Earthquake: 59% of India at risk, but our engineers aren’t ready

Surprisingly, earthquake-resistant construction is not taught at all at the undergraduate level in engineering courses and comes in only at postgraduate levels, even though 59% of the country falls in regions that are "liable to seismic damage" as per the National Institute for Disaster Management's seismic zoning.

"Earthquake-resistant design and construction is not being taught at undergraduate level. The design of earthquake-resistant construction is taught at postgraduate level and, therefore, budding engineers and architects are not exposed to design principles.

Therefore, they resort to software which specializes only on RCC construction. Masonry construction with earthquake-resistant design is barely practised in India," said Shailesh Kumar Agrawal, executive director of the Building Material and Technology Promotion Council under the housing ministry.

What needs to be done to make this vast number of unreinforced buildings safe? The solution is technique called retrofitting, which is building in horizontal and vertical steel reinforcements under the guidance of an engineer. Such retrofitting would cost about 20% of the total cost of a new building, according to Agrawal, although it will vary according to specific conditions.
Another major concern is the multi-storied housing that has mushroomed in urban areas. These are built on a framework of RCC beams and pillars with brick walls added later. Experts say that with proper earthquake-resistant design, these buildings can be safe.

"Multi-storeyed RCC pillars & beam construction would only be safe if it is designed based on earthquake-resistant design principles and that design is implemented at the site with strict quality control of material and placement of reinforcement (steel). The principles for RCC construction are different from masonry construction, but the basic philosophy is same.

Vertical and horizontal bands are normally used for masonry construction, whereas ductile detailing is used for RCC construction," Agrawal said.

A common feature in urban multistoried housing is the parking space created at the ground floor level by having no walls, just pillars or stilts. Such buildings are very vulnerable and dangerous unless special measures are taken, Agrawal said.

"The deficient building with open ground storey can be retrofitted by providing additional symmetrically placed shear walls or bracings or energy absorbing devices," said Paul.