Facing future earthquakes

IN THE wake of the recent earthquake in Gujarat and the recent experience the people at Chennai had, modifications in building by-laws have to be made to protect buildings from damage and the subsequent loss of life and injuries.Normally reinforced concrete buildings of proper design are not affected under moderate intensity earthquakes. Full range of Indian Standard codes of practice for the design of structures is available and these codes are being modified periodically based on the experience and technical advances.

These codes include criteria for earthquake design of structures, ductile detailing of R.C. structures subject to seismic forces and earthquake design and construction of buildings. It has been reported that buildings designed and constructed by the Central Public Works Department in Gujarat have withstood the earthquake much better than those constructed by private agencies with or without engaging the services of professionals such as architects and structural engineers. It is only because that the designs made by the department are in compliance with the codal provisions while in the private sector the codal provisions could have been violated. I.S. 456, the revised edition of 2000, has prescribed that the grade of concrete for all RCC works should be M20 (1.1.5:3) mix with the minimum cement content of 300 kg. per cu. metre. The minimum thickness of slab should be 110mm and the minimum cover to be provided for slabs, beams, columns and footings is 20mm, 25mm, 40mm and 50mm respectively.

Designing buildings that can resist earthquake forces will involve large sizes of RCC members and increase in the quantity of reinforcing steel. Approximately the total cost will be about Rs. 20 per sq. ft. more and the builders may be reluctant to comply with the codal provisions. While square columns render them more efficient, architects prefer to restrict the size to 9 inches in one direction to avoid column projection in the rooms. Some time they choose two storeys free standing columns to suit the taste of aesthetics which result in a weak spot in the building. Architects also wish to have long cantilevers (supporting on one side only) which is not advisable to resist earthquake forces.

Building activities in our country are regulated by the local authorities through registered architects or licensed engineers or licensed surveyors. While the Council of Architecture makes regulations to promote the standard of professional conduct/self- discipline required of an architect, the obligation of licensed engineers/surveyors is prescribed by the local authorities. The local authorities issue licence to professionals with minimum qualifications and prescribed experience.

As per the regulations made by the Council of Architecture in exercise of powers conferred by the provisions of the Architects Act, the architect should ensure that his professional activities do not conflict with his general responsibility to contribute to the quality of environment and future welfare of society. The architect should conduct himself in a manner which is not likely to lessen the confidence of the public in the profession.

The National Building Code (prepared by the Bureau of Indian Standards) lays down a set of minimum provisions designed to protect the safety of the public with regard to structural safety, fire hazards and health aspects of the buildings; so long as these basic requirements are met, the choice of materials and the method of design and construction is left to the ingenuity of the architect/engineer.

The building by-laws should be amended to make the architect and/or builder accountable for failure of structures. The different players in the construction of a building are the architects, structural engineers, statutory bodies, promoters, contractors, owners and material suppliers.

The present trend is that the engineers/architects go in for soft options instead of evincing keenness in their jobs and trying to increase the level of their competence. There are cases where architects depend on the contractors/promoters for preparation of estimates/for quoting the selling rates which often goes against the interest of the clients/buyers. Practically there is no participation of engineers in the day-to-day activities at the site. Consequently the quality of work suffers. Many contractors do not have financial resources or technical competence. Materials used are of inferior quality and some of the contractors are litigants interested in earning only through litigation rather than doing proper work. The financial institutions supported by the government advance loans on buildings and the valuation reports furnished by the professionals do not indicate the deviations made or the quality of works.

The statutory authorities should incorporate a clause in the application form that the architect ensure the compliance with relevant disaster safety codes in the design of the buildings. In this context it is relevant to point out that the Ministry of Urban Development has issued a notification on March 21, 2001, the extract of which is furnished below:

Structural design

1. Each building constructed in urban areas shall be structurally designed by a registered professional engineer who shall be designated as structural engineer on record who shall sign all building plans submitted to the city authorities for approval obtaining completion certificate.

2. The structural design of a building having more than ten floors shall be proof-checked by a professional engineer selected out of a panel approved by the city authorities or by in-house engineers of the city authorities. The proof checker shall also sign the structural drawings.

3. A complete set of structural calculations and structural drawings of each building duly signed by the structural engineer on record and the proof checker if the building is taller than ten floor shall be submitted to the city authorities with a stability certificate that the building has been designed according to the provisions of the latest building by-laws and codes.

4. The appointment of structural engineer on record shall be made directly by the client/owner and intimated to the city authorities.

5. The same structural engineer on record who signs the drawings submitted to the city authorities for approval, shall sign the stability certificate as well as the drawings submitted for completion certificate.

6. In the event of the client/owner desiring to change the structural engineer on record before the completion of the project, a procedure stipulated by the city authorities shall be followed to ensure that the responsibility of certification of structural stability of the buildings is not divided.

Construction

1. Construction of each building in urban areas shall be supervised by a professional engineer who will certify that the building has been constructed according to the drawings and specifications prepared by the structural engineer on record.

2. Each construction site of a major project shall have fully equipped site laboratory. A complete record of tests of all construction materials used on the project shall be maintained at the site.

3. A system of quality control and quality audit shall be introduced on each construction site of a major project.

Other points: In case of structural design submitted by the structural engineer/architect is found to be faulty then their registration/licence will be cancelled and they will be blacklisted as is done in the case of contractors.

It is necessary that the local authorities should examine the issue of licensing/registration of structural engineers by a committee of experts drawn from reputed engineers, academicians and architects.

Parties suffering damage may claim compensation from the consultants or builders. In the United States, customers could sue the architect/consultant for injuries arising out of negligence in design or supervision. In case of purchase of flats, it is essential to get an indemnity bond from the promoter to indemnify the buyer from any action taken by any authorities and also to obtain a certificate from the structural engineer that the design and execution have been done in compliance with the I.S. codes. However it is essential to have proof of negligence if alleged.

The architects' (professional conduct) regulations made by the Council of Architecture cover all aspects to promote the standard of professional conduct/self-discipline of an architect. If these regulations are followed, the professional lapses in the failure of structures can be avoided.

C. H. GOPINATHA RAO

Former national president,

Institution of Valuers

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