Strength of Joints that Combine Bolts and Welds

Abstract

The capacity of each connector type in a shear-splice type of joint is reflected by its shear strength and shear deformation characteristics. When two or more types of fasteners share the load, it is clear that it is not satisfactory to simply combine the ultimate strength of each individual fastener type. Each of the different fastening elements has a different ductility and, in general, each reaches its ultimate strength at a different value of overall connection deformation. The strength of joints that combine bolts and fillet welds that act in the same shear plane has been examined. The study has shown that the rules provided in the AISC LRFD Specification do not adequately reflect the actual strength of this type of joint. Using test results from the University of Alberta and others, expressions are presented for the capacity of the various elements that make up a bolted-welded joint. These expressions enable the capacity of a combined bolted-welded joint to be predicted with a reasonable degree of accuracy. The examination showed that transverse fillet welds do not work well in combination with bolts because of the limited ductility of the former.