Nicolas Boissonnade

• Ph.D., Blaise Pascal University, Clermont-Ferrand
• Professor at Université Laval

This paper investigates the local buckling behavior of extruded aluminum circular hollow sections (CHS) under combined compression and bending loads. Based on non-linear shell Finite Element (F.E.) models validated against experimental tests, systematic numerical analyses were conducted to explore the performance of aluminum CHS members as influenc...

This paper presents the local buckling behavior of steel Circular Hollow Sections (C.H.S.) by means of numerical investigations towards a better characterization of the initial imperfection in the response of C.H.S. sections to compression. The results of non-linear shell F.E. sensitivity studies on geometrical imperfections are provided, comparing...

This paper investigates the local buckling behavior of steel Circular Hollow Sections (CHS). Design recommendations for CHS are known to be somewhat conservative and sometimes inappropriate, namely with respect to section classification. CHS sections also provide a peculiar response to local buckling, being quite sensitive to initial geometrical im...

This paper describes a parametric study addressing the resistance of U‐profiles (channel profiles) subject to bending and torsion to lateral torsional buckling. In case of U‐sections, the torsional moment results, in the majority of cases, from an unavoidable eccentricity of the applied load from the shear centre. The behavior and resistance of the...

17 The local buckling behaviour of hot-rolled and welded I-sections under simple load cases at elevated 18 temperatures is investigated numerically through extensive numerical analysis. Advanced shell Finite 19 Element (F.E.) models are firstly developed and validated against existing experimental data for I-20 sections under fire conditions and th...

This paper reports on in-depth finite element analyses relative to the local buckling behaviour and ultimate resistance of mono-symmetric I-sections under combined load cases. Non-linear numerical models are first developed and validated against existing test results and then used to carry out extensive parametric studies considering wide ranges of...

The resistance capacity of rolled T-section columns comprising slender webs is investigated in this paper. Both (i) cross-sectional behavior influenced by local buckling and (ii) member behavior influenced by global buckling are investigated through extensive numerical analyses. Regarding cross-section resistance, current design rules rely on the t...

This paper studies the ultimate resistance of mono-symmetric hot-rolled and welded sections under axial compression, major-axis bending or minor-axis bending as affected by local buckling and material yielding. Following the development of advanced non-linear shell finite element models and their validation against existing test data, extensive non...

This paper investigates the resistance capacity of hot-rolled and welded I-sections subjected to combined loading as influenced by plasticity and local buckling effects. Extensive numerical parametric studies through validated finite element models are carried out to consider different steel grades, section shapes and various load cases including b...

Current standards usually deal with local/global interactive buckling behaviour rather roughly through combining the traditional Effective Width Method (E.W.M.) with member buckling curves; this leads to long and tedious design calculation processes, sometimes also providing inaccurate resistance predictions. A more economic and simple design metho...

The accuracy of different fire design methodologies for hollow cross-sections subject to compression and major-axis bending is studied and compared in this paper. For that purpose, a numerical model based on shell finite elements is developed and validated against existing experimental results available in the literature. Comprehensive numerical pa...

Existing design rules in current major standards for the cross-section resistance of I-shaped sections still suffer from several discrepancies and from a lack of accuracy. Accordingly, code design recommendations deserve improvements towards simplicity and economy. The current paper presents investigations achieved by means of extensive numerical s...

The present paper investigates the resistance of stainless steel I or H sections as influenced by yield extent and local stability issues. In particular, the influence of a rounded stress-strain law with large strain hardening effects on the buckling response of sections is studied. Extensive shell non-linear numerical parametric studies led to a 7...

The present paper focuses on the rotational capacity of H.S.S. steel sections; in particular, the influence of local buckling is accounted for by means of a new generalized cross-sectional slenderness parameter, which is used to characterize the cross-sectional rotational capacity, and, by extension, the available deformation capacity. Careful shel...

The resistance and design of steel sections such as I and H-shapes usually depends in great extents on their ability to resist buckling, as a result of high width-to-thickness b / t ratios in the plates constituents. Consequently, these sections remain quite sensitive to imperfections. Information on imperfections, a key data for F.E. simulations,...

Eurocode 3 Part 1-1 gives several specific plastic interaction formulae applicable to compact double symmetric I sections. However, the effect of torsion is not satisfactorily treated. Recently, proposals have been made to extend existing formulae to the case of torsion but these proposals do not cover all internal forces and moments. Therefore, an...

