ISTANBUL TECHNICAL UNIVERSITY DEPARTMENT OF GEOMATICS ENGINEERING
W1 ch3
Prof. Dr. Ergin TARI
translated by Res. Assist. Serpil ATEŞ
ISTANBUL TECHNICAL UNIVERSITY DEPARTMENT OF GEOMATICS ENGINEERING
Please NOTE
Following notes of Engineering Surveying lecture are
composed as of Baykal 2009 by preserving numbering
on sections, figures and equations with slight changes on
subscripts and notations (such as T->TO T’->TF) in
general.
Baykal 2009: Baykal, O., Mühendislik Ölçmeleri 1,
Metinler (in Turkish), Birsen Yayınevi, ISBN: 978-975-511524-5, İstanbul, 2009.
Prof. Dr. Ergin TARI
translated by Res. Assist. Serpil ATEŞ
TRANSPORTATION and
TRANSPORTATION STRUCTURES –
GENERAL DEFINITIONS
Transportation, Transportation Structure: Transportation is explained as
the phenomena of replacement of living creatures (human and animal) and
goods (solid, liquid, gas) and energy with respect to human demand and
benefit. Man-made engineering structures serve for transportation are called
transportation structures [Müller, 1984, p.8]. According to this definition, all
highway, rail, water and air transportation systems; liquid and gas pipelines, cable
systems such as electricity, telegraph, telephone and internet are in the concept of
transportation structures. There are many different features that must be taken into
account at design, construction and management phases aforementioned
engineering structures. It is impossible to consider all of these features in the
context of this course. Therefore, highways and railways will be considered,
however, it is possible to use given information about geometric design and layout
for other transportation structures.
Engineering Surveying-Prof. Dr. Ergin TARI
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TRANSPORTATION and
TRANSPORTATION STRUCTURES –
GENERAL DEFINITIONS
Classification of Highways: All of the roads can not be built at
same standards. They are classified according to certain parameters.
These classifications are taken into account at determination of
design criterion (standards).
Classification parameters are;
1. habitation (urbanization) status
2. traffic volume
3. topography of the terrain
Engineering Surveying-Prof. Dr. Ergin TARI
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TRANSPORTATION and
TRANSPORTATION STRUCTURES –
GENERAL DEFINITIONS
1- Urbanization status:
Highways are divided into two groups according to urbanization status; urban
roads and non-urban roads [KGM; 2005, s.8,9], [Müller; 1988, s.68,70].
2- Traffic volume:
Quality and quantity of the vehicles have an important role in determination of
road standards. Annual average daily traffic or maximum hourly traffic are taken
into account at design of the highways and amount of the future 15-20 years’
traffic is estimated [Umar; Yayla; 1997, p.83-91].
3-Topography of terrain: Topography of terrain is divided into three groups;
plane, rough and mountainous. This classification is important at selecting design
speed. A highway can be constructed through these 3 types of terrain. But the class
(classification) should not be changed frequently.
A highway should also not be constructed from plane terrain to the mountainous
terrain or in the opposite direction by neglecting the rough terrain.
Engineering Surveying-Prof. Dr. Ergin TARI
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TRANSPORTATION and
TRANSPORTATION STRUCTURES –
GENERAL DEFINITIONS
Classification of Railway: There are 4 types of railways according to
topographic characteristic of the terrain; flat terrain railway, hilly terrain
railway, mountainous terrain railway and mountain railway [Evren;2002, s.14].
According to urbanization and transportation distance; intercity railway,
suburban railway and urban railway can be a classification (tram, high speed
tram, subway) [Evren; 2002, s.14].
There are different railway classifications; according to types of trains that use
the railway; complex line (common route for passenger and freight train),
passenger line; according to number of the tracks single and double track;
according to power source that provide motion; steam-operated, diesel,
electrical; according to track width; normal line (aperture between rail axes
is 1500 mm), wide and narrow line.
Engineering Surveying-Prof. Dr. Ergin TARI
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TRANSPORTATION and
TRANSPORTATION STRUCTURES –
GENERAL DEFINITIONS
Design Speed (Vp): is a base speed for design criterion (geometric
standards) determination. Design speed for highways is defined in different
forms at various sources;
[Umar; Yayla; 1997, s.81]: maximum safe speed without influence of
other vehicles at normal weather conditions.
