Brace

[Anne651]

For eccentrically braced frame, with link beam, what would e usually be?

As well, it says in the code the laterally support the top and bottom flange of the link beam at the end. How to support the bottom flange laterally? Connect an angle to the jbottom/top of the closest beams/joist?

How about the portion regarding link rotation? how to find link rotation?

 

[Anne651]

In addition, knee brace is essentially a special eccentric brace. So knee braces are designed as eccentric braces. Am I correct?

 

[ash060]

A knee-braced frame can only be used with R=3 check the AISC 341 Commentary and they are listed in section C-11.

They are considered OMF. Design guidelines are also given

 

[Anne651]

Can an eccentric bracing and a x bracing been used in the same building? But how would RdRo be, which Seismic force should be used?

As well, S16-01, what does 27.7.9.2 and 27.7.11.1 mean? What exactly does the code mean?

 

[DHKpeWI]

I assume you are asking what R and Omega to use and that you mean concentric and eccentric bracing? The larger R and Omega are used to determine the seismic force per ASCE7 2005 Section 12.2.3.2. If you are using the Table 12.2-1 Section H, then use R = 3, Omega = 3 and Cd = 3. This allows you to avoid the specific seismic detailing of AISC 341. There is another post on this site about whether you are required to use Omega is you use the R = 3 approach. It seems to me I have still designed connections for Omega level forces, as well are drag struts but that might be conservative.