The recent tremors in Bhubaneswar have finally woken the city planners from their hibernation. The BDA is planning to amend building norms to retrofit old multi-storey structures to make them earthquake-resistant in view of the May 21 tremors that shook the state.
Comprehensive Survey of City Building Structure
BDA will identify such buildings by conducting a survey, though for all practical purposes, most buildings constructed till 2007 would come under the scanner. The 2007 cut-off is being mulled because BDA made structural stability certificates from empanelled structural engineers mandatory for multi-storey constructions in 2008. Buildings which came up after that are being regarded as safe enough to withstand quake jolts to a great extent. Public buildings such as hospitals will come under scrutiny first.
A technical group led by Pitabasa Sahoo, planning member, BDA, has been working on the proposal. Experts from IIT Bhubaneswar (IITBBS), IIT Kharagpur, Geological Survey of India (GSI) and India Meteorological Department (IMD) are part of the group. The group held its first meeting on Saturday. Sahoo, who chaired the meeting, declined to comment stating that “the details are yet to take concrete shape”.
Quake Alarm Systems in High Rises
BDA is mulling the IITBBS recommendation of creating a probabilistic hazard map of the city to evaluate earthquake risk on important buildings, so that proper measures can be taken such as reinforcing the structure if needed. Since a few seconds can be critical during a quake for saving lives, high-rise buildings may be considered to have alarm systems, sources said.
“The recent earthquake was indeed a lesson. A slight increase in magnitude would have proved devastating. In the light of this earthquake, the BDA initiative is laudable,” an IIT professor present in the Saturday meeting said.
Construction Compliance for Builders
Sources said the buildings would be retrofitted to comply with seismic zone-III requirements. The owners would be given a deadline to comply with after which action would be taken.
Among others, buildings under construction would be checked by independent organizations for their compliance with seismic zone-III needs. Geological conditions such as information about faults, folds, lineaments and fractures would be considered while granting permission for future buildings of more than two floors, if the move gets the government nod.
BDA is also considering IITBBBS proposal to carry out geophysical investigations, (seismic/ gravity/ magnetic) to determine the shallow surface properties such as thickness of loose soil and basement depths. “Seismic waves are amplified several times while propagating through loose soil. Buildings constructed over loose soil and poor foundation would be investigated for their seismic risk,” said an expert.
Courtesy: The Times of India