Shock Absorbers for Buildings..!

by Mr. M.A. SIRAJ

Massive destruction of houses, buildings and property in the recent earthquake in Nepal has led property buyers to question if the structures being bought for residential or / commercial purpose by them are quake-proof.

Most developers would say that the structures they offer are made to quake-resistant specification. But the fact is that they carry only ‘D’ category guarantee under the National Building Code as approved by the National Disaster Management Authority which only ensures that they will not collapse.

Although quake-proof technology has been in place for several years and is rigorously applied in developed countries, the certification system is virtually non-existent in India.

However, it is being talked about now that the quake ravaged property on a wide swath of land in Nepal and India two months ago. The last fortnight witnessed the launch of ‘Taylor Protected’, a certification for edifices that are fitted with shock absorbers to resist earthquakes.

Mr. Sandeep Donald Shah, Managing Director of Taylor Devices India, says currently buyers have to merely depend on the verbal assurances from developers on their constructions being quake-safe and there is nothing by way of a certifying system.

Categories of quake-proof buildings..!

More than 58.6% of the landmass of India is prone to earthquakes of moderate to very high intensity.

Going by the standards of the developing countries, nearly all buildings in India are unsafe and do not measure up to even C-category safety in the event of an earthquake.

The National Disaster Management Authority (NDMA) of India has four distinct categories of earthquake-resistant buildings:

‘A’ category buildings are those that remain operationally useful even after the earthquake. They house facilities such as hospitals, fire stations, government offices, railway stations etc. An earthquake does not impact them in any measure and they stay intact and fully operational.

‘B’ category buildings are ‘Immediate occupancy’ edifices which can be used immediately after the earthquake.

‘C’ category buildings are structures which are damaged and will have to be vacated and repaired and restored before use.

M.A. SIRAJ

‘D’ category buildings are ‘Collapse Prevention’ buildings which will have to be vacated and demolished and cannot be reused. Their repair would be uneconomical.

Shah, who has a Master’s degree in Earthquake Civil Engineering Dynamics from Sheffield University, says, ‘This is (D-category) the minimum to follow under the NBC and is rated as IS-1893 under the code formulated in 2002. The categories have not been updated since then. People buy buildings worth millions of rupees, but they offer the lowest protection.’

According to Shah, the concept of ‘quake-protected’ buildings originated in the United States in 1955 in the hands of Douglas Taylor who came up with powerful shock absorbers.

The company has since acquired 97 patents for various devices and systems it has developed. He says even retrofitting is possible in existing buildings to upgrade their quake protection capacity and rating.

Under ‘Taylor-protected’ certification, giant shock absorbers are fitted in foundations and walls, capable of absorbing nearly 60 per cent of the energy released by tremors.

These carry a 35-year warranty. Apollo Hospital in Delhi, Terminal-2 building of the Mumbai Airport and several other under-construction structures in Delhi have deployed the Taylor devices for protection against earthquakes. Currently, the company is deploying it in Palais Royale, a 90-storey under-construction building in Mumbai.

Cost factor..!

Shah says a ‘B’ category certified building would cost only Rs. 360 per sq. ft. over the budgeted cost charged by the developers. He says the cost is quite affordable going by what people spend on construction. For the ‘A’ category certification, buildings need to be designed to take the devices from the foundation stage.

“Since operational facilities such as hospitals have multiple ducts for oxygen, gases and operation theatres, they need to plan beforehand and cannot take retrofitting”.

Shah pleads for introduction of the quake-protected certification and monitoring the compliance at least in public building to ensure safety of structures and human lives.

According to him, buildings in Japan can resist earthquakes ranging in magnitude from 7 to 9 on the Richter scale.

The author can be reached at maqsiraj@gmail.com

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