Civil Engineering/pile foundation

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Expert: - 12/10/2009


Question
dear sir
thanx alot for your previous answers ,
-if we have tower without basement , water level is -1.5m ,
top of cap different from top of ground floor(0.7m) ,
in this case should we add tie beams to the caps and put the slab on grade in ground floor level,should we add boundary wall around the building between the ground and cap level,
-what is the recommendations for capped piles or piled raft subjected to horizontal loads (seismic or wind)load,how it affects the piles?should we design the pile to resist this loads?  

Answer
Hi Maher,

Yes, in this case include tie-beams and place the fllor slab on grade. But remember that tie beams are only really necessary for one or two piles pile-caps to resist moments in the weaker direction. (so for one pile cap, need beams in both directions, for 2-piles cap, need beams only in direction prependicular to axis of the two piles).

Whether you provide a "boundary wall" depends on your external ground usage, etc., but I would have thought a perimeter ground beam between the pile caps, with the external wall sitting on this would suffice.

If you do not have any basement walls to resist overall lateral loading, then the pile caps/piles will need to be designed to resist this. The same applies to a raft, although in this case the lateral load will be more evenly distributed.  

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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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