1/1/2017

TRAINING REPORT

chennai metro l & t construction

REPORT OF INPLANT TRAINING ACTIVITIES

At

CHENNAI METRO

LARSEN AND TOUBRO PVT. LTD.

Presented to

THE PROJECT MANAGER

LARSEN AND TOUBRO PVT.LTD

BY

PDS HEMANTH KUMAR

BIJJAMWAR RAHUL

HARSHAL TIKAM

VISVESVARAYA NATIONAL INSTITUTE OF

TECHNOLOGY - NAGPUR

CONTENT

SNo. TOPIC1 The CHENNAI METRO2 EHS Department3 ROLE OF L&T4 SURVEY5 BATCHING PLANT6 QUALITY CONTROL7 CONSTRUCTION OF STATIONS8 DIAPHRAGAM WALL9 TUNNEL10 BROAD OUTLOOK OF STATION11 MECHANICAL ELECTRICAL AND

PLUMBING12 CONSTRUCTION EQUIPMENT

AND VEHICLE USED13 CONCLUSION

CHENNAI METRO

Chennai Metropolis has been growing rapidly and the traffic volumes on the roads have also been increasing enormously. Hence the need for a new rail based rapid transport system has been felt and towards this objective the Government of Tamil Nadu have decided to implement the Chennai Metro Rail Project. This project aims at providing the people of Chennai with a fast, reliable, convenient, efficient, modern and economical mode of public transport, which is properly integrated with other forms of public and private transport including buses, sub-urban trains and MRTS

A Detailed Project Report (DPR) relating to the Chennai Metro Rail Project was prepared and submitted by the Delhi Metro Rail Corporation Limited (DMRC) who have successfully designed and implemented the Delhi Metro Rail Project. The DPR envisages the creation of 2 initial corridors under the proposed phase-1 of the Chennai Metro Rail Project as shown below:

Corridor Length

Washermenpet to Airport 23.1 kms

Chennai Central to St.Thomas Mount 22.0 kms

Total 45.1 kms.

The details of the two corridors are given below:

Corridor-1:

Washermenpet–Broadway (Prakasam Road)–Chennai Central Station–Rippon Building–along Cooum River–Government Estate–Tarapore Towers–Spencers–Gemini–Anna Salai–Saidapet–Guindy–Chennai Airport

Corridor-2:

Chennai Central–along EVR Periyar Salai–Vepery–Kilpauk Medical College–Aminjikarai–Shenoy Nagar–Annanagar East-Anna Nagar 2nd avenue–Tirumangalam–Koyambedu-CMBT–along Inner Ring Road–Vadapalani–Ashok Nagar–SIDCO–Alandur–St. Thomas Mount.

The portions of Corridor-1 with a length of 14.3 kms. from Washermanpet to Saidapet, and Corridor-2 with a length of 9.7 kms. from Chennai Central to Anna Nagar 2nd Avenue will be underground and the remainder elevated. The alignment and stations given above are tentative and subject to change during detailed design and execution.

ENVIORNMENT HEALTH SAFETY (EHS) DEPARTMENT

The EHS department of Larsen and Toubro is based on EHS Management System and Procedures that follows the codes ISO14001 and OHSAS 18001.

OHSAS stands for Occupational Health Safety Assessment Series. Occupational safety means the safety norms to be followed on a construction site or any other workplace for that matter. The EHS Procedures can be divided into 3 parts:

1. System Procedures (S.P): It defines all the legislative requirements that are to be followed on site and also defines the roles and responsibilities of the staff and workmen working in the direction of safety.

2. Control Procedures (C.P): It defines all the measures required to control the no. of accidents on site thus ensures a safer environment at the working site. It also defines the use of PPE (Personal Protective Equipment) like Safety Helmet, Gloves, Safety Jacket, Safety Shoes etc. while on site.

3. General Procedures (G.P) : It defines all the methods of workmen welfare and safety materials used.

EHS department organises a training for the workmen so that each of them can safely work at site.

Safety vests:

High visibility safety vests at first glance appear to be the same now as they have been for many years. But there have been many improvements and variations made to make reflective safety vests more effective and comfortable for workers. Depending on the estimated potential hazards of your job, the type of vest you wear may or may not be American National Standards Institute (ANSI) and Occupational Safety & Health Administration (OSHA) approved.

