The structural behaviour and design of extruded aluminium alloy T-stubs connected by swage-locking pins under monotonic loading are investigated in this study. Thirty experiments were performed and the test set-up, testing procedure and experimental results, including failure modes, ultimate load-carrying capacity, deformation capacity and load-displacement response, are reported. Component tests were also carried out on the swage-locking pins to assess their load-carrying capacities under pure tension, pure shear and combined tension and shear; these tests were complemented by tensile coupon tests on the pin and T-stub plate material. Resistance functions to predict the capacity of the swage-locking pins were developed and assessed against the test results. The EN 1999-1-1 (EC9) design rules for predicting the resistance of extruded aluminium alloy T-stubs were also evaluated and found to be safe-sided, but rather conservative relative to the experimental results. Improved resistance predictions were achieved through application of the continuous strength method (CSM).