huge deflection in truss structure 4

[untuksignupsaja]

hi all, i just learning SAP2000 to create simple bridge structure. I'm confused, why point 4 (showed in pictured) has huge displacement? Isn't it held by frame 1, 2, and 3? And how to model it so frame 1, 2, and 3 hold point 4? thanks

 

[LQQD]

Hi, there may be many causes forma that. Try running the analysis using the standard solver,Yyou may select this option on " analysis-analysis options". Afterwards check the analysis log on "-analysis-show last run details", the will be some instability warnings for some nodes, That might help you to get to the root of the problem. Also do a hand calc for absolute weight and forces applied, then check it with the output table called "base reactions", you may acces this table pressing Ctrl+t and then checking the last box.

 

[Guest262653]

If you're considering pinned members only, you're lacking bracing at the top chord.

 

[Shz713]

How many DOF are you including in your model? Besides, check what forces are being transferred to adjacent members, y9ou may need to use releases to force them act as truss members
(only tension and compression).

Lastly, if you want to specifically work on bridge structures, I recommend using CSiBridge.

Cheers

Shoot for the Moon, even if U miss, U still land among Stars!

 

[Jatfuentes]

untuksignupsaja,
The problem is tha the joint is not connected. Give a Zoom in the joint, and you will see that that joint is not connected.