Discussion of 'Shear Lag in Rectangular Hollow Structural Sections Tension Members: Comparison of Design Equations to Test Data' by Bo Dowswell and Stacey Barber

摘要

In a slotted hollow section to gusset plate connection, the load transfer will produce a strain concentration at the start of the welds as a result of shear lag. This phenomenon generates an uneven strain distribution in the connection, since only a portion of the tube cross section is attached to the gusset plate. In general, the magnitude of this phenomenon and the strain at the beginning of the welds are directly influenced by the weld length (l) in the direction of loading. Moreover, when this strain exceeds the material's ultimate strain, the tube will fracture there. This fracture may take place near the slot or at the weld return region, depending on the fabrication detail, and it will be followed by crack propagation around the entire cross section (Fig. 1), producing a circumferential fracture (CF).