and fire resistance
Loading:
F=29.685KN
Ultimate bending moments:
M=FL/10=29.685x2.74/10
Reinforcement:
M=8,134KN
K=0.04<0.156
Z/d=0.953>0.95
..As =8.134x106/0.87x0.95x250x90
Use Ø 10 at 150(523mm2)
Transverse steel
Use Ø 10 at 250 (314mm2)
=8.134KNm
=438mm2
APPENDIX (D)
CONCRETE SKELTON
BENDING MOMENTS AND SHEAR FORCES CALCULATION
APPENDIX (E)
CONCRETE SKELTON
DESIGN OF SELECTED SLABS
Typial Floor slab
Two Way Slab
Slab (C-E)-(4-5)
4.25m
Reference
BS8110
Table 3.3
Table 3.4
Calculation
Durability
Resistance:-
and
Output
Fire
Cover = 20mm
fire resistance is
O.K.
Nominal cover for mild condition of exposure
= 20mm
Maximum fire resistance of 125mm slab with
20mm cover >1h
Loadings:-
Self wt. Of slab =0.125x24= 3.00 KN/m2
Finish
= 1.50KN/ m2
Characteristic dead load = 4.50KN/ m2
Characteristic imposed load= 1.50KN/m2
Design load=1.4x4.5+1.6x1.5=8.70KN/m2
gk = 4.5 KN/ m2
qk= 1.5 KN/ m2
F = 8.7KN/ m2
Ultimate bending Moments:Lx = 4.25m, Ly = 5.75m
Interior panel:Sec.2.2
Negative moment at continuous edges:Sec.4.4
(AppendixD) Mx1 = 9.0 , Mx2 = 9.2 KN/m
My1 = 5.2, My2 = 5.4 KN/m
Sec.2.2
Positive moment at mid-span
Sec.4.4
(AppendixD) Mx = 7.57 KN m/m
My = 3.59 KN m/m
Shear forces:-
Sec.2.2
V sx1 = 14.4V sx2 = 14.4KN
Sec.4.4
(ApepndixD) V sy1 = 5.7, Vsy 2 = 5.6 KN
Reinforcements:b = 1000mm
d = 125-20-10-10/2 = 90mm
b=1000mm
d = 90mm
At Continuous edge:Mx=9.2KN m/m
k = 0.0444<0.156
z/d=0.94665
Reference
BS8110
Calculation
Output
..As=9.20x106/0.87x0.9467x250x90=497 mm2
.. Use Ø10 at 150mm (523 mm2)
My2 = 5.4 KN m/m
K = 0.0266
Z/d = 0.97 > 0.95
Top Ø10 at 150
(523 mm2/m)
.. As = 5.4x106/0.87x0.95x250x90=291mm
Top Ø10 at 250
(314 mm2/m)
.. Use Ø 10 at 250mm (314mm2)
At mid span:Mx = 7.57 KN m/m
k = 0.037
Bottom Ø10 at
2
Z/d = 0.95
6
2 175(449 mm /m)
As = 7.57x10 /0.87 x 0.95x 2.50x90=407mm
.. Use Ø10 175 (449 mm2)
My = 3.59 KN/m
K = 0.0177 < 0.156
Z/d = 0.98>0.95
As=3.59x106/0.87x0.95x250x90=193mm2
.. Use Ø10 at 250mm (314 mm2)
Table 3.8
Shear:-
Vsx1 = Vsx2 =14.4KN,
υ = 14.4x103/103x90 = 0.16<4 N/mm2
100As/bd = 100x523/103x90 = 0.58
.. υc = 0.7 > 0.16 N/mm2
Vsy1 = 5.7
υ = 5.73/103/1x103/103x90 = 0.063<4.0
N/mm2
100As/bd=100x314/103x90=0.35
Bottom Ø10 at
250(314 mm2 /m)
Shear is O.K.
Shear resistance
is O.K.
Shear is O.K.
Shear resistance
is O.K.
.. υc = 0.59 > 0.063 N/mm2
Table 3.9
Table 3.10
Reference
BS8110
3.12.11.2.7
Deflection:Basis span/effective depth ratio = 26
M/bd2 =7.57x106/103x902=0.935
.. Modification factor = 1.97
.. Allowable L/d = 26x1.97 = 51.22
Actual L/d = 4250/90 = 47.22 < 51.22
.. Deflection is O.K.
Calculation
Cracking:
h = 125 < 250mm
Clear distance between bars:= 250-10 = 240mm
3d = 3x90 = 270> 240
No further check required
.. cracking is O.K.
Deflection
O.K.
is
Output
Crack width is
O.K.
Typical Floor Slab Design
Two way slab
Slab (D– E)-(2-4)
4.25m
Reference
BS8110
Calculation
Output
Ultimate bending moments:Lx = Ly = 4.25m
Interior panel
Sec 2.2
Negative moment at continuous edges
Sec 3.3
(AppendixD) Mx1= 5.4/m , Mx2 = 9.0 KNm/m
My1 = 3.7 KNm/m , My2 = 8.5KNm/m
Sec 2.2
Positive moment at mid-span:Sec 3.3
(AppendixD) Mx = 4.16KNm/m
My = 5.16 KNm/m
Shear Forces:
Vsx1 = 9.1KN , Vsx2 = 10.2KN
Sec 2.2
Vsy1 = 9,7KN , Vsy2 = 10.8KN
Sec 3.3
Reinforcements:b = 1000 ,
d = 90mm
At continuous edges:Mx2 = 9.0KNm/m
k = 0.0444 < 0.156
z/d = 0.948
Top Ø 10 at 150
.. As = 9.0x106/0.87x0.948x250x90=485mm2 (523mm2/m)
.. Use Ø 10 at 150 (523 mm2)
My2 = 8.5KNm/m
K=0.042 < 0.156
Z/d = 0.95
.. As = 8.5x106/0.87x0.95x250x90=457mm2
.. Use Ø 10 at 150 (523mm2)
At mid span:-
Mx = 4.16 KNm/m
Bottom Ø 10 at
k = 0.0205 < 0.156
250
2
z/d = 0.976 > 0.95
/m)
B.W(314m
.. As = 4.16 x 106/0.87x0.95x250x90 =
224mm2
.. Use Ø 10 at 250 (314mm2)
Reference
BS8110
Table 3.8 Shear:
Table 3.9
Calculation
Output
Vsx2 = 10.2KN
υ = 10.2x103/103x90 = 0.1133<4.0N/mm2
100 As/bd = 100x523/103x90 = 0.58
.. υc = 0. 70 N/mm2 > 0.1133 N/mm2
Shear is O.K.
Vsx2=10.8KN,
v =10.8x103/103x90=0.12<4.0N/mm2
100As/bd=100x523/103x90=0.58
υc = 0. 70 N/mm2 > 0.12 N/mm2
Shear is O.K.
Shear resistance is
O.K.
Shear Resistance
is O.K.
