Though it has been sometime since the city was upgraded to the Zone III (where earthquakes up to 5 to 5.5 on the Richter Scale can be expected) of the seismic zoning map, not much attention is being given to this fact by structural engineers while designing buildings.
Pointing out that there was a 20 per cent chance of an earthquake of the magnitude of 6.5 on the Richter Scale occurring in the city, K. Balaji Rao, Scientist F, Structural Engineering Research Centre (SERC), said, “There is a need to specify the hazard more specifically so that structures can be designed to face it.”
The ‘code of practice' for ensuring structural stability issued by the Bureau of Indian Standards (BIS) needs more exhaustive scientific grounding so that spatio-temporal variations due to the impact of earthquakes can be accounted for in the vulnerability index, he said.
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Dr. Rao was delivering a lecture on ‘Probabilistic seismic hazard analysis of India' organised as part of the National Technology Day celebrations at the SERC. He stressed the need for a comprehensive fragility analysis of various categories of buildings and a model to predict the “peak ground acceleration” expected in case of an earthquake along all 771 seismic faults in the country. “A standard that is more holistic is required so that it can be enforced,” he added.
K. Ramanjaneyulu, Scientist F, SERC, spoke on the need for continuous structural health assessment and performance evaluation of bridges.
Giving a presentation on a ‘User knowledge base toolkit' developed at SERC to aid in assessment and retro-fitting of largescale structures, he said, “Even when periodic assessments are carried out, officials of the Highways Department or Railways do not know what to look for.”
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He said that remote monitoring systems using fibre optic technology must be made mandatory during the construction of bridges and flyovers so that maintenance could be a scientific process.