drag strut force

[jec67]

Hello All:

I have a building which I am designing that measures 200'x200'. The roof is constucted of metal deck on bar joists. The walls are cmu non-load bearing walls that will be used for shear walls. One of these walls has a "jog" in it resulting in a 16' offset. The wall jog is in the same direction that the bar joists are spanning. That is, the shear force in the offset walls is perpendicular to the joists.

I am planning to design a drag strut for the discontinuity in the diaphragm at the jog. I have seen drag struts for this type of situation that do not span the entire distance (from the wall jog to the exterior wall that is perpendicular to the drag strut). How would one go about designing such a strut?

 

[DaveAtkins]

I would use steel angles between the joists. Make sure to note on the drawings that the joist supplier must design the joist top chords for the drag strut force, which crosses the top chord. Then detail an angle that will "drag" the force into the CMU -- it will probably be fastened to a CMU bond beam along the wall with expansion bolts.

DaveAtkins