Plastic design of stainless steel continuous beams

Abstract

In this paper an experimental study on eight simply-supported and four two-span continuous beams employing austenitic and duplex stainless steel rectangular hollow sections (RHS) is reported. In parallel with the tests, finite element models were developed. Upon validation against the experimental results, parametric studies were conducted to expand the available structural performance data over a range of cross-section slendernesses, structural systems and load configurations likely to occur in practice. The obtained experimental and numerical results along with collated test data were used to assess the accuracy of EN 1993-1-4 design provisions and to explore the possibility of plastic design for stainless steel indeterminate structures, simultaneously accounting for the effect of strain-hardening at cross-sectional level and moment redistribution exhibited by structures employing stocky cross-sections.

Numerical modelling and design of hot-rolled and cold-formed steel continuous beams with tubular cross-sections

“…In this section, the ultimate loads Fu,FE generated from the parametric study together with the experimental ultimate loads Fu,test obtained from [4] are utilized to assess the accuracy of the current design provisions of EN 1993-1-1 [1] and the continuous strength method (CSM) [11,12,[17][18][19] in predicting the capacity of hot-rolled and cold-formed steel SHS and RHS indeterminate structures. Note that the comparisons performed in the present study are based on the measured (or modelled) geometries and material properties (using area-weighted average material properties for the cold-formed sections), and all partial safety factors are set equal to unity.…”

“…The bending resistance of Class 3 sections is also under-predicted when based on the elastic moment capacity M el [11,12]. To address this shortcoming, the continuous strength method (CSM) has been developed and thoroughly validated as an alternative design approach that rationally exploits material strain hardening and the spread of plasticity at the cross-sectional level [11,12], and this method has recently been extended to indeterminate stainless steel [16][17][18] and aluminium alloy structures [19], which combines the merits of traditional plastic analysis (i.e. allowing for moment redistribution) and the CSM for determining the cross-section bending resistance (i.e.…”

“…Extension of the CSM to the design of indeterminate structures has recently been proposed, and assessed using experimental and numerical data on stainless steel and aluminium continuous beams [16][17][18][19] mechanism. This approach provides a more rational basis for allowing for moment redistribution than traditional plastic analysis, which simply assigns the plastic moment capacity M pl to all hinges, without accounting for the varying rotation demands at the different hinges.…”

“…Previous studies [16][17][18][19]31] suggest that the CSM for indeterminate structures is applicable to box-sections with p 0.48   , which corresponds to a normalised deformation capacity (ε csm /ε y ) of 3.6, according to the CSM base curve (see Eq. (3)), while global elastic analysis should be used for box-sections with p 0.48   .…”

“…The continuous strength method (CSM) is a deformation based design approach that provides an alternative treatment to cross-section classification and enables the effective exploitation of strain hardening [15]. The CSM has recently been extended to the design of stainless steel and aluminium alloy continuous beams [16][17][18][19], and shown to provide more accurate and consistent capacity predictions. The purpose of the present paper is to investigate the feasibility of applying the CSM to hot-rolled and cold-formed steel continuous beams, based on the recent CSM proposals for hot-rolled and cold-formed steel cross-sections under isolated loading (i.e.…”