Using Concrete expansion anchor bolts to hang heavy weight from concrete ceiling/floor pad
I am on a job where we are being directed to install concrete expansion bolts into a concrete ceiling,insert pieces of 3/8″ all-thread into the anchors,suspend pieces of uni-strut attached to the all-thread, and hang a lot of weight from the uni-strut pieces. I think this is silly and dangerous. My understanding of these bolts is that their main strength is to resist shear or side to side forces, and live most of their lives just sitting there waiting for something bad to happen. I assume that their pull-out or uplift strength is kind of secondary considering that the main seismic stress these bolts are likely to undergo is side to side. Hanging pipes and ducts in commercial building is quite common, but the weight of what is suspended is much less compared to the application we are being asked to use the bolts for. This application also depends a lot on the integrity of the concrete and its resistance to breakout, an unknown because it is an old building. My understanding is that these bolts are not made to live their lives constantly under high pull-out stress. Any opinion or enlightenment you can throw my way?
Replies
You said that already.
This sounds like Layaway litigation.
Or, the lawsuit time bomb. This sounds scary dangerous for a long time into the future.
I'd bolt unistrut to the ceiling using red heads and a bunch of them, then hang the rods from these.
http://www.unistrut.com/literature/index.php?archive=&horizon=&doc=KwikWash&zm=&pg=1
Epoxy the anchors in
Epoxy the anchors in
Doing it twice won't necessarily make it any better.