Page 14 - CO April 2017 Full Issue

METRO RUSH COVER STORY Powered by outmoded by forming watertight joints by simply cutting into the According to Vivek Singhal, COO Urban Infrastructure, Tata Projects, “We are one of the concrete of adjacent panels. fastest construction company in the metro space and poised for leadership position. Today we are PRE CASTMETRO PORTALS: Starting with simple precast segments that were tied together to form involved with Delhi, Mumbai, Ahmedabad and Lucknow metros” a full span of the metro portals, L&T now supplies an entire span Metro rail systems can either be elevated as in the ‘U’ girders, these trough-like heavy concrete structures are cast at a case of Hyderabad Metro, or underground or a combination of the dedicated yard under standard factory conditions and then shifed two as in the case of Delhi Metro. Tey have to be sturdy enough being cast as a single piece to fast track project completion. “Called to bear the weight of a city’s heavy trafc, as well as resilient enough to the site where they are merely lifed and placed into position to battle fuctuating environmentalconditions like sea level rise and using a combination of heavy duty cranes. Pre cast technology is storm surges, especially in the case of underground pathways and also being used by L&T for construction of station buildings where tunnels. Plus with people increasingly using stations not only as in both the concourse and platforms are now precast and erected mobility destinations but as centers’ for leisure and business, our in place at the station buildings thereby fast-tracking completion forthcoming metro rail infrastructure will need to be fexible of these complicated structures along the metro corridors. Except enough to adapt to evolving requirements. for laying of foundations and erection of pillars which are both in- So this month, we decided to take a look at what are the key situ processes, over 85 per cent of the works are now precast.”, says, technologyand social trends shaping up the metro rail infrastructure S V Desai, Executive Vice President & Head – Heavy Civil in India. Infrastructure, L&T Construction. According to NVS Reddy, MD, Hyderabad Metro Rail Ltd, DRIVERLESS TRAINS: “Te innovation of constructing Metro stations New Metro rail lines across India are being equipped with the in pre-cast format and erecting them on central communication-based train control (CBTC) system that will enable piers as balanced cantilever structure has set a them to go driverless and also run more trains at greater frequency. new bench mark.”Balanced cantilever technology Unlike the traditional system, where the trains have to maintain includes constructing several concrete sections of a gap of three minutes, CBTC allows trains to follow each other a span on top of the piers using a bridge builder. within one and a half minutes on the same track. With the help of Pier width is confned to about 2 m at road level, sensors on the track and other systems, the trains maintain distance accommodating 2 rail tracks on the viaduct with each track between each other automatically. equivalent to 7 bus lanes or 24 car lanes. Brijesh Dixit, MD, Maharashtra Metro Rail Corporation Te viaduct on the Noida Metro rail services, a 30-km Noida Greater (Maha Metro) says, that while the existing Metros Noida metro link project is being constructed by a specialised are opting for this system in their new lines, new technique of pre-cast pier caps and precast U-girders. Te project Metro projects like Pune and Nagpur are beginning recently entered the national Limca Book of Records for setting a with this state-of-the-art signaling system. Kochi record for the most girders in a month on a single Metro line project Metro has also opted for this new system. New in the country. According to Dr. Mangu Singh, MD, DMRC's, the lines in the Delhi Metro, Bengaluru Metro, feat has signifcantly expedited the progress of the Lucknow Metro, Hyderabad Metro and Mumbai corridor. "We broke our own record in October last Metro Phase III are moving to this new system as well. year when we erected 218 U-girders which converts Siemens Limited and Siemens Rail Automation have already won to approximately 3 kms of twin Metro elevated the `287 crore order from Nagpur Metro for their CBTC solution viaduct in one month. We have registered it for called Trainguard. Other companies such as Alstom, Nippon and the record as well," Singh said.Te contractor for Tales are also getting active in this space. this line is CEC (Taiwan)-SAM(India). INCREASING ROLE OF TRENCH CUTTER TUNNEL BORING MACHINES (TBM) EQUIPMENT: Revolutionising Underground Construction: L&T, the pioneers of Trench cutter equipment in India introduced According to S V Desai, Executive Vice President & Head – the machines frst time for constructing for underground stations. Heavy Civil Infrastructure, L&T Construction, the selection of “We installed India’s frst secant pile wall for the Delhi Metro the tunnelling methods for underground rail constructiondepends Rail project at Hauz Khas.”,says, Desai. Currently the company on the ground conditions, surface features and dimensions of the has supplied cutter-based diaphragm walls for the Chennai Metro tunnel. Based on the constraints and location, the stations can be Rail (CMRL) project as well. Here the trench cutters were used constructed using: to pierce through very hard soil and rock for the construction of • Top Down Method with diaphragm walls underground stations. Besides providing access, trench cutters also • Bottom Up Method with Soldier pile/Sheet pile / Secant pile ensure that the soil does not collapse on the edges as the excavation • Combined Top Down and Bottom Up Method (Diaphragm progresses. Trench cutters not only enhance both the quality and walling with shear pins)” speed of the joint construction between the panels but also make One of the most recent examples of the use of technology is for the installation and removal of temporary stop end structures the proposed Metro 3 or the 33.5 Km long fully underground 14 construction opportunities|aPrIL 2017