Civil Engineering/Gantry girder

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Expert: - 8/6/2011


Question
Dear sir,     we are going to construct a factory building of 17.7m span & 6m bay length having two 25 ton crane of 6m wheel base.At one place two colums are omitted making a bay length of 18m.We are using a tapper I section of 1700mm ht at midspan & 750mm at support.Now my question is -          1.For a 18m I beam how to controll the deflection.  2.for transportation purpose we have to divide the beam in two segment & joining it at midspan.Is there any problem facing for to keep a joint at midspan

Answer
Hi Goni,

1. For use as a gantry beam, the only way you can keep the deflection within limits is to provide sufficent 2nd moment of inertia (i.e. Z value) and by using the highest grade of steel available. The former can be achieved by greater depth or thicker flanges.

2. Joining at mid-span is OK, so long as you design the connection to take the full moment and shear that it will be subjected to.

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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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