Non-ANSI approved traffic safety vests are used in what is termed Class 1 environments, which are low traffic areas, like those faced by parking lot attendants. The most often used colors:

Orange safety vest

Yellow safety vest

Lime green safety vest

A sign board indicating the use of PERSONAL PROTECTIV EQUIPMENTS at site for safety.

The construction site is filled with many such sign boards indicating the safety measures that are to be taken while working at the site.

EHS department also issues a safe to startcard on dialy basis after observing that safety measures are taken at the site where work has to be done

As the site consists of various engineers, sub-contractors, electricians, supervisors and workmen, L&T follows a unique system of colour coding that helps in identification of people working on the site.

The colour codes is the colour of helmet wore by the person. The colour codes are as follows:

Green Helmet: For Safety Supervisor

Red Helmet: For Electrician

Purple Helmet: For Supervisors

White Helmet: For Engineers

Yellow Helmet: For Workmen

Also the EHS department maintains a log sheet which indicates the location, activity, s/c, and no. of workmen working at that location. This helps to ensure that no workmen is anyway in danger of any fatality or danger.

The “GOLDEN SAFETY RULE” says that for a work which is above the height of 1.8m should be done with the help of a life line is the site do not comprise anchorage.

EHS department also ensures that the no. of Near Miss cases are maintained low as “A Near Miss could be Next Accident”. And the lower the no. of near miss cases lower is the chance of any fatality on site. It also organises a PDCA (Plan Do Check Act) cycle wherein the officers go for a safety drive.

When any new employee or workmen or trainee join the site, he undergoes a “safety induction process” in which he is taught the various safety measures to be maintained at the site. The induction process of a trainee is done by the safety officer or safety in-charge of the site.

Before allowing a workmen to join the site he also undergoes a medical check-up and then a screening test by the incharge of the department he is to work in. On passing the screening test he undergoes the induction process and then he is ready to work

ROLE OF L&T IN CHENNAI METRO

PROJECT

Larsen & Toubro (L&T) and Afcons Infrastructure were the only two companies who bid for completing the Government Estate to Saidapet section (contracts UAA-02 and UAA-03) of the International Airport to Washermenpet metro line. This section was originally awarded to Gammon & Mosmetrostroy, but they abruptly pulled out of the project earlier this year due to rising costs and left behind material & equipment worth at least Rs 200 crore

After canceling Gammon & Mosmetrostroy’s contract and encashing their Rs 100 crore bank guarantee , the CMRL invited bids for completing the 2 sections:

• BW-UG-02 (originally UAA-02) – Design and construction of balance works of underground stations at Government Estate, LIC Building and Thousand Lights and associated tunnels

• BW-UG-03 (originally UAA-03) – Design and construction of balance works of underground stations at AG-DMS, Teynampet, Nanadanam, Saidapet and Saidapet ramp portion and associated tunnels

Here’s a map which shows these 2 sections which happen to be continuous

The project budget for BW UG 02 IS 473.6 Crores and the duration is 787 days

For the metro project the fund contribution is 21% by central government

20% by state government Remaining 59% by JICA (JAPAN INTERNATIONAL COOPERATION AGENCY)

SURVEYS AND INVESTIGATIONS DONE BEFORE CONSTRUCTION

Basic Survey Soil Investigations Preliminary building survey Building assessment plan

Basic survey:

•  Land surveying : To determine the boundaries and areas of parcels of land, also known as property survey, boundary survey or cadastral survey.

•  Topographic survey : To prepare a plan/ map of a region which includes natural as well as and man-made features including elevation.

•  Engineering survey : To collect requisite data for planning, design and execution of engineering projects. Three broad steps are

1)  Reconnaissance survey : To explore site conditions and availability of infrastructures.

2) Preliminary survey : To collect adequate data to prepare plan / map of area to be used for planning and design.

3)  Location survey : To set out work on the ground for actual construction / execution of the project.

Soil investigations:

The first stage of soil investigation for the metro work had begun in different places near the Madras High Court for collecting soil data for construction of metro stations and underground tracks. As part of the soil investigation work bore-holing was being executed to collect soil data.

Each bore-holing needs two to three days and as a whole 30 to 45 days for getting soil data for a particular stretch,. Once the collection of soil data is over the second stage would be the shifting of underground utilities after which tender would be awarded for track and station works.

