Truss Members

[B.Pascall]

Hi,

I am currently trying to run the analysis on a structure however the brace/truss members I placed in the roof pose an error as shown in the attached PDF file (truss members) as well as some instability errors type 2.

The braces in the roof are all truss members (only axial forces act) and also removed them from the cladding load distribution but when I run the calculation the error message appears with instruction (as the PDF). I switched on the forces in the Fx direction as the instruction but the error still comes up when I run the calculation. 

Any assistance will be greatly appreciated,

Thanks

Brent

[Rafal.Gaweda]

Aren't they joists ?

Just in case file please.

[B.Pascall]

Yes they are joists, P 2.5 to be exact. 

I tried to attach the actual file but I get a error message saying the file extension is not a valid extension to attach.

First time uploading to the autodesk forums so im in unfamiliar grounds for the moment.

Regards

Brent

[B.Pascall]

My correction, I wont really consider the member/s to be joists but really pipes which acts as a tie only in axial loading.

[B.Pascall]

Find attached the file as requested.

http://www.filemail.com/t/5emdr5wv2dbdhfh

[Rafal.Gaweda · Accepted solution]

1. Use Full code combinations instead

2. Instabilities are caused by split truss bars : 144 145 152 153 . Either you define them as a one bar (each ;  without intermediate node) or delete truss bar property from them and apply correct releases