[Kiper; 1988, s.11]: maximum safe speed at normal traffic flow and in
normal weather conditions (including rainy weather).
[Pietzsch; 1979, s.28]: maximum safe speed of %85 of the vehicles
in case of normal traffic flow at clean and wet road without the lose
of flow.
Engineering Surveying-Prof. Dr. Ergin TARI
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TRANSPORTATION and
TRANSPORTATION STRUCTURES –
GENERAL DEFINITIONS
Design Speed Selection
A design speed is selected for each project which will establish criteria for several
geometric design elements including horizontal and vertical curvature, superelevation, cross
sectional features, and sight distance. In general, the selected design speed is based on the
following road design elements:
1. Functional Classification. The higher class facilities (i.e., arterials) are designed with a
higher design speed than the lower class facilities (i.e., collectors and locals).
2. Urban/Rural. Design speeds in rural areas are generally higher than those in urban areas. This
is consistent with the typically fewer constraints in rural areas (e.g., less
development).
3. Terrain. The flatter the terrain, the higher the selected design speed can be. This is
consistent with the typically higher construction costs associated with more rugged terrain.
4. Traffic Volumes. On some facilities (e.g., unmarked rural collectors), the design speed
varies by traffic volumes; i.e., as traffic volumes increase, higher design speeds are used.
Engineering Surveying-Prof. Dr. Ergin TARI
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TRANSPORTATION and
TRANSPORTATION STRUCTURES –
GENERAL DEFINITIONS
Design speeds according to road classes in Turkey [KGM; 2005,
p.7-9]
Road and Link Road (2x2)
Terrain class: Plain Rough Mountainous
Vp(km/h) : 120 100
80
Urban road
Terrain Class
Plain
Highway
Multi Lane
100 60
Two Lane
90 60
Urban Road
Multi Lane
80 60
Two Lane
70 50
Rough
80 60
80 60
70 50
60 30
Mountainous
80 60
60 50
60 40
60 30
Engineering Surveying-Prof. Dr. Ergin TARI
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TRANSPORTATION and TRANSPORTATION
STRUCTURES – GENERAL DEFINITIONS
Non-urban road
Land Class
Multilane
Road (2x2)
Two lane road
1.class
2.class
4.class
Plane V P ( km / s )
100 90
Rough V P ( km / s )
90 80
80 70
70 60 60 50 40 30
Highland V P ( km / s )
80 60
70 60
60 40 50 30 30 20
Engineering Surveying-Prof. Dr. Ergin TARI
100 80 80 70
3.class
70 60 50 40
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TRANSPORTATION and TRANSPORTATION
STRUCTURES – GENERAL DEFINITIONS
Design speed is the maximum speed that can be safely applied at
railways and also called track speed limit. This speed is used to
determine geometric standards for railways. In addition, applicable
maximum speed is defined considering locomotive traction, cooper
load and operating conditions. This speed is used to plan the
operation [Evren; 2002, s.90-91].
Engineering Surveying-Prof. Dr. Ergin TARI
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TRANSPORTATION and TRANSPORTATION
STRUCTURES – GENERAL DEFINITIONS
Road Geometry: highway or railway is a narrow engineering structure that
has very large length compared to the width and forms a space surface. The
vertical (longitudinal) geometry of this surface is defined with route and the
horizontal geometry is defined with typical cross sections and superelevation.
Route (Alignment): is a line belonging to road geometry that can be exactly
defined along the road.
Route Definition for Highway: For divided roads; is axis of the central
(island) reserve, for two-lane roads; if roadside shoulders has same width is
platform axis, if roadside shoulders has different width-pavement axis is
selected as a route axis [Müller; 1988, s.86]. In the climbing lane and road
expansion regions, only the main platform is taken into account.
Route Definition for Railway: for single track railway is route axis, for
double track railway; pavement axis is the route axis for the railway.
