![]() ; Odenbreit, Christoph ![]() in Structures (2022), 44 Structural elements of building have to meet a multitude of requirements. Besides the static load bearing capacity, common requirements are the structural integrity and efficiency during the construction ... [more ▼] Structural elements of building have to meet a multitude of requirements. Besides the static load bearing capacity, common requirements are the structural integrity and efficiency during the construction stage and sufficient fire resistance. Within the French CIFRE research project COMINO, an innovative type of composite beam was developed for buildings beams with a span of 6 -12m, which need fire resistance until 2 hours with no additional supports at construction stage. The developed solution is composed of a steel U-section acting as a formwork in construction stage for a reinforced concrete part that provides the fire resistance. In the exploitation stage, the steel and the reinforced concrete are acting together as a composite beam. In construction stage, when the concrete is not hardened and thus the stabilizing effect is not present, the steel beam, is subjected to Lateral-Torsional Buckling. In order to investigate the structural behaviour of the new developed steel section in construction stage, a single full-scale test has been carried out at the Laboratory of Structural Engineering of the University of Luxembourg. This article focuses on the stability of the steel beam made of thin-walled steel parts without considering any stabilizing effect. The test results are then compared to the results of numerical investigations and to the analytical solutions of EN 1993. [less ▲] ![]() Schäfer, Markus ![]() Report (2022) Background Documents for prEN 1994-1-1 Detailed reference viewed: 56 (1 UL)![]() Schäfer, Markus ![]() Report (2021) Development of second generation for Eurocode 4, part 1: prEN 1994-1-1: November 2021- Draft + Respons on comments Detailed reference viewed: 55 (1 UL)![]() Schäfer, Markus ![]() Report (2020) Development of second generation for Eurocode 4, part 1: prEN 1994-1-1: April 2020 Detailed reference viewed: 146 (5 UL)![]() Schäfer, Markus ![]() Report (2019) April draft of second generation for Eurocode 4: EN 1994-1-1; Outcome from SC4.T6 Detailed reference viewed: 123 (6 UL)![]() Turetta, Maxime ![]() ![]() Scientific Conference (2018, September 05) For many categories of buildings, the structural elements must be fire resistant to allow people to evacuate and firefighters to intervene. A new type of steel-concrete composite solution dedicated to ... [more ▼] For many categories of buildings, the structural elements must be fire resistant to allow people to evacuate and firefighters to intervene. A new type of steel-concrete composite solution dedicated to steel building structures is under development to resist against this fire situation. The solution is composed of a steel U section acting as a formwork for a reinforced concrete part that provides the fire resistance. In order to keep the habits of steel construction, the solution is unpropped in construction stage and the concrete is casted on site. Thus the solution has to resist against three majors situations: the construction stage without propping, the exploitation stage and the fire situation. The steel part of the composite beam is then designed to face the construction stage without propping. The present paper describes the numerical investigations carried out on the load bearing capacity of this steel section in construction stage. The objective of these investigations is to finally propose a steel solution stable and resistant for its use during construction stage. The numerical model of the steel section and its boundary conditions are presented. A first elastic calculation is used to determine the Eigen modes of the beam that give the shape of initials imperfections. Then analysis considering materials non-linearity and geometrical imperfections (GMNIA calculation) are carried out. A sensitivity study on the influence of the geometrical imperfections on the load bearing capacity of the beam is performed. Then, with the more conservative initial imperfection, a study on the global stability of the beam without any intermediate restraint is carried out. Finally, to overcome the problem of instability in construction stage, the restraint induced by the perpendicular steel decks is investigated. [less ▲] Detailed reference viewed: 178 (18 UL) |
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