Full-scale testing of beam-to-RHS column connections with partial joint penetration groove welded joints and assessment of safety from brittle fracture

This paper concerns the applicability of partial joint preparation (PJP) groove welds to beam-to-column connections. Two full-sized beam-to-column connections, with rectangular hollow section columns and PJP groove welds at the ends of the beam flanges, were tested under cyclic loads. All the specimens were made with one-sided connections. When the unfused regions created by PJP groove welds were reinforced by fillet welds so that the welded joints have a sufficient cross-sectional area, the connections showed sufficient deformation capacity, although ductile cracks initiated at the weld toes and grew stably. Test results were well reproduced by non-linear FE analyses. Strains sustained at points around internal discontinuities were found to be low because of greater cross-sectional areas of welded joints compared with the cross-sectional area of the beam flanges. Fracture toughness properties of numerically modelled connections were evaluated by using a failure assessment diagram approach, which was modified by considering the effect of enhanced apparent toughness of material due to the loss of crack tip constraint. Both the test results and the fracture mechanics-based assessment demonstrated that it is unlikely to initiate brittle fracture at these discontinuities when materials used in the connections have sufficient fracture toughness.