Post Installed Tilt Panel to Slab Connection for a Seismic Retrofit
Post Installed Tilt Panel to Slab Connection for a Seismic Retrofit
(OP)
I'm working on a seismic retrofit of an old building, and have no idea if the tilt panels are connected to the slab. The owner doesn't want to spend money scanning the concrete for this info so now I want to add this connection in to bring it up to code. My method would be to drill a hole from the the exterior, through the tilt panel, and then about 12" into the existing slab. Then I want to epoxy-grout lengths of #4 rebar into this hole to tie the panel and slab together. However, I am getting killed by Appendix D and provision D.3.3.4 since the panels are only 5.5" thick, and I'm only considering the slab to be 6" thick. This means that my brittle concrete breakout or pullout failure modes will govern every time over the ductile steel strength and I feel a little stuck because of it. Does anybody know another avenue that I can pursue or some provision that will help me out? Maybe an idea for an easier and better way to connect the panel and slab? This problem seems to a recurring theme is high seismic areas so send any and all creative solutions you have.






RE: Post Installed Tilt Panel to Slab Connection for a Seismic Retrofit
Why not connect the panel to the strip footing at the outside face of the panel rather than to the slab?
Is there an interior finish/look/useage that prevents you from using an angle and afterset bolting to the panel and slab?
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: Post Installed Tilt Panel to Slab Connection for a Seismic Retrofit
I had thought about connecting the panel to the strip footing, but the owner is keeping costs low and want to excavate as little as possible. Even excavating down far enough to be level with the slab is more than he wants to do.
Adding an angle on the interior was another option we briefly considered, but I would have had to put the bolt into the slab at 8" back from the edge. This interfered with some of their access since they would need to be at 1'-0" o.c. around the entire perimeter.
Sorry to shoot down your ideas, but that's one of the reasons I'm feeling a bit stuck at the moment.
RE: Post Installed Tilt Panel to Slab Connection for a Seismic Retrofit
If adding dowels to a reinforced slab, I would take the bars in far enough to develop them
msquared's suggestion may prove to be a cheaper method of anchorage than this.
RE: Post Installed Tilt Panel to Slab Connection for a Seismic Retrofit
I'm not an experienced seismic guy (wind is my thing)... I guess you can't use frictional sliding resistance?
RE: Post Installed Tilt Panel to Slab Connection for a Seismic Retrofit
RE: Post Installed Tilt Panel to Slab Connection for a Seismic Retrofit
And I agree that Appendix D is a big pain. I understand that they want the ductile failure to govern, but in my case there just isn't enough concrete there to make that feasible. The steel is ALWAYS going to be stronger than the concrete. My maximum failure mode is pullout and that is only at 46% of capacity so why can't we call that good? We're already adding extra safety factors (pullout is at 23% of capacity in a non-seismic region) to account for seismic regions so why isn't that good enough?