Engineering Surveying-Prof. Dr. Ergin TARI
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TRANSPORTATION and TRANSPORTATION
STRUCTURES – GENERAL DEFINITIONS
Figure 3.1: Intersection Points and Deviation Angle of
Horizontal (Vertical) Route Geometry
Engineering Surveying-Prof. Dr. Ergin TARI
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TRANSPORTATION and TRANSPORTATION
STRUCTURES – GENERAL DEFINITIONS
Route Geometry: longitudinal geometry of the road is determined with the
design of route geometry. Despite it is a space curve, route geometry is not
determined with closed function such as f(x, y, z)=0. Horizontal and vertical
route geometry are designed separately [Müller, 1984, s.9].
Horizontal Alignment: is designed with using line segment, arc and transition
curves in respect to guidelines and design criterion. Superelevation and
superelevation runoff are also designed in route geometry. The base map of the
route geometry is a large-scale (1/1000;1/2000) topographic map. Digital
Terrain Model (DTM) is used as a basis on computer aided design.
Horizontal Intersection Point: is the breakpoint of two consecutive line
segments of the horizontal route geometry (Figure: 3.1). Despite lack of
compliance with this definition, starting and end points of the route are also
considered as a intersection point. While they are not a route point, intersection
points play very important role in the calculations.
Engineering Surveying-Prof. Dr. Ergin TARI
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TRANSPORTATION and TRANSPORTATION
STRUCTURES – GENERAL DEFINITIONS
Figure 3.2: Defining Point Chainage (Stationing) on Horizontal
Route Geometry
Engineering Surveying-Prof. Dr. Ergin TARI
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TRANSPORTATION and TRANSPORTATION
STRUCTURES – GENERAL DEFINITIONS
Horizontal Deviation Angle: is an angle (∆i) between line segments
at intersection points of horizontal route geometry (Figure 3.1). This
angles are the main quantities of the horizontal geometry
computations.
Distance from the origin-Km (Chainage-stationing): The
horizontal distance measured through horizontal geometry from the
selected beginning point to any point of the route. For example, at
Figure 3.2; stationing of P is S0T1 line + T1T'1 curve + T'1T2 line +
T2P curve. Distance from the origin is written in this form;
kmp = kilometer + meter, fractions of meter (14+038,673)
Engineering Surveying-Prof. Dr. Ergin TARI
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TRANSPORTATION and TRANSPORTATION
STRUCTURES – GENERAL DEFINITIONS
Chainage gives a unique identification of all highway points in a
manner that is virtually equivalent to using true x, y, and z
coordinates.
In other words:
Highways are measured along the centerline, rather than
Cartesian coordinates.
Stations are measured in km (there are also Imperial units for
stationing) along a horizontal plane
So 14+038,673 should be read as
10 kilometers and 38.673 meters from the point of origin on
the roadway horizontally, which is at 0+000.000
Engineering Surveying-Prof. Dr. Ergin TARI
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TRANSPORTATION and TRANSPORTATION
STRUCTURES – GENERAL DEFINITIONS
Main Point, Detail Point: Connection points from one geometric
element to another on vertical and horizontal alignment of the road
called main points (beginning and end points of circular arc,
transition curves, superelevation runoff (ramp)...etc.). Stationing of
this points which are shown with different letters, computed with
calculation except some special cases.
Although it is shown as a continuous line at graphical design, layout
of the route cannot be done in the same way. The route must be
transferred to the ground point by point. The frequency provided by
main points is extremely poor. So the detail (intermediate) points
stationing with the formula below are also transferred to the terrain.
kmPi = k∆l ; k = 1,2,3,...,n (with ∆l as 20, 25, 50 meters) (3.1)
Engineering Surveying-Prof. Dr. Ergin TARI
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TRANSPORTATION and TRANSPORTATION
STRUCTURES – GENERAL DEFINITIONS
During application projects, point densification may
be required in some parts of route with taken
∆l=(5,10)m. In addition to those points, existing
transportation structures, watershed lines and intersect
points are also called detail point. Stationing of this
points is calculated by measuring horizontal distance
to a closest point with known stationing.
Engineering Surveying-Prof. Dr. Ergin TARI
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TRANSPORTATION and TRANSPORTATION
STRUCTURES – GENERAL DEFINITIONS
Direction of Horizontal Curvature: Direction of the curves on the
horizontal route geometry becomes important at computations.
