Which type of joint's faying surfaces are important in the performance of the joint when stressed?

When evaluating the performance of structural joints under stress, the significant role of faying surfaces becomes particularly critical in slip-critical joints. In these joints, the faying surfaces—the areas where the connected pieces of steel are in contact—must be meticulously prepared and remain free of contaminants to ensure adequate friction, preventing any relative movement between the connected parts when subjected to loads.

In slip-critical applications, the design relies on the friction generated between these faying surfaces to resist applied forces. The quality of this surface, influenced by factors like surface roughness, cleanliness, and bolt tension, is essential for achieving the required friction to hold the joint together without slipping. Consequently, proper inspection and preparation of the faying surfaces are crucial for the effectiveness of the joint.

Alternatives such as bearing type and welded joints do not place the same emphasis on the faying surfaces in the context of resisting slipping. Bearing-type joints transfer loads through contact points with bolts acting primarily in shear, while welded joints rely on the continuity of the weld metal to carry loads. Friction-type joints, while they highlight the importance of surface contact, are much less common in structural applications compared to slip-critical joints, which are specifically designed to exploit frictional resistance.