Building technology for quake-hit zones

By R. Ramabhadran Pillai

KOCHI, FEB.3. When the biggest earthquake of this century shook the Gujarat landmass, man-made structures collapsed like a pack of cards. As a dazed administration is frantically trying to rebuild the ravaged towns, one of the challenges will be the reconstruction of houses and other buildings. Making stronger structures with the aid of modern technology will be one of the priority areas in the quake-hit areas.

A revolutionary concept adopted by an engineering and building products company in Kerala can cater to the current demand for dwelling units in Gujarat. The company, based at Perumbavoor in Ernakulam, makes use of soil which is compressed in a machine to form bricks. These bricks are not made in the conventional shape, but have a four-way interlocking design which provides for greater cohesion horizontally and vertically. The bricks are about five times more in size and three times in strength than the conventional kiln-burnt bricks. No cement is required to join the bricks and they have a good finishing on all sides which means no plastering is necessary on the outside or inside of the building once the walls are made.

The blocks are ready to use as soon as it is manufactured. Another advantage is that no skilled mason is needed to build the walls of the structure as the alignment is achieved in the normal course of raising the walls. This is because the bricks interlock with the adjoining ones to have perfect symmetry. Anyone can place the blocks one after the other as no cement is used to join them. This effectively reduces the cost of construction.

An individual can lay 450 blocks per day. The construction of a 50 sq.m. house requires about 4,000 blocks and this can be achieved in two or three days.

As the interlocked blocks are not bonded with cement, it provides greater stability in quake-prone areas. With the traditional mortar, if there is soil movement, the bricks come under strong tension that the bond eventually cracks. This initiates a continuous cracking process which is difficult to correct. In the case of interlocking blocks, the whole wall will adjust progressively without damage or cracking, thus providing greater stability. But tests are still being conducted to establish the safety of buildings based on the interlocking brick technology in earthquake-prone zones.

The interlocking blocks have been deployed in construction in the Middle East, Africa and Canada. In India, it is being used in Orissa ravaged by cyclones. The technique is effectively used for community re- development projects on a cost-effective manner. In many places, a ``social engineering'' concept is followed where the home owners and community members can construct their own dwelling units. The greatest advantage of the project is that it is immediate. The process is useful in rehabilitating communities devastated by natural calamities such as earthquakes, cyclones and floods.

Another notable advantage is that the rescue team in disaster areas need the minimum of raw materials. The block-making machine can be transported to a disaster area and the reconstruction process can be started immediately. The machine can make 150 blocks per hour. The local soil can be used in most cases, but pure sand cannot be converted into blocks unless there is a 10 per cent clay content. Clay has to be added to such soil. Apart from this, a ``soil stabiliser'' is also used.The Gujarat soil being ideal for cotton cultivation, contains clay and the technology can be adopted there, according to the Perumbavoor- based company sources. The company is currently undertaking an old age home project in Kottayam and is vying for a project in Lonavala in Maharashtra. The company has also sent proposals to the Gujarat Government for the reconstruction project in earthquake-affected areas. It is ready to start work immediately if the sanction is given. The company is also ready to transfer the technology to Government agencies.

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Section  : Southern States
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