Deflection:-
Basic span/effective depth ratio = 26
2
6
3
2
Table 3.10 M/bd = 4.82x10 /10 x90 = 0.51
.. Modification factor
= 2.0
.. Allowable L/d = 26x2 = 52
Actual L/d = 4250/90
= 47.22<52
.. Deflection is O.K.
M/bd2 = 5.16x106/103x902
.. Modification factor
.. Allowable = 26x2
Actual L/d =
.. Deflection is O.K.
Deflection is O.K.
= 0.637
= 2.0
= 52
= 47.2<52
3.12.11.2.7 Cracking :
h = 125 < 250mm
clear distance between bars = 250-10 = 240mm
3d = 3x90 = 270 > 240
No further check required
.. cracking is O.K.
Crack
O.K.
width
is
Typical Floor Slab Design
Two way slab
Slab (B-C) – (4-5)
4.25
Reference
BS8110
Calculation
Output
Ultimate bending moments:Lx = 2.75, Ly = 4.25m
Interior Panel
Negative moment at continuous edges
Sec 1.1
Mx1 = 4.4, Mx2 = 5.4 KN/m
Sec 4.4
(AppendixD) My1 = 2.8 , My2 = 2.2KNm/m
Sec. 1.1
Sec.4.4
(AppendixD)
Positive moment at mid-span:Mx = 3.43KNm/m
My = 0.98 KNm/m
Shear Forces:
Vsx1 = 106KN , Vsx2=10,5KN
Vsy1 = 2.9KN , Vsy2 = 2.6KN
Reinforcements:b = 1000 ,
d = 90mm
At continuous edges:Mx2 = 5.4KNm/m
k = 0.0267
z/d = 0.97 > 0.95
.. As = 5.4x106/0.87x0.95x250x90=291mm2
.. Use Ø 10 at 175 (314 mm2)
My1 = 2.8KNm/m
.. Use Ø 10 at 250 (314mm2)
At mid span:Mx = 3.43 KNm/m
.. Use Ø 10 at 250 (314mm2)
My = 4.73KNm/m
b = 1000
d = 90
Top Ø 10 at 250
(314mm2/m)
Top Ø 10 at 250
(314mm2/m)
Bottom Ø10 at 20
(393mm2/m)
Bottom Ø10 at
250 (314mm2)
.. Use Ø 10 at 250(314mm2)
Reference
BS8110
Table 3.8 Shear:
Calculation
Vsx2 = 10.6KN
υ = 10.6x103/103x90 = 0.11782<4.0N/mm2
100 As/bd = 100x314/103x90 = 0.35
.. υc = 0.59 N/mm2 > 0.1178 N/mm2
Vsx1= 2.9KN
υ = 2.9x103/103x90 = 0.0.032N/mm2 <4.0
.. υc = 0.59 N/mm2 > 0.032 N/mm2
Table 3.9
Output
Shear is O.K.
Shear resistance is
O.K.
Deflection:-
Basic span/effective depth ratio = 26
M/bd2 = 3.43x106/103x90 = 0.423
Table 3.10 .. Modification factor = 2.0
.. Allowable L/d = 2x26 = 52
Actual L/d = 2750/90=3056<52
.. Deflection is O.K.
Cracking :
3.12.11.2.7 h = 125 < 250mm
clear distance between bars = 250-10 = 240mm
3d = 3x90 = 270 > 240
No further check required
.. cracking is O.K.
L/D ratio is O.K.
Crack
O.K.
width
is
Typical Floor Slab
Two-way Slab
Slab (B-C)-(2-3)
4.25m
Reference
BS8110
Calculation
Output
Ultimate bending moments:Lx = 2.25, Ly = 4.25m
Interior Panel
Sec.1.1
Negative moment at continuous edges
Sec.3.3
(AppendixD) Mx1= 3.6KNm/m , Mx2 = 4.5 KNm/m
My1 = 1.2, My2 = 3.7 KNm/m
Sec.1.1
Positive moment at mid-span:Sec.3.3
(AppendixD Mx = 1.98KNm/m
My = 0.13 KNm/m
Shear Forces:
Vsx1 = 8.9 , Vsx2=9.5KN
Sec.1.1
Vsy1 = 1.3 , Vsy2 = 1.9KN
Sec.3.3
(AppendixD
Reinforcements:At Continuous edge:
Mx2 = 4.5KNm/m
.. Use Ø 10 at 250 (314 mm2)
My2 = 3.7KNm/m
.. Use Ø 10 at 250mm (314mm2)
At mid span:-
Mx = 1.98 KNm/m
.. Use Ø 10 at 250 (314mm2)
My = 0.13KNm/m
.. Use Ø 10 at 250mm (314mm2)
b = 1000
d = 90
Top Ø 10 at 150
(523mm2/m)
Top Ø 10 at 175
(449mm2)
Bottom Ø10 at
200 (393mm2/m)
Reference
BS8110
Table 3.8 Shear:
Calculation
Vsx2 = 9.5KN
υ = 9.5x103/103x90 = 0.106<4.0N/mm2
100 As/bd = 100x314/103x90 = 0.35
.. υc = 0. 59 N/mm2 > 0.106 N/mm2
Output
Shear is O.K.
Shear resistance is
O.K.
Vsx1 = 1.9KN
υ = 1.9x103/103x90 = 0.021N/mm2<4.0mm2
υc = 0. 59 > 0.021 N/mm2
Table 3.9
Deflection:-
Basic span/effective depth ratio = 26
2
6
3
Table 3.10 M/bd = 1.98KNm/mx10 /10 x90 = 0.244
.. Modification factor
= 2.0
.. Allowable L/d = 2x26 = 52
Actual L/d = 2750/90=3056 < 52
.. Deflection is O.K.
Cracking :
h = 125 < 250mm
3.12.11.2.7 Clear distance between bars = 250-10 = 240mm
3d = 3x90 = 270 > 240
L/D ratio is O.K.
No further check required
.. Cracking is O.K.
Crack
O.K.
width
is
APPENDIX (F)
CONCRETE SKELTON
DESIGN OF BEAMS
Typical Floor
Beam 1-7/B
2.0
4.25
4.25
4.25
4.25
2.0m
125
375
250
Ref.
Calculation
Out put
BS8110
Table
Cover=20mm
Durability and Fire Resistance
3.3
Fire resistance
Nominal
cover
for
mild
condition
of
exposure
=20mm
Table
is O.K.
Fire
resistance
for
250mm
wide
beam
with
30mm
cover
3.4
to main reinforcement >1hr
Loadings:-
Span No. (1)
L = 2.0m
Self wt. Of beam:0.375x0.25x24+0.375x0.02x20
Self wt. Of wall:
2.625x0.21x15+0.05x2.625x20
Self wt. of facing wall
Equivalent D.L. from slab
= 2.4KN/m
=9.32KN/m
= 5.91KN/m
=2.81KN/m
Characteristic D.L.
=20.44KN/m
Characteristic L.L.
= 0.94KN/m
Span No. 2:
L = 4.25m
Self wt. Of beam
=2.40KN/m
Self wt. Of wall
=9.32KN/m
Self wt. of facing wall
Equivalent D.L. from slab:
4.5+4.5x2.25x5/16
Characteristic D.L.
