Blurred maximal cyclically monotone sets and bipotentials

Let X be a reflexive Banach space and Y its dual. In this paper we find necessary and sufficient conditions for the existence of a bipotential for a blurred maximal cyclically monotone graph. Equivalently, we find a necessary and sufficient condition on $\phi \in \Gamma_{0}(X)$ for that the differential inclusion $y \in \bar{B}(\epsilon) + \partial \phi(x)$ can be put in the form $y \in \partial b(\cdot, y)(x)$, with $b$ a bipotential.Comment: Revised version, corrections in theorem 6.

Efficient implementation of a component-based joint model

This paper deals with a nonlinear analysis of beam-to-column steel joint. The connection uses an end-plate welded to the steel cross-section of a steel-concrete composite beam and bolted to the column flange. The proposed model developed herein combines the knowledge of prior studies that used the component-based approach, on one hand and the Finite Element algorithmsin plasticity, on second hand. The originality of this work is to efficiently take into account possible gaps between the end-plate and the column flange in case of plastic deformation of some components of the joint during the cyclic loading. The numerical investigation aims topredict the behavior of this type of joint in presence of the gap during the cyclic loading

A variational formulation for constitutive laws described by bipotentials

Inspired by the algorithm of Berga and de Saxce for solving the discretisation in time of the evolution problem for an implicit standard material, we propose a general variational formulation in terms of bipotentials

Blurred constitutive laws and bipotential convex covers

In many practical situations, incertitudes affect the mechanical behaviour that is given by a family of graphs instead of a single one. In this paper, we show how the bipotential method is able to capture such blurred constitutive laws, using bipotential convex covers

Steel-based applications in earthquake-prone areas

Steel-Earth project aims at distributing among technicians, engineers, design companies and standardization bodies the results of three past RFCS projects (Steel-Retro [3], Opus [2] and PrecaSteel [1]), providing useful tools for the design and for the retrofit of existing buildings. Technical documents and practical applications to case studies, regarding design of steel and composite steel/concrete buildings and innovative steel-based techniques for the retrofit of existing r.c. and masonry constructions, have been elaborated and collected into a volume distributed during the final workshop of the dissemination project. Pre-normative and background documents concerning the design of steel and composite structures and the rehabilitation of existing constructions have been prepared. A lot of attention has been paid to the analysis of the influence of overstrength factors on the seismic design of steel and composite structures. The prepared documents have been distributed to the attending people and to the members of WG 2 (CEN/TC 250/SC 8/WG 2 “Steel and Composite Structures”) during the final workshop of the project. Technical sheets, working examples and background documents have been translated into several languages (German, French, Italian, Romanian and Greek) and are free available on the website of the project (https://www.steelconstruct.com/site/), where information regarding Steel-Earth are also presented.11 Workshops in Italy, Greece, Germany, Belgium, Portugal, Spain and Romania and 5 conferences in Emilia-Romagna have been organized, as well as 2 practical courses for engineers and academic people in Pavia (Italy). Flash-drives with the technical documents and applications elaborated in Steel-Earth have been distributed to the attending people

Influence of variability of material mechanical properties on seismic performance of steel and steel-concrete composite structures

Modern standards for constructions in seismic zones allow the construction of buildings able to dissipate the energy of the seismic input through an appropriate location of cyclic plastic deformations involving the largest possible number of structural elements, forming thus a global collapse mechanisms without failure and instability phenomena both at local and global level. The key instrument for this purpose is the capacity design approach, which requires an appropriate selection of the design forces and an accurate definition of structural details within the plastic hinges zones, prescribing at the same time the oversizing of non-dissipative elements that shall remain in the elastic field during the earthquake. However, the localization of plastic hinges and the development of the global collapse mechanism is strongly influenced by the mechanical properties of materials, which are characterized by an inherent randomness. This variability can alter the final structural behaviour not matching the expected performance. In the present paper, the influence of the variability of material mechanical properties on the structural behaviour of steel and steel/concrete composite buildings is analyzed, evaluating the efficiency of the capacity design approach as proposed by Eurocode 8 and the possibility of introducing an upper limitation to the nominal yielding strength adopted in the design

Efficient implementation of a component-based joint model

This paper deals with a nonlinear analysis of beam-to-column steel joint. The connection uses an end-plate welded to the steel cross-section of a steel-concrete composite beam and bolted to the column flange. The proposed model developed herein combines the knowledge of prior studies that used the component-based approach, on one hand and the Finite Element algorithmsin plasticity, on second hand. The originality of this work is to efficiently take into account possible gaps between the end-plate and the column flange in case of plastic deformation of some components of the joint during the cyclic loading. The numerical investigation aims topredict the behavior of this type of joint in presence of the gap during the cyclic loading

Exact solutions for the coupled warping beam problem

International audienceExact solutions for coupled warping beam problem are developed in the present paper. The torsion and shear warping problems are considered together, and three beam formulations are considered, regarding the influence of the bi-moment and bi-shear terms. In the first case, where the bi-moment and bi-shear terms are neglected, the exact solutions have a simple polynomial form. In the second and third cases, the exact solution have a more elaborate form, consisting of hyperbolic terms. The coupling between the modes results from the lack of symmetry of the cross-section and is captured in the exact solution for all modes. © 2023 Elsevier Lt