Connection between drag truss and post

[denguy]

Hello,

I need help coming up with an adequate fastener between the drag truss and the posts supporting it.

After calculating the drag strut force, it comes out to be about ~4500 lbs, and it's being supported by a 7x7 post each end.
The drag truss length is 36.25'.

How would I go about calculating the force at the support so that I can provide adequate connectors to transfer this drag strut force to the post?

Please let me know if there's any other information I can provide. Thank you!

 

[JAE]

A sketch would help.
Assume this is a wood structure?
Drag trusses collect lateral forces and usually deliver those forces to a shear wall, a brace, or a moment frame. Not sure what you mean by “post”.

Wind or seismic or both?



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[denguy]

JAE

Yes, this is a wood structure. My boss drew a plan that had a drag truss laying on top of a 7x7 wood column at both ends and told me to calculate the drag strut force which I was able to do.
However, I'm not so sure about the connection to the columns. Am I supposed to calculate the uplift force based on the drag strut force?

To simplify the plan looks something like this

-----------------SHEAR WALL-------------------------
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7x7 POST------------DRAG TRUSS-------------------7X7 POST
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-----------------SHEAR WALL-------------------------

*the second vertical dash line represent the right side wall (could not get it to space correctly)

This is for seismic.

Thanks

 

[JAE]

I wouldn’t call that a drag truss. As I mentioned above a drag truss actually collects and drags lateral forces from a diaphragm into some element that serves as a lateral brace for the structure.

In your sketch the truss you call a drag truss isn’t dragging anything. It is at the center point between two shear walls so it really has very little lateral forces in it.

The columns offer no lateral stiffness so there won’t be much lateral force between them and the truss. Just some local wind uplift and the vertical gravity loads.

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