Direction of the curvature is defined with location of the curvature
center according to direction of the chainage increase. Curves are
named as right curve (curve to right) or left curve (curve to left)
according to this direction.
Superelevation: Although transition curves can reduce the effect of
radial force on a vehicle this can also be further reduced or even
eliminated by raising one side (the one away from curve center) of
the road relative to the other. The difference in height between the
two sides of the road is known as the superelevation. In some
sources, horizontal inclination of the road platform caused by the
height differences mentioned above, called superelevation [Umar,
Yayla; 1997, s.136-137].
Engineering Surveying-Prof. Dr. Ergin TARI
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TRANSPORTATION and TRANSPORTATION
STRUCTURES – GENERAL DEFINITIONS
Vertical Alignment: is established with adding curves and line segments end
to end considering guidelines and design criterion. Vertical route geometry is
designed on the profile base.
Profile: is the intersection of physical earth and vertical surfaces along the
horizontal alignment of the road. Design of the horizontal route geometry and
computations should be finished in order to create profile.
Vertical Intersection Point: is the breakpoint of two consecutive line
segments of the vertical route geometry (Figure 3.1). Despite lack of
compliance with this definition, starting and end points of the route are also
considered as intersection points. Vertical intersection points are represented
with U. Horizontal projection of any vertical intersection point coincides with
any route horizontal geometry point. Therefore, vertical intersection points has
stationing.
Vertical Deviation Angle: is an angle between extension of consecutive line
segments(Figure 3.1). These angles are the main quantities (magnitudes) of
the vertical geometry computations.
Engineering Surveying-Prof. Dr. Ergin TARI
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TRANSPORTATION and TRANSPORTATION
STRUCTURES – GENERAL DEFINITIONS
The horizontal and vertical alignments are not designed independently.
Instead they should complement each other. This is especially true for
new construction projects. Poorly coordinated designs can detract from
the benefits and emphasize the deficiency of each alignment.
Horizontal alignments and vertical profiles are among the most
important permanent design elements for a highway. Excellence in their
design and coordination increases the highway’s utility and safety,
encourages uniform speeds, and can greatly improve the highway’s
appearance. This usually can be accomplished with little additional costs.
The designer should coordinate the layout of the horizontal and vertical
alignment as early as practical in the design process. Alignment layouts are
typically completed after the topography and ground line have been
drafted. Computer visualization software are used to visualize how the
layout will appear in the field. Alternatives to ensure that the most pleasing
and practical design is selected.
Engineering Surveying-Prof. Dr. Ergin TARI
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TRANSPORTATION and TRANSPORTATION
STRUCTURES – GENERAL DEFINITIONS
Figure 3.3: Grade line, Ground line, Grade Elevation
and Ground Elevation of Profile
Engineering Surveying-Prof. Dr. Ergin TARI
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TRANSPORTATION and TRANSPORTATION
STRUCTURES – GENERAL DEFINITIONS
Direction of Vertical Curvature: curvature direction of curve arcs on vertical
route geometry is very important. According to location of curve center, there
are 2 different types of vertical curves. If the center of the curve directed to the
ground it is called closed curve or crest vertical curve; if the center directed
to the sky it is called open curve or sag vertical curve [Umar; Yayla; 1997,
s.168].
Center Line Point: Each of the horizontal alignment main and detail points
that has calculated layout elements and marked on the ground are called center
line [Umar; Yayla; 1997, s.113]. Stationing of the center line point is also the
name of the point.
Cross Section: Sections that are perpendicular to the horizontal route
geometry. Stationing of the center line must be written on the cross sections.
Engineering Surveying-Prof. Dr. Ergin TARI
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TRANSPORTATION and TRANSPORTATION
STRUCTURES – GENERAL DEFINITIONS
Cross Section: Sections that are perpendicular to the horizontal
route geometry. Stationing of the center line must be written on
the cross sections.
A cross section is a vertical plane A cross section is a vertical
plane (slice) taken at right angles to the road control line
showing the various control line showing the various elements
that make up the roads structure..
It is normally viewed in the direction of increasing chainage.
