Longitudinal fillet welds in thin-walled C450 RHS members

This paper describes a series of tests on longitudinal fillet welds in high-strength (450 MPa nominal yield stress), cold-formed rectangular hollow section (RHS) members that have a thickness less than 3 mm. The effect of load conditions, end return welds, and RHS orientation on weld strength is investigated. The experimental weld strength is compared with the predicted strength using existing Australian, American, Canadian, and European design standards. The test results are also compared with the proposed design rules for longitudinal fillet welds in RHS members derived from the previous research project on C350 (350 MPa nominal yield stress) RHS members. A reliability analysis method is used for calibration. All load and resistance factor design standards produce adequate reliability indices. A nonlinear finite-element analysis is carried out to simulate the failure mode and load carrying capacity. The finite-element model has given reasonable predictions in load-deflection curves, stress values, failure mode, and local deformed shape. Design rules are recommended for longitudinal fillet welds in thin-walled, high-strength, cold-formed RHS members.