Fillet Weld Design for Rectangular HSS Connections

The 2010 AISC Specification for Structural Steel Buildings has expanded the scope in Chapter K ("Design of HSS and Box Member Connections"�) with a new Section K4, "Welds to Branches."� This paper describes the background to this development and examines the structural reliability of the weld effective length provisions contained therein. The latter is achieved by using a database of 31 welded square/rectangular hollow structural section (HSS) K-, T- and cross- (or X-) connections in which all test specimen failures were reached by fracture of the welded joints. The potential inclusion (or exclusion) of the sin θ effect, whereby fillet weld capacity is increased for loading not parallel to the axis of the weld, has also been investigated. In conclusion, some design examples are given to illustrate the weld design method, performed to the 2010 AISC Specification in both LRFD and ASD.