Nepal’s one of the worst earthquakes till date, has scarred the country as well as the entire world. News and pictures floating in the media and internet shows the havoc created and upheaval in the lives of Nepalis residing in the area. Some parts of North India too felt the tremors of the earthquake which many think how earthquake resistant their homes really are. Earthquake-resistant structures are structures designed to withstand the earthquake tremors. While no structure can be entirely immune to the damage from earthquakes, the goal of earthquake-resistant construction is to erect structures that can withstand seismic activity better than their conventional counterparts.
Delhi is in the Seismic Zone 4, which means the risk of damage from earthquake is very prevalent in the city. Experts feel that 70 per cent of the buildings cannot withstand earthquake on the Richter scale of 6.
Srikumar Ghosh, immediate past president, Indian Association of Structural Engineers told Magicbricks that various factors are required to be analysed to know how disaster prepared are the upcoming high rises of Noida and Delhi. He also revealed what a prospective buyer should verify before investing.
Building codes are sets of regulations governing the design, construction, alteration and maintenance of any structure. Such codes decide and specify the minimum requirements to adequately safeguard the health, safety and welfare of building occupants.
Approvals required while constructing a residential building:
Ghosh says, “Before constructing any residential building, it is mandatory for a developer irrespective of its brand and presence in the market to get the structural design cleared by the municipal authorities. Further, builders are also required to get certification from registered structural engineers who will assure that the development is building code compliant.”
Do earthquake resistant buildings not succumb to the tremors?
“The meaning of an earthquake resistant structure is that cracks may develop in the building but it will not fall apart. During earthquake people working or living in the structure will feel side-to-side shaking. The resistant structures don't get affected as the framing is done using concrete pillars and other materials in such a manner to support walls, roofs and other stuff inside,” Ghosh says.
The Indian Standards on Earthquake Engineering data shows that India is one of the most disaster prone countries. About 85 per cent area is vulnerable to one or multiple disasters and about 57 per cent area is in high seismic zone including the capital of the country.
The Bureau of Indian Standards (BIS) has the following seismic codes, which are mandatory for developers to follow:
- IS 1893 (Part I), 2002, Indian Standard Criteria for Earthquake Resistant Design of Structures (5th Revision)
- IS 4326, 1993, Indian Standard Code of Practice for Earthquake Resistant Design and Construction of Buildings (2nd Revision)
- IS 13827, 1993, Indian Standard Guidelines for Improving Earthquake Resistance of Earthen Buildings
- IS 13828, 1993, Indian Standard Guidelines for Improving Earthquake Resistance of Low Strength Masonry Buildings
- IS 13920, 1993, Indian Standard Code of Practice for Ductile Detailing of Reinforced Concrete Structures Subjected to Seismic Force
Are short buildings safe as compared to the high rises?
With high-rises getting serious concerns during earthquakes, low rises are always ignored. It is a myth to say that smaller buildings are at a lesser risk of falling and are safe. Smaller buildings may also be among the worst hit if not much attention is given to their construction and therefore are at the greater risks of falling.
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What should a person do if the building is old from the time when safety norm was not prevalent?
In such a scenario, Ghosh suggests, “If a person is facing the challenge of old developed buildings with no such safety norms then s/he must get together with other residents and with a mutual consent should appoint a structural engineer. The engineer will further verify the strength of the building to accordingly take action of reconstruction. Also, a buyer should keep in mind, while buying a house, s/he must take copies of the actual design and layout of structure, in future if there is any need.”
Manoj Gaur, member, CREDAI, Western U.P. says, “As a developer we know that Delhi NCR people are living on Seismic IV zone and we as a responsible developer have to abide by the laws made to make sure the buildings can withstand a fair amount of jolts.”
He continues, “Some of the norms followed by the developer community are related to the soil testing, use of concrete and the right mixture of cement.”
As a buyer who usually spends lifetime savings to own a property, make sure you do not compromise on safety aspects as it will be compromising on your valuable life.