Subsurface investigations:

Subsoil conditions are examined using test borings, provided by soil engineer (geotechnical).

Number of borings and location of borings depends on building type and site conditions.

Typically for uniform soil conditions borings are spaced 100-150′ apart, for more detailed work, where soil footings are closely spaced and soil conditions are not even borings are spaced 50′ apart.

Larger open warehouse type spaces, where fewer columns are present (long span) required less boring samples.

Borings must extend to firm Strata (go through unsuitable foundation soil) and then extend at least 20 feet more into bearable soil.

Location of borings samples are indicated on engineer plan.

Borings are not taken directly under proposed columns.

Borings indicate: depth, soil classification (according to the unified soil system), and moisture content and sometimes ground water level is shown as well. (Physical properties: particle size, moisture content, density).

Soil report recommendation should be based on testing of materials obtained from on site borings and to include:

Bearing capacity of soil.

Foundation design recommendations.

Paving design recommendations.

Compaction of soil.

Lateral strength (active, passive, and coefficient of friction).

Permeability.

Frost depth.

Surface investigations:

High Water Table.

Presence of trouble soils: Peat, soft clay, loose silt, or fine water bearing sands.

Rock close to the surface (require blasting for excavations).

Dumps or Fills.

Evidence of slides or subsidence.

The soil of Chennai mostly consists of clay, sedimentary rocks and sandstone.  Part of city like T. Nagar, West Mambalam, Anna Nagar, Villivakkam, Perambur and Virugambakkam have clay soil. The water level is now at an average of 4.70 metre,therefore there was a need of dewatering borewells while construction.

Building Assesment Plan:

General information was collected regarding the building itself, such as the age, construction features, use, furnishings, renovations, local pollutant sources and general maintenance.

Environmental measurements including comfort parameters such as light, sound, temperature and relative humidity as well as pollutant concentrations such as particulate matter, volatile organic compounds (VOCs), biological contaminants and radon were collected at three or more sites within the indoor study space and at one outdoor site for each building.

 Based on observations of engineering; properties during geotechnical construction are an integral part of the design of underground structures. This research presents instrumentation as a tool to assist with these measurement observations, determine the need for modifications to loading or support arrangement. Also apart from above construction control, instrumentation is also indispensable for site investigation, design verification and safety of the structure. Instrumentation used in the construction of tunnels and subways can be implemented in three stagesbefore, during operation and during operation are examined. Metro Railway Tunnels are constructed in populated area and have a more comprehensive instrumentation and monitoring program that additionally includes monitoring of ground conditions, underground water levels, tilt and settlement of nearby buildings or other structures of interest in the vicinity of the tunnel alignment. Instrumentation monitoring for metro railway tunnels includes monitoring of the structures under construction together with the ground, buildings and other facilities within the predicted zone of influence. Furthermore, instrumentation and subway tunnels in and around them increase accuracy of the different

layers of the earth and excavation of the surrounding structures and make safety and accuracy. This paper presents the features of sophisticated instrumentation available today for geotechnical monitoring. A wide range of sophistic have been described with their applications ted electronic and mechanical instrumentation with different instrumentation schemes used to meet the requirements of different types of structures.

The settlement marker is used to measure a localised settlement or heave of roads, slopes, embankments, utility pipes and cables.

Building settlement markers: Ground settlement markers Pavement settlement markers Trackmeters Tilt meters Vibration monitoring sensors Strain gauges

Batching plant

A concrete plant, also known as a batch plant or batching plant or a concrete batching plant, is equipment that combines various ingredients to form concrete. Some of these inputs include water, air, admixtures, sand, aggregate (rocks, gravel, etc.), fly ash, silica fume, slag, and cement.

Different grades of concrete used were prepared in batching plant as per requirement such as M45 for piling and D-wall, M35 for slab and M20 for PCC.

Capacity of batching plant is 1 m3 per batch Ingredients used were OPC 53 cement, fly ash, 20mm & 12mm coarse aggregate ,

reversed and manufactured sand ,water and admixtures. Super plasticizer used was polycarboxylate ether ( Fosroc auromix 400) used for

increasing initial settling time (0.7% used) 20 % of flyash was used for concrete preparation.

A Batching Plant has following parts HOPPER: It is the place where all the materials required for the mix design is

dumped and it contains a net of iron bars that filters the big pieces and stops them from entering in the plant.

