Sixteen cables of Vidyasagar Setu, which hold the structure from the sides and are not visible from outside, will be replaced, the state government has decided.
The replacement of the 16 “holding down” cables will mark the first “comprehensive overhauling” of the bridge, which was inaugurated on October 10, 1992, said engineers at the Hooghly River Bridge Commissioners (HRBC), the custodian of the structure.
The bridge has another 152 cables — called “stay cables” — which are visible from outside. Two sets of piers, with their foundations in the river bed, on either side hold the cables from the top.
Engineers at the HRBC, a state government agency, said the 16 holding down cables lie beneath the two sets of piers and ensure that the cables above hold the tension of the entire structure.
“These holding down cables, as their name suggests, are crucial as they help the stay cables above to maintain the correct tension of the bridge despite the traffic heavy,” said an HRBC official.
Spanning 823 metres, Vidyasagar Setu is the longest cable-stayed bridge in India.
Two companies, Freeman Fox and Partners and the Bharat Bhari Udyog Nigam Limited, were involved in the construction of the bridge, which continued for 22 years.
“The decision to replace the 16 cables was taken after the bridge and the cables were inspected by a team of experts. A team of engineers from a French firm will replace the 16 holding down cables,” the HRBC official said.
“Traffic on the bridge — around 90,000 vehicles use the bridge daily on average — will not be disrupted during the work. The actual work of replacing the cables will start in July after groundwork is completed. The new cables will be imported from Germany.”
Before the imported cables are fitted, the holding down cables will be temporarily replaced with other cables.
Engineers said each cable has three layers. The innermost layer is made of a bunch of non-galvanised cables and the outer layer is made of rubber. There is an intermediate layer made of wax, which prevents water seepage.
“This is the first time that the holding down cables will be replaced,” an HRBC engineer said.
The HRBC had earlier decided to replace 14 of the 152 stay cables. Traffic restrictions were drawn up for the nights of April 29 and 30 for a “taut string test” of the cables, ahead of the replacement, but it had to be put on hold because of unavailability of machines.
Sandalwood
A consignment of 200kg of red sandalwood worth around Rs 10lakh was seized from a car on Bhukailash Road, in Kidderpore, on Friday, police said.
Five persons in the car were arrested when they allegedly could not produce documents for the consignment.
