COVENANT UNIVERSITY
NIGERIA
TUTORIAL KIT
OMEGA SEMESTER
PROGRAMME: BUILDING
TECHNOLOGY
COURSE: BLD 323
DISCLAIMER
The contents of this document are intended for practice and leaning purposes at the
undergraduate level. The materials are from different sources including the internet and
the contributors do not in any way claim authorship or ownership of them. The materials
are also not to be used for any commercial purpose.
BLD 323: DESIGN OF REINFORCED CONCRETE STRUCTURE I
CONTRIBUTOR: MR I.O OMUH, MR O JOSHUA
1.
The floor shown below with an overall depth of 225 mm is to be designed to carry an imposed
load of 3 kN m−2 plusfloor finishes and ceiling loads of 1 kN m−2. Calculate the design loads
acting on beams B1–C1, B2–C2 and B1–B3 andcolumns B1 and C1. Assume that all the column
heights are 3 m and that the beam and column weights are 70 and60 kg m−1 run respectively
2.
A simply supported rectangular beam of 7 m span carries characteristic dead (including selfweight of beam), gk, andimposed, qk, loads of 12 kN/m and 8 kN/m respectively (Fig. Q2). The
beam dimensions are breadth, b, 275 mm andeffective depth, d, 450 mm. Assuming the following
material strengths, calculate the area of reinforcement required.fcu= 30 N/mm2fy= 500 N/mm2
Fig. Q2
3. A reinforced concrete beam which is 300 mm wide and 600 mm deep is required to span 6.0 m
between the centresof supporting piers 300 mm wide (Fig. Q3). The beam carries dead and
imposed loads of 25 kNm−1 and 19 kNm−1respectively. Assuming fcu= 30 N/mm2, fy= fyv= 500
N/mm2and the exposure class is XC1, design the beam.
Fig Q3
4.
A reinforced concrete floor subject to an imposed load of 4 kN/m2 spans between brick walls as
shown below. Designthe floor for exposure class XC1 assuming the following material
strengths:fcu= 35 N/mm2fy= 500 N/mm2
Fig Q4
5.
Fig. Q5 shows a part plan of an office floor supported by monolithic concrete beams (not
detailed), with individual slab panels continuous over two or more supports. The floor is to be
designed to support an imposed load of 4 kNm−2 and finishes plus ceiling loads of 1.25 kNm−2.
The characteristic strength of the concrete is 30 Nmm−2 and the steel reinforcement is 500
Nmm−2. The cover to steel reinforcement is 25 mm.
(a) Calculate the mid-span moments for panels AB2/3 and BC1/2 assuming the thickness of the
floor is 180 mm.
(b) Design the steel reinforcement for panel BC2/3 (shown hatched) and check the adequacy of the
slab in terms of shear resistance and deflection. Illustrate the reinforcement details on plan and
elevation views of the panel.
Fig. Q5
6.
A 400 mm square column carries a dead load (Gk) of 1050 kN and imposed load (Qk) of 300 kN.
The safe bearing capacity of the soil is 170 kNm−2. Design a square pad footing to resist the loads
assuming the following material strengths: fcu= 35 N/mm2fy= 500 N/mm2
Fig Q6
7.
A short-braced column in which fcu= 30 Nmm−2 and fy= 500 Nmm−2 is required to support an
ultimate axial load of 2000 kN. Determine a suitable section for the column assuming that the area
of longitudinal steel, Asc, is of the order of 3 per cent of the gross cross-sectional area of column,
Acol.
Fig Q7
MULTIPLE CHOICE QUESTIONS
1. One of the objective of Structural design is(a) to ensure that the structure must carry the load safely,
not deform excessively and have adequate durability and resistance to the effects of misuse and
fire. (b) To calculate the bending moments, shear forces and deflection of beams (c) to determine the
load combination that should produce the worst possible effect on the structure in terms of bending
moment, shear force and deflections. (d) To determine the minimum area of reinforcement is provided to
control cracking of concrete.
2. The product of the characteristic load and the partial safety factor is called (a) factorised load (b) Design
load (c) dead load (d)live load
3. What kind of loads do finishes, fixtures and partitions constitute?(a) Dead load (b) Wind Load (c) Live
load (d) none of the above
4. What kind of loads are denoted by Qk? (a) Dead load (b) Wind Load (c) Live load (d) none of the above
5. What is the self-weight of a reinforced concrete beam of a breadth 250 mm, depth 450 mm and length
6000 mm, assuming that the gravitational constant is 10 m/s2 and density of reinforced concrete = 2400
kg/m3? (a) 16.2kN/m (b) 16.2kN (c) 162kN (d) 16200kg/m
6. Which of the following is not a design philosophy in structural design? (a) Permissible stress design (b)
Load factor method (c) Limit state design (d) Simplified design
7. Which of the following statements is false? (a) Reinforced concrete is a composite material, consisting
of steel reinforcing bars embedded in concrete. (b) Concrete has high compressive strength but low
tensile strength. (c) Steel bars can resist high tensile stresses but will buckle when subjected to
comparatively low compressive stresses. (d) Reinforced concrete is an economical structural material
which is strong in compression and weak in tension.
