Steel knee braces 1

[ronstruc]

Does anyone know if knee braces are allowed to be used for lateral resistance(eccentrically braced frames) in a steel structure? I have looked in the seismic provisions manual and I can't find where it says they are not allowed, however my gut feeling is they wouldn't be allowed. I know that a beam can be eccentrically loaded but I am not sure about the column. I do know that K-braces are not allowed. I believe the SDC is D; IBC 2003 is the governing code.

 

[SacreBleu]

For seismic, they are now prohibited - see Thread726-122340

 

[ronstruc]

Thank you for the information.

 

[broncosfan]

We use knee braces alot to stabilize mechanical platforms that extend above the roof steel. There aren't a whole lot of options for a platform that only sticks 3 feet above the roof. What do people do in high seismic areas for this situation? Thanks.

 

[Taro]

It might be OK to use knee bracing for small components like mechanical platforms. You could design them to remain essentially elastic to alleviate the concerns about column failure. And the consequences of failure are not as dramatic as for the main building lateral system.

 

[amirhamed]

Hi there.Who can answer this ? What's wrong with using a frame with simple joints and with concrete shear wall???