Civil Engineering/Water Pressure

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Expert: - 2/10/2010


Question
Dear Arshad Khan,
I hope that you are fine and keeping good.
My Question is that,
we have to design a Steel Production factory.
I have worked out the foundations. The ground water table is at Natural ground level. I have heard that when the water table is quiet high we need to cater upthrust forces..
What is this phenomenon called and how to cater it in design.
Can you recommend any good book regarding geotechnical design.

Best Regards,
Muhamamd Umar

Answer
Hi Umar,

Upthrust or floatation is only a problem when you construct a basement or tank or swimming pool below the ground water level. Otherwise, for just buidling foundations this is a temporary problem for keeping the excavations dry, which can be done by localised pumping.

Even with pools and basements it is normally a temporary problem during construction only- once the weight down (say of the pool water or building on top of basement) equals or exceeds the buoyancy upwards (weight of water displaced),then there will not be a danger of floatation.

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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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