Profile: The Fasteners House specializes in providing all-thread rods, and fasteners. Anchor bolts that have been bent are placed in concrete and used to support structural steel columns, light poles, highway sign structures, bridge rail, equipment, and a variety of other uses. The bent part, or leg, of the anchor bolt creates resistance, preventing the bolt from pulling out of the concrete foundation when force is applied. J-bolts, also known as round hooks, feature a circular bend that is often used in concrete as a hold bolt anchor or as part of a hold down bolt cage design.