CHENNAI: The High Court appointed Monitoring Committee has identified hundreds of multi-storeyed buildings in the city that have violated development control regulations, said one of its members.
According to MG Deivasahayam, about 1,500 to 2,000 buildings have been identified by the committee and nobody knows how safe these illegal buildings are, as violations pertain to failure to abide by fire safety norms, floor space index and building elevation, he said.
These concerns have arisen close on the heels of the multi-storeyed under-construction building that collapsed in Moulivakkam killing 61 workers.
“We don’t know about structural stability of buildings in the city due to lack of expertise in evaluating the structural design as well as soil tests in both Chennai Metropolitan Development Authority (CMDA) and local bodies,” he said.
The authorities, he added, should set up a technical committee to issue structural stability certificates. Or, the other option is to seek the assistance of experts from institutions like IIT-Madras, Structural Engineering Research Centre or Anna University to certify the safety of the structure, before builders are given clearance.
TM Ramakrishnan, a leading structural consultant, told City Express that the soil across Chennai should be classified differently, as clay and unconsolidated sediments are likely to amplify earthquake impact.
In the case of the ill-fated building at Moulivakkam, Ramakrishnan expressed doubts as to whether the piling work was done properly. “The site is 500 metres away from the lake bed and piling foundation should have gone deep, till you hit the rock,” he said.
The practice of using pre-cast multi-storeyed building concrete, though time saving, was not the best choice for the city, he said.
“This technology comes handy in cities located on inert zones like Singapore and Hyderabad. But in Chennai, it should not be done as the soil conditions are not suitable. Also, the city is classified under Hazard III zone (greater vulnerability to quakes),” he said.
“There is a need for comprehensive soil analysis. Also, it is very important to have a deep foundation depending on the height and load of the structure,” Ramakrishnan added.
K P Subramaniam, former professor of Urban engineering in Anna University, said there was also a need for the government to look at single channel of planning permission rather than focusing on dual channel of permission.
At present, the builder has to obtain the plan approval from CMDA, and then the building permit from the local body concerned.
“CMDA should entrust the approval part to local body and focus only on plans,” he said.