ISTANBUL TECHNICAL UNIVERSITY DEPARTMENT OF GEOMATICS ENGINEERING · 2013. 3. 7. · maps by using...

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ISTANBUL TECHNICAL UNIVERSITY DEPARTMENT OF GEOMATICS ENGINEERING

Prof. Dr. Ergin TARI Translated by Res. Assist. Serpil ATEŞ

PHASES OF TRANSPORTATION

STRUCTURES

A highway or a railway goes through many phases until performing

community service. These phases will be explained under the titles of;

transportation survey, decision, preliminary study, preliminary project,

application project (final project), construction and management [Baykal;

1984], [Evren; 1993, s.132], [KGM; 2002], [KGM; 2005]. Compatible

teamwork starting with preliminary study through preliminary project is

imperative for entrie construction phases. This team may consists of

transportation specialist (highway or railway), geology specialist, geodesy

specialist, geotechnical specialist, hydraulic specialist, structural specialist,

material specialist, electrical specialist, mechanical specialist, agriculture

specialist, forest specialist, landscape specialist. Lack of any of these

specialists may cause cost increase.

2 Engineering Surveying-Prof. Dr. Ergin TARI


STRUCTURES

TRANSPORTATION SURVEY PHASE

National transportation network is determined with

transportation survey. This network consists of the planned

future transportation structure types, network nodal point,

network connections. Zoning operation is carried out with

determining the proper zones from the point of economic,

social and transportation aspects [Evren; 1993, s.132].



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DECISION PHASE

It is the phase of deciding on constructing a highway or railway in transportation network, which combine two specific nodes. The main factor of making this decision is reaching certain level of transportation demand which is the component of the economical and social development of the region. In addition to these, political and strategic developments may also influence the decision.

Transportation demand shows estimated traffic volume of road after 20-30 years following the opening, and plays an important role in determining road standards. Subjected traffic is called design traffic volume at highway [Umar; Yayla; 1997; p.82–90]. For railways, estimated passenger (number) and load (tons) amount of one way and in a year is taken into account. They are referred as passenger and load transport demand [Evren; 1993, s.134].



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PRELIMINARY STUDY PHASE

Although, an infinite number of route can be identified for a road between two path in theory, a few of them can be applied. Scope of the preliminary study is to identify applicable solutions and achieve appropriate one with comparing this solutions with respect to certain criteria.

Different route solutions can be produced very quickly and cost-effectively with determined minimum radius of circular arc and maximum vertical grade on 1/25,000 scaled digital topographic base maps by using software such as; Autodesk Civil 3D, Bentley Road Railway Suites, Netcad Net Pro…etc. Subjected maps can be obtained from General Command of Mapping [General Command of Mapping Web Page; March, 2006].



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PRELIMINARY STUDY PHASE (cont’d)

Route selection can be performed on topographic maps manually. In that case, the zero-polygon (zero line) is used to determine horizontal route geometry[Umar; Yayla; 1997, p.99–100], [Evren; 1993, p.144-146], [Müller, 1984, s.167-168]. However, manual route selection should not be preferred for important projects because of the long survey time, high cost and problems in finding appropriate solution.

Terminal points (start and end points) and strategic constraint points of the route are given; traffic and topographic obligatory points are determined at the beginning of the route selection. The constraint points for passenger and load exchange on route are called traffic obligatory points. The constraint point at the changing the grade of the natural terrain are called topographic compulsory points [Evren; 1993; p.142-143]. These are geometrically regions with certain width.



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A selection and elimination is performed between defined routes at route

selection process. The routes;

that have high construction cost (according to criterion such as;

engineering structures, earthwork, route length),

that have insufficient geological and geotechnical characteristics (1/100

000 scaled geologic maps can be used),

that have high operation and maintenance cost because of the topography

( high amount of cut and fill )

are left out of assessment. Other options are examined on the field in detail

(preliminary survey) and a report is prepared for each route option.



