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Civil Engineering/Wall Edge Footing

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Expert: - 4/24/2001


Question
Dear Sir,
I have an edge wall footing(L shape) for a reinforced concrete wall. The wall is 6m in height above the ground level and basically, the only load on this wall is wind since it's located in an open area, in addition to its own weight. The problem with this wall is when the wind force is applied on the internal face(from inside) as the resultant of soil reaction is located way outside the footing! The net soil pressure is 6 Kips/Ft2, and the max. depth where we can place the footing is limited to only 7 Ft, so no matter what we do it's hard to analyze the system! Now we can not, for economical reasons, have huge sections for the wall and its footing.
Please note that we have no other elements to connect the system with.
Please advise.
Thank you.
Sami

Answer
Hi Sami,

The only way this can be designed is to have a fairly long and thick base, so that it's centroid helps to balance the out-of-balance moment due to the wall selfweight and wind. This can also be made easier if you are allowed to mobilise the weight of the soil above the base. Please note, however, that in this case the wall must be temporarily propped, until the soil backfill has been placed after construction of the base and wall.

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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