India site report: Making connections

Over the years Delhi has become one of India’s major commercial and residential hubs taking its population to more than 16 million. As a result there are an increasing amount of vehicles choking up the road networks.

To ease transportation across the city, in 1995 Delhi Metro Rail Corporation (DMRC) was formed with equity participation from the Union Government of India and State Government of the National Capital Territory of Delhi. The aim was to build and operate a world class metro. The master plan for Delhi Metro was for a network of underground, elevated and street level corridors of more than 400 km. The plan was for the network to be completed in four phases.

Work for Phase 1began in 1998 and was made operational in 2002. Phase 1 has a total route length of 65 km with 13 km underground and 59 stations. The second phase of the project was completed in 2010. It extended the system by another 120 km adding 80 stations. It covered 15 km of elevated and 5.16 km of underground track on one stretch, connecting Central Secretariat and India’s federal parliament to the outskirts of the city. A further 14 km of underground and 8 km of elevated track was added to link the metro with Delhi’s suburbs known as National Capital Region.

Now work is underway for the third phase of the project, which will extend the system by another 140 km. Cost of construction is INR 35,242 crores (US$ 5.7 billion). The Japan Bank of International Cooperation is funding 52.68 % of the total fund requirement while the Union Government of India and Government of Delhi are paying 10.64 % each. Interest free subordinate debt for central taxes and land is 14.47 %.

The third phase will add 47 km of underground lines while the remaining lines will be elevated corridors covering a total number of 90 stations. The project will connect arterial roads of Delhi comprising the Ring Road, outer Ring Road and parts of Old Delhi. It will also take the metro to Faridabad and Bahadurgarh, cities in the neighbouring state of Haryana. Contractors for the third phase are Indian construction company Larsen and Toubro and Shanghai Urban Construction Group (SUCG joint venture entity), Hindustan Construction Corporation (HCC) and Samsung Engineering joint venture, Afcons, ITD-ITDchem, Pratibha and Femc. Civil subcontractors are SB Protech.

Bringing benefits
Ever since its commissioning, the metro has brought immense social and commercial benefit to Delhi and the National Capital Regions. With more than 200 train sets of both four and six coaches, Delhi Metro carries almost 2 million passengers daily. According to estimates by Central Road Research Institute of India and the Central Government Road Research Institute, up to 2011 the metro has helped in removing 150,000 vehicles, including cars, buses, two wheelers and auto rickshaws from the roads of Delhi. It has also played a major role in preventing more than 200,000 tonnes of emissions of harmful gases. It has also helped in saving at least 660 accidents and 132 fatal accidents. Economic benefits in terms of emission savings cost and annual fuel and time costs saved on road passengers are estimated to be around INR 4,905 crores (US$ 797 million).

Completion of the third phase by 2016 is expected to further reduce vehicle population as the metro will carry an additional 4 million passengers. It will interlink the residential, commercial and industrial areas of the capital city along with its outskirts.

The 140 km link will have seven corridors that will be built over busy roads and railway crossings connecting Delhi and Mumbai, which are both densely populated commercial and residential areas. A record number of 25 tunnel boring machines are going to work simultaneously on the project. At four points the tunnels are going to pass below the operational tunnels of Delhi Metro. At one section the metro will pass over the existing viaduct of Airport Express metro Link that presently connects the city centre with Delhi’s new modernised international airport.

Anuj Dayal, senior official spokesman, DMRC, said, “Taking into account the complexities in way of project execution, we are employing the latest and safest construction technologies available. For underground corridors, we are primarily using tunnel boring machines. We have opted for underground corridors wherever the alignment passes through congested areas as our intention is to cause minimum possible inconveniences to the people during construction work. For the third phase, we are using an advanced box pushing technique as it will help us to carry out construction without carrying out large excavation or digging.”

Lifting challenges
Despite the advanced construction techniques being adopted, challenges are galore for crane operators working on the project. Vivek Gautam, senior site engineer of joint venture company Hindustan Construction Corporation- Samsung (HCC-Samsung), explains, “One of the biggest challenges is the given limited shaft area for lowering and retrieving sections of tunnel boring machines as the project is taking place in heavily congested city areas.”

