The Calcutta Metropolitan Development Authority (CMDA) has sought “traffic clearance” from Lalbazar to conduct a load test on Bijon Setu following the bridge inspection committee’s concerns over its health.

This is the second time that the CMDA has sought help from the police in conducting the test on the bridge that connects the Bypass to Rashbehari Avenue over the rail tracks at Ballygunge.

The test, according to CMDA engineers, will decide the bridge’s weight-bearing capacity.The CMDA had earlier proposed to close down the bridge between September 13 and 16 for the test. But it had to be postponed after the police said closing the bridge a fortnight ahead of Puja could trigger a traffic mess.

This time, the police are still to take a call. “No decision has been taken regarding Bijon Setu,” Santosh Pandey, DC, traffic, said.The CMDA had then said that postponing the test — apparently to make way for puja shopping in the Gariahat area — would delay the assessment of the bridge’s stability.

Calcutta has had three bridge collapses in the past six years, leading to the deaths of more than 30 people. Several diversions will have to be put in place before allowing the CMDA to carry out the load test on the bridge, the police said.“There are many schools along the Rashbehari connector and hospitals on the Bypass. There is no other alternative to crossing the tracks at Ballygunge to either reach Ruby or Gariahat,” an officer said.

“Buses and other vehicles will have to diverted either around No. 4 bridge or Dhakuria bridge. A coordination between at least four traffic guards will have to be worked out.”The police are looking for a “safe period” for the test — a time when traffic flow will be low and schools and other institutions will be closed, another officer said.

Several shops have come up under the bridge and some have drilled holes into the columns to install AC units, a CMDA engineer said. “A delay will jeopardise the task of assessing the exact condition of the bridge.”In September 2018, a few weeks after the Majerhat bridge collapsed, the government had carried out a preliminary health audit of 11 bridges and flyovers across Calcutta and Howrah.

A firm headquartered in Los Angles in the US and a consultancy agency in Calcutta had marked Bijon Setu “grey”, suggesting repairs, after Sealdah, Ultadanga and Chingrighata flyover, which were marked “red”. Code red meant these structures needed immediate repairs.After completing the load tests on the three, the CMDA now wants to carry out the test on Bijon Setu, which recently received a fresh coat of paint.

The bridge may look fine externally but it is imperative to find out the strength of the deck slabs above the tracks and the steel girders inside because that is the part that bears the maximum load, the CMDA engineer said.

“We will mount two loaded trucks and check the stress on the steel rods and the concrete. We will then calculate the deviation because of the load and compare it with the ideal weight meant for the bridge,” the engineer said. “The result of the load test will indicate the condition of the bridge.”

Bridge advisory meet

The urban development department’s bridge advisory committee will meet CMDA engineers and officials on Friday to review the progress of the health audit on several bridges and flyovers in the Calcutta metropolitan area.

The health studies are being conducted to assess the condition of the bridges and take remedial action if needed.