Why do I sometimes need to add oversized mounting plates to restraints attached to concrete?
The seismic restraint manufacturer has probably designed the steel restraint so that it is stronger than the material it is anchored to. A good example is when we are required to anchor to a thin layer of lightweight concrete. The concrete may not be strong enough on its own to hold the anchors. The addition of a larger mounting plate or embedded steel plate will distribute the forces over a larger area. 9) What is “special inspection” for anchor bolts? The actual installation of the bolt into the concrete is a critical part of the restraint system. If the bolt is not embedded deeply enough or properly set into the concrete, it could fail in an earthquake. Special Inspection requires an independent authority to watch the installation of the bolt to ensure that it is done properly. Once this is done, for purposes of calculating the correct anchor size, the allowed mathematical value of the anchor can be increased and save the cost of many more bolts. 10) Is it possible that your buildin
