Civil Engineering/pile foundation

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Expert: - 12/8/2009


Question
QUESTION: Dear MRArshad
Could you  PLZ give me your opinion if i can (use group of piles with cap under each column and add tie beam between the caps with slab above)
and if it.s ok , could you tell me if it.s better than using raft on piles ?and which one is more economical?
our building is 45 stories with maximum  column load is       (7000 ton)
best regards

ANSWER: Hi Maher,

The choice between using a raft or pile caps and slab depends on many variables such as overall loading, footprint of building, whether you have basements or not and also the soil conditions. For the column load mentioned, it is perfectly feasible to use pile caps and a slab above, particularly if you do not have deep basements or high water table. This would be more economical than using a thick raft.

---------- FOLLOW-UP ----------

QUESTION: MRARSHD
in this project we have one basement (3.2m height)and the level of water     (-3.7m)so is it still ok to use cap instead of raft  

Answer
Hi Maher,

Yes, you can use pile caps and to help in waterproofing and also ease of construction, you can intergrate the basemnet slab with the pile caps (so top of pile caps is same level at the basment floor. In this case, if you make the basement slab at least 300mm thick, you can eliminate the tie-beams. (the slab can act as tie-beams).

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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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