Here’s your quick guide to earthquake safety
On Sunday night there was a high magnitude quake in Iran-Iraq that caused a huge loss of life and property. Even though the birth of the tallest mountains has taken place in the Indian Sub-Continent through a series of earthquakes, the Indian community at large is least aware about earthquake safety measures. Last year, experts from Ministry of Home Affairs had warned that multiple highmagnitude earthquakes likely to strike North India.
It is fundamentally important that all are aware of at least the basic earthquake safety information, and the foremost is that earthquake resistant buildings are of 4 types. Detailed definitions are contained in National Disaster Management Authority guidelines. To summarise the 4 types, Category A: Operational – Building will not sustain any structural or non-structural damage during a major quake. Category B: Immediate Occupancy – Building will sustain minor non-structural damage but no structural damage. It will be safe for occupation immediately after a major earthquake. Category C: Life Safety – Building will get structurally damaged, will have to be vacated and repaired. Category D: Collapse Prevention – Building will sustain severe structural damage; repairs will not be economically feasible and the building will need to be demolished.
Earthquake Resistance Category provides essential safety information to the end users. Due to lack of public awareness all buildings are being built to the minimum standard i.e. Category-D. Technical jargon like Zone 4/5 is being used to confuse people. Zones depict the seismic hazard, and has no relevance as to how safe the building will be against an earthquake. Many, putting up buildings are not technically competent on earthquake safety know-how. The National Building Code 2016 recommends techniques like base-isolation and dampers should be used to prevent loss of lives and property against earthquakes.
It is important that before buying or leasing property, a written certificate be obtained as to what is its earthquake resistance category. The category of the building can also be found out by obtaining all the structural drawings and then consulting a structural engineer for undertaking performance based design assessment as per ASCE-41.
Schools should periodically conduct structural safety audit as children are trained to go under the desk when a quake happens. It should be ensured that schools are allowed to operate only if they have structural drawings and conduct safety audit.
Amongst others, the most susceptible are BuildingsOn-Stilts (those having open car park on ground floor), Flat-Slab buildings (mostly office/commercial) and Unreinforced Masonry buildings. These can pancake collapse, causing many casualties. If a corporate was to have its office in an unsafe building it would be a huge risk. There would be huge legal implications if people die in collapsed buildings.
The most cost-efficient way to upgrade buildings is to simply install dampers, these are like the shock absorbers and absorb the earthquake energy, so the building remains unharmed. Taylor Devices manufactures the world’s best dampers and have done over 650 projects in all parts of the world. These dampers are built using aerospace technology and comes with 35 years warranty. Seismic dampers can cost efficiently upgrade a Category-D building to Category-B at a very nominal cost of ` 350 per sqft.