JMIKS Fasteners supplies double ring anchor bolts in mild steel and stainless steel. This through bolt has two expansion rings that grip the concrete at two points for a firmer hold.
Double ring through bolt for push-through and pre-positioned installation.
Drill the hole to the anchor length minus the thickness of the nut and the fixture, then blow out the dust.
Place the anchor and tap it in with a hammer.
Tighten the projecting nut: the tapered bolt is pulled into the clips, which expand against the hole wall. The two clips give a double grip.
The two rings share the load over a longer part of the hole, which gives a firmer grip than a single ring anchor bolt of the same size.