Girt/Horizontal Brace Connection to Column

[Szubert80]

I`m trying to find a prying force on bolted connection as shown on attached pdf.
The girt span may vary from 5.5m to 10m but 40kN reaction was given as governing lateral load. The gusset plate and girt`s connecting plate are stiffened with 3/8" plates at opposite sides. I would like to ask you guys how to calculate prying force on these bolts?
My main concern is, where exactly apply the lateral load, because the distance from bolts center to the point of load will dictate the prying at the very end of connecting plate.

 

[DaveAtkins]

I don't think there is any prying. Just shear on the bolt due to direct tension or compression in the brace.

DaveAtkins

 

[Szubert80]

Hi Dave,

Because this brace acts also as a girt there is lateral load in addition to axial tension/compression like you mentioned. I have shown direction of 40kN load on the section views. So these bolts need to be checked for shear and tension. The question is what is the tension in these bolts? If there is no prying (which might be the case as the 3/8" stiffeners will reduce the flex in the connecting plate ) should only 40kN be used for design?

 

[canwesteng]

There might be some prying, I would check it as if the plate is the bottom flange of a W-beam, and the stiffener is the web. You can probably make some conservative assumptions in that calc to prove no prying occurs.

 

[KootK]

I'm with Dave on this one and don't feel that there will be appreciable prying action.

If there is no prying (which might be the case as the 3/8" stiffeners will reduce the flex in the connecting plate )

I believe that to be the crux of it.

On another note, this seems like kind of a costly way to make a girt/strut connection. Why not just two horizontal plates bolted together? One projecting from the girt, one as as stiffener in the column.

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.

 

[Szubert80]

The reason for the plates to be in vertical position rather than horizontal like KootK suggested is that diagonal brace is connecting to it at one end. The other end should be actually detailed with 2 horizontal plates but most of the girts throughout the building has 1 or 2 diagonals connecting to it, and detailer just used the same connection macro for all of them.