High strength friction grip (HSFG) bolts are a staple in structural steelwork due to their unique load-bearing mechanism. Comprising high-tensile strength bolts, nuts, and washers, these fasteners are meticulously tightened to a specific shank tension.
Unlike conventional bolts, where the transverse load across the joint is primarily borne by the shear strength of the bolt shank, HSFG bolts rely on friction. The tightening process induces a clamping force between the connected plates, generating immense frictional resistance. This friction becomes the primary force resisting slippage or shear movement within the joint.
The advantage of this approach is twofold. Firstly, it allows for a more efficient use of materials, as the bolt shank’s cross-sectional area can be reduced since it’s not the primary load-bearing element. Secondly, it enhances the joint’s overall strength and rigidity, as the clamping force and friction create a tightly integrated connection that resists both shear and tensile forces.
However, the successful implementation of HSFG bolts necessitates meticulous attention to detail during installation. The bolts must be tightened to the precise tension specified in the design, and the contact surfaces between the plates must be clean and free of any debris or coatings that could compromise the frictional interface.
When properly installed, HSFG bolts offer a robust and reliable solution for connecting structural steel members, contributing to the safety and longevity of the overall structure.