Civil Engineering/foundation

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Expert: - 1/2/2009


Question
QUESTION: Hello,
I have a foundation of an existing 4x10 meters with isolated footing and reinforced concrete grade beam. I want to ad a 10x10m building next to it and would preffer to connect it rather than leave a gap between them. What would be a good way to connect them. I though of casting the new footing and later after some settlement occured to cast a reinforced or maybe post tensioned concrete beam connected to the two older footings thus making a kind of composite beam.

ANSWER: Hi Daniel,

This very much depends on the nature of the ground and the expected short term and long term settlements, as well as on the ratio of self weight to future imposed loading.

However, in principle what you have proposed sounds good.

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

QUESTION: Thank you,
In your opinion it would be better to try connecting the two structures in a proffesional manner on the 10 meter side or it would be to leave an intentional seismic and settlement gap between the two.

Answer
Hi Daniel,

If you are connecting the foundations, then it would be better to also connect the rest of the building, especially if you are in a seismic zone. Also, in order to mitigate the differential settlement, make the new foundations a bit bigger than needed, and wait till the initial settlement has occured before casting the connections.

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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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