Hourly wind pressure for 1/10 years for deflection

[ali07]

Reference as per CSA S-16-01 or NBC.
As we check deflection of building for 1/10 years wind pressure and design structural elements for 1/50. Appreciate if somebody can provide Canadian Code reference for above.

 

[engn555]

To check wind deflection as per the NBCC 2005, you can either use the 1/30 year pressure directly, or the 1/50 year pressure modified by the (fractional) servicability limit state coeffiecient (found in Part 4 of the NBCC).

The appendix in the NBCC (C I think???) that lists the wind loads (as well as the snow loads, earthquake loads, etc) provides both the 1/30 and 1/50 year pressures.

 

[ali07]

Hi engn555

I believe 1/30 is no longer valid as per NBCC 2005 for design. It is changed to 1/50 now. 1/10 and 1/50 are listed as per Appendix C, Division B of NBCC 2005.

My question was not that you mentioned, it was " WHAT IS THE CODE REFERENCE FOR 1/10 WIND PRESSURE FOR DRIFT/DEFLECTION CHECK".

I need to know the code clause.

 

[engn555]

Your right. Sorry I thought it was 1/30 but it is 1/10.
Lower limit was what I was going for.
Not sure if there is a specific clause that spells out the deflection check as such. Just a serviceability limit state equation, I=0.75 for service vs I=1 for strength. Not every calculation is explicity spelled out in the codes, particularly ones that deal with serviceability.
If you're familiar with Canadian design and references, you should check out the example problem at the end of Introduction to Wood Design by the CWC. It illustrates this approach.

 

[ali07]

Yes you are right, it's hard to find reference to clause here, you can find solved example in Steel textbooks but where the reference comes from, hard to find out, right.

 

[engn555]

I think ulitmately the reference would be the specific clause in Section 4 that contains the servicability limit state equations.

 

[Lion06]

I can't speak for the Canadian Code, but it is explicitly stated in IBC that you can use 0.7 times the 50-year wind to check serviceability (This 0.7 factor equates to the 10-year wind).