Circa 80's Walmart construction

I have been asked to design store front windows for an old Walmart building.  This is in NE Texas so seismic concerns are low, wind is primary.  Walmart typical construction is CMU bearing walls around the perimeter.  I know I have 12” CMU and a 4” brick veneer.  The wall is 18’-8” to joist bearing.  The building is 180’ x 290’.  The joists run in the 180’ direction and the roof girders (WF) run in the 290’ direction.  It is a cantilever beam girder system.  There are 2 expansion joints running in the 180’ direction.  I can see double joists and a complete break in the roof deck.  The joists occur at the splice of the cantilever girder system, 6’ from the column centerline.

 

I do not have any drawings for the building.  I’m hoping there may be someone on the list who has designed Walmarts back in this older style of building, or other box retailers, who can give me some insight on the lateral stability of the building.  What I can’t figure out is how the middle portion of the building, between the 2 expansion joints, achieves lateral stability. For wind parallel to the expansion joints I don’t see how any shear can be carried across the joint since the deck is severed.  The girders continue through it, but it means the 5 girders bend in their weak axis to transfer the shear across the joint.  The interior columns are pipe columns and the bottom chords of the roof joists are attached with the single 2x2 angle brace from the last bottom chord web point to the column.  The bottom chord does not extend to the column.  I don’t think this makes a moment connection, not to mention a slender pipe column for a frame.  Can anyone shed some light on how the section of building between expansion joints would be stable?

 

Before I go cutting up shear walls I would like to know how the building is braced.

 

Thanks.

 

Rich