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The report of this phase include;

Vertical and horizontal geometry of the route,

Location and approximate size of the engineering structures,

Geologic and geotechnical structure of the ground, landslide areas,

low loading capacity soil areas along the route,

Groundwater and surface water status according to seasons, flow and

drainage possibilities,

Location and performance of borrow pits,

Agriculture land status along the route, positive and negative effects

of the route on these lands,

Approximate expropriation status [Umar; Yayla; 1997, p.98].


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Existing geological maps are used for ground researches. At critical

areas in respect to loading capacity, soil research pits can be dug.

Water information can be provided from General Directorate of

Hydraulic Works and Turkish State Meteorological Service, in

addition to field surveys. At this stage, status of the existing and

planned engineering structures (highway, railway, high-voltage

transmission line, water transport pipes, irrigation channel…etc.)

must be taken into account. During field survey, using hand-held

GPS receivers with ±10m position accuracy provides a great

convenience.



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Eliminination process is continued with the information provided from field survey and one route is determined on 1/25000 scaled topographic maps. Width of the route is determined according to road type and standard. For example for highway, route width is changin from 1-4 km [KGM, 2002], [KGM, 2005].

At the second step of preliminary study, 1/5000 scale maps are used as a base map. These maps, which are provided from General Directorate of Land Registry and Cadastre, should be updated [KGM, 2002], [KGM, 2005]. If there is no existing map of the region, the topographic map is produced. The route determined on the 1/25000 scaled maps is implemented to 1/5000 scaled map and different route alternatives are surveyed along this route. At this survey, documents required by at specifications are preperad for each route according to the following subjects [KGM 2002], [KGM, 2005], [Evren; 1993], [Umar; Yayla; 1997]:



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Issues to be taken into account at route selection;

a) Route geometry survey: The horizontal route geometry is designed on

1/5000 scaled map, the vertical route geometry is designed on 1/5000-

1/500 scaled profile. In addition, in order to calculate earthwork cross-

sections are taken at 100m interval for highway, 500m interval for railway.

The cross section intervals are densificated at engineering structure areas,

high cut and fill areas and lanslide areas. Elevation information of 1/5000

scaled maps are used while taking cross sections and profiles.

b) Preliminary geologic and geotechnical survey: superficial

observations are made and soil research pits are dug where needed. Maps

and cross sections which show geological and geotechnical characteristics

of soil, are prepared with existing geological maps, aerial photos and

remote sensing images



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Issues to be taken to account at route selection (cont’d);

b) Preliminary geologic and geotechnical survey (cont’d): Existing and hazardous landslide regions and regions that have low loading capacity are identified at this documents. Given documents are produced and a report will be prepared for each route alternative. Strength and weakness of route alternatives according to soil survey and precaution taken at problematical areas are explained at the report.

c) Hydrologic and hydraulic survey: Flood plain and drainage basin of streams which affect route are determined on 1/25000 or 1/100000 scaled maps. Basin rainfall information which is provided from General Directorate of Meteorology is used to calculate flood rate. For big river basins, direct measurement values provided from General Directorate of Electrical Power Resources Survey and Development Administration and General Directorate of State Hydraulic Works are taken into account. In addition, maximum water level, flooding risk ...etc. information of streams are also collected. In the light of this information, approximate solutions about surface water drainage, approximate location and size of engineering structures are determined for each route alternative. These information must be taken into account at route design.



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d) Existing and designed other facilities:

The location of existing and designed highway and railway facilities;

airport, transformer, energy transmission line, liquid and gas

pipeline, telegraph, telephone and internet cable lines, irrigation

channel, dam, lagoon...etc. is determined. It is required that route

alternatives do not intersect with these facilities and changes at this

facilities must be as small as possible. For inevitable intersections

and changes, solution suggestions should be prepared.



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e) Climatological conditions: winter conditions plays an important

factor at road maintenance and operation. At rough and mountanious

terrain, routes that have low amount of cut and fill and pass through

south and east shoulders are preferred.

f) Environmental impact assessment: Possitive and negative affects

on existing and planned settlement, industry, agriculture, forestry,

tourism, hitorical ruin...etc. areas are investigated according to

related regulations.



