Background:In recent years, there have been increased interests by the steel structures community to characterise the large-deformation response of T-stubs to evaluate the deformation capacity of bolted joints. However, little information exists on the influence of second-order effects on the response of bolted T-stubs and, consequently, there are no existing guidelines on how to include these effects in design. Objective:In this paper, we assess the influence of second-order effects in T-stubs bolted to a rigid support through a parametric investigation, using finite element analysis. Methods:Both material and geometrical non-linearities were considered since they are known to have a critical impact upon the performance of T-stubs. A benchmark model is first generated and validated and then used to carry out a parametric investigation. A method to assess the contributions of membrane forces to the overall deformation response of a T-stub is also proposed based on the introduction of a non-dimensional parameter Ψ. Results:The combination of geometric parameters that are most affected by second order effects, induced by large displacement, was identified. A direct correspondence was found between the extent of second order effects that has developed and the index Ψ: a higher index implies a greater influence by second order effects.

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Deformation maps on the plastic and ultimate failure of T-stubs with a single bolt-row in tension are developed. The maps condense a large body of information within a two dimensional parameters space onto which different modes of deformation, including the régime boundaries, are plotted for any practical combination of geometric and material properties encountered in a T-stub. Its fidelity is demonstrated with experimental data from literature, and through a detailed parametric investigation by high-fidelity finite element analysis. The predictive capability of two existing analytical models are also assessed against predictions by the finite element model. Their shortcomings, and applicability, are critically assessed and discussed.