Das Ermüdungsverhalten von Lärmschutzwandstehern und deren Befestigung auf Kunstbauten wird experimentell untersucht und bewertet. Die durchgeführten Analysen behandeln neben dem Ermüdungsverhalten des Schweißnahtanschlusses zwischen Lärmschutzwandsteher und Fußplatte auch die zur Befestigung der Steherkonstruktion im Betonbauteil verankerten Gewindebolzen. Als dynamische Einwirkung wird die bei Zugvorbeifahrt sich einