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Civil Engineering/Ductile Detailing of Flat Slab


Dear Sir,

I am currently working on Flat slabs in severe earthquake zones. For my current example, the gravity forces are more predominant (contribution = 95-96%) whereas the earthquake forces (generated due to structure itself and tank supported on Flat slab) are contributing to 4-5% only. However, due to codal requirement we are force to do the ductile detailing. So my question is, how to do the ductile detailing in Flat slab?

Hi Prafull,

Ductility is normally only required for those elements that are required to resist lateral loading.Flat slabs, due to their nature cannot provide much lateral stiffness, so i would just detail any shear walls and all columns for ductility.

If you must details the slabs too then I would suggest just adding closely spaced links for all "columns strip" slab rebar, especially within a zone 0.2 to 0.25 of the span, in all 4 span directions from each column.

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Arshad Khan


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.


Employment history: 40 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.

.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)

•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 •2013: IEK International Conference, Kisumu, Kenya

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 2010)

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