Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

Modeling Members With Overhangs

Status
Not open for further replies.

JoshH726

Structural
Aug 3, 2010
83
0
6
US
Are rigid elements the best way to model simply supported roof purlins overhanging an inclined truss (eg pratt, scissor, etc)? The help file does include some guidance on using rigid elements to represent the offset. My question comes into the correct fixity and trying to capture a realistic simply supported condition. Releasing rigid element i- (top of inclined member) or j-end (bottom of My and Mz at both supports would cause a warning for the members rolling over. One approach I've found is releasing i-end My and Mz in one support and releasing i-end Mx and strong axis (My or Mz depending on orientation) moment at the other support. This leaves an weak axis bending in the connection, which would be counter intuitive for a simply supported connection. Does this connection get designed to resist the weak axis bending? Any thoughts would be appreciated.
 
Replies continue below

Recommended for you

I'm not 100% certain that I'm understanding your situation. Though I've got a pretty good idea.

My tendency is to use end releases NOT in the rigid links themselves, but in the simply supported members that frame into them. Most of the time, this is easier in that the orientation of the member's local axis is easiest to understand. I don't think this should lead to instabilities though I may not have your exact situation pictured correctly.

 
Status
Not open for further replies.
Back
Top