= 5.91KN/m
= 7.66KN/m
= 25.29KN/m
Equivalent L.L.=1.5+1.5x2.25x5/16
Span No. 3
Self wt. Of beam
L = 4.25m,A=3.95m2
= 2.55KN/m
.375x0.25x24+2x0.375x0.025x20+0.25x0.02x20=
2.65KN/m
Equivalent D.L.from slab= 4.5+(1+α- α2)F/L
4.5+(1+0.32-0.1)4.5x3.95/4.25
Characteristic D.L.
= 9.60KN/m
= 12.25KN/m
Characteristic L.L. =1.5+1.5x1.22x3.95/4.24 =3.2KN/m
L=4.25m,A’=3.93
Span No. 4:
Self wt. of beam = 2.65KN/m
Equivalent D.L=4.5+8.61x1.22x3.95/4.25 = 14.26KN/m
Characteristic D.L.
= 16.91KN/m
Equivalent L.L.=
1.5+1.5x1.22x3.95/4.25
= 3.2KN/m
Span No. (5)
L=4.25m, A’ = 3.93
Self wt. of beam
= 2.65KN/m
Equivalent D.L .=4.5+8.61x1.22x3.95/4.25 =14.26KN/m
Characteristic D.L.
= 16.91KN/m
Equivalent L.L.=1.5+1.5x1.22x3.95/4.25
= 3.2KN/m
Span No. (6)
Self wt. of beam
Equivalent D.L.
Characteristic D.L.
Characteristic L.L.
L=2.0m
Point load No. (1)
Self wt. of beam = (2+2.125)1.85
Self wt of wall = 2.125x9.76
Self wt. of facing brick=2.125x5.91
Self wt of balcony =2x3.835
Equivalent D.L. from slab=
4.5x2.125+4.5x2x5/16
Characteristic D.L.
Equivalent L.L.=
1.5x2.125+1.5x2x5/16
= 2.65KN/m
= 2.81KN/m
= 5.46KN/m
= 0.94KN/m
=7.63KN
= 20.740KN
= 12.558KN
= 7.670KN
= 12.373KN
= 60.971KN
= 4.128KN
Point load No. (2)
Characteristic D.L.
Characteristic L.L.
= 56.3KN
= 6.3 KN
Point Load No. (3)
Self wt. of beam
Self wt. of balcony =3.835x4.125
Equivalent D.L. from slab
Characteristic D.L.
Equivalent L.L.
= 7.63KN
=15.82KN
= 12.373KN
= 35.823KN
= 4.128KN
Typical Floor
Beam (1-4)-D
2.0
4.25
125
375
250
Ref.
Calculation
Out put
Table
Cover=20mm
Durability and Fire Resistance
3.3
Fire resistance
Nominal
cover
for
mild
condition
of
exposure
=20mm
Table
is O.K.
Fire
resistance
for
250mm
wide
beam
with
30mm
cover
3.4
to main reinforcement >1hr
Loadings:-
Span No. (1)
L = 2.0m
Self wt. Of beam:0.25x0.37x24+0.02x0.375x20
Self wt. Of wall
Self of facing wall
=2.40KN/m
=9.32KN/m
=5.91KN/m
Characteristic D.L.
=17.63KN/m
Equivalent L.L.
=zero
Span No. 2
Self wt. Of beam:0.26x0.375x24+0.04x0.375x20
Self wt. Of wall
Equivalent D.L. from slab
4.5x4.25x5/16+4.5x2.25x5/16
Characteristic D.L.
=2.55KN/m
=9.32KN/m
=9.14KN/m
=21.01KN/m
Equivalent L.L.
1.5x4.25x5/16+1.5x2.25x5/16
=3.05KN/m
Point Load No. 1:
Load from beam
2.00x1.60
2.00x1.85
=3.29KN
=3.70KN
Wt from walls=9.76x2.00
=19.52KN
Wt from facing wall=5.91x2.00
= 11.82KN
Wt from balcony =3.835x2.00
= 7.67KN
D.L. from slab=4.5x4.25
=19.13KN
Total D.L.
=65.04KN
Total L.L.=1.5x4.25
=6.375KN
Point Load No. 2
D.L. from beamB-D/3=26.49x2.125 =56.29KN
L.L. from beam B-D/3=2.98x2.125 =6.33KN
Design of Beams
Typical Floor
Beam (A-I) -2
2.0
4.25
4.25
4.25
4.25
2.0m
125
375
250
Ref.
Calculation
Out put
BS8110
Table
Cover=20mm
Durability and Fire Resistance
3.3
Fire resistance
Nominal
cover
for
mild
condition
of
exposure
=20mm
Table
is O.K.
Fire
resistance
for
250mm
wide
beam
with
30mm
cover
to
3.4
main reinforcement >1hr
Loadings:-
Span No. (1)
L = 2.0m
Self wt. Of beam:Equivalent D.L. from slab
= 2.65KN/m
= 2.81KN/m
Characteristic D.L.
=5.46KN/m
Characteristic L.L.
= 0.94KN/m
Span No. 2:
L = 4.25m
Self wt. Of beam
=2.65KN/m
Equivalent D.L. from slab:
3.52x4.5x1.19/4.24+4.5
Characteristic D.L.
= 8.93KN/m
= 11.58KN/m
Equivalent L.L.=1.5+1.5x3.52x1.19/4.25
Span No. 3
Self wt. Of beam
Self wt of wall
Self wt. of facing wall
Equivalent D.L.from slab=
= 2.98KN/m
L = 4.25m
=2.4KN/m
=9.32KN/m
= 5.91KN/m
4.5+4.5x4.25x5/16
Characteristic D.L.
= 10.48KN/m
= 28.11KN/m
Characteristic L.L. =1.5+1.5x4.25x5/16
Point load No. (1) & (2)
Self wt. of beam = 4.125x1.85
Self wt of balcony =4.125x3,835
Equivalent D.L. from slab=
4.50x2.125+4.5x2x5/16
Characteristic D.L.
Equivalent L.L.=
1.5x2.125+1.5x2x5/16
=3.50KN/m
=7.63KN
= 15.82KN
= 12.373KN
= 35.823KN
= 4.13KN
Typical Floor
Beam (A-I) -4
2.0
4.25
4.25
4.25
4.25
2.0
375
260
Ref.
Table
3.3
Table
3.4
Calculation
Out put
Durability and Fire Resistance
Cover=20mm
Nominal cover for mild condition of exposure =20mm Fire resistance
Fire resistance for 250mm wide beam with 30mm if O.K.
cover to main reinforcement >1hr
Loadings:-
Span No. (1)
L = 2.0m
Self wt. Of beam:0.25x0.375x24+0.02x0.375x20
Self wt. Of wall:
2.625x0.21x15+0.02x2.625x20
Self wt. Of facing wall
Characteristic D.L.
=2.40KN/m
=9.32KN/m
= 5.91KN/m
=17.63KN/m
Equivalent L.L.
