Faultlines in realty

Date : May 2, 2015

Ravi Sinha & Vivek Shukla

Immediately after the earthquake in Nepal last week a builder sent a group WhatsApp message saying: “Our project in Noida is NCR’s first and only earthquake- resistant structure with seismic zone V compliance approved by IIT Bombay. Possession next month.” Well, hard as it is to swallow the blatant opportunism in the face of such a tragedy, the message also brings forth the lack of awareness about proper building norms in this regard. If the sincerity of the real estate developers in this part of the world is that high then ideally they should incorporate the safety techniques used in their project in their marketing brochures.

The missing code?

Looking at the devastation caused in Nepal last week one is forced to think how safe our multi-storeyed buildings are actually. Are we living in virtual house of cards or a stringent code is being followed to make buildings stronger. After a massive earthquake it is but natural to wonder if it’s possible to build an earthquake-proof building? The answer is yes and no. “There are of course, engineering techniques that can be used to create a very sound structure that will endure a modest or even a strong quake. However, during a very strong earthquake, even the best engineered building may suffer severe damage,” says Dr. Chandra Ghosh, a noted Civil Engineer working for National Institute of Disaster Management (NIDM). According to NIDM, over 90 per cent of our so-called Reinforced Framed Buildings across India are vulnerable to any kind of natural disaster. “The construction process of most of these go unchecked. We are moving at a tremendous pace and most of the ongoing constructions are not following any guidelines,” claims Prof. Anil Dewan of School of Planning and Architecture. The Bureau of Indian Standards (BIS) — the national standard body of India— is supposed to monitor construction standards and ensure that the builders are complying with the different provisions of the building code. According to BIS about 85 per cent area of the country is vulnerable to one or multiple disasters and about 57 per cent area, including the capital of the country, falls in high seismic zone. Disaster prevention involves engineering intervention in buildings and structures to make them strong enough to withstand the impact of an earthquake or to impose restrictions on land use so that human casualities in case of such a disaster can be minimised. Though the National Building Code (NBC) of India that mostly talks about the fire and life safety, has also introduced a clause to restrict the use of foundations vulnerable to differential settlements in severe seismic zones, it is not intended to lay down regulations that will be mandatory for builders to follow. The NBC Code only says that it “has been endeavoured to ensure that as far as possible structures are able to respond, without structural damage to shocks of moderate intensities and without total collapse to shocks of heavy intensities.” The larger question is whether this is enough. The residents of Gurgaon staying on 18th floor or higher height do not think so. “If a high intensity earthquake in Nepal could sway my apartment then what will happen if we have one in Delhi”, asks Gaurav Chaudhry, a resident of Gurgaon.

Claims and reality

In terms of a reality check, most of the high-rise projects in cities like Mumbai and Delhi are being designed to withstand a tremblor of a certain intensity. However, these intensities may vary as per the corresponding seismic zone of a particular area. The developers point out that the buildings that are designed worldwide are earthquake-resistant but not earthquake-proof. From a policy standpoint, across the Indian cities there is no provision for structural safety and stability of existing buildings; there is no specified law for the redevelopment of old and dilapidated buildings. BIS has published a number of codes to ensure proper quantity of reinforcement and ductile detailing to achieve the desired level of earthquake-resistance. Compliance to these codes and their periodic checking by the agencies concerned, however, is a missing link. Structural engineers suggest that officials from respective authority should conduct periodic checks of all under-construction buildings to ensure that right building techniques are employed by builders and issue safe-structure certificates to buildings. Grading the buildings on the structural level safety should also be mandatory to enhance buyers’ confidence. The developers, meanwhile, would like us to believe that their projects are designed to be earthquake-resistant in all possible manners with the best structural engineers and designers of the country. Mohit Goel, CEO of Omaxe admits that the recent earthquake in Nepal and the damage to life and property that it inflicted is a serious cause of concern for those in Delhi NCR. He, however, maintains the assumption that all buildings will be impacted would be an over statement. Rattan Hawelia, Chairman & Founder, Hawelia Group, points out that the construction industry has gone through major technological advancement. Of late, building design, especially for high rise and special buildings, has become a complex process, that integrates many skills, products and techniques into its system. Structural engineers, however, have a different take. Dr Rajeev Dua, Head of Optimization Consultants recommends that developers should join hands with the best names of structural engineers from around the globe that have a proven track record and required knowledge in designing of high-rise buildings. Right from the soil investigation and wind stability conditions to the apt foundation design as per the height and shape of the building, these high rise structures can be made capable of bearing all types of loads and deflections in case of an earthquake. The spotlight has suddenly been on the need for stronger buildings that can weather the natural calamity. However, there is no standardised mechanism of due diligence for the buyers today to understand whether their high rise building is actually earthquake proof or not. Though ideally the recent calamity should have resulted in some learning for the Indian real estate, the focus of the developers is yet on lip service than on preventive and corrective measures. Samir Jasuja, head Prop Equity, has a suggestion for all the would be buyers of flats in residential and commercial buildings. They should ask realty firms whether they constructed earthquake resistant buildings. As that is not enough, they should talk to engineers of realty firms in this regard. Globally, in Japan which is one of the most earthquake-prone country there has been extensive use of rubber padding and roller in foundationsso that in case of an earthquake the building could roll up to 3 meters instead of bending which often leads to crack or collapse. This, however, seems to be too far fetched in a country where the law book is silent about fixing responsibility. So no one knows who is to blame — the architect, engineer or the developer — in case a building collapses in an earthquake the onus of responsibility will be.

Test of strength

Experts say that engineers design buildings to withstand as much sideways motion as possible in order to minimise damage to the structure and give the occupants time to get out safely. Buildings are basically designed to support a vertical load in order to support the walls, roof and all the stuff inside to keep them standing. Earthquakes present a lateral, or sideways, load to the building structure that is a bit more complicated to account for. One way to make a simple structure more resistant to these lateral forces is to tie the walls, floor, roof, and foundations into a rigid box that holds together when shaken by a quake. The most dangerous building construction, from an earthquake point of view, is unreinforced brick or concrete block. Generally, this type of construction has walls that are made of bricks stacked on top of each other and held together with mortar. The roof is laid across the top. The weight of the roof is carried straight down through the wall to the foundation. When this type of construction is subject to a lateral force from an earthquake the walls tip over or crumble and the roof caves in like a pack of cards. Based on the 2011 Census, the Technology Building Council categorised the type of buildings in India — bricks, concrete, bamboo, etc. Among these, only 2.6 per cent of our building stock is reinforcement-framed. Of these, as many as 90 per cent are vulnerable to damages as these are unauthorised constructions. Of the total number of buildings, 45 per cent are made of bricks without pillars, which are highly vulnerable to earthquake.

Source And Courtsey By :- http://www.tribuneindia.com/news/real-estate/faultlines-in-realty/74818.html