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g) Engineering structures: The location and size of engineering structures

such as; tunnels, underpass, overpass, viaduct, retaining wall... etc. is

determined.

h) Traffic survey: The traffic report is prepared including; existing traffic

volume, estimated traffic volume of next 20-25 years and traffic count if

needed.

i) Borrow pits: A report is prepared including location and performance of

borrow pits that will be used at construction such as; grovel, stone and

water,...etc.

j) Manufacturing and operating cost: Studies mentioned above are

dimensioned (quantities) and cost analysis is done.



STRUCTURES Issues to be taken to account at route selection (cont’d);

All of the operations provide preliminary design for each route [Umar; Yayla; 1997; p.104]. After preparing preliminary design, economic comparison is done between route alternatives. Although there are various economic analysis methods for investment determination, the most common method is cost-benefit analysis [Umar; Yayla; 1997, p.105–110]. The most appropriate route is determined according to other characteristics of the route alternatives in addition to economic comparison.

At third stage of the preliminary study, the most appropriate route is surveyed in the field. Layout of route points in certain intervals (such as 100m) and painting the points with white color make field surveys easier. Certain changes may be necessary at appropriate route after field and office surveys. Information and documents similar to preliminary design is prepared again for appropriate route in consider to these changes. By adding preliminary, lanscape and lighting projects of engineering structures (such as station, bridge, viaduct,...etc.) and other necessary information, preliminary design of the appropriate route is prepared. This project is finalized with approval of the authorized agency.



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PRODUCTION OF LARGE-SCALE MAP

1/5000 and larger scale maps are called large-scale maps [BÖHHBÜY; 2005, Article: 1]. Large scale maps are the main infrastructures of road projects. In order to produce these maps, it is necessary to select one of the TUD-54 or TUTGA networks. TUD-54 shoul be used only at compulsory cases. TUDKA network is taken into account for elevations.



STRUCTURES PRODUCTION OF LARGE-SCALE MAP

Large-scale map (1/5000, 1/2000, 1/1000) production procedures shall be applied in the following order:

1. The route was determined on the 1/25000 scale maps at the first stage of the preliminary study. This route determines an area of large scale map.

2. 1/25000 scale map of Turkey that shows sheet names has sheets including route. This map includes; approximate locations of TUTGA-99A GPS points, four letter names of this points and approximate point locations of TUDKA-99 levelling network [General Command of Mapping Web Page; March 2006]. With specifying the name of the TUTGA-99A points and locations of TUDKA-99 points which are close to the route; coordinates and speed of these points, point protocoles and elevations are purchased from General Command of Mapping. TUD-54 points are marked on 1/25000 scale maps. The protocole and coordinates of these maps can be provided with sheet names. Point protocoles are the documents containing information to find points in the field. With the help of these, points can be found and controlled in the field. If the information is not reliable, it should not be used at latter processes.



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3. Point Densification:

Side distances of Turkish National Fundemental GPS Network 1999 (TUTGA-99A) is 25-50 km and about 15 km at earthquake zones [Ayhan; v.d. ; 2002]. At Turkish National Horizontal Control (Triangulation) Network these values are; (25-35) km for first order points, (10-30) km for second order points [BÖHHBÜY; 2005, Article:8]. According to the large scale map production regulations, point density is inadequte and point densification is necessary for both networks.

Turkish National Vertical Control (Levelling) Network (TUDKA-99) points are generally near the existing highway and railway and line length between points is (1-1,5) km [Demir; Cingöz; March; 2006]. Point density decreases while depart from the route and a new vertical control network that connected to TUDKA-99 must be established.


STRUCTURES

PRODUCTION OF LARGE-SCALE MAP (cont’d)

3. Point Densification (continue):

Hierarchical structure of point densification, numbering of points, selection of point location, measurements and evaluation of measurements are described at Large Scaled Map Production Regulation (BÖHHBÜY) in detail.

