Construction flaws caused crash at Manapakkam: CMRL officials

Construction flaws led to girders crashing, killing a man; CMRL begins investigation and safety audit to prevent future incidents.

The construction flaws appear to have led to the girders crash at Manapakkam in which a 43-year-old person was crushed to death on Thursday night.

According to officials of Chennai Metro Rail Limited (CMRL) a detailed investigation into the incident has begun. “Prima facie, it appears that the method of construction is at fault. The I-girders should have been secured well,” an official said. In addition, the vibration from movement of heavy vehicles over an undulation of a recently closed pothole on the road too could have triggered the incident. It could have been prevented if the girders were firmly secured, the official suspected.

Around 9.45 p.m., as 43-year-old Ramesh, a resident of Nagercoil was travelling past Manapakkam, the girders from the under-construction flyover fell on him. At this location, a double-decker corridor’s construction has been ongoing for years. While the flyover is at the first level, CMRL’s phase II elevated corridor 5 runs above it.

Last week, very close to the location where the incident occurred, CMRL claimed a ‘historic engineering feat’ after erecting a 33.3 metre U-girder for the elevated corridor. While the U-girders are fixed here for building the Metro Rail’s elevated stretch, the I-girders are deployed for the building of the flyover linking Mugalivakkam with MIOT Hospital. These I-girders are also long, unlike the standard 25 metre girders, measuring 33.3 metres, officials said.

“The instability could have been also because of the I-girder length. Shorter spans usually don’t cause such issues. Even in the case of the OMR, we had a 30 metre long I-girder and there were no incidents. Here, too, if the steel A-frame holding the I-girders at both points were held tight, the accident would have not occurred. We also suspect there may have been uneven loading on the frame. Only a detailed investigation will reveal the reasons,” another official said.

CMRL has begun an extensive safety audit. Wherever the I-girders have been placed, like for instance, in Mount-Poonamallee Road or the IT Corridor, a team of engineers are checking every span. “We are placing additional rods in between the I-girders and strengthening them with welding yet again at both ends,” he said.

CMRL officials also said, the U-girders placed in most parts of the elevated corridor for the phase II project are safe. There are also safety officers who periodically check each site, they said.