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| A barge damaged the girders under Howrah bridge in June 2005, that has left the structure over-stressed, says a recent survey. A Telegraph picture |
Rabindra Setu (Howrah bridge) had missed a disaster by a whisker when the mast of a barge got stuck in its underbelly on June 24, 2005, a survey has revealed.
The mishap, however, has left part of the 62-year-old icon of the city overstressed. To restore it to its normal condition, around Rs 50 lakh and eight tonnes of steel will be required.
The survey, conducted by Rites, pegs the overstress at more than 10 per cent of the bridge?s load-handling capacity. The report has been submitted to Calcutta Port Trust (CPT), custodian of the bridge.
CPT officials fear the stress is much more than what Rites has estimated. ?The Rites findings are based on a study of the traffic load conducted in 1982-83. Since then, the number of vehicles plying on the bridge has increased manifold,? an official explained.
The survey has found a six-mm deformation in the affected girders. Of the six panels of girders running from the Howrah to Calcutta end, parts of two have been damaged. ?Had the girders shifted a few more millimetres, the damage would have been substantial and the affected parts would have to be replaced,? the official said. Even vehicular movement would have to be stopped for a few days.
?The stress on the structure is beyond the permissible limit and it needs to be repaired as soon as possible. If neglected, the stress could lead to permanent damage,? another official warned.
Repairs will start from mid-January and the steel and other material have arrived at the site.
Another study will be carried out to measure the traffic load and whether any measure is necessary to strengthen the structure. Apart from the number of vehicles plying on the bridge, the types of vehicles ? heavy, light and medium ? using it will be taken into account.
Also to be considered is the number of pedestrians using the bridge and at what time of the day and the year the load is maximum.
?The study may be taken up along with the repairs,? an official said, adding it will help ascertain the exact level of the overstress.
Apart from the girders, around 400 ft of the trolley guide, set up for maintenance, have to be repaired. Work will be done in two phases. The affected trolley guide will be replaced in the first phase and the damaged girders will be strengthened in the second. Additional stiffeners will be required in the second phase.
During the survey, Rites experts had conducted ultrasonography and magnetic particle tests to find out whether the integrity of the girders was intact. Fortunately, no ?inside crack? was detected.