You are here:

Civil Engineering/Deflection of flexural members

Advertisement

Expert: - 12/10/2008


Question
Dear sir,
 Do I Have to check Deflection of Beams  with service loads or ultimate loads. Staad uses the critical load i.e., Ultimate load for computing section displacements, please throw some light on it.

Answer
Hi Ahmed,

Most codes stipulate a total deflection limitation of span/250 for service loads only (DL+LL)and span/350 to 500 for service live loads for areas that have non-brittle and brittle finishes respectively which could get damaged- such as perimeter beams supporting glazing.

In STAAD, you should have all load combinations- SLS and ULS, so that you can compare against the appropriate load case. For very long span beams (say over 8-10m), you can stipulate a pre-camber equal to expected self-weight deflection, so that only the live-load deflection needs to be considered for damage to supported items.  

Civil Engineering

All Answers

Answers by Expert:

Ask Experts

Volunteer

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)

©2012 About.com, a part of The New York Times Company. All rights reserved.