Civil Engineering/Projected loads

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Expert: - 12/3/2009


Question
Dear Arshad Khan,
I hope that you are keeping good. My question are regarding  a stadium that i have to model and design in etabs.
You can see the pictures here, gravity load and projected gravity load etabs description(i have upload the pdf-one page only) and etabs model here..
http://cid-60157d8f9414c461.skydrive.live.com/browse.aspx/Public/Stadium%20Pictu...
My question are..
1)shall i take the load on the ramp (green color where people will sit in gravity direction or projected gravity direction) projected gravity will treat it as WCos(theta) and that makes sense to me.. what do you say.

2)Is it correct to model the cantilevel beams(the stands) this way and design the columns or shall I manually find out the loads and do it in a column design program.

3) how to apply wind load to the upper cantilever roof of stadium.. (any tips on that)(I believe defining wind load and selecting exposure from area and selection front direction as windward)what are your view!

4)Regarding R value, in y direction there are retaining walls in one direction on one side only.. what do you say about R value and shall i take the top story as roof in auto seismic loads and why??

I know you are quiet busy so and i'll be very greatful if you can help me out on that...

Thanks in advance!  

Answer
Hi Muhammad,

1. Yes projected gravity load is correct. Also remember to add in the dynamic loading due to crowds, as per your local code requirements.

2. So long as your load distribution from slabs to beams is correct, you can use ETABS. But you should always do hand calculations as a check.

3. This is complex and I do not think ETABS is suited for such shapes- best to use codes to determine the loading (mainly up-lift, I would imagine), and apply that to the model.

4. I am not sure what R value to take (don't have UBC ready to hand)- suggest you err on the conservative side, and yes use top story as top of roof.  

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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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