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Expert: - 4/25/2010


Question
QUESTION: What load factors shall be considered in P delta analysis using Etabs

ANSWER: Hi Mohammed,

Basically you do the normal load combinations with normal factors, as pdelta analysis is an iterative analysis to assess additional moments/deflections caused by lateral sway and inter-storey drifts.

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

QUESTION: Thanks for the reply. I was actually interested to know the recommendations of Etabs who I think call for a dead load factor of 1.2 in the latest version instead of the 1.0 in earlier Etabs version. Thanks

Answer
Hi Mohammed,

I think you need to follow the recommendations of the code you are using, whether it is BS 8110, Eurocode or UBC or IBC- these will guide you on the load factors and combinations. Usually for seismic loading, the combination is 1.0 x all dead load + 0.25 x live load, so long the latter is not a storage facility.

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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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