BELT CONVEYOR: It carries the material required from the hopper to the compartment bin.

COMPARTMENT BIN:A compartment where all the material i.e. the coarse agg,, fine agg. Are segregated and there are different compartments for each material so that no mixing happens before the starting of plant.

MAIN STRUCTURE: It is the part where all the mixing happens. It comprises of following parts:i) Aggregate gate: These are air pressure controlled gates that open at the time of

mixing and aggregate from bin is sent to the bucket for further process.ii) Skip wire Bucket: This carries the aggregates from the gates to the pan mixer. It

rests on load cells that calculate the amount of aggregate in it and thus carries only the required amount.

iii) Pan Mixer: It the part which does the mixing of the various components required for the mix design. The aggregates from the gates are filled in the sip bucket and are carried to this pan mixer. The cement, Fly Ash from the silos are sent to the cement weigher and are sent to mixer. Similarly water from water weigher is sent to the pan mixer. Here mixing is done for 30seconds and then the concrete of the required mix design is ready.

iv) Control Unit: The whole process of mixing is controlled from a computer called the control unit of the plant. The weight and mix design of the concrete is decided and fed in a computer which runs the plant automatically to give us the required mix.

2) SILOS: These are storage unit that stores cement and fly ash and supplies them to the batching plant when required. The Silos at plant have a capacity of 100ton for cement storage and 40 ton for flyash storage . They also consists of a SAFETY VALVE to stop the silo from bursting while its filling and when it gets emptied.

3) CHILLING PLANT are used for concrete mixing and cooling applications with 4oC and 1oC chilled water temperatures, as per the process requirement to obtain required temperature on site (28-320C).Capacity of tank is 50,000 L.

4) CONCRETE PUMP: A mechanical device which is used to pump concrete from one place to another.These pumps can pump concrete to a height of 60m. It consist of 2 cylinders viz. Pumping and Differential Cylinders that acts alternately to pump concrete.

QUALITY Department

This department is responsible for ensuring the quality of work on site, also it conducts various tests on material used for construction and ensures that no faulty material is being used.

This department is also called QA/QC (QUALITY ASSESSMENT/QUALITY CONTROL) DEPARTMENT.

QC- is responsible for controlling the assured quality and is a site level work.

QA- is responsible for assurance of quality to client and is all done at the tender level.

The department follows ISO9001, 2005 for defining the quality of the material used in the project

The PQP contains Quality Management System, Management Responsibility, Resource Management, Product Realization and Measurement Analysis and Improvements

Tests on cement

NORMAL CONSISTENCY: The consistency is measured by the Vicat apparatus using a 10mm diameter plunger. Acceptable limit is 5-7 mmfrom bottom.

COMPRESSIVE SRENGTH : Cubes of 50 mm2 area are prepared and tested after 3,7 & 28

days after curing and they must satisfy limits as per IS standards.

INITAIL SETTING TIME AND FINAL SETTING TIME: Initial setting time should not be less than 30 minutes for OPC and final setting time should be around 10 hours.

FINENESS TEST: The percentage of residue retained on 90 micron sieve should not exceed 10%.

SOUNDNESS TEST: Soundness value of cement according to Le-Chatlier test should not exceed 10mm.

AGGREGATE

These are used for the following reasons:1. Reduces the Heat of Hydration of cement.2. Reduces the Shrinkage effect of cement.3. Its economical.

These are of 2 types:

1. Fine aggregate(less than 4.75mm particle size)2. Coarse aggregate(more than 4.75mm )

TESTS ON AGGREGATE

FLAKINESS AND ELONGATION INDEX SIEVE ANALYSIS SPECIFIC GRAVITY TEST(PYCNOMETER) FINENESS MODULUS BULKING OF SAND

TESTS FOR ADMIXTURES

To test the quality of admixture various test are carried out.

The following are the desired results of the tests on the aggregates:

1. Dry Material Content: +/- 3% of the value stated by the manufacture.2. Relative density:+/- 0.2 of the value stated by the

Manufacturer.3. pH: Should not be less than 6.4. Ash content: +/- 1 of the value stated by the manufacturer.

TESTS ON CONCRETE

COMPRESSIVE SRENGTH : Cubes of 150x150 mm2 area are prepared and tested after

3,7 & 28 days after curing and they must satisfy limits as per IS standards.