HCC-Samsung is working on CC-34 package, one of the vital pockets of third phase. The project comprises construction of a 250 metre station that will connect the densely populated Dhasrath Puri area in West Delhi with the domestic airport. The station is being constructed at a depth of 26 m from the surface with a width of 28 m.

On site a Manitowoc MLC 100 hydraulic crawler crane supported by a 75 tonneTelcon Tata (TFC 280) friction duty cycle crawler crane is being used to lower a 20 tonne diaphragm wall cage. The MLC 100 is working with a 34 m boom. It is also helping prepare the diaphragm walls by lowering and then removing stop end frames at both sides of the diaphragm wall cage. Other work for the 100 tonne MLC 100 includes holding the hopper attached with termi pipe along with the TFC 280 for pouring concrete. TFC 280s are being used for the third phase, particularly for concrete pouring and unloading 20 – 23 tonne precast concrete girders from trailers for the superstructure.

Gautam says, “Although the hydraulic crane is not working to its optimum capacity we opted for the crane because with its longer boom it will be able to lower and retrieve sections of TBM and other heavier materials at deeper depths, bypassing the restrictions posed by limited shaft area, during the later part of the project. Furthermore, it is safe and has higher uptime as is required in our compressed work schedules.” The majority of the cranes working at the third phase of the project have been hired by contractors from crane rental companies.

Latest generation
DMRC has strictly stipulated in its tender documents prohibiting the use of old generation cranes in the third phase which were used in the first and second phase. Dayal explains why, “We have decided to introduce new age cranes to further enhance safety and performance. The new cranes should have in built safety features and better stability for undulation which may be encountered at the construction sites.” DMRC has engaged independent agency for certifying the cranes to be used at its site.

Also working on site is a Kobelco CKL 1000-I. The lattice boom crawler crane was manufactured in India and is working at CC-27 station, which is being constructed by L&T-Shanghai Urban Construction Group JV. Aided by a longer boom, the new 100 tonne capacity crane is being used to lower diaphragm wall cages at CC-34 project, which is supported by a TFC 280 crane. Dipankar Ghosh, plant and machinery manager at L&T-SUCG says, “We have reconfigured the boom from 30 to 35 metres to provide a better reach required at our job site, which has restricted space. With a longer boom the crane can easily lift the longer diaphragm wall cage for lowering. The crane will be much more suitable with its longer boom to lift and lower universal and vertical beams that will be required for cut and cover construction methods at our site in the future.”

At the L&T-SUCG CC27 project, a 500 tonne Liebherr LTM 1500 configured with 165 tonnes of counterweight and a 31.7 m boom, is being used to lower a 100 tonne TBM shell. The crane will also be used to lower 180 tonne cutter head sections of TBM along with erecting gantries between 30 to 35 tonnes at the site, which has a limited lowering shaft area.

While working with a longer boom is proving beneficial for the crane operators, precautions are taken during slewing and lifting operations, especially at congested locations or sites where high tension electricity lines are yet to be removed. To bypass any issues, crane operators are provided with permits to lift prior to starting any lifting operation. Lifts are carried out in the presence of competent lifting supervisors.

Raising demand
The third phase of the project has created demand for newer cranes at a time when crane manufactures and dealers in India are facing shortage in orders due to delayed implementation of infrastructure projects.

Jayakara Kalmadi, Telcon-Hitachi product manager, cranes and senior manager, business development, says, “We have supplied 8 to 10 units of TFC 280 for the project.”

“Ninety per cent of new variants TRX series mobile slew cranes for the project have been supplied by us,” Sheetal Malik, Escorts Construction Equipment general manager, sales, adds. Despite demand for new units, however, there has not been much improvement in the rental rates as the Indian crane market continues to face an excess supply of cranes. There are 150 to 160 cranes working on the third phase of the Delhi Metro project and the numbers are likely to exceed that as the project gains momentum.