Design of Connectors in Web-Flange Beam or Girder Splices

Splices in beams and girders are often required when the lengths of members are limited by fabrication, transportation, or handling facilities available, or by the construction process. Splice plates are lapped across the joint and bolted to the webs and the flanges of the beam in order to transfer the load. This type of splice is usually referred to as a web-flange splice. Current design methods for the connectors in web-flange splices vary. For example, Fisher and Struik recommend that the web splice be assumed to transfer all of the shear and that the flange splice be assumed to transfer all of the moment at the section. The bolt group on one side of the web splice is designed on the assumption that the shear force acts at the centroid of the bolt group on the opposite side of the splice. In a commonly used British design manual, the same approach is recommended. Ballio and Mazzolani present two alternative approaches for design of web-flange splices. In both approaches, the moment at the location of the splice is proportioned between the web splice and the flange splice. For the web splice, the first approach considers the shear force to act at the centroid of the opposite bolt group. This is similar to the recommendation of Fisher and Struik. In the second approach, the bolt group on one side of the web splice is designed assuming that the shear force acts at the centerline of the splice. Bresler, Lin and Scalzi, Salmon and Johnson, and Nethercot also use this second approach, and they further recommend that the web splice be designed to transmit both the eccentric shear force and the portion of the moment that the web was designed to carry. However, Salmon and Johnson suggest that the effect of the eccentricity can be neglected except in cases where the shear and moment are high, and Bresler, et al. recommend neglecting the effect of the eccentricity when the eccentricity is much less than the depth of the web.