portal frame gable end wind load analysis 1

[wrxsti]

hi, im getting this high axial load at the center of propped portal
causing my rafters to fail in minor bending

see image

any ideas?

 

[JoshPlumSE]

Not much to go on here. I suggest displaying your deflected shape to see if there are supports that you did not intend. Or, if there are diaphragms that are behaving badly.

Maybe display your load and track that load through the structure.

 

[JoshPlumSE]

Also, what's the lateral resisting system in the non-braced frame direction?

 

[wrxsti]

thanks for response josh
here are some more images
i need to rotate my center cols to strong axis in frame direction on this model
but last time i rotated it it didnt change the values much

 

[KootK]

Take this as just the vaguest of hunches. Shot in the relative dark. If you're willing and haven't resolved this yet, please post a deflected shape of this area for the load case of wind applied to your gable end wall.

 

[wrxsti]

 

[wrxsti]

 

[KootK]

Thanks. More questoins:

 

[wrxsti]

the def i believe is from the first problem with a monster lat load accumulating at the ridge somehow

i offset the truss at the ridge to simulate actual structure since they wont meet exactly at ridge

( i would prolly move them in some more but the purlin joint was easily accessible at the time )

the first post had it at the ridge with a strut connecting the props but gave same problem

the weird curvature i think is just graphics it looks straight when you zoom in

 

[KootK]

The diagonals in your horizontal trusses seem to be tension and compression members. Is that what you want or should they be tension only?

What load case is it it that produces that weird axial load that concerns you?

 

[wrxsti]

tension only im going to take out the compression ones and see if it helps for the direction

longitudinal (load case b) for wind

 

[KootK]

Can we get strong axis moment and shear diagrams for that wind post that hits the peak and is heavily deflected?

 

[wrxsti]

 

[wrxsti]

ooops just realized i had the point loads and udls on

 

[KootK]

Are you modelling any kind of diaphragm on the roof or is it just the skeleton that you've been showing?

 

[wrxsti]

just skeleton

 

[wrxsti]

 

[KootK]

So is this a moment or a shear diagram? Either way, do you know why the graph stops before the top?

 

[wrxsti]

 

[wrxsti]

not sure