Span No. 2
= Zero
L = 4.75m
Self wt. Of beam
0.25x0.375x24+0.04x0.375x20
Self wt. Of wall
2.625x0.21x15+0.05x2.625x20
Equivalent D.L.:
4.5+2.75x4.50x5/16
=2.55KN/m
=10.90KN/m
= 12.68KN/m
Characteristic D.L.
= 26.13KN/m
Equivalent L.L.= 1.5+1.5x2.75x5/16
= 2.79KN/m
Span No. 3
L = 4.25m
Self wt. Of beam
= 2.55KN/m
Self wt. Of wall
=10.90KN/m
Equivalent D.L.
4.5x4.25x5/16+4.5x1.23x7.7/5,75
=13.39KN/m
= 26.84KN/m
Equivalent L.L.
1.5x4.25x5/16+1.5x1.23x7.7/5.75
Point Load No. 1:
Self wt. Of beam 2.00x1.85
Self wt. Of beam 2.00x1.60
Self wt. Of wall 2.00x9.76
Self wt. Of facing wall 2.00x5.91
Self wt. Of balcony =2.00x3.835
Equivalent L.L.= 1.5x4.25
Point Load No. (2):
D.L. from Beam 4-6/C
L.L. from Beam 4-6/C
=4.46KN/m
=3.70KN
= 3.20KN
= 19.52KN
=11.82KN
=7.67KN
= 6.38KN
= 52.13KN
= 7.84KN
APPENDIX (G)
CONCRETE SKELTON
DESIGN OF SELECTED COLUMNS
DESIGN OF REINFORCED CONCRETE WALL
Column Design
Column No. B-2
Ref.
BS8110
Table
3.5
Table
3.6
Calculations
Output
Min. cover to
Durability & Fire Resistance:
link
20mm
Nominal cover for mild condition of exposure=20mm Fire (used
30m
resistance for 250x500 column with 20mm cover>1hr
fire resistance
is O.K.
Loadings
Beam Loads (KN)
Beam
Location
Column Design Loads (KN)
Total
Imposed
II
Read
I
II
III
I
III
I
A-1/2
156.0
138.7
119.9
16.16
143.64
1-7/B
155.9
139.4
119.5
16.16
143.64
S.W
14.0
14.0
14.0
---
14.0
Total
325.9
291.8
252.4
32.32
309.28
A-I/2
127.9
108.0
96.6
20.68
107.40
1-7/B
312.5
273.0
245.6
26.24
288.40
14
14.0
14.0
14.0
---
14.0
780.3
686.8
609.5
79.04
711.08
A-I/2
127.9
108.0
96.6
20.48
107.4
1-7/B
312.5
273.0
245.5
26.24
288.9
S.W.
14.0
14.0
14.0
---
14.0
Total
1234.7
1081.8
965.6
125.76
1120.88
A-I/2
127.9
108.0
96.6
20.48
107.4
1-7/B
312.5
273.0
245.5
26.24
288.9
S.W.
14.0
14.0
14.0
---
14.0
Total
1689.1
1476.8
1321.7
172.48
1530.68
A-I/2
127.9
108.0
96.5
20.68
107.40
1-7/B
312.5
273.0
245.5
26.24
288.18
14.0
14.0
14.0
---
14.0
Load
Case
Roof
4th
S.W.
Total
3rd
2nd
1st
S.W.
II
III
Total
2143.5
1871.8
1677.8
219.2
1940.48
Total design loads
Case (I) = 1940.48+0.6x219.2=2072 KN
Case (II) = 1871.8KN
Case (III) = 1677.8KN
Moments
Floor Top
No
Bottom
I
II
III
I
II
III
M(x)
---
---
---
-21.0
-27.9
-7.5
M(y)
---
---
---
-34.8
-40.4
-17.2
-
-27.9
-7.5
-40.4
-17.2
-27.9
-7.5
-40.4
-17.2
-27.9
-7.5
Loading
Case
Roof
4th
M(x)
21.0 27.9 7.5
21.0
M(y)
34.8 40.4 17.2
34.8
3rd
M(x)
21.0 27.9 .7.5
21.0
M(y)
34.8 40.4 17.2
34.8
2nd
M(x)
21.0 27.9 7.5
21.0
M(y)
34.8 40.4 17.2
-
-40.4
-17.2
-22.1
-22.1
-14.9
-14.9
34.8
1st
M(x)
21.0 27.9 7.5
22.1
M(y)
34.8 40.4 17.2
14.9
Column No. D-2
Calculations
Output
Durability and fire resistance:
Min. cover to
20mm
Table Nominal cover for mild condition of exposure=20mm Fire link
resistance for 250x500 column with 20mm cover>1hr
(used 30m fire
3.3
resistance
Table
3.4
Ref.
Loadings
Beam Loads KN
Beams
Locations
Column Design Loads KN
Total
Imposed
II
Dead
I
II
III
I
III
I
A-1/2
66.0
44.5
61.1
16.16
55.14
1-4/D
183.7
164.9
138.9
20.8
168.14
S.W
14.0
14.0
14.0
---
14.00
Total
263.7
223.4
214.0
36.96
237.28
A-I/2
126.7
107.6
94.6
21.0
105.7
1-4/D
311.4
267.7
254.3
29.28
282.2
S.W.
14.0
14.0
14.0
--
14.0
Total
715.8
612.7
576.9
87.24
639.7
A-I/2
126.7
107.6
94.6
21.0
105.7
1-4/D
311.4
267.7
254.3
29.28
282.2
S.W.
14.0
14.0
14.0
---
14.0
Total
1167.9
1002
939.8
137.52
1041.6
A-I/2
126.7
107.6
94.6
21.0
105.7
1-4/D
311.4
267.7
254.3
29.28
282.2
S.W.
14.0
14.0
14.0
---
14.0
Total
1620
1301.3
1302.7
187.80
1443.5
A-I/2
126.7
107.6
94.6
21.0
105.7
1-4/D
311.4
262.7
254.3
29.28
282.2
S.W.
14.0
14.0
14.0
---
14.0
Total
2072.1
1780.6
1665.6
238.08
1845.4
Load
Case
Roof
4th
3rd
2nd
1st
II
III
Total design loads
Case (I) = 1845.4+0.6x238.08=1988.2KN
Case (II) = 1780.6KN
Case (III) = 1665.6
Moments
Floor No.
Top
Bottom
I
II
III
I
II
III
M(x)
---
---
---
-21.0
-29.7
-5.9
M(y)
---
---
---
12.9
18.1
3.6
Load Case
Roof
4th
M(x) -
-
-5.9
-21.1
-29.70
-5.9
M(y) 12.9 18.1 3.6
12.9
18.1
3.6
M(x) -
-21.1
-29.7
-5.9
M(y) 12.9 18.1 3.6
12.9
18.1
3.6
M(x) -
-21.1
-29.7
-5.9
M(y) 12.9 18.1 3.6
12.9
18.1
3.5
M(x) -
-23.7
-23.7
-23.7
5.8
5.8
5.8
21.1 29.7
3rd
-
-5.9
21.1 29.7
2nd
-
-5.9
21.1 29.7
1st
-
-5.9
21.1 29.7
M(y) 12.9 18.1 3.6
Column No. B-4
Ref.8110
Table
3.3
Table
3.4
Calculations
Durability and fire resistance:
Nominal
cover
for
mild
condition
of
exposure=20mm
Fire resistance for 250x500 column with 20mm
cover>1hr
Output
Min cover to
link
20mm
(used
30m
fire resistance
is O.K.