SLUMP TEST: Slump of workable concrete should be around 80-120 mm , pumpable concrete 150 mm and 170±25 mm for concrete used for D-wall and piles.

TEMPERATURE should be around 28 to 320C on site.

CONSTRUCTION OF THE STATIONS & TUNNELS

Cut-and-cover methods Mining methods

CUT AND COVER METHOD

Bottom up method: Buildings with underground basements are built by bottom-up method where sub-structure and super-structure floors are constructed sequentially from the bottom of the sub-structure or lowest level of basement to the top of the super-structure and is called as bottom-up method which is simple in both design and construction

Top down method:Top-down construction method as the name implies, is a construction method, which builds the permanent structure members of the basement along with the excavation from the top to the bottom. Top-down method is mainly used for two types of urban structures, tall buildings with deep basements and underground structures such as car parks, underpasses and subway stations

Out of 3 stations, LIC and Thousand Lights stations are constructed by top down method and government estate station is constructed by bottom up method

PROCEDURE

The typical construction procedure of top down construction is as follows

         Construct the retaining wall.

         Construct piles. Place the steel columns or stanchions where the piles are

constructed.

         Proceed to the first stage of excavation.

         Cast the floor slab of first basement level

         Begin to construct the superstructure

         Proceed to the second stage of excavation; cast the floor slab of the second

basement level.

         Repeat the same procedure till the desired depth is reached

         Construct the foundation slab and ground beams, etc. Complete the basement

         Keep constructing the superstructure till it gets finished.

INSTALLATION OF RETAINING WALL

The underground retaining wall which is usually a diaphragm wall, is installed before excavation commences. EXCAVATION AND INSTALLATION OF STEEL STRUT

The soil is excavated just below roof slab level of the underground structure. Struts are installed to support the retaining walls, which in turn support the soil at the sides

Construction of underground structure

The roof slab is constructed, with access openings provided on the slab for works to proceed downwards. The roof slabs not only provides a massive support across the .

Construction of underground structure

The next level of slab is constructed, and  this process progresses downwards till the base slab is completedConstruction of underground structure

The side walls are constructed upwards, followed by removal of the intermediate struts. The access openings on the roof  slab are then sealed.

Backfilling and reinstatement

After the underground structure is completed, the soil is backfilled to the top strut level before the strut is removed. This is followed by completely backfilling the top of the underground structure and  finally reinstating the surface areas.

DIAPHRAGAM WALL

A diaphragm wall is a structural concrete wall constructed in a deep trench excavation, either cast in situ or using precast concrete components.

Diaphragms walls are often used on congested sites, close to existing structures, where there is restricted headroom, or where the excavation is of a depth that would otherwise require the removal of much greater volumes of soil to provide stable battered slopes.

The walls generally range in thickness from 500-1,500 mm and can be excavated to depths of over 50 m. Excavation is typically carried out using rope-suspended mechanical or hydraulically-operated grabs. Specific ground conditions or greater depths may require the use of hydromills – hydraulically-operated reverse circulation trench cutters – to penetrate into hard rock by ‘cutting’ rather than ‘digging’. Hydromills can achieve depths of up to 80 m.

The excavation stability is maintained by the use of a drilling fluid, usually a bentonite slurry. This is a controlled mixture that has thixotropic properties, meaning that it exerts a pressure in excess of the earth and hydrostatic pressures on the sides of the excavation. The walls are constructed, using reinforced or unreinforced concrete, in discrete panel lengths generally ranging between 2.5-7 m. Purpose-made stop ends can be used to form the joints between adjacent panels, with a water bar incorporated across the joints. More complicated arrangements such as ‘L’ or ‘T’-shaped panels can be constructed where additional bending moment capacity or wall stiffness is required.

The units are installed in a trench filled with a special mixture of bentonite and cement with a retarder added to control the setting time. Ground anchors are used to tie the panels or posts to the retained earth to provide stability.

