F3125 Structural bolts are designed for steel to steel structural connections. There are two main type of structural bolts: tension control bolts and heavy hex bolts.
Tension control (TC) bolts are pre-assembled fasteners with a rounded head and a splined end that shears off when the nut is properly torqued and the manufacturer's desired torque value is achieved. A great advantage to TC bolts is simpler installation and the amount of labor it saves. The installation tool is called a shear wrench, which is a lightweight tool that is quick, can be used by a single worker, and reduces fatigue. Birmingham Fastener distributes tension control bolts from 5/8” diameter to 1 1/4” diameter.
Heavy hex bolts are the industry standard for structural bolting applications. Heavy hex bolts have a larger bearing surface to distribute the load. These structural bolts have a shorter thread length and a longer shank length. In structural bolting applications, this allows the bolt's threads to not be in the shear plane (where the two plates meet up). Generally, you don't want threads to be in the shear plane, because it can reduce the strength of the connections.