Knee Braces

[00Z]

I am planning on using knee braces to resist seismic loads on a deck attached to a single family home. (I can't show that the existing walls are adequate to resist the load, heavy snow loads).

I was discussing this with a colleague and he told me a local building department here in California told him knee braces are not allowed under the new code because there is no R-value listed for knee braces. I was planning on using 1.5 for timber frame.

Has anyone else come across this restriction?

 

[frv]

What SDC?

 

[woodman88]

Sounds more like a local interpretation of the code. Call up (or better e-mail them so you can get a e-mail for your records back) the building department for your site and ask them if a R of 1.5 would be allowed for a deck with timber knee braces.

Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.

 

[00Z]

frv - It's SDC D

woodman88 - I probably should send an email, but I didn't want to raise a question they weren't concerned about.

I discussed using a cantilever column with the client and he doesn't want to use steel, or embed a wood post in concrete.

 

[ATSE]

Usually a knee brace translates to strong beam-weak column. Cardinal sin for seismic (capacity) design.
Rarely a good idea, but maybe okay with an R=1.