Loadings
Beams
Locations
Beam Loads KN
Total
I
II
III
Column Design Loads KN
Imposed
Read
I
II III I
II
A-1/4
159.5
140.3
123.5
16.8
145.88
1-7/B
73.9
52.1
66.7
16.64
62.86
S.W
14.0
14.0
14.0
---
14.00
Total
247.4
206.4
204.2
33.44
222.74
A-I/4
301.2
264.1
233.9
27.2
295.6
1-7/B
147.0
90.1
144.5
32.9
122.6
14
14.0
14.0
14.0
--
14.0
709.6
574.6
596.6
93.5
634.94
A-I/4
301.2
264.1
233.9
272.0
275.6
1-7/B
142.0
90.1
144.5
32.9
122.6
S.W.
14.0
14.0
14.0
--
14.0
Total
1171.8
942.8
989
153.6
1047.14
A-I/4
301.2
264.1
233.9
27.20
275.6
1-7/B
147.0
90.1
144.5
32.9
122.6
S.W.
14.0
14.0
14.0
--
14.0
Total
1634
1311
1381.4
213.7
1459.34
A-I/4
301.2
264.1
233.9
27.20
275.6
1-7/B
147.0
90.1
144.5
32.9
122.6
S.W.
14.0
14.0
14.0
--
14.0
Total
2096.2
16792
1773.8
2738
1871.54
Load Case
Roof
4th
S.W.
Total
3rd
2
1
nd
st
III
Total design loads
Case (I) = 1871.54+0.6x273.8=2036 KN
Case (II) = 1679.2KN
Case (III) = 1773.8.8KN
Moments
Floor No.
Top
Bottom
I
II
III
I
II
III
M(x)
---
---
---
-25.3
-32.0
-10.4
M(y)
---
---
---
-6.6
7.2
18.0
Load Case
Roof
4th
M(x) -
-
-10.4
-25.3
-32.0
-10.4
25.3 32.0
3rd
M(y) -6.6
7.2
18.0
-6.60
7.2
18.0
M(x) -
-
-10.4
-25.3
-32.0
-10.4
25.3 32.0
2nd
M(y) -6.6
7.2
18.0
-6.60
7.2
18.0
M(x) -
-
-10.4
-25.3
-32.0
-10.4
25.3 32.0
1st
M(y) -6.6
7.2
18.0
-6.60
7.2
18.0
M(x) -
-
-10.4
0.3
0.3
0.3
18.0
-3.9
-3.9
-3.9
25.3 32.0
M(y) -6.6
7.2
Column No. D-4
Ref.
BS8110
Table
3.3
Table
3.4
Calculations
Output
Durability & Fire Resistance:
Nominal cover for mild condition of exposure=20mm
Fire resistance for 250x500 column with 20mm
cover>1hr
Min. cover to link
20mm (used 30m
fire resistance is
O.K.
Loadings
Bearing Locations
Column Design Loads KN
Beam Loads KN
Total
Imposed
II
Dead
I
II
III
I
III
I
A-1/4
75.7
52.3
69.4
16.80
64.4
1-4D
78.5
54.2
72.1
19.36
66.92
S.W
14.0
14.0
14.0
---
14.00
Total
168.2
120.5
155.5
36.16
A-I/4
204.9
145.0
183.8
33.1
1-4/D
74.9
29.1
90.6
---
28.0
S.W.
14.0
14.0
14.0
---
---
Total
462.0
308.6
443.9
A-I/4
204.9
145.0
183.8
1-4/D
74.9
29.1
90.6
S.W.
14.0
14.0
14.0
Total
755.8
496.7
732.3
A-I/4
204.9
145.0
183.8
1-4/D
74.9
29.1
90.6
S.W.
14.0
14.0
14.0
Total
1049.6
684.8
1020.7
A-I/4
204.9
145.0
183.8
1-4/D
74.9
29.1
90.6
S.W.
14.0
14.0
14.0
Total
1343.4
872.9
1309.1
II
III
Load
Case
Roof
4
th
3rd
2nd
1st
173.5
33.1
62.7
14.0
14.0
173.5
28.0
62.7
14.0
33.1
14.0
173.5
28.0
62.7
14.0
33.1
14.0
173.5
28.0
62.7
14.0
14.0
Total design loads
Case (I) = 1343.4 KN
Case (II) = 872.9KN
Case (III) = 1309.1KN
Moments
Floor No.
Top
Bottom
I
II
III
I
II
III
M(x)
---
---
---
-8.4
0.6
-13.6
M(y)
---
---
---
1.9
17.6
-14.2
M(x) -8.4
0.6
-13.6
-8.4
0.6
-13.6
M(y) 1.9
17.6 -14.2
1.9
17.6
-14.2
M(x) -8.4
0.6
-13.6
-8.4
0.6
-13.6
M(y) 1.9
17.6 -14.2
1.9
17.6
-14.2
M(x) -8.4
0.6
-13.6
-8.4
0.6
-13.6
M(y) 1.9
17.6 -14.2
1.9
17.6
-14.2
M(x) -8.4
0.6
-13.6
-3.9
-3.9
-3.9
M(y) 1.9
17.6 -14.2
0.3
0.3
0.3
Load Case
Roof
4th
3rd
2nd
1st
Reinforced Concrete Wall Design
BS 8110 ref.
Table 3.3
Calculations
Effective height Le=0.875x2.625=2.297
Le/h=2.297/0.15=15.3>12
Durability and Fire Resistance:
Nominical cover for mild condition of
exposure = 20mm
Fire Resistance of 150mm Wall >1hr
Fig. 3.4
Output
150mm
thick
slender wall
Cover = 20mm
Fire resistance is
O.K.
Loading:
Table 3.25
Self wt.of wall =0.15x5x3.125x24=56.3KN
Load from
roof=0.20x24x1.9x1.9/4x1.9=02.3KN
Finishing =1.5x1.9x1.9/4x1.9=00.7KN
Load from lift=wt. Of all machinery +twice
max. suspended load
Wt. Of machine = 350kg
Suspended load = 1.5(car wt. + 630)
= 1.5(750+650+630)=2070
Load from lift=350+2070x2=4490kg
Factor of safety = 7
Design load from lift =
7x4490x9.81/1000=308KN
Load per meter = 308/4x1.9 =40.6KN
..Total design load =
56.3+2.3+0.7+40.6=100KN/m
The wall support its self wt. and the load
from roof of well and the machine lift .
