Thermal modelling for concrete frame building in Middle East

[jonathanpye]

hi engineering colleagues...
I'm designing a concrete framed building in Qatar which has several movement joints, and I have some questions :
1. what is maximum spacing of movement joints ?
2. what temp variation should I include in my STAAD Pro design analysis model ? should this be min peak to max peak, min average to max average ? there are also max sun radiation temperatures published which are 84 degrees C (183 degree F) !!! I was thinking of designing for a 40 degree C range (104 degree F)... does this sound about right ?

Many thanks !

 

[ishvaaag]

The best advice is to find the codes ruling the construction in such country, that way you will avoid surely a number of issues.

http://www.catnaps.org/islamic/regulations.html#qbr

"The Qatar National Buildings Specifications (QNBS) no longer exists and has been replaced by the Qatar Construction Specifications (QCS), Third Edition 2007, a copy of which is available for Qrs.500. Engineering offices are required to have a controlled copy for reference. I understand that an updated version is to be published some time in or following 2010. The specifications are mandatory on all state projects as of the beginning of 2008, per Ministerial decision No. 155."

... controlled copy ... the mistery of the law (Mastery?) ... that's prior to republican Rome! We happen to have a nice number of controlled codes in the west, eh, just not to be befooled ...

QCS 2007

on construction joints
"12.2.2.2 The spacing of construction joints in water retaining structures shall not exceed 5 m."

on movement joints for concrete structures
"12.3 MOVEMENT JOINTS
12.3.1 General
1 Movement joints for expansion and contraction shall be constructed in accordance with the details and to the dimension shown on the Drawings or where otherwise ordered by the
Engineer and shall be formed of the elements specified."

I find QCS 2010 effectively exists ...

This on movement joints ...
"12.3 MOVEMENT JOINTS
12.3.1 General
1 Movement joints for expansion and contraction shall be constructed in accordance with the details and to the dimension shown on the Drawings or where otherwise ordered by the
Engineer and shall be formed of the elements specified.
2 Movement Joints in Water Retaining Structures shall be in accordance with the details and to the dimension shown on the Drawings and EN 1992-3.
3 The Contractor shall pay particular attention to the effects of climatic extremes on any material which he may desire to use on any movement joint and shall submit for approval by the Engineer his proposals for the proper storage, handling and use of the said materials having due regard for any recommendations made by the manufacturer in this connection."

What leaves you without further guide (with the exception of maybe highway/bridge structures) on how to apply the thermal ranges, total, differential, average etc ...

Try then some lecture on thermal actions for the kind of building at hand, imagine the actual daily and yearly cycles, investigate what the data given is, think how all this you expect to affect your structure and then decide for one set of thermal loads able to reconcile all this.

Info on thermal actions for example in

BS EN 1991-1-5:2003 Incorporating Corrigendum No. 1
Eurocode 1: Actions on structures — Part 1-5: General actions — Thermal actions