tube collectors between joist seats 3

[smvk3]

I am designing an occupancy category IV structure that is in a seismic design category of D. The structure is steel bar joists on CMU bearing-shear walls. Where the joists bear on top of the CMU walls, to transfer the diaphragm load to the top of the wall, I am debating whether to use tube collectors between the joists seats per the attached or utilize the joist seats themselves as a rollover load. The question I have is would I need to amplify the load on either the joist seat or the tube collector by the overstrength factor to satisfy the intent of section 12.10.2.1 of ASCE 7-05? Without the overstrength factor applied, the rollover load at each joist seat would be between 2,000 and 4,000 lbs.

 

[Gopher13]

Thanks for the star!!! Pretty sure it's my first one. Fitting it comes on a non-technical comment.

 

[bones206]

jayrod - eccentricity in what sense? I wouldn't think in-plane shear delivered eccentric to the wall centerline would cause an issue.

 

[jayrod12]

I meant either the joists would need to get shifted inwards on the wall, causing eccentric loading, in order to have your continuous tube be able to be anchored into the cores. Or you need to have some other form of connection between the collector and the wall if you want your joists concentric.

 

[bones206]

I see what you mean now. There’s probably a way to do it with some creative detailing, but I agree that in the final analysis that creative detailing will probably end up only lining the contractor’s pocket.

 

[KootK]

I agree that in the final analysis that creative detailing will probably end up only lining the contractor’s pocket.

I wouldn't let that deter any innovation. I see the evolution of it being something like this:

1) The savings do just wind up in the contractor's pocket.

2) The contractor starts to prefer your design services, in part because of your awesome, cost saving detail.

3) Everybody in EOR land starts to adopt your awesome, cost saving detail because they have to in order to stay competitive.

4) The savings do start to wind up in the owner's pocket and, more importantly, come to represent efficiencies that make us more efficient as a society and a species.

It's the holiday season now so messages of hope like this are important.