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Bhanu P Lohumi
Tribune News Service
Shimla, April 27
In the wake of the deadly earthquake in Nepal on April 25, the safety of fast-mushrooming stilt buildings in Himachal Pradesh, which falls in seismic zone IV and V, has come under scanner.
A stilt building is an open ground-storey building in which upper storeys rest on columns on the ground floor. The ground storey, which does not have any partition walls, is left open for the purpose of parking. Therefore, the ground storey of these buildings is relatively weak and vulnerable during an earthquake.
“Open ground-storey buildings have consistently shown poor performance during past earthquakes across the world and a large number of such buildings collapsed and during our visit to Gujarat after the earthquake in January 2001, we found that even the two to three-storeyed stilt buildings collapsed, while the normal building only suffered some damage”, said Arun Bapat, an earthquake expert.
“The old houses constructed on hills are safer than the new houses built in open spaces, as they have one side on the rock and woods used in structures bend and bear the shock. The concrete RCC buildings are not flexible and collapse during quakes,” he added.
“In a layman’s language, stilt buildings can be explained as buildings on chopsticks, which are severely stressed. These chopsticks like columns swing back and forth as inverted pendulums during an earthquake.
The earthquake is also a warning for the Himachal Government which is toying with the idea of regularising high-rise buildings with deviation up to 70 per cent without conducting any study of structural safety and earthquake resistant features.
“A Gujarat-like earthquake in Shimla, which has turned into a concrete jungle and become highly vulnerable to earthquakes, can spell doom as most structures are ecologically fragile slopes,” said Prof SS Chandel of NIT Hamirpur. There construction of buildings, especially private ones, without adherence to earthquake-resistant features was an invitation to impending disaster, he added.
The destruction in the hill state will be much more than caused in Gujarat as the collapse of one-weak structure atop a slope would have “cascading effect”.
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