A Quantitative Weld Sizing Criterion and Applications in Load Capacity Evaluation of Hollow Structural Section Joints

Abstract

Existing weld sizing procedures for hollow structural section (HSS) connections in Codes and Standards are empirical in nature, often resulting in oversized welds. There is a growing interest in quantitative weld sizing for ensuring both structural safety and cost-effective construction of lightweight hollow section structures. In this study, a mesh-insensitive traction stress method is introduced for evaluating strength of fillet-welded HSS joints. The results are then generalized into a closed-form expression with a clearly defined mechanics basis. This expression relates weld throat shear stress to fillet weld size and remote load, with its dimensional geometric parameters being determined through a detailed parametric finite element analysis (FEA) of circular hollow section (CHS) and rectangular hollow section (RHS) connections with various dimensions. The effectiveness of the closed-form expression is demonstrated by comparing the predicted failure loads with those measured from a large number of HSS test data available from literature. Furthermore, the proposed quantitative weld sizing criterion can lead to as much as 20% weld size reduction from those determined using existing empirical-based weld sizing criteria, which can be very beneficial for welding-induced distortion control in construction of lightweight thin-walled structures.