8. Fire protection of reinforced concrete members is largely achieved by specifying (a) limits for nominal
thickness of cover to the reinforcement, and minimum dimensions of members. (b) Fire resistant
paints for the reinforced concrete members (c) fire preventing equipment to be mounted near reinforced
concrete members (d) The maximum water/cement ratio
9. The moment of resistance of a beam section is not affected by: (a) the service stress, fs (b) The effective
depth of the section, d(c) Strength of concrete (d) the breadth of the section, b
Figure Q 10 is a first floor of a classroom. Using the figure and the design data provided, answer
questions 10 - 18
Fig Q 10
Design Data
Characteristic strength of concrete (fcu) = 30 N/mm2; Characteristic strength of steel (fy) =500 N/mm2;
Diameter of main tension steel Assume =20 mm; Cover to main reinforcement= 25 mm; Overall depth of
slab= 180mm; Finishes and partitions load= 1.5 kN/m2; Characteristic imposed load = 3.5 kN/m2; Unit
weight of concrete = 24.0 kN/m3; Beam dimensions; b = 250mm, h = 400mm
10. What is the dead load from the slab?(a) 29.9kN/m2 (b) 51.49kN/m2 (c) 23.99kN/m2(d) 5.82kN/m2
11. What is the design load on beam A1-D1?(a) 30.86kN/m (b) 51.49kN/m (c) 23.99kN/m (d) 5.82kN/m
12. What is the design load on beam A2-D2? (a) 30.86kN/m (b) 51.49kN/m (c) 23.99kN/m (d) 5.82kN/m
13. What is the design load on beam A3-D3? (a) 30.86kN/m (b) 51.49kN/m (c)23.99kN/m (d) 5.82kN/m
14. What is the design moment on Support B of Beam A3-C3? (a) 90kNm (b) 96kNm (c) 2590.92kNm (d)
86.36kNm
15. What is the ultimate moment of resistance of supports B and C on beam A3-C3 if the effective depth is
357mm?(a)149.12kNm (b)187.2kNm (c) 2590kNm (d) 96kNm
16. The design coefficient, K for span BC in beam A3-D3 is(a) 0.090 (b) 0.156 (c) 0.043 (d) 0.253
17. The lever arm, z for span BC in beam A3-D3 is (a) 0.95d (b) 0.97d (c) 0.89d (d) 0.775d)
18. The required area of steel reinforcements for support B or C on beam A3-C3 is (a) 130mm2 (b) 585
mm2(c) 625 mm2 (d) 522.4 mm2
19. A singly reinforced concrete beam designed withfy= 500 Nmm2 contains 4Y25 to give an As of 1960
mm2 of tension reinforcement. If the effective span is 7 m. Assuming a lever arm, z and effective depth,
d of 0.95d and 400mm respectively, Determine the design moment. (a) 324kNm (b) 324kN/m (c)
290.78kNm (d) 290.78kN/m
20. Using the details from Q 19, determine the design load that the beam can carry assuming that the load
occurs as a point load at mid-span of the beam. (a) 52.9kN/m (b) 52.9kN (c) 185.14kN (d) 185.14kN/m
8.
The floor shown below with an overall depth of 225 mm is to be designed to carry an imposed
load of 3 kN m−2 plusfloor finishes and ceiling loads of 1 kN m−2. Calculate the design loads
acting on beams B1–C1, B2–C2 and B1–B3 andcolumns B1 and C1. Assume that all the column
heights are 3 m and that the beam and column weights are 70 and60 kg m−1 run respectively
9.
A simply supported rectangular beam of 7 m span carries characteristic dead (including selfweight of beam), gk, andimposed, qk, loads of 12 kN/m and 8 kN/m respectively (Fig. Q2). The
beam dimensions are breadth, b, 275 mm andeffective depth, d, 450 mm. Assuming the following
material strengths, calculate the area of reinforcement required.fcu= 30 N/mm2fy= 500 N/mm2
Fig. Q2
10. A reinforced concrete beam which is 300 mm wide and 600 mm deep is required to span 6.0 m
between the centresof supporting piers 300 mm wide (Fig. Q3). The beam carries dead and
imposed loads of 25 kNm−1 and 19 kNm−1respectively. Assuming fcu= 30 N/mm2, fy= fyv= 500
N/mm2and the exposure class is XC1, design the beam.
Fig Q3
11. A reinforced concrete floor subject to an imposed load of 4 kN/m2 spans between brick walls as
shown below. Designthe floor for exposure class XC1 assuming the following material
strengths:fcu= 35 N/mm2fy= 500 N/mm2
Fig Q4
12.
