Monday, 7 January 2008

Facade Shore - 2.5% + wind... but where is it from?

Whilst carrying out a design today for a large facade retention scheme I began to ask the question "why am I designing for 2.5% of self weight plus wind?". I asked around the other members of our design team to see if they knew where this originated from... but no-one seems to know the answer!

Even the usual suspects 5973 and 5975 don't seem to give this specific requirement. PJB told me how he had been asked to design for 10% plus wind in the past by ARUP but had always for as long has he could remember designed to 2.5% plus wind. Alwyn is still wondering if he had it on a hieroglyphic somewhere...

If you can shed any light on this please let me know! My eyes often have a tendency not to see somethings... such as speed-cameras, so it could be me, either way, any help with this one would be appreciated!


1 comment:

Ben Beaumont said...

It would appear that we have an answer thanks to Thilini at Balfour Beatty - CIRIA C579.

Lateral loading under section 8.11 includes these values but are slightly modified for connections and for overall stability.

Load cases for connections being designed to carry the greater of: a) 2.5% of self weight plus wind load on section of facade being restrained by these connections, or b) Horizontal loads resulting from the out-of-plub characteristics of the facade in this section being restrained plus wind on this section... phew, a mouthful!

OTM load combinations are given in a table on page 169..

Thats all from me. Have a good wkend! Thanks again T.