Reinforcement:
Reinforced with nominal steel
Vertical reinforcement
Minimum vertical reinforcement
Area=0.25%x1000x150=300mm2/m
Use T12 at 250 each face
( 904mm2/m )
Horizontal reinforcement:
Minimum horizontal reinforcement area =
300mm2
T12 at 250
Use T10 at 200mm each face =786mm2/m
T10 at 200mm
APPENDIX (H)
CALCULATIONS
CALCULATIONS OF REINFORCEMENTS BARS
BREAKDOWN OF RATE ESTIMATES
ABSTRACT AND CALCULATION OF QUANTITIES
Total Reinforcement /m3
(1)
Slab:
The steel in one metre square = 22m
22x0.616 = 13.552 kg
The amount of steel/m3 = 13.552/0.125 = 108.5
(2)
% over lap
= 11.0
Total steel/m3
= 120kg
Beam/Appendix F
1- A-I/1
2- A-I/2
3- A-I/4
4- A-I/5
5- A-I/6
6- A-I/7
7-1 7/A
8-1-7/B
9-1-4/D
10-5-7/D
11-1-7/E
= 158
= 98
= 120
= 120
= 117
= 158
= 102
= 102
= 145
= 113
= 102
Total
=
1335
Average = 1335/11 = 125 kg/m3
(3)
Columns, (Appendix G), Fig 5.4
Column E-4 , E-5
8x3.125x2x1.578=78.9
8x3.125x3x0.888=66.6
Total
=
145.5
Stirrups:
1.60x6x3.125x0.222x2 = 13.30
1.60x8x3.125x0.222x3 = 26.60
Total
=
39.90
Total = 145.5 + 39.90 = 185.4
10% overlap
= 14.6
Total
= 200kg
200kg = [0.25x0.5x3.125x5]m3
1m3 = 200÷ 0.25x0.5x3.125x5 = 103.0kg
B-5
B-6,D-2,B-4,B-2
D-4 , D-5
D-6, E-2, E-6
= 161.0
= 139.0
= 87.0
= 126.0
Average = (2x103 + 1x161+4x139 + 2x87+3x126) / 12
= 125kg/m3
(4)
Concrete Wall
The steel in one metre square
10x0.888
12x0.616
= 8.88
= 7.39
--------= 16.27
The amount of steel/m3 = 16.27/0.15 = 108.5
10% overlap
= 11.0
Total steel/m3
= 120kg
Breakdown of Rate Estimates
Description Unit
Plaster:
For 1m2
(i) Ceiling
Cement
Sand
Labour
Site
overhead
Kg
M3
M2
M2
Quantity
Rate
Cost(DS)
Average
cost for 5
stories
7.5
0.05
1.00
1.00
500
1700
300
100
375
85
300
100
375
85
400
135
860
1000
375
85
250
50
375
85
335
70
860
900
187.5
126.0
37.5
300.0
50.0
187.5
126.0
37.5
400
70
701.0
825
187.5
126.0
37.5
200.0
50.0
187.5
126.0
37.5
270
70
601.0
700
Total
(ii) Walling
Cement
Sand
Labour
Site
overhead
Kg
M3
M2
M2
7.5
0.05
1.00
1.00
500
1700
250
50
Total
Painting
For 1m2
(i) Ceiling
Pomastic
Wall Filler
Gypsum
Labour
Site
overhead
Total
(ii) Walling
Pomastic
Wall Filler
Gypsum
Labour
Site
overhead
Total
Gallon
Gallon
Kg
M2
M2
Gallon
Gallon
Kg
M2
M2
0.0625
0.021
0.50
1.00
1.00
0.0625
0.021
0.50
1.00
1.00
3000
6000
75
300
50
3000
6000
75
200
50
Description
Brickwork
For 1m2
1 Brick thick
Brick
Cement
Sand
Labour
Site
overhead
Unit
Quantity
Rate
Cost(DS)
Average
cost for 5
stories
Number
Kg
M3
M2
M2
150
15
0.05
1.00
1.00
7.5
50
1700
400
100
112.5
750
85
400
100
1125
750
85
540
135
2460
2650
Total
(ii)
Brick
Facing
(½ brick thick)
Brick
Cement
Sand
Labour
Site overhead
Number
Kg
M3
M2
60
10
0.03
1.00
33
50
1700
700
1980
500
51
700
1980
500
51
950
M2
1.00
50
50
3281
70
3575
bag
M3
M3
Kg
M3
M3
7
1
0.50
125
1
1
2500
3500
2200
140
10000
2000
17500
3500
1100
14000
10000
2000
48100
17500
3500
1100
17500
13310
2675
55600
7
1
2500
3500
17500
3500
17500
3500
Total
R.
Concrete
(i) Beam,
Columns
Cement
Gravel
Sand
Steel bars
Labour cost
Site overhead
Total
(ii) R.C. slab
with beams
Cement
bag
Gravel
M3
Sand
Steel bars
Labour cost
Site overhead
Total
M3
Kg
M3
M3
0.50
120
1.00
2200
140
9000
2000
1100
16800
9000
2000
49900
1100
16800
12000
2675
54000
Description
Brickwork
Machine brick
(1brick thick)
Brick
Cement
Sand
Labour
Site
overhead
Total
Unit
Quantity
Rate
Cost(DS)
Average
cost for 5
stories
Number
Kg
M3
M2
M2
120
20
0.05
1.00
1.00
33
50
1700
600
100
3960
1000
85
600
100
3960
1000
85
800
135
5745
6000
Section (A)
Loadbearing Walls
Item
No.
Wall
No.
Dimensions
Width Height
Opening
Width Height
0.90
Wall
thick
brick
1
---
-----
Quality
1 Brick
m2
3.15*
1
1-4/A
3.50
2
4-5/A
3
Quality
1½ B m2
4.25
3.00
1½
---
-----
-----*
12.75
5-6/A
4.25
3.00
1½
---
-----
-----*
12.75
4
6-7/A
1.65
0.90
1
---
-----
1.485*
-----
5
1-3/B
4.25
3.00
1½
1.0
2.10
-----
10.65
6
3-4/B
1.775
3.00
1½
----
-----
-----*
5.325
7
5-6/B
2.50
3.00
1
----
-----
7.5
-----
8
3-4/C
1.775
3.00
1
0.8
2.1
3.645
-----
9
4-5/C
3.95
3.00
1
---
-----
11.85
-----
10
5-6/C
3.95
3.00
1
---
-----
9.225
-----
11
1-2/D
1.65
3.00
1½
---
-----
-----
4.95
12
2-4/D
3.95
3.00
1
1.00
2.1
9.75
-----
13
5-6/D
3.95
3.00
1
---
-----
11.85
14
1-2/E
1.65
3.00
1
-----
-----
4.95
-----
15
2-4/E
3.95
3.00
1
-----
-----
11.85
-----
16
4-5/E
3.95
3.00
1
-----
-----
11.85
-----
17
5-6/E
3.95
3.00
1
-----
----
11.85
-----
18
1-2/F
1.65
3.00
1½
-----
----
---
4.95
19
2-4/F
3.95
3.00
1
1.0
2.10
9.75
-----
20
5-6/F
3.95
3.00
1
-----
-----
11.85
----
21
3-4/G
1.775
3.00
1
0.80
2.10
3.645
-----
22
4-5/G
4.00
3.00
1
---
-----
12.00
-----
23
5-6/G
3.95
3.00
1
1.25
2.1
9.225
-----
24
5-6/G
2.50
3.00
1
-----
-----
7.50
-----
25
1-3/H
3.95
3.00
1½
1.0
2.10
-----
9.75
26
3-4/H
1.75
3.00
1½
-----
-----
-----
5.10
27
1-4/I
3.50
0.90
1
-----
-----
3.15
-----
28
4-5/I
4.25
3.00
1½
-----
-----
-----
12.75
-----
29
5-6/I
4.25
3.00
1½
-----
-----
-----
12.75
30
6-7/I
2.00
0.90
1
-----
-----
1.80
-----
No.
