Can expansion anchors (like Kwik Bolt TZ2) be used in an overhead application with sustained load and can have a stand-off distance between the concrete and the steel baseplate? I am trying to design overhead protection
plating in a tunnel that will require a standoff distance between the concrete ceiling and a protection plate. What is the construction procedure for something like this? Does Hilti have a sample detail that would show a similar
connection?
Hi Dan,
Using an expansion anchor overhead is no issue. To achieve a stand-off condition with an expansion anchor, the anchor will need to be installed and torqued against the concrete. You would be able to use nuts and washers to then "suspend" the baseplate away from the concrete. This is what Hilti calls stand-off with clamping, because the nut is clamping the concrete to set the anchor. The biggest difference with adhesive and expansion anchors in stand-off conditions, is that you must have the nut and washer that will be used for the installation torque against the concrete (clamping) for expansion anchors. For adhesive anchors, there is no installation torque required so that extra nut against the concrete is not needed. I attached a photo of stand-off with clamping for reference.
Thanks,
Dani
Hi Dan,
The included nut and washer for the KB-TZ2 must be used to apply the torque value specified in the anchor's Operating Instruction. It will be up to engineering judgement to determine appropriate hardware and how to best specify the standoff condition.
Regards,
Matthew