Abstract : Currently, the European standard Eurocode 3 Part 1-1 does not include any design approach for the resistance of U-shaped members subject to combined major-axis bending and torsion. However, this is a very practical load case for this type of member as the loads are generally introduced through the plane of the web of U sections. Thus, a...

In order to predict the ultimate resistance of members by means of numerical simulations (GMNIA-geometric and material non-linear analysis with imperfection), it is indispensable to realistically assume geometric and material imperfections. For I-shaped profiles, it is possible to find several studies concerning the influence of geometric (for exam...

The second part of the study on the ultimate capacity of hot-rolled steel I-sections under combined compression and bending moment, focussing on parametric studies and design, is presented herein. An extensive numerical parametric study was carried out, using the verified finite element (FE) models from the companion paper, to generate further stru...

An experimental and numerical study of hot-rolled steel I-sections under combined compression and bending moment is presented herein. A total of two stub column tests and 12 mono-axial or bi-axial eccentric compression tests on HEB 160 cross-sections with two different material grades (S235 and S355) were carried out. The tested cross-sections were...

The continuous strength method (CSM) is a deformation-based structural design method that enables material strain hardening properties to be exploited, thus resulting in more accurate and consistent capacity predictions. To date, the CSM has featured an elastic, linear hardening material model and has been applied to cold-formed steel, stainless st...

Eurocode 3 Part 1–1 gives several specific plastic cross-section interaction equations for I sections. However, the case of U sections is not explicitly addressed. In order to overcome these limitations, an extensive numerical parametric study has been conducted. So as to obtain realistic plastic section resistances, material non-linear analyses (M...

The present paper focuses on a new, alternative design philosophy: the Overall Interaction Concept (O.I.C.). This concept, based on the well-established resistance-instability interaction and the definition of a generalised relative slenderness, was thought and built to i) improve actual design practice, ii) increase accuracy, iii) advance simplici...

This paper presents a series of twelve buckling tests on rectangular and circular hollow section beam-column of nominal steel grade S355. The columns were fabricated by either the hot-rolling or the cold-forming process, and were subjected to different load cases through the application of eccentric compression: mono-axial bending (My) or bi-axial...

Advanced numerical analyses become more and more popular for design and research. Yet, such numerical simulations are still very delicate as the obtained results may highly depend on the assumed geometric imperfections. For double symmetric I sections, it is generally accepted to introduce an equivalent geometric imperfection affine to the Eigen-mo...

This paper deals with analytical approaches to the elastic stability of U-shaped members under bi-axial bending. The influence of pre-buckling displacements is highlighted and it is shown how they influence elastic instability of the member. Also, it is studied in which cases instability and second order effects should be accounted for when U-shape...

In steel construction open sections are mainly used to carry high major axis bending. However, in some cases they cannot be prevented from being subjected to torsion, as for example U sections loaded in the web plane or crane girders. However, even if torsional loading is of practical interest for open steel sections, Eurocode 3 does not contain ge...

In steel construction open sections are mainly used to carry high major-axis bending. However, in some cases they cannot be prevented from being subjected to torsion, as for example U sections loaded in the web plane or crane girders. However, even if torsional loading is of practical interest for open steel sections, Eurocode 3 does not contain ge...

Present paper details bending tests on rectangular hollow sections (RHS) and square hollow sections (SHS). The tests primarily aimed at providing data on ultimate load carrying capacities as well as rotations and curvatures in the inelastic range at plastic hinges locations. These bending tests were designed to investigate reserve capacities and pl...

The present paper investigates the cross-sectional resistance of cold-formed tubes; in particular, attention is paid to the influence of various material laws on the carrying capacity. Owing to the fabrication process, coupons from cold-formed tubes usually exhibit a rounded stress-strain relationship, whose shape is known to be influenced by many...

The elastic stability of tapered beams has been investigated many times in the past. However, most of these studies consider beams subjected to bending moments only and therefore they do not consider the influence of axial force on the stability of the member. Consequently, flexural and torsional buckling modes under pure compression or combined co...

The present paper focuses on the rotational capacity of H-shaped steel sections; in particular, the influence of local buckling is accounted for by means of a generalized cross-sectional slenderness, which is used as a new parameter to characterize the cross-sectional rotational capacity, and, by extension, the available deformation capacity. Caref...

