CONSTRUCTION OF OVERHEAD BG LINE BETWEEN MADRAS BEACH AND LUZ CORNER, ON TRESTLES FROM 263 TO 305 (MASS RAPID TRANSIT SYSTEM) ON PRE-STRESSED BEAMS IN CHENNAI, TAMILNADU.
Client: Indian Railway Construction Co.Ltd., New Delhi
Location: Chennai, India
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The project consisted of the construction of cast-in-situ and pre-cast, pre-stressed concrete box girders for up and down tracks, up to a maximum span of 30 m, including parapets, kerbs, gang path made from pre-cast slabs, complete at an elevation of 5 to 10 m from the ground level. The work was done in the densely populated area of Chennai, Luz-corner, crossing a very busy main road where vehicular traffic remains open for 24 hours. Most of the PSC box girder beams were cast over temporary trusses spanning the trestle columns. Centring has been specially designed for the bottom, sides and top slab considering the weight of the beam and various sequences of operation for the casting of beams.
A high strength concrete of M-50 grade along with superplasticizer and admixtures were used for beams and cantilevers. Before casting the beams, 9 cables to a particular profile was installed at a pre-designed location. After the casting of beams, designed number of strand wires, duly painted with waterproof epoxy paint, were inserted in the cables and on pre-determined sequences they were stressed to designed load by special heavy-duty hydraulic jacks.
Pre-cast box beams were casted on the already completed area, on specially prepared beds at design elevation, practically using the same sequence of operations as that of cast-in-situ girder beams. The entire work was completed in two and half years against heavy odds of busy traffic area, involving around 70 PSC box girder beams with other related items.