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Civil Engineering/Joints in concrete structures

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Expert: - 10/16/2011


Question
1) Should vertical expansion in abutment wall to be continued in footing and what is the reaon.
2) What is criteria for construction joints in conc.

Answer
Hi Arif,

Joints in concrete are required for two main reasons- to prevent early-age cracking of the concrete and to limit temperature stresses due to expansion/contraction. Another possible reason could be to permit differential settlement (e.g between a column and grade slab).

So long as you take care of early-age cracking in long foundations (by having pour-strips), then the foundations normally do not any movemnet joints, as they are burried and daily/seasonal temperature variations are low. The joints for abutments can start from top of foundation as these are subject to external temperature changes. Even here, you can mimimise the number of joints by doing a thermal analysis and adding extre rebar to cater for stresses due to temperature changes.

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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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