INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

Modelling Trusses in Etabs or Staad

Modelling Trusses in Etabs or Staad

(OP)
In Truss Analysis, which software is better to produce a reliable result, Etabs or Staad?

I tried modelling thru Etabs and Staad. Etabs gives a more conservative output compared to Staad. Resulting to more failed members in Etabs.

RE: Modelling Trusses in Etabs or Staad

I don't know why either would give a different answer. Are you using p-delta or other iterative analysis in one?

RE: Modelling Trusses in Etabs or Staad

If both models are identical they would be remarkably similar. I suspect you have modeled something differently.
Try end conditions, support conditions, load magnitude/direction, code requirements, etc.

RE: Modelling Trusses in Etabs or Staad

Review your shear, moment, and deflection diagrams in both software packages.

This was drilled into my head by my senior and I try and drill into the heads of all our young engineers. The diagrams don't care what software was used to create them and will reveal real fast any wrong member or node fixities. This advice applies for a simply beam to a full building model all these software packages are very good at visualizing the results and some can even animate the deflection which can show you weak points in a frame model and soft stories in a building model.

Also of large importance with Staad and Etabs or any node based software are member unbraced lengths and how they are captured in the software. I know a beam with a node added at mid point but not segmented in Staad will have an unbraced length eqaul to the distance between the end nodes, likewise if it was segmented the unbraced length would be the distance from end node to the mid point node.

RE: Modelling Trusses in Etabs or Staad

Is your etabs truss within a full building model where floor/roof diaphragms might be affecting the truss behaviour?

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

RE: Modelling Trusses in Etabs or Staad

I've never used Etabs.....but STADD will take into account elongation, shear deflection, etc that some software meant for nothing but truss analysis doesn't. That may explain some of the differences. Hard to say without seeing it.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close