Saturday, October 6, 2012

Assess Chennai buildings seismic vulnerability

C Shivakumar
 
The vulnerability of buildings designed prior to Chennai being classified under seismic zone III should be assessed again, according to an expert.

Former IIT professor and consultant of United Nations Development Programme A R Santhakumar told Express that vulnerability of Chennai buildings is yet to be assessed fully to identify whether they are disaster resistant constructions especially those built prior to 2000.

The buildings were designed when Chennai was classified as seismic zone II (low intensity zone). After 2000, Bureau of Indian Standards based on various scientific inputs from a number of agencies including earthquake data supplied by IMD, has classified Chennai under seismic zone III (moderate intensity zone).

The buildings have to be studied keeping mind the safety for a zone III level earthquake. According to a paper published in Natural Hazards and Earth System Sciences An Open Access Journal of the European Geosciences Union in 2011, a total of 93.8 per cent of houses built of earthern and stone and brittle burned brick are vulnerable to quake of moderate to severe intensity. It also states that sand dunes and beach ridges in the coastal best of Chennai have also been converted into residential area as such the true landform has been altered.

Prof Santhakumar also stressed on the need for setting up a group that monitors the structural safety of buildings. Neither Chennai Metropolitan Development Authority nor Chennai Corporation look into the structural safety of buildings, the former dean of Anna University claimed.

To a query over the collapse of the more than 50-year-old building in Triplicane, he said there is a need to audit buildings that are more than 50-year-old so that the ones which are vulnerable could be renovated. He also urged the builders to construct buildings while taking into account the coastal conditions of Chennai.

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