Clerestory - Tension Only Bracing

[slickdeals]

Greetings,
I have a project that has a clerestory roof (a high roof) which looks like this:
|-------------|
| High roof |
-------- ----------

It has a metal deck with rigid insulation, no concrete. It is located in SDC "D". Is there any provision in the code (IBC 2003/ASCE 7-02) that will allow me to use tension only bracing to bring the forces down to the lower diaphragm instead of designing a SCBF or SMF. I have shear walls + steel beams framing this building below the high roof.

Any help is appeciated.

Thanks

 

[slickdeals]

Are knee braces allowed in seismic design? particularly in SDC "D".

 

[msquared48]

Any possibility of continuing four steel columns up from the steel framing below to take the lateral in cantilever action?

I don't know why knee braces couldn't be used, but, if you have room for diagonal knee braces, why not just use small shearwalls? Seems like the site obstruction issue would still be there with the knee braces anyway.

Mike McCann
MMC Engineering

 

[slickdeals]

The roof is about 14' high, which would be the length of my cantilever. Are there any other suggestions?

Thanks

 

[msquared48]

3 Dimensional tube steel moment frame, pinned at the base?

Mike McCann
MMC Engineering

 

[tedamiao]

I do not thick tube steel moment frame is good option. R factor is very low (R=1.5 for tube) and it is super hard to have approved moment connection per current code for tube.

Wide flange is first choice if considering moment frame I believe.