Wall No.
Dimensions
Thickness
Brick
1
A-B/1
Width
W
1.65
2
B-D/1
4.25
3
D-E/1
4
Height
h
0.90
Wall
1B
Reduction
b
h
Wall
1.5B
1
---
---
1.485
---
3.00
1½
1.5
1.2
---
10.95
2.65
0.90
1
---
---
2.385
---
E-F/1
2.65
0.90
1
---
---
2.385
---
5
F-H/1
4.25
3.00
1½
1.5
1.2
---
10.95
6
H-I/1
1.65
0.90
1
---
---
1.485
---
7
D-E/2
4.25
3.00
1½
1.0
2.10
---
10.65
8
E-F/2
4.25
3.00
1½
1.0
2.10
---
10.65
9
B-D/3
4.25
3.00
1
1.0
2.10
10.65
---
10
F-H/3
4.25
3.00
1
1.0
2.10
10.65
---
11
A-B/4
1.65
3.00
1½
---
---
---
4.95
12
B-D/4
4.25
3.00
1
1.25
3.0
9.00
---
13
D-E/4
4.25
3.00
1½
---
---
---
12.75
14
E-F/4
4.25
3.00
1½
---
---
---
12.75
15
F-H/4
4.25
3.00
1
1.25
3.0
9.00
---
16
H-I/4
1.65
3.00
1½
---
---
---
4.95
17
A-D/5
6.25
3.00
1½
1.50
3.00
---
15.00
1.25
3.00
18
D-E/5
4.25
3.00
1½
1.5
3.0
---
8.25
19
E-F/5
4.25
3.00
1½
1.5
3.0
---
8.25
20
F-I/5
6.25
3.00
1½
1.50
3.0
---
15.00
1.25
3.0
21
A-D/6
6.25
3.00
1½
1.25
3.00
---
15.0
22
D-E/6
4.25
3.00
1½
0.75
1.0
---
11.25
1.0
---
11.25
3.00
---
15.00
0.75
23
E-F/6
4.25
3.00
1½
0.75
0.75
24
F-I/6
6.25
3.00
1½
1.25
25
B-C/5
1.25
3.00
1
0.8
2.1
2.07
----
26
G-G’/5’
1.25
3.00
1
0.8
2.1
2.07
---
Sum of Walls:-
(1) 1B
(i)
Typical
floors
=
[120.56+37.32+47.04+4.14]5=
1045.30m2
(ii) Parapet
=
076.50
(iii) Others 46.5x2+[9.752+12.75x2]4
=
0273.00
-----------------Total
=
1395m2
(2) 1 ½ B
(i)
Typical floors= [51.38+40.35+110.10+52.50]5=
1271.65m2
(ii) Peirs
=
228.00
(iii) Stair case wall
=
267.00
(iv) Lift Wall
=
90.00
Total
=
1856.65
(v) Others = 1856.65 – 273
1584m2
Plaster
(1) Walling:-
=
(i) Walls plastered on one side
=1047m2~ 1450
(ii)Walls plastered on both sides
=
2979-1047-229-267-90
1
3
4
7
~
1
3
5
0
Total plastered area = 1347+1047
=
3750m2
(2) Ceiling :
Total area = 21x16.75x 5
=
1759m2
4.75 x 1.20 x 5
= 0029
Total
= 1788
Reduction, thickness of walls
1B = 93x0.26 x 5
=
121
1 ½B = 103x0.37 5
=
191
Peirs = 18x0.81 x 0.35 x 5 =
026
338
Net
= 1450m2
Load bearing
(1) Peirs 1 ½B
18x0.81x3.125x5
=
228m2
=
267m2
=
90m2
(2) Stair case walls 1 ½B
4.75x3x3.1256
(3) Lift wall 1 ½B
1.6x3x3.1256
(4) Parapet 1B
2(21+16.76)0.90+24.75x0.90 =
76.5m2
(5) Beams:
5x2[21+16.75)x0.325x0.225+[4.25+4.0]0.375x0.225
x6=32m3
(6) Slabs
(1) 5x21x16.75 x 0.125
=
219.84
(2) Lift = 2.2 x 2.2 x 0.2
=
0.97
(3) Lift + stair = 4.75 4.750.125
=
2.82
(4) Landing = 1.4x5.0x0.125x5
=
4.38
Total
=
(5) Stair Slab
228.01
=
11.25
Total
239.2m3
=
Section B
Reinforced Concrete Skeleton
Walls
Item No.
Wall
No.
Dimensions
Width
Height
Opening
1
1-4/A
6.25
0.90
Wall
thick
brick
1
Width
Height
Quantity
M2
---
-----
11.250
2
4-5/A
4.25
2.75
1
---
-----
23.375
3
5-6/A
4.25
2.75
1
---
-----
23.375
4
6-7/A
2.00
0.90
1
---
-----
3.60
5
1-2/B
1.75
2.625
1
---
-----
9.188
6
2-4/B
3.875
2.625
1
1.00
2.10
16.144
7
5-6/B
2.50
3.00
1
----
-----
15.00
8
3-4/C
1.75
3.00
1
0.80
2.10
7.14
9
4-5/C
4.00
2.625
1
---
-----
21.00
10
5-6/C
2.50
2.625
1
1.25
2.10
7.875
11
1-2/D
1.50
2.625
1
---
-----
7.875
12
2-4/D
3.875
2.625
1
1.00
2.10
16.144
13
5-6/D
3.85
2.625
1
---
-----
20.213
14
6-7/D
1.75
3.000
1
1.25
2.10
5.250
15
1-2/E
1.50
2.625
1
-----
-----
3.938
16
2-4/E
3.87
2.625
1
-----
-----
10.159
17
4-5/E
3.97
2.625
1
-----
----
10.421
18
5-6/F
3.85
2.625
1
-----
----
10.106
222.054
Item No.
Wall
No.
