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. For purposes of calculating the correct anchor size, the allowed mathematical value of the anchor can then be increased and save the cost of many more bolts.