Chennai may be re-classified

By Feroze Ahmed

CHENNAI, SEPT. 26. With Chennai expected to be re-classified as zone III (presently zone II) in the seismic map which identifies it as more prone to earthquakes, the Government is drafting a tighter set of regulations for planning and construction activities in the city.

The revised classification identifies eastern regions in Tamil Nadu and Andhra Pradesh - from the Tiruvannamalai- Vellore belt in the south to Visakhapatnam - as geologically more unstable than before.

It would place the region under the same category as Ahmedabad, which faced a major earthquake following the Gujarat disaster early this year. The revision is expected to come into effect soon.

A disaster management committee headed by the Public Works Department will draw a list of recommendations to tighten municipal laws before the re-classification comes into effect.

Stipulations like FSI will take a backseat to stability. ``Structural engineers will play a primary role in construction of buildings and will have to certify its stability'', a PWD official said.

The priority will be to preventing buildings from collapsing and structures will be designed in such a way as to stand vibrations caused by quakes or strong winds.

``Many Government buildings have huge columns and can withstand such loads. For instance, the Central Public Works Department and other Government buildings in Gujarat were not affected by quake. But most private buildings have smaller columns'', an official said.

The PWD, the Town and Country Planning Department (TCP), the Municipal Administration and Water Supply (MAWS) Department, the Chennai Corporation and the Chennai Metropolitan Development Authority (CMDA), constitute the committee.

They are scheduled to meet in October to draw a preliminary draft for the new regulations based on the `Criteria for Earthquake Resistant Design of Structures' of the Bureau of Indian Standards.

The CMDA, the Chennai Corporation and the TCP will be executing authorities, once the recommendations are approved by the Government.

The rules will be strictly implemented for five-storey structures, PWD officials said. Simple safety construction procedures can be followed for smaller buildings.

Existing structures will have to be retrofitted to stand the new classification but the need for legislation towards such effort will be looked into only later as the exercise will involve high expenditure, the officials said.

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