GUWAHATI, April 28: The Assam Real Estate and Infrastructure Developers Association (AREIDA) informed that the combination of shallow depth, short distance from epicentre and high magnitude of Wednesday’s quake has generated highly destructive seismic forces on the buildings in the state.
“The impact of the earthquake was definitely in the heavy and devastating category. We have today extensively surveyed the earthquake damage and find that these are primarily non-structural damage like wall cracks and the load bearing RCC frame has performed well in all the buildings inspected. Wall cracks and other non structural damage have been found which only prove that the RCC frame has performed on expected lines with sufficient ductility to shake without failure,” AREIDA president P.K. Sharma said in a statement here.
Sharma appealed to the people of the state not to panic or spread panic.
“Those living in (seismic) zone V must be aware of the expected behaviour of buildings during earthquakes as the mandatory norms as laid down by the BIS Codes are a balance between safety and affordability,” he said.
“The norms stipulate: (a) minor earthquake: no damage; (b) moderate earthquake: no damage to structural members but cracking and damage to non structural components allowed; (c) heavy and devastating earthquakes damage to even structural members allowed, but building must be standing with no loss of human lives,” Sharma stated.
“One of the mandatory objectives of earthquake resistant constructions is to achieve the required ductility in the building RCC frame. Ductility is the elasticity of the RCC structure of beams, columns slabs and foundation, giving it the ability to shake and sway without deformation when subjected to seismic forces. It is the most desirable quality for good earthquake performance as this enables the structure to absorb energy and save the building from collapse,” he informed.
“The ductile RCC frame is connected to non-ductile non-RCC members like walls, which are essentially non structural components and these obviously develop cracks as they cannot shake without deformation like the ductility or elastic RCC frame. Provisions of the BIS earthquake codes never intended to prevent wall cracks in a massive earthquake like this one,” he said.
“We therefore request all to act with responsibility in dealing with this natural calamity and strongly discourage the offensive practice of spreading panic, which has already been notified as a criminal offence under Section 54 of the National Disaster Management Act 2005,” the AREIDA president said.