As a result, a) project horizontal control network composed of points with; known coordinates at 3⁰ Transversal Mercator plane, known ellipsoidal and orthometric heights; b) project vertical control network composed of points with; known orthometric heights and known plane coordinates is established. These networks have many common points (such as traverse points).



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4. Detail Survey: Detail survey is the process of determining geometrical details along the route to produce large scale map. Different terrestrial surveying and photogrammetric techniques can be used at detail surveys such as Prismatic method+levelling, real time kinematic GPS (RTK) and electronic tacheometer. At prismatic method+levelling horizontal locations are determined with prism and steal tape and the height of the points are determined with levelling. This technique has small application area and not appropriate for large scale map production for road projects. RTK GPS technique is still under development and some problems can not be solved yet. Building edge, tree, telephone and electiric pole can not measured with this technique directly. Application of this technique in forested and densely populated areas is almost impossible. Electronic tacheometry is the most useful one of the surveying techniques. However, the cost is increased and some details can not be measured if the area of the map is large.



4. Detail Survey (cont’d):

Photogrammetry is the most economic technique and should be considered primarily for large scale map production for road projects. However, this technique may also have some problems at heavily vegetated and densed regions.

At each technique, detail surveys must have processing and digitally transferring abilities. [BÖHHBÜY; 2005].


STRUCTURES


APPLICATION PROJECT (FINAL PROJECT) PHASE

Application project is the model of the designed road to be built. In this model, information can not be incomplete and conflict with any other. The main stages of application project phase are summarized below:

1.At preliminary study phase, a 1/2000 or 1/1000 scale strip type map of terrain, which is approved on 1/5000 scale map and centered the appropriate route and has the width of (200-400) m for highways and railways, (800-1000) m for state highway, is produced. In addition, a 1/500 scale map of the engineering structures (station, bridge, tunnel, junctions) regions is produced [KGM, 2002], [KGM, 2005], [Umar; Yayla; 1997, p.104].

2.The horizontal route geometry is designed again in detail on 1/1000 and 1/2000 scaled maps considering the approved route.


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STRUCTURES APPLICATION PROJECT (FINAL PROJECT) PHASE (cont’d)

3.Profile along the designed horizontal geometry and cross section

perpendicular to designed horizontol geometry (generally at 20m intervals)

are prepared using map elevation information. Route vertical geometry is

designed on profile and implemented to cross sections. Earthwork is

calculated.

4.Appropriate geometry is obtained by changing necessary parts of the road

geometry created at stage 1 and stage 2. Horizontal route geometry is

finalized with the approvement of related agency.

5.Main points and intermadiate points (generally at 20m interval) are set out to

the field and ground elevations of these points are determined with levelling

in the field (profile). In addition, levelling is carried out to obtain cross

sections perpendicular to the route. Designed vertical and horizontal route

geometry is implemented on profiles and cross sections, small corrections

will be done along vertical geometry if necessary cross section production

with field surveys shall be cancelled by approval of related agency. 24 Engineering Surveying-Prof. Dr. Ergin TARI

APPLICATION PROJECT (FINAL PROJECT) PHASE (cont’d)

6. Earthwork volume (cubage) is calculated, Bruckner diagram is prepared,

avarage hauling distance is determined.

7. Along the route, drilling is done at required rate and depth (geotechnical

study). Geotechnical report is prepared according to observations at

borehole and the laboratory test results of soil samples. This report includes

the following information:

Cross sections and profiles that show geological structure,

Information about loading capacity and slope stability,

Land slide risk zones,

Information about underground water,

Information about ground where engineering structures are located,

Locations and performance of borrow pits (sand, gravel, stone, water)


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This information is used to determine usibility of excavation

materials at embankment areas, superstructure thickness, maximum

embankment height (according to slope stability), inclination of the

embankment and excavation slopes, underground water

drainage,...etc [Umar; Yayla; 1997, p.104 -105 ile 250–256].

8. Necessary reports are prepared with detailed hydraulic and

hydrologic surveys. These reports are use at design of engineering

structures which prevent roads from surface water damage and at

drainage project design.

