Staad modelling

[ANURAAG ATHREYA]

I am experiencing a mysterious hogging bending moment at pinned supports in a staad model. Please provide a solution to eliminate that hogging bending moment.

 

[ldeem]

check your loads to be sure no concentrated moment at the ends and then look at text output. It could be a the graph is not accurate.

 

[SteelPE]

Something is suspect with the end supports. As it's graphically showing a pin at each end

One comment........ I try to avoid using a pin-pin connection for a beam like this. You will always end up with some catenary action that will throw off your results. To avoid this result, I will typically fix the far right support releasing the appropriate moment conditions and the axial direction of the beam (typically Fx but it looks like it's Fz in your model.... can't really tell) in that far right support.

 

[JoshPlumSE]

If this were RISA, I would immediately guess that there is a "Top of Member" offset on that beam. If STAAD has an equivalent function then this is probably what's happening.

 

[WARose]

Could you post your edit input (as a .txt file)? I can then have a look.

You are probably using a newer version than I have. (Hence my request.)

 

[canwesteng]

Could also have offset loads too. Better question to ask, is there anything in your model or load conditions that would cause this? Very rarely is it software error, especially for such a simple problem.

 

[Liam Nesson]

Best to provide the STAAD file, there could be a lot of different reasons.

You could just also try release the member at the ends closest to the support, double click the member, change releases, and release Mz. However its better to fully understand why it is happening.

 

[patswfc]

Agree with Josh that the beam having an offset is the most likely culprit. If this is the case STAAD should also show an axial force in the beam.

 

[WARose]

@ ANURAAG ATHREYA: Just so you know (since you appear to be new here), it is considered bad form to post a new thread and just abandon it. You need to provide the requested info or just say you've resolved it on your end.