Engineering Surveying-Prof. Dr. Ergin TARI
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TRANSPORTATION and TRANSPORTATION
STRUCTURES – GENERAL DEFINITIONS
Ground Elevation: is the elevation of center line points (for profile) and
characteristic points of natural terrain (for cross section). Ground elevation
shows natural topographic characteristics of the terrain (Figure 3.3)
Ground Line: is obtained by combining sequential points of known ground
elevation with line segments (Figure 3.3 and 3.4). Ground line shows natural
characteristic of terrain graphically along profile and cross section route.
Engineering Surveying-Prof. Dr. Ergin TARI
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TRANSPORTATION and TRANSPORTATION
STRUCTURES – GENERAL DEFINITIONS
Grade (Project) Elevation: is the design elevation of the vertical route
geometry points on the profile base. It is determined with computation (Figure
3.3).
Grade (Project) Line: is the graphical visualization of vertical route geometry
designed on profile (Figure 3.3). Grade and ground elevation of any P point is
obtained from vertical route geometry (Figure 3.3). With known grade and
ground elevation, typical cross section is transferred to cross sections of P.
Thus, grade line is obtained on cross sections (Figure 3.4). Grade elevation of
the cross section points is determined with computation.
Typical Cross Section: is a section that represents horizontal and vertical
geometry of transportation structure which is perpendicular to horizontal route
geometry without superelevation [Evren; 2002, s.129], [Müller, 1984, s.206].
Engineering Surveying-Prof. Dr. Ergin TARI
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TRANSPORTATION and TRANSPORTATION
STRUCTURES – GENERAL DEFINITIONS
While obtaining grade line (project line) of cross section, superelevation
application must be taken into account on horizontal alignment. Generally,
one type cross section is not enough along the transportation structures.
Special cross section types are used at; subways, climbing line sections of the
highways, high level excavation and fills require retaining wall, bridges and
culverts…etc.
Typical cross section represents; inclination of embankment slope and
excavation slope, size of bottom, interception and side ditch, divided roads,
number of lanes, width of shoulders, pavement and central (island) reserve,
number of railway lines, line width and distance between line axis…etc.
Typical cross section is one of the main elements of transportation structure
standards determination and must be considered with design speed.
Engineering Surveying-Prof. Dr. Ergin TARI
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TRANSPORTATION and TRANSPORTATION
STRUCTURES – GENERAL DEFINITIONS
Figure 3.4: Grade line, Ground line and other Definitions of CrossSection
Engineering Surveying-Prof. Dr. Ergin TARI
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TRANSPORTATION and TRANSPORTATION
STRUCTURES – GENERAL DEFINITIONS
Earthwork: Closed areas created by grade line and ground line of profiles and
cross-sections show the necessary earthwork. Filling-excavation must be done
in the areas where grade (project) heights are smaller-bigger than ground
heights.
Complex Cross-section: Cross-section that has both filling area and
excavation (cut) area.
Girder Cross-section: Cross-section that has only cut area.
Cut and Fill Slope: Inclined surface created between the road and the territory
at the end of the earthwork.
Side ditch: Ditch that provides the drainage of rain water fall to the cut slope
and the road surface.
Engineering Surveying-Prof. Dr. Ergin TARI
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TRANSPORTATION and TRANSPORTATION
STRUCTURES – GENERAL DEFINITIONS
Interception Ditch: created ditch when needed at junction point of
escarpment and territory (Figure 3.4).
Bottom Ditch: applied at junction point of fill slope and territory. The aim of
the bottom ditch is to prevent the collapse the bottom of fill slope due to
rainwater (Figure 3.4).
Relocation, Variant: certain part of the horizontal geometry need to be
changed at the end of the route horizontal geometry design and route vertical
geometry design in parallel with this route horizontal geometry. Relocation is
the horizontal geometry changes within the cross-sections. Variant is the
horizontal geometry changes out of the cross-sections. Profiles and crosssections must be updated at variant, but they are not updated at relocation.
Engineering Surveying-Prof. Dr. Ergin TARI
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Engineering Surveying-Prof. Dr. Ergin TARI
translated by Res. Assist. Serpil ATEŞ
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