Dimensions
Width
Height
Opening
1
A-B/1
2.00
0.90
Wall
thick
brick
1
Width
Height
Quantity
M2
---
---
3.60
2
B-D/1
4.25
2.75
1
1.5
1.2
19.776
3
D-E/1
4.25
0.90
1
---
---
9.65
4
D-E/2
4.00
2.625
1
1.0
2.1
16.80
5
B-D/3
4.00
2.625
1
1.0
2.1
16.80
6
A-B/4
1.75
2.625
1
---
---
9.188
7
B-D/4
3.75
2.625
1
1.25
2.625
13.126
8
D-E/4
3.75
2.625
1
---
---
19.688
9
A-B/5
1.75
2.525
1
---
---
8.838
10
B-D/5
3.75
2.525
1
1.25
2.525
5.051
1.50
2.525
11
D-E/5
3.75
2.525
1
---
---
11.363
12
A-B/6
1.75
2.625
1
--
---
9.188
13
B-D/6
3.875
2.625
1
1.25
2.625
13.782
14
D-E/6
4.00
2.625
1
0.75
1.00
18.00
---
14.85
0.75
15
A-D’/7
8.25
0.90
1
---
189.70
Parapet Wall
2 (21.0+16.75) 0.90
= 2.33.975m2
=
67.95
+ 4.752x0.90
=
08.55
Total
=
76.50m2
Stair Case Wall
4.75x2.625 x 3 x 6
=
225 m2
Total amount traditional brick:-
= 225 + 77 + [222 + 190]5
=
=
2060 m2
(2) Stair Case
=
225 m2
(3) Parapet
=
77 m2
=
2362 m2
=
214.5 m2
(1) Walls
=
(222 + 190)5
Total
Facing Brick
(1) Walls:-
(1) 2[21+14.75] x 3.0
(2) Parapet = 6x 4.25 x 0.9 =
23.0
(3) Stair case = 4.75 x 3 x 18 =
256.5
Total = 5 x 214.5 + 23 + 256.5 = 1352m2
(ii) Openings
Doors and Windows
(1) 1.5 x 1.2 2
=
3.60
(2) 1.0 x 2.1 x 4
=
8.40
(3) 1.25 x 2.2 x 2
=
5.25
(4) 2 x 0.75 x 1.0 x 2
=
3.00
2362 m2
(5) 2 x 0.5 x 1.0
=
1.00
Total
=
106.25 m2
=
1245m2
(1) Walls 2x 2362
=
4724m2
(2) Parapet 2 x 76.5
=
0153 m2
(3) Stair case 2 x 225
=
0450 m2
(4) Well side 5.1 x 3.0 x 6
=
0092 m2
(5) Beams sides
=
0929 m2
= 21.25 x 5
The net area
Plastering
(1) Walling:-
--------Total
=
6348 m2
Reduction facing brick
=
1245 m2
---------
=
5103 m2
(i) Like loadbearing
=
1450 m2
(ii) Saffit of beams = 12 x 5
=
0060 m2
Net
Ceilings:
----------Total
=
1510 m2
Beams
Roof
Item Beam
No. No.
Dimensions
Height
Number
Width Length
of
beams
1
Quantities
M3
1
A-I/1
0.350
0.25
21.0
1.84
2
A-I/2
0.450
0.25
21.0
1
2.36
3
A-I/4
0.400
0.25
21.0
1
2.10
4
A-I/5
0.400
0.25
21.0
1
2.10
5
A-I/6
0.450
0.25
21.0
1
2.36
6
A-I/7
0.350
0.25
21.0
1
1.84
7
1-7/A
0.350
0.25
16.75
2
2.93
8
1-7/B
0.400
0.25
16.75
2
3.35
9
1-7/D
0.400
0.25
16.75
2
3.35
10
1-7/E
0.400
0.25
16.75
2
1.57
23.8
Beams
Typical Floors
Item Beam
No. No.
Dimensions
Height
Number
Width Length
of
beams
1
Quantities
M3
1
A-I/1
0.375
0.25
21.0
1.969
2
A-I/2
0.50
0.25
21.0
1
2.625
3
A-I/3
0.50
0.25
4.25
2
1.062
4
A-I/4
0.50
0.25
21.0
1
2.625
5
A-I/5
0.60
0.30
21.0
1
3.78
6
A-I/6
0.50
0.25
21.0
1
2.625
7
A-I/7
0.375
0.25
21.0
1
1.969
8
1-7/A
0.375
0.25
16.75
2
3.14
9
1-7/B
0.50
0.25
16.75
2
4.188
10
4-6/C
0.50
0.25
8.50
2
2.126
11
1-4/D
0.50
0.25
6.25
2
1.562
12
5-7/D
0.50
0.25
6.25
2
1.562
13
1-7/E
0.50
0.25
16.75
1
2.094
31.34
Stair Case: Beams
No.
Beam
hm
tm
Lm
Volume
1
0.50
0.25
4.75
0.594
2
0.50
0.25
4.75
0.594
3
0.50
0.25
1.45
0.181
4
0.50
0.25
1.45
0.181
5
0.50
0.25
5.00
0.625
6
0.50
0.25
3.55
0.44
7
0.50
0.25
3.55
0.444
8
0.50
0.25
5.00
0.625
Total
Total
3.688
Columns
Typical Floor
Item Column
Dimensions
Number
No. No.
Length Width Height
of
Column
1
B/2
0.50
0.25
2.625
2
Quantities
M3
0.656
2
B/4
0.50
0.25
2.625
2
0.656
3
B/5
0.50
0.25
2.625
2
0.656
4
B/6
0.50
0.25
2.625
2
0.656
5
D/2
0.50
0.25
2.625
2
0.656
6
D/4
0.50
0.25
2.625
2
0.656
7
D/5
0.50
0.25
2.625
2
0.656
8
D/6
0.50
0.25
2.625
2
0.656
9
E/2
0.50
0.25
2.625
1
0.328
10
E/4
0.50
0.25
2.625
1
0.328
11
E/5
0.50
0.25
2.625
1
0.328
12
E/6
0.50
0.25
2.625
1
0.328
6.56
Stair Case : Columns
No.
hm
tm
Lm
Volume
1
0.5
0.25
2.625
0.328
2
0.5
0.25
2.625
0.328
3
0.5
0.25
2.625
0.328
4
0.5
0.25
2.625
0.328
Total
Column
Total
1.312
Sum of Concrete Work
(1) Beams:-
(1) Typical Floor
=
4x31.5
=
126m3
(2) Roof
=
24
(3) Stair Case
=
31
---
--Total
=
181m3
(2) Columns:-
(1) Typical Floor
=
6.50x5
=
=
6x1.313
=
32.5m3
(2) Stair case
8m3
-----Total
=
41.0m3
(3) Walls:-
0.15x6 [1.75 x 4 x 3.125 – 0.80 2.0]
18.25m3
(4) Stair Case;
=
2(1.2x1.2x0.125) + 3 (2.10x0.125+0.3x1.05/2)1.2
=
1.872m3
Total
=
6x1.872
=
11.232m3
(5) Slab:
(i) Like loadbearing
=
239.25m2
(ii) Concrete wall
=
018.25
-----------
-Total
257.50m3
=