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Civil Engineering/concrete slab strength

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Expert: - 8/21/2007


Question
hi,
I am building a concrete slab that will cross a creek in my backyard, the creek has a 10' gap and the slab will be 16' long and 8' wide.  The concrete strength will be around 3000psi and the rebar will have around 60,000psi yield strength.  I will be moving a tractor across the creek and sometimes carrying heavy loads (a few tons).  How thick should the concrete be and how should the rebar be spaced to safely hold the load?  
Thank you
Cameron

Answer
Hi Cameron,

This is not an easy question to answer as you have not given full details- i.e. weight of tractor, exact maximum laod to be carried, wheelbase of tractor, weight distribution, etc. In any case, I cannot offer a full design service over tghis medium.

However, just for guidance (without doing calculations), I would expect the slab to be between 10-12 inches thick and with rebar of 20mm at approximately 150mm spacing at the bottom, both ways.

You will need to employ an engineer to doa  proper design, though!

Hope that helps!

Kind regards,

Arshad

Civil Engineering

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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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