Experimental and numerical investigation of SHS truss T-joints reinforced with sidewall plates

This paper presents a study on the behaviour of cold-formed SHS truss T-joints reinforced with a pair of sidewall plates. This type of reinforcement may be used in tubular joints where the chord and the brace have the same width and is very efficient particularly for failure modes involving the chord sidewall. An experimental programme and a numerical study are presented and discussed, while the research covered reinforced joints with a pair of sidewall plates and their unreinforced counterparts, the braces being subjected to axial compressive forces. The geometry of the reinforcement plates varied in thickness and in length. The results from the experimental tests were thoroughly discussed, and in a second step were used to calibrate a numerical study that was the basis to a parametric analysis involving the most relevant parameters affecting the joint behaviour. The joint resistances obtained were compared with those forecasted by Eurocode 3-part 1.8, ABNT NBR 16239, and analytical solutions available in the literature. These comparisons indicated that the available methods for the design of these joints lead to scattered predictions: for the unreinforced joints, the results were very conservative, mainly for increasing chord sidewall slenderness values. On the other hand, the analytical and codes proposals for reinforced joints with sidewall plates with similar thickness of the chord overestimate the observed values in the majority of cases. Finally, this paper proposes two alternative design equations for the studied joints that are more accurate in predicting their resistance when compared to the presented experimental and numerical results.