New Design Criteria for Gusset Plates in Tension

This paper presentes the following observations and conclusions for tensile gusset plate connections: 1. All ultimate failure modes consist of a tensile tear across the last row of bolts, with various stages of shear yielding along the outside lines of bolts. The extent of the latter depends on the connection length. 2. The governing block-shear model is shown to be the one incorporating tensile ultimate stress on the net area between the last row of bolts, and a uniform effective shear stress acting on the gross area along the outside bolt lines. 3. The effective shear stress acting along the outside bolt lines can be assumed to be uniformly distributed, with the magnitude given as a function of the total connection length, and material yield and ultimate stress levels. From the above, three equations are developed which accurately predict the ultimate strength of 39 gusset plate tests. The accuracy of the proposed model is not affected by such factors as plate boundaries, fastener size or edge distance to the first bolt line. Typical design curves for A36 steel are presented to demonstrate thee ease with which tensile gusset plate thicknesses selected to give maximum connection efficiency. The 39 gusset plate tests considered in the development of the final strength model have included a wide range of strength parameters. However, it may prove worthwhile to conduct additional tests, especially with connection lengths within the range of 10 to 16 in. (254 to 406 mm). This study did not address the problems of compressive gusset plate connections, nor the related problem of gusset plate bucklin, which are important future considerations. Also, the combined effect of multiple members framing into one gusset plate, and gusseted connections in close prxomity to boundary elements are important areas to investigate further. (Author)