M45 grade of concrete is used with Fe 500 steel reinforcement Thickness of d wall is 800mm at entrances and 1 metre thick at station Depth of D wall varies from 22 to 26 m accordind to the hard strata depth Polymer used for stability of soil is bentonite \couplers placed in the reinforcement panel to connect the steel bars of slab with D

wall Minimum width of panel of steel cage is 2.5 Guide wall is constructed before excavation for Dwall for soil stability. It is

constructed using M20 grade of concrete and it is about 1.5 m deep and 1.2 m thick Grouting is done to stop seepage due to defects in the wall Cuffer wall is constructed parallel to Dwall which is used for finishing and additional

protection against seepage KODEN test is done to check verticality of d walls.

Sequence of construction of D wall:

Guide wall construction Trenching upto feet level of required depth Pouring bentonite mixto provide stability Cage lowering and placing the couplers properly Tremie lowering Concreting the d wall Grouting of d wall

Plunge columns: A plunge column is a structural steel or concrete section embedded in a freshly poured concrete pile, eliminating the need for baseplates and holding-down bolts.

Construction procedure is same as that of D-wall Plunge column rests on pile of 1.2 meter diameter I steel section reinforcement in used while construction which is then filled with

concrete. M45 grade concrete is used Plunge column acts as a support to horizontal slab of long span resting on D wall.

STUB COLUMN: These are additional column provided temporarily to support auxillary loading and support during construction.

SLAB : It is a horizontal structure used to transfer vertical loading to coloumn and D-wall.

RCC Slabs Construction at three different levels i.e. at roof level, concourse level and base level present at different depth and serving different purpses.

M35 Grade of concrete and HYSD Fe500 is used for construction Slab is two way reinforced by steel rods which are attached to d wall by couplers and

mechanical joints. Pullout test is performed initially to ensure fixidity of bars Thickness of slab is around 800 mm with minimum cover of twice the maximum size

of coarse aggregate used. Additional lateral reinforcement is provided to avoid shear failure. Additional water proofing sheet are laid while concreting to avoid seepage Temporary PCC layer of M20 Concrete was laid below steel reinforcement before

concreting. Concrete was properly compacted using needle vibrator and maximum height upto

which pouring pipe can be raised is 1.5 meter to avoid segregation.

TUNNEL Total length of metro in phase 1 is 46 km out of which 23 km is underground

tunnel. Internal diameter of tunnel is 5.8 meter Tunnel is made of many rings of width 1.4 meter. Each ring consist of six segments 275 mm thick made of M50 grade concrete. One ring consist of 5 majour segments and a key that is used for locking. Tunnel of initial diameter 6.6 meter is dug by TBM machine Grouting of 120 mm is done by cement concrete and sodium silicate to

accelerate the hardening process to avoid seepage. TBM applies a force of 25,000 to 40,000 knm Soil excavated is carried using belt conveyer or trolleys. Average speed of excavation is 5 cm per minute. Temporary tracks and ventilation pipes are provided . Distance between two tunnels is 7.7 m. There will be cross passages after every 250 m in case of any emergency.

BROAD OUTLOOK OF METRO STATION Metro station has four entrances and exits. Station has three levels- 1)Roof level 2)Concourse level 3)Platform

level Roof level is 3 to 4 meters below ground level. Concourse level is 6 meters below roof level Level difference between concourse and platform level is 8 m. Platform is at height of 2 m from base level Concourse level consist of ticket vending machines ,retail

shops ,signal equipments and control room ,communication equipments ,anciliary substation room ,AC and ventilation monitoring room ,cleaner room ,refuse and toilets ,first aid room.

Platform level consist of rail track , signalling equipments ,power supply lines.

Vent Shafts are provided at the ends of station to maintain pressure balance

Station length is 220 to 250 m and width is about 22 m. The station box is dog bone structure

ANCILIARY BUILDING It is the heart of metro station which provides power ,water and

cool air to station. It consist of DG compound, transformer room, chiller

plant ,storage tank .

Before constructing the anciliary building shoring of the periphery of the site is done to avoid the failure of surroundind buildings

Construction sequence: Soft pile of 300 mm dia are constructed at the periphery of the

site Soldiers piles are provided as additional support to soft piles Struts are fixed to provide lateral support After the entire process of excavation and construction soldier

piles can be removed if possible for future use Anciliary building is G+2 structure

Mechanical electrical and plumbing (MEP)

These departments govern the following operations: Air ventilation at stations Tunnel ventilation Power supply Electrical supply Fire fighting Car alarm system

Plumbing system Water supply Drainage management Signalling and telecommunication system Lift and escalators Traction system

Construction equipments and vehicles used