MUMBAI: The Andheri (E) road cave-in on Tuesday was caused by corrosion of steel in a slab, it has been revealed prima facie.
Consultant D S Joshi, who made the submission to the BMC, told TOI that material from the site had been sent for laboratory tests to ascertain the reasons for the corrosion. “I would be able to give the exact reasons once the report is available. It would take about a week,” he added.
Meanwhile, the BMC on Wednesday decided to conduct an audit of all concrete slabs over nullahs across the city.
The 30-ft road in Gundavali village has two lanes on either side of a 20-ft-wide nullah. The road was built by laying slabs atop portions of the nullah in 1985.
N V Merani, chairman of the Standing Technical Advisory Committee (STAC), said the nullah’s water could have eroded the earth below the slabs. “The other possible reasons could be lack of maintainance or poor quality,” he said, adding that laboratory results could only shed light on the extent of loss of strength due to corrosion and not the reasons behind the same.
“This can be found out only through close inspection of the corroded section by an experienced engineer,” he said.
Two weeks ago, the STAC had raised the issue of old civic bridges with the BMC. There are 253 bridges in the city; of these, 102 are over waterways, 17 are flyovers, 41 road overbridges, 93 foot over-bridges and subways.
“We did a study of 34 old bridges three years ago. By now, they should have been repaired or reconstructed. But nothing has moved,” said Merani.
The STAC had recommended that a separate chief engineer be appointed to exclusively monitor bridges and concrete roads. The BMC has created a post not filled it up. “The MMRDA is constructing flyovers and roads and handing them over to the BMC. The corporation needs to appoint a person to that post. We have even suggested that if they cannot promote an engineer, they can get someone on deputation. But decisions in the BMC are ad-hoc,” he said.