Abstract Membrane structures made from technical textiles or foils have been part of the built environment for decades. They appear in a wide range of applications, from private homes to public buildings and open spaces. Because membrane materials are exposed to climatic conditions, they are subject to aging and are therefore not supposed to last indefinitely. In contrast, most supporting elements age in a way similar to conventional building materials. As a result, it is often only the membrane skin that requires treatment or replacement after a number of years, enabling the entire structure to begin a “second life.” Membrane structures can be preserved through various approaches, and regular maintenance plays a crucial role in achieving long‐term durability.
In recent years, considerable steps have been made in the field of membrane structures. After many years of development, the first European design standard for tensioned membrane structures has been published. This work was accompanied by numerous advancements in testing and modelling of structural membranes. This contribution provides an overview over the contributions of the Institute for Metal and Lightweight Structures at the University of Duisburg-Essen, Germany, in this context. Additionally, it displays developments since the publication of the design standard and provides an outlook on the planned work for the coming years. The goal of the efforts is the transformation of the first design standard into a Eurocode for membrane structures and a set of accompanying product and testing standards.
Flame straightening corrects deviations in steel structures but induces residual stresses and microstructural alterations, potentially affecting safety. This study evaluates its impact on preset beam ends for a steel corridor connection. Deviations resulted from differential building settlement and thermal torsional deformation. A cyclic vein heating process (up to 800 degrees C) was simulated on a Q355B steel beam end using Abaqus coupled temperature-displacement analysis to generate the residual stress field, which was then used as an initial condition in mechanical analysis. The bearing capacity, energy dissipation under cyclic loading, and fatigue life under wind loads were compared before and after straightening. Results indicate that flame straightening has negligible effects on ultimate bearing capacity and displacement ability. It may slightly enhance energy dissipation at small displacements due to earlier localized yielding. Importantly, while fatigue life remains adequate for designed wind loads, it degrades significantly under high-stress fatigue conditions. Thus, flame straightening is a viable correction method under moderate service loads but is not recommended for members experiencing high-stress dynamic or fatigue loading.
Welded box columns made of high-strength steels (HSS) are characterized by high buckling resistance and low self-weight. The residual stresses introduced by the welding process are of particular importance. In the area of the weld seams, the cooling process creates residual tensile stresses that are in equilibrium with the compression stresses distributed across the cross section. In Europe, the buckling resistance is insufficiently covered by the rules of EN 1993-1-1 and -1-12. The present rules were validated for steel grades up to S355, so the application is quite conservative for columns made of HSS, especially in the medium slenderness range. As part of the IGF-FOSTA research project P1588, residual stress distributions of welded box sections were determined for the steel grades S460-S960. The buckling resistance was investigated experimentally and by structural-mechanical calculations. The results led to recommendations for a revision of the buckling curve assignment and residual stress distributions of compression members with welded HSS box sections.
