About 75 per cent of the girder has been launched while remaining work on the delicate job was to be completed on Sunday night
Work on to launch the 90-metre-long steel girder weighing 1,300 tonnes at Gokhale bridge. Pic/Anurag Ahire
Notwithstanding the one-day delay in launching the girder for the reconstruction of the Gokhale bridge near Andheri railway station, BMC officials are hopeful of completing the project on time. The launching of the 90-metre-long steel girder weighing about 1,300 tonnes was expected to be completed on Sunday night.
The work of launching this girder started on Saturday night and about 75 per cent of the work had been completed. The contractor and BMC officials were hoping to complete the launch on Saturday itself however, moving an enormously heavy girder, such as this, has its own set of problems.
BMC officials say progress of the girder launch has been safe. Pic/Anurag Ahire
There are not many things that come in the 1,300-tonne range to understand the enormity of the task at hand. A 747 Boeing jet weighs a minimum of 300 tons, thus the launching of the girder is equivalent to manoeuvring four 747 Boeing jets at height of 13 metres over a temporary steel scaffolding known as trestle.
Once the girder is pulled, due to intertie it continues to move on its own motion, even when the pulling is stopped. Thus, the pull and resultant motion has to be within desirable limits, else, the girder could shoot off beyond the trestle on which it is resting on and result in a major disaster. On Saturday night, as the girder movement was more so the engineers had to reduce the number of steel ropes pulling it. Though only 75 percent of girder has been launched, BMC officials are content that its progress so far has been safe and remaining launch will be resumed and completed in about two hours on Sunday night.
During the work of the girder launching Andheri West MLA Amit Satam, and Andheri East MLA Rutuja Latke deputy municipal commissioner (DMC) Ulhas Mahale and chief engineer of bridge Vivek Kalyankar were present.
The almost finised work on Sunday. Pic/Sameer Markande
DMC Mahale said that after this girder is launched on the trestle it will be moved about 14 metres sideways in the north direction 7.5 metres above its destination on the pillars. A BMC official said said, “Usually the girder is lowered about 1-2 metres and this would be the first time in India that a 1,300-tonne steel girder will be lowered 7.5 metres. At the Vidyavihar Rail Overbridge the girder was lowered to 4 feet.” The launch height is on the higher side as this is reconstruction of the bridge over an existing approach road. Usually the approach roads are constructed after the launching and lowering of girders. BMC is deploying two such enormous girders for the reconstruction of the Gokhale bridge. The work of lowering the girder will be done under the guidance of a special expert.
“Western Railway allows us a 15-day mega block for lowering the girder, but we are trying to complete this task in 11 days, as it had been officially stated. For that, we will use a lowering block and jack which will be temporarily installed on pillars. This girder will be lowered by 550 mm per night. The girder was launched at a height of 13 metres as there is already an approach road built 6 metres high, an official added. Due to technical difficulties we even can’t launch the girder from the side where the approach road has been built,” a civic official said.
DMC Mahale said that the bridge on one side will be opened to traffic by February 15, 2,024 and the entire bridge is expected to be completed by May 2024. The length of the bridge is 485 metres. 90 metres of bridge is over the railway lines. The bridge is 24 metres wide with a footpath. The part of the bridge had collapsed in 2018. The bridge has been closed to traffic since November 7, 2022. Initially, BMC was only going to construct access roads within the city limits, while the railways will construct the bridge. After the bridge closed for traffic, it was decided that BMC would construct the entire bridge.