Joanna Nseir

University of Applied Sciences Fribourg, Switzerland

We extend the problem of finding an optimal structure with maximum load-bearing capacity to the case of multiple materials. We first consider a reinforcement optimization case where the structure consists of a fixed background matrix material with given strength properties and optimize the reinforcement topology within this material. We discuss the...

The present work addresses the problem of maximizing a structure load-bearing capacity subject to given material strength properties and a material volume constraint. This problem can be viewed as an extension to limit analysis problems which consist in finding the maximum load capacity for a fixed geometry. We show that it is also closely linked t...

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 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...

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 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 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...