9. Drainage application projects are prepared for underground and

surface waters.


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10.Application projects of engineering structures (tunnel, viaduct, bridge, headwall, station, retaining wall,...,etc.) are prepared.

11.Application projects of traffic signs, signalization, lighting, wire fence, railing,...,etc. are prepared.

12.Expropriation plans and lists are prepared.

13.All projects are dimensioned (quantities) and cost analysis is done for all.


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CONSTRUCTION PHASE

Construction phase is all of the actions layout of designed road

project items(geometry, material,...etc.) to physical earth.

At this stage, mission of a geomatics engineer is to organize and

manage layout (set out) process of road geometry according to

required accuracy.


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CONSTRUCTION PHASE (cont’d)

The main topics of layout process is briefly described below;

1. Infrastructure (earthwork) works: Establishing designed

horizontal, vertical geometry and cross section geometries in the

field. Engineering structures are also included in the scope of

infrastructure. In this context, some parts of the terrain line are

excavated and some parts are filled. All of the cut and fill processes

called earthwork [Umar; Yayla; 1997, p.16], [Evren;1994].


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Layout works during earthwork;

a) Scarp (side slope) pegs (stakes) are piled.

b) Horizontal route geometry is marked with pegs in the field.

c) Cross section directions and inclinations of side slopes are determined for each center line point in the field.

d) When earthwork comes to a certain stage, drainage structures such as side ditch, bottom ditch,...etc. are layout to the field.

e) The surface acquired after earthwork is called level surface. To establish vertical and horizontal slopes designed at project, tinny leveling (rigging) is done [Umar; Yayla; 1997, p.16] and final control of the project lines and infrastructure works are finalized. Required accuracy for earthwork is (1-2) cm at horizontal and vertical[Müller;1988, p.30].


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2. Engineering structures: Construction of the engineering

structures such as tunnel, viaduct, bridge, headwall, station,

retaining wall,...etc. is generally started before earthwork.

Therefore determination of engineering structure location and other

layout works must be done carefully. Because the faults cannot be

corrected. Required accuracies for engineering structures cannot be

found at examined references.


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3. Superstructure (Pavement): Pavement is composed of sub-base layer, road

base layer and surface base layer at highways [Umar; Yayla; 1997, p.16]; in

addition to sub-base, base layers, rails and sleepers at railways [Müller, 1984a,

p. 26–27]. The thickness of these layers is determined according to quality and

quantity of traffic volume, soil characteristics, loading capacity of infrastructure,

etc. Surface is referred pavement at highways and rails at railways. To ensure

safety and comfort, this surface must be exactly same geometry with the one in

the designed project. Vertical geometry of pavement layer at highways is more

important and required accuracy is ±(5–6)mm at normal highway and is ±(1-

3)mm at state highways or motorways [Müller;1988,p.30]. Required layout

accuracy of rails is dependent on design speed (e.g. it is ±(0.6-0.8)mm at 120

km/s speed, for horizontal and vertical alignment). According to [Drake; p.269]

and [Evren; 2002, p.233], the required accuracy is ± 0.67 mm for speeds up to

160 km/s, and ±0.33 mm for 200 km/s.


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MANAGEMENT PHASE

Completed road will be serve the community as long as possible. Therefore

maintenance and repair/restoration of a road fatigued by external factors is

very important.

At highway; traffic signs, lane lines, wearing course and slopes are

controlled constantly and necessary repairs are done.

At railway; rail wear, deformations on rail geometry, ballast efficiency and

safety are important for operation efficiency. In this context, worn rails are

changed and re-ballasting is done.

Determination of the deformation at highway and railway engineering

structures such as; tunnel, viaduct, bridge, headwall, station, retaining

wall,...etc. is the important maintenance/repair works of geomatics engineer.

PHASES OF TRANSPORTATION STRUCTURES


ISTANBUL TECHNICAL UNIVERSITY DEPARTMENT OF GEOMATICS ENGINEERING · 2013. 3. 7. · maps by using...

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