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Expert: - 9/2/2003


Question
Can buildings be constructed to withstand earthquakes, floods, bombs, and other natural & human distasters? Which materials should be used? How can buildings be made safe?

Answer
Hi Hassaan,

Yes, to a limited extent one can design against all these disasters, but it is a question of how much you are willing to pay. Most buildings are designed as a compromise between cost and risk, but some critical structures, such as nuclear power plants, dams, etc, are usually "over-designed" so that the risk of failure is much reduced. Check out this website and links from it:  http://www.seismic.ca.gov/

Buildings in seismic regions are designed to be ductile, so that they shed energy when an earthquake occurs. Another way to prevent damage is to isolate the foundations on flexible pads, or to install tuned mass dampers that counteract the vibrations.

Floods are a bit more difficult to design against, as they can undermine foundations, etc. However, by looking at historical data one can assume say a 1-in-50 or 100 year flood level and design against the forces.

Bombs and flying aircraft are much more difficult to design against as the applied forces are difficult to predict. In the UK, we design buildings not to collapse if one of the main columns, etc is knocked out. Such provisions do not exist in the US codes, but no doubt will be incorporated after 9/11.

Materials that make a building ductile are steel and reinforced concrete with special seismic detailing of the rebar. Masonry is not too good as a ductile material, but timber is pretty good for houses.

I hope this helps!!

Kind regards,

Arshad  

Civil Engineering

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Arshad Khan

Expertise

I can answer any questions to do with civil and structural engineering consultancy and construction industry in East Africa and the Middle East, and specifically with the analysis and design of reinforced concrete structures. My particular expertise is in the aseismic design and optimisation of tall buildings.

Experience

Employment history: 36 years in Construction and consultancy in the UK, Kenya, Tanzania, Uganda, Ethiopia, Eritrea, South Africa, Somalia, Zambia, Austria, Bahrain, Kuwait, Doha and the U.A.E.

Organizations
.Fellow of Institution of Structural Engineers (UK) .Fellow of Institution of Civil Engineers(UK) .Member of the Institution of Engineers, Kenya .Registered Engineer, ERB, Kenya .Member of the Architectural Association of Kenya (Engineers Chapter) .Chartered Engineer (UK)

Publications
•1984: International Conference on the Art and Practice of Structural Design, London •1994: 3rd Int. Kerensky Conference in Structural Engineering, Singapore •2008: International Conference on High-Rise Towers, Abu Dhabi

Education/Credentials
BSc, 1st Class Hons, in Building Engineering, University of Bath, UK MSc in Concrete Structures and Technology, University of London. Diploma of Imperial College, UK.

Awards and Honors
•Science Congress Special Award (for 2-seater Hovercraft - 1968) •Institution of Civil Engineers Award for outstanding performance at Bath University (1975) •Concrete Society Postgraduate study Bursary Award (1976) •Consular Representative for British High Commission, Nairobi. (1995 to 1998) •Examiner for Institution of Civil Engineers Professional Interviews, Nairobi. (1997 to 1998) •Branch Representative in Vienna for PI assessment for Inst. of Struct. Engrs. (1999 to date)

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