CHENNAI: Metro rail tunneling caused cracks in 212 buildings in the city, reveals an RTI application filed by TOI. The RTI also shows that the damages are not limited to old buildings in north Chennai.
The RTI reply from metro rail said damages were reported in 212 buildings along the metro route in Washermenpet, Mannadi, High Court, Nehru Park , Egmore, May Day Park, Government Estate, May Day Park, Chennai Central and Shenoy Nagar, Anna Nagar Tower after boring for the underground line started in 2012.
In a reponse to the query as to why the vibration monitoring report of the Ripon Buildings and Victoria Public Hall has not been sent to Chennai Corporation, inspite of repeated requests from the corporation, CMRL said the reports are for internal monitoring and are not meant for sharing with any other agency. "The vibration monitoring report has not sent to the corporation as there were no events on cracks or damage recorded on Ripon Building and Victoria public hall due to the tunneling," read the reply.
As for the damages to the heritage buildings due to the underground tunneling, the CMRL said, "Damages were reported in Arcot Lutheran Church, Tamil Wesley Church and the compound wall of law college building." According to the rules, metro rail must undertake the responsibility for the repair of any damage to existing structures caused by tunneling or construction work. However, CMRL stated that "the cost of repairs is met directly by the contractors" and they do not have records on the amount spent for the repairs of the affected buildings.
S Neeta, a member of CSI Tamil Wesley Church, which had developed cracks due to the construction work, said CMRL did not repair the damage. "They conducted a meeting with parish members. But there was no follow up. Experts from Anna University said that a major restoration is necessary for the church". A senior metro rail official said the church developed crack as the machine had to be stopped and restarted as a few people living in old houses refused to move out on time. "The church walls developed cracks due to the jerk triggered when the machine was restarted," he said.
"If any building is vulnerable they should dig soil from near the foundation and fill it with sands. Sand can absorb vibration and save the building," said former professor of civil engineering department in Anna University.
A CMRL official said, "We are using data from many devices — crack meter, inclinometer, deflection meter to monitor vibrations during the underground tunneling."