Fig. Q5 shows a part plan of an office floor supported by monolithic concrete beams (not
detailed), with individual slab panels continuous over two or more supports. The floor is to be
designed to support an imposed load of 4 kNm−2 and finishes plus ceiling loads of 1.25 kNm−2.
The characteristic strength of the concrete is 30 Nmm−2 and the steel reinforcement is 500
Nmm−2. The cover to steel reinforcement is 25 mm.
(a) Calculate the mid-span moments for panels AB2/3 and BC1/2 assuming the thickness of the
floor is 180 mm.
(b) Design the steel reinforcement for panel BC2/3 (shown hatched) and check the adequacy of the
slab in terms of shear resistance and deflection. Illustrate the reinforcement details on plan and
elevation views of the panel.
Fig. Q5
13.
A 400 mm square column carries a dead load (Gk) of 1050 kN and imposed load (Qk) of 300 kN.
The safe bearing capacity of the soil is 170 kNm−2. Design a square pad footing to resist the loads
assuming the following material strengths: fcu= 35 N/mm2fy= 500 N/mm2
Fig Q6
14.
A short-braced column in which fcu= 30 Nmm−2 and fy= 500 Nmm−2 is required to support an
ultimate axial load of 2000 kN. Determine a suitable section for the column assuming that the area
of longitudinal steel, Asc, is of the order of 3 per cent of the gross cross-sectional area of column,
Acol.
Fig Q7
MULTIPLE CHOICE QUESTIONS
21. One of the objective of Structural design is(a) to ensure that the structure must carry the load safely,
not deform excessively and have adequate durability and resistance to the effects of misuse and
fire. (b) To calculate the bending moments, shear forces and deflection of beams (c) to determine the
load combination that should produce the worst possible effect on the structure in terms of bending
moment, shear force and deflections. (d) To determine the minimum area of reinforcement is provided to
control cracking of concrete.
22. The product of the characteristic load and the partial safety factor is called (a) factorised load (b) Design
load (c) dead load (d)live load
23. What kind of loads do finishes, fixtures and partitions constitute?(a) Dead load (b) Wind Load (c) Live
load (d) none of the above
24. What kind of loads are denoted by Qk? (a) Dead load (b) Wind Load (c) Live load (d) none of the above
25. What is the self-weight of a reinforced concrete beam of a breadth 250 mm, depth 450 mm and length
6000 mm, assuming that the gravitational constant is 10 m/s2 and density of reinforced concrete = 2400
kg/m3? (a) 16.2kN/m (b) 16.2kN (c) 162kN (d) 16200kg/m
26. Which of the following is not a design philosophy in structural design? (a) Permissible stress design (b)
Load factor method (c) Limit state design (d) Simplified design
27. Which of the following statements is false? (a) Reinforced concrete is a composite material, consisting
of steel reinforcing bars embedded in concrete. (b) Concrete has high compressive strength but low
tensile strength. (c) Steel bars can resist high tensile stresses but will buckle when subjected to
comparatively low compressive stresses. (d) Reinforced concrete is an economical structural material
which is strong in compression and weak in tension.
28. Fire protection of reinforced concrete members is largely achieved by specifying (a) limits for nominal
thickness of cover to the reinforcement, and minimum dimensions of members. (b) Fire resistant
paints for the reinforced concrete members (c) fire preventing equipment to be mounted near reinforced
concrete members (d) The maximum water/cement ratio
29. The moment of resistance of a beam section is not affected by: (a) the service stress, fs (b) The effective
depth of the section, d(c) Strength of concrete (d) the breadth of the section, b
Figure Q 10 is a first floor of a classroom. Using the figure and the design data provided, answer
questions 10 - 18
Fig Q 10
Design Data
Characteristic strength of concrete (fcu) = 30 N/mm2; Characteristic strength of steel (fy) =500 N/mm2;
Diameter of main tension steel Assume =20 mm; Cover to main reinforcement= 25 mm; Overall depth of
slab= 180mm; Finishes and partitions load= 1.5 kN/m2; Characteristic imposed load = 3.5 kN/m2; Unit
weight of concrete = 24.0 kN/m3; Beam dimensions; b = 250mm, h = 400mm
30. What is the dead load from the slab?(a) 29.9kN/m2 (b) 51.49kN/m2 (c) 23.99kN/m2(d) 5.82kN/m2
