Bangalore Metro Rail Corporation Ltd. (BMRCL) has successfully erected a 65-m-long composite steel girder over the Salem railway line bridge along the Outer Ring Road (ORR) metro line. The operation was completed on January 30 near Rainbow Hospital, between ISRO and Doddanekkundi metro stations, according to a BMRCL press release.
“The girder launch was particularly challenging due to the lack of service roads, a restricted opening in the railway underpass, and the skewed crossing of the railway track,” officials said. While such operations typically require two cranes of 400-500 tonne capacity, the BMRCL opted for a single 700 tonne crane to minimise traffic disruptions. The girder was divided into three sections — two side spans of 14.5 m each and a central portion of 36 m — to align with the crane’s operational capacity.
“The composite girder, weighing 575 tonnes and featuring four girders with a depth of 3.4 m, was necessary to accommodate the existing railway line and future expansions by the Railways and K-RIDE. While U-girders are generally used for Phases 2A and 2B metro construction, longer-span composite girders are being deployed at key traffic junctions, flyovers, and railway crossings,” an official said.
To facilitate the erection, passenger train services on the Bengaluru-Salem line were halted, and traffic on the ORR was temporarily diverted. The Bengaluru traffic police permitted road closures from 9 p.m. to 6 a.m. while the Railways blocked the track between 11.30 p.m. and 3.30 a.m. Nearly 70 workers, including BMRCL engineers and contractor SNC personnel, executed the operation over three nights.
With the girder successfully installed, the remaining work, including the erection of the balance portion, deck slab, and parapet, is expected to be completed within two months, easing traffic movement in the area.
Published – January 31, 2025 08:26 pm IST