How 60% of high-rises are not earthquake-resistant in NCR? What can be done to minimize the earthquake devastation?

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RE: How 60% of high-rises are not earthquake-resistant in NCR? What can be done to minimize the earthquake devastation?

In the mad rush of erecting high-rises in the cities, the developers seem to have missed out one very vital aspect that could make the entire skyline crumble in just one quiver under the surface of the earth. Yes! It is scary and extremely alarming, but true! The high-rise constructions as old as 10 years which comprise of at least 60% of the total construction in both commercials, as well as residential segment, have not been made to be earthquake resistant.

According to the Head of Disaster Management, Haryana Institute of Public Administration (HIPA) has stated that despite Delhi-NCR coming under the Zone 4 levels of the seismic zone within India, a sizeable majority of the high-rise constructions have not complied with the retrofitting measures.

Seismic Zones in India

The seismic zone is the area of land that is prone to be affected during an earthquake. A patch of landmass can be divided into five zones depending on the intensity and level of risk of getting affected by earthquakes. The damage risk factor being highest at Zone 5, it eventually subsides with the subsequent zones such as Zone 4 being on high damage risk alert, Zone 3 and 2 being moderate and low damage risk zone respectively. Zone 1 is supposed to be the least damage risk zone, but no area within the boundaries of India has been marked under this zone.

Zone MSK IS Code Area
5 IX 0.36 Parts of Kashmir, Western and Central Himalayas, North and Middle Bihar, North-East Region, Rann of Kutch, Andaman and Nicobar Island
4 VIII 0.23 J&K, Himachal Pradesh, Uttarakhand, Sikkim, North Punjab, Chandigarh, western Uttar Pradesh, Terai, North Bengal, Sundarbans, Delhi and some parts of Maharashtra
3 VII 0.16 Kerala and parts of Tamil Nadu, Karnataka, Andhra Pradesh, Telangana, Maharashtra, Gujarat, Madhya Pradesh, Rajasthan, Uttar Pradesh, Jharkhand, Orissa and West Bengal
2 VI 0.10 The remaining parts of Andhra Pradesh, Tamil Nadu, Karnataka, Telangana, Maharashtra, Chhattisgarh, Orissa, Jharkhand, Madhya Pradesh and Rajasthan
1 V NA NA

 

Earthquakes in India

Some of the most devastating earthquakes in the country – Gujarat earthquake in 2001 and 2006, Tsunami in 2002 in Andaman and Nicobar, West Bengal in 2008 to name a few; are but the reminders of some of the most testing times that the populations in these places have survived. Mass destruction and collision of the building and loss of lives that have left a deep mark in the memories the citizens of this country. Yet, the necessary measures to make a building earthquake-resistant have never been raised before by the home buyers or the developers until recently.

Sky Scrapers in Delhi-NCR

Delhi-NCR that falls under Seismic Zone 4 is currently home to a total number of 29 tall buildings with a height exceeding 100 meters with the number of floors ranging from 22 to 51. Further, another set of 28 tallest constructions is in the offing where the number of floors is supposed to reach up to 80. These apart several high-rises start from as low as 10 floors to 16 floors at an average that are being owned by the middle and upper-middle-class population of the city. Given the scenario, if the buildings are not made to be retrofitted, these buildings will prove to be death traps for the home buyers.

Recommended Retrofitting Measures

As experts recommend, it is pertinent to real estate developers to follow the mandatory parameters to make the building earthquake resistant. They emphasized particularly in Gurgaon as this satellite city had been the pioneer in hosting skyscrapers and house some of NCRs oldest constructions.

Experts have attributed this to the lack of awareness among developers as well as home buyers alike. Even in the face of an imminent threat, the awareness levels among the people at large for earthquake safety is extremely low and therefore no one seeks answers on how safe a building is.  They further added that implementing appropriate safety norms for the construction of critical buildings such as hospitals, schools and high-rises have never been prioritized by the agencies. Hence, no initiative to guide the developers about the same has been taken.

None of the buildings in Gurgaon have ever been audited for their architectural and infrastructural designs from the safety point of view.

Experts recommend that the developers can design the buildings as per the parameters applicable for Zone 3 and use dampers to make them compliant to Zone 5. This will serve the purpose of most cost-effectively.

According to industry experts, high earthquake-prone areas worldwide such as USA and Japan use shock-absorbers or dampers that soak up the impact of the earthquake, leaving the buildings as it is even after experiencing an earthquake of a very high magnitude. These low to no maintenance houses have a life of more than 100 years.

Last but not Least

Like it is important to have a roof over the head of every citizen, it is equally important to make that roof sturdy enough for generations live a safe and secured life under it. Awareness about retrofitted building should be spread among the buyers and it has to be made mandatory for developers to deploy the appropriate technology to make the building safe and secured.

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Shock Absorbers

  • The same device/ technology that controls the vibratory motion in the car can be deployed in building houses to make them quake-resistant.

How does it work?

  • Also known as dampers, these can be attached to the column and the beam at each lever of the building.
  • There are several types of dampers but the most basic model includes a piston head placed within a cylinder filled with silicone oil. These are hidden in between walls.
  • When the earthquake strikes, the horizontal movement of the building makes the piston placed within the dampers to create a thrust against the oil, thereby transforming the impact of the quake into heat.

Several Other Tried and Tested Retrofitting Measures:

  • Levitating Foundation or Base isolation
  • Pendulum Power
  • Replaceable Fuses
  • Rocking Core-wall
  • Carbon-fiber Wrap
  • Cardboard Tubes

 

   

 

Answered on July 22, 2020.
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