New Delhi, March 15: The entire National Capital Region lies in a high-risk Seismic Zone IV, but the fact remains that most of the buildings in delhi, Gurgaon and Noida are not earthquake-resistant, reports Times of India.The report says, Delh government and the authorities of Gurgaon and Noida should learn lessons from the devastating Japanese earthquake.
According to Delhi government, 6.5% houses in Delhi have high damage risk and 85.5% have moderate damage risk (going by the Vulnerability Atlas of India (1997), in the event of an earthquake of intensity 8).
If an earthquake of the magnitude of the one in Japan struck Delhi, experts say that devastation will be unimaginable.It's the same story in the rest of NCR, be it Noida or Gurgaon.A month ago, the MCD set up a panel of structural engineers.
Their job – to ensure that buildings coming up in Delhi are structurally sound and have earthquake resistant measures in place.This is years after the National Building Code in 2005 directed state governments to ensure that all new buildings follow the Indian seismic code which is recommendatory.
While Delhi's building bylaws may talk about structural safety, implementation is lax to non-existent. The civic agency has conducted no safety audit in recent times either.
Says Dr Shailesh Agrawal, executive director of Building Material and Technology Promotion Council, an autonomous body under the ministry of housing, “Codes are in place but enforcement is lacking. Without strict monitoring, it will be difficult to minimize losses.” Adds an official from urban development department, “The experience of past earthquakes has shown the vulnerability of multi-storey reinforced concrete buildings. There are a number of such buildings in Delhi, particularly those with an open ground storey to accommodate vehicle parking.”
As Prof. SM Akhtar of Jamia Milia Islamia points out, the growing unauthorized colonies are particularly vulnerable.
“The over-densification of the city is a dangerous trend, especially since no amount of precautions can save such settlements,” says the structural engineering expert.
A recent survey by GeoHazards International, an NGO, in collaboration with the United Nations, on the top 10 most vulnerable cities in the world put Delhi in the third place, right after Kathmandu and Istanbul.
The parameters on which the study was based were building frailty, fire and landslide potential, and the rescue and medical care abilities of local authorities. The results were based on the scenario of a 6.0 level quake. The toll: 38,000.
Prof. Khalid Moin, another structural engineering expert, says losses in such a scenario cannot be avoided. “What we can do is reinforce our building bylaws, which are actually quite effective if followed properly,” he stresses. He claims most new buildings are following the norms.
Adds Arun Sahai, chairperson (Delhi chapter) of Builders Association of India, “Most builders are following norms, though admittedly, not all.''
Sanjay Chandra, MD of Unitech, claimed the company not only follows the building code but also has tied up with a foreign technology company, which has developed braces used as frictional dampener to reduce the effect of seismic waves on the building.
Engineering experts say the biggest risk facing Delhi is not just the lack of safety controls but also the over-densification. Pockets with highrises or illdesigned colonies exist without consideration of earthquake resistance. Unplanned areas are also prone to heavy damage Connaught Place, numerous district centres and highrises are high-risk areas due to vertical configurations.
Walled City, trans-Yamuna and scattered pockets of unplanned settlements are also vulnerable Experiences of past earthquakes have outlined the vulnerability of multistorey reinforced concrete buildings if not designed and constructed correctly.Huge number of such buildings, particularly those with space for parking, could also pose a major challenge in the event of a strong earthquake The first code of practice for earthquake-resistant design was developed in India in the 1930s after the 1935 Quetta earthquake.
The Bureau of Indian Standards developed its first code on seismic design in 1962. in 2005, the National Building Code came out with specific codes for ensuring safety measures.However, implementation has been sketchy. MCD, which is to give the structural safety certificate, had no empanelled structural engineers on the roll till a month ago As per the Vulnerability Atlas of India (1997), for shaking intensity VIII, 6.5% houses in Delhi have high damage risk and 85.5% houses have moderate damage risk Buyers must ensure that the builder gives them the ‘structure certificate'.
They can, if they want, check if earthquake resistant elements — in the foundation, depth of the project, reinforcement of walls, plinth beams etc — have been incorporated.
There is no such term as “earthquake proof” as no building can be entirely safe from earthquakes. The actual term used is “earthquake resistant”, which means that minimum damage to life and property is caused following an earthquake.
Earthquake resistant buildings in India are in zone III, IV (in which Delhi falls) or in Zone V. The latter have structures designed in what the industry calls “collapse prevention”
The minimum standard being followed in the developed markets of the world is “life safety” – which is in a category higher than what is being followed in India
In India, buildings are designed to prevent a total building collapse. However, there may be a loss of life due to falling masonry walls. “Life Safety” design i.e. minimum design being followed in developed countries, does not permit the use of un-reinforced masonry walls
The existing guidelines in Delhi only make it mandatory for builders to ensure that there won't be a total collapse of the building in the event of an earthquake. This is not good enough.
The guidelines must adopt the “life safety'' standard, which aims to prevent falling masonry and so on leading to loss of lives.
Also, the implementation of these norms, now dependant on selfcertification by builders, needs to be made more rigorous. Certification must be given by a body of experts.
Demanding that all existing buildings must be made quake-resistant is unrealistic, but the government must ensure that at least buildings that would be crucial in a crisis situation, like hospitals, fire stations and police stations are retrofitted to make them safe.
This is not something to be achieved by and by, but a task that must be taken up immediately.