This paper deals with the application of the Overall Interaction Concept (O.I.C.) to the practical design of hollow structural shapes. More precisely, the concern here is to demonstrate the ability of the O.I.C. to accurately account for the influence of local buckling on the cross-sectional carrying capacity. In this respect, detailed investigatio...

With the introduction of the Eurocodes, a new design philosophy for the design of cylindrical shells against buckling was made available to structural engineers in Europe: the "Overall Method", which makes use of the so-called "Overall Slenderness" of the shell to determine the appropriate (local) buckling reduction factor. There is a certain simil...

Hot-rolled structural steel hollow sections typically display largely homogeneous material properties around the cross-section with low residual stresses, due to the uniform cooling pattern associated with the production of uniform sections of constant thickness. This leads to a stress-strain response with a clearly defined yield stress and an exte...

This paper reports the results of an analytical, numerical and experimental investigation dealing with I-section steel members acted by a combination of major-axis bending and axial ("beams subjected to tension"), which is relatively rare in practice and, therefore, has received little attention in the past. In particular, there are no guidelines f...

The Overall Interaction Concept (O.I.C.) stands as a new design approach that aims at a straightforward design check of the stability and resistance of steel members. It was developed in response to the expansion of high strength steel products, where instability has more influence and deserves specific attention, especially at the cross-sectional...

The behaviour of so-called 'cellular members' against lateral torsional buckling is investigated. These beams comprise regularly spaced web openings, and are especially used for their high resistance-to-weight ratio, the possibility of integrating service pipes within their height, and for aesthetic reasons. Such profiles usually exhibit a complex...

Present paper deals with the numerical modeling of the lateral torsional buckling phenomenon of rolled or welded steel profiles. More precisely, the definition of initial imperfections is of concern, the aim being here to investigate the influence of both geometrical and material imperfections on the bending resistance of such members. In this resp...

Present paper deals with the behavior of so-called cellular members against lateral torsional buckling. These beams comprising regularly-spaced web openings are especially used for their high resistance-weight ratio, the possibility to integrate service pipes within their height, and aesthetics. Such profiles usually exhibit a complex behavior, sin...

Cellular members are I-section steel members with evenly spaced round web openings. The main advantage these members have over plain-webbed I-section members is their optimized material use in strong-axis bending. Consequently, they are principally used for applications in which they are loaded in bending, but they are also applied in cases where t...

In diesem Aufsatz wird eine neue Nachweismethode zur Überprüfung des Biegedrillknickverhaltens von Verbundträgern vorgestellt. Es wird eine neue Methode beschrieben, die auf der reduzierten Schlankheit gekoppelt mit dem Gebrauch von Knickkurven basiert. Dadurch gelingt es, die Momentengrenztragfähigkeit Mb,Rd zu bestimmen. Diese Methode wird als “h...

The paper investigates the shear resistance of I-girders longitudinally stiffened by trapezoidal stiffeners. It first reports on 4 full-scale tests performed at RWTH Aachen, on stiffened panels with strong closed stiffeners. As expected, failure in the subpanels has been governing. A devoted FEA shell model is then described and validated towards t...

Present paper focuses on the design of stiffened plates under bending and shear that are used in steel or composite bridges. Special attention is paid to situations involving one or two stiffeners, where Eurocode 3 Part 1.5 provides specific rules. First, the paper describes briefly the FEM numerical models used in parametric studies. Then, compari...

Present paper focuses on the practical design of web-tapered I-beams in bending. Both linear stability and non-linear behavior are studied, by means of FEM calculations. Practical examples demonstrate the suitability of the Ayrton-Perry concept for the design of tapered members.

This paper presents a special thin-walled plane beam finite element that accounts for the in-plane cross-section local deformation. The element is based on the superposition of a classical beam displacement field and of an additional field describing local effects, with an approximation on the local second-order membrane stress field. The theoretic...

p>The paper summarizes the investigations on shear resistance of I-girders longitudinally stiffened by closed trapezoidal stiffeners, performed in the frame of a European RFCS project (RFS-CR-03018) designated as “ComBri” (Competitive Steel and Composite Bridges by improved Steel Plated Structures), with configurations typical of what may be expect...

In recently build structures, instability problems have become of prime importance, mainly because of the general tendency to increase the structural and members slenderness, coupled with the development of high strength steels. In that way, tapered I-members become more and more usual since they allow significant material savings and a consistent...