31. What is the design load on beam A1-D1?(a) 30.86kN/m (b) 51.49kN/m (c) 23.99kN/m (d) 5.82kN/m
32. What is the design load on beam A2-D2? (a) 30.86kN/m (b) 51.49kN/m (c) 23.99kN/m (d) 5.82kN/m
33. What is the design load on beam A3-D3? (a) 30.86kN/m (b) 51.49kN/m (c)23.99kN/m (d) 5.82kN/m
34. What is the design moment on Support B of Beam A3-C3? (a) 90kNm (b) 96kNm (c) 2590.92kNm (d)
86.36kNm
35. What is the ultimate moment of resistance of supports B and C on beam A3-C3 if the effective depth is
357mm?(a)149.12kNm (b)187.2kNm (c) 2590kNm (d) 96kNm
36. The design coefficient, K for span BC in beam A3-D3 is(a) 0.090 (b) 0.156 (c) 0.043 (d) 0.253
37. The lever arm, z for span BC in beam A3-D3 is (a) 0.95d (b) 0.97d (c) 0.89d (d) 0.775d)
38. The required area of steel reinforcements for support B or C on beam A3-C3 is (a) 130mm2 (b) 585
mm2(c) 625 mm2 (d) 522.4 mm2
39. A singly reinforced concrete beam designed withfy= 500 Nmm2 contains 4Y25 to give an As of 1960
mm2 of tension reinforcement. If the effective span is 7 m. Assuming a lever arm, z and effective depth,
d of 0.95d and 400mm respectively, Determine the design moment. (a) 324kNm (b) 324kN/m (c)
290.78kNm (d) 290.78kN/m
40. Using the details from Q 19, determine the design load that the beam can carry assuming that the load
occurs as a point load at mid-span of the beam. (a) 52.9kN/m (b) 52.9kN (c) 185.14kN (d) 185.14kN/m
BLD 324: SOIL MECHANICS
CONTRIBUTOR: MR O. JOSHUA, MR A. AJAO
Question 1:
a. A 4m deep compacted fill is to be placed over the soil profile as shown in Fig.1 below. A
consolidation test on a sample from point ‘A’ reveals the following results: Cv = 0.65, Cr =0.10,
℮₀= 1.20 and  c =175KN/m3. Compute the ultimate consolidation settlement (δ) due to the
weight of the fill.
(30 marks)
b. Explain the following terms:
I.
Atterbergs limits
II.
Normal consolidation
III.
Over consolidation
IV.
Hydrostatic stress
V.
Geostatic stress
(10 marks)
Proposed fill
3m
 =20.0KN/m3
2m  =19.2KN/m3
 =19.8KN/m3
2.6m
7m
Fine sand with little fine to
coarse silt (SM)
Dr = 20%
 =16.00KN/m3 soft clay
5m
A
///////////Bed rock/////////////////
Fig. 1
Question 2:
a. What do you understand by the term “Bearing Capacity in Soils”?
(4 marks)
b. With the aid of a diagram only, show the different modes of bearing capacity failures.
(6 marks)
c. State the assumptions on which Terzaghi based the use of his bearing capacity formulars. (5
marks)
d. A proposed continuous footing as shown in Fig.2 below will support the exterior wall of a new
proposed Departmental Building. With the ground water table below the bottom of the foundation
footing, compute the ultimate bearing capacity and the wall load required to cause a bearing
capacity failure using the Terzaghi formular.
(15 marks)
P
C = 21.50KN/m2
Ø = 22o
Ground level
150mm
300mm
Fig. 2
Question 3:
900mm
 = 22.8KN/m3
 concrete = 23.6KN/m3
a. In Rankine solution to lateral earth pressure problems, state the assumptions guiding his theory.
(7 marks)
b. Discuss earth retaining structures under the two major stabilisation systems.
(8 marks)
c. A cantilever wall has moved sufficiently to create an active condition as shown in Fig. 3 below. Find
the total lateral thrust on the wall due to the retained soil if the water table starts at a level 5m from
the top of the wall.
(15 marks)
5m
  22.4 KN / m3
C=0
Φ=36o
8m
Fig.
Question 4.
 sat  23.8KN / m3
3
a. Below is a gradation curve of a soil sample.
Distribution curve
Distribution curve,
4.75, 99
4.75
Distribution
curve,
3.35, 88
3.35
Distribution curve,
2
2, 72
0.853
Distribution curve,
0.853, 0.422
54
Distribution curve,
0.001, 1
Distribution curve,0.251
Distribution
curve,
0.422,
36
Distribution
curve,
0.152
0.251,
30
0.152,
25
Distribution curve,
0.075
0.075, 15
0.001
Liquid limits = 65%
Plastic limits = 45%.
Classify the soil sample with the Unified Soil Classification System (USCS).
(7 marks)
b. Discuss soil composition and further explain what differentiate soil mechanics from fluid and
solid mechanics and also explain with the aid of its idealized form.
(8 marks)
c. Compute the density, unit weight, void ratio, porosity and degree of saturation of an undisturbed
sample of moist soil from the following data:
Volume = 0.0504m3
(15 marks)
NB: See overleaf for relevant tables and charts needed for all questions.
(12 mark