The behaviour and design of stainless steel I-section beams under concentrated transverse loading are investigated in this study. Twenty-four experiments on stainless steel I-sections, formed by the welding of hot-rolled plates, were performed. The tests were conducted under two types of concentrated transverse loading − internal one-flange (IOF) and internal two-flange (ITF) loading. The experimental setup , procedure and results, including the full load-displacement histories, ultimate loads and failure modes, are reported. A complementary nonlinear finite element modelling study was also carried out. The models were first validated against the results of the experiments. A parametric investigation into the influence of key parameters such as the bearing length, web slenderness and level of coexistent bending moment, on the structural response was then performed. Finally, an assessment of current design provisions for the resistance of stainless steel welded I-sections to concentrated loading is presented. The results show that the current design formulae yield safe-sided, but generally rather scattered and conservative capacity predictions, with considerable scope for further development.

Two key reference loads: (i) the plastic collapse load and (ii) the elastic buckling load are commonly used to determine the slenderness and hence the resistance of structural steel elements in international design standards. Utilising numerical methods, the plastic collapse loads are typically obtained through a Materially Nonlinear Analysis (MNA) based on small displacement theory (i.e. a first order plastic analysis). However, such analyses can often yield ambiguous or even spurious results due to, for example, the load-deformation paths not reaching a peak value or reaching a peak value but only after unrealistically large deformations, resulting in misleading predictions of plastic collapse loads and mechanisms. In this paper, a standardised means of determining plastic collapse loads from numerical MNA based on attaining a tangent stiffness of 1% of the initial slope of the load-deformation curve is presented. Furthermore, for analyses that terminate prematurely, an extrapolation technique to predict the full load-deformation paths and hence estimate the plastic collapse load is proposed. The accuracy and practicality of the proposed approach over existing methods is illustrated for a wide range of structural scenarios, with an emphasis on structural elements under concentrated transverse forces.

A comprehensive investigation into the structural behaviour of austenitic stainless steel welded Isection beams under concentrated transverse end-one-flange loading is reported herein. Ten physical experiments are first described. The experimental results are then presented in terms of the full loadweb shortening responses, ultimate loads, out-of-plane deformation fields and failure modes. An extensive finite element modelling study accounting for geometric, material and contact non-linearities was also performed. After successful model validation against the test results, a parametric investigation was conducted considering a range of bearing lengths, different distances of the bearing load to the member end and web slenderness values. The combined experimental and numerical data set was used to assess current European and North American design provisions for the resistance of stainless steel welded I-sections to concentrated end-one-flange loading. The results show that the current design formulae generally lead to safe-sided but rather scattered and conservative capacity predictions with considerable scope for the development of improved design formulae.

Recent investigations have highlighted the need for improved provisions for determining the resistance of stainless steel I-sections under concentrated transverse loading. Such provisions, which reflect the particular characteristics of the material, have been developed and are described herein. A review of the existing European design formulae for members under concentrated transverse loading is firstly presented. Then a series of parametric studies, based on validated finite element models are described covering I-sections with a range of web slenderness values and different stainless steel grades. On the basis of the numerical results, together with existing experimental data, revised design equations are presented and assessed through reliability analysis performed in accordance with Annex D of EN 1990.The new provisions yield enhanced ultimate load predictions and are expected to be included in the next revision of EN 1993-1-4.

The connection concept is a key point in the design of steel structures which affects fabrication, erection procedures and the final costs. Welding processes have been extensively used for tubular trussed girders by combining shop welding with bolted flange solutions to facilitate straightforward connection procedures during erection. The present research addresses the behaviour of innovative beam‐to‐column bolted connections for steel rectangular hollow sections (RHS) which combine simplicity in fabrication and erection, favourable aesthetics for the case of visible structures and structural effectiveness. Four cruciform prototypes were tested under a static non‐reversible bending moment with different bolted conditions: i) non‐friction and ii) friction connection. The experimental results show that the proposed geometry with friction connections is able to develop a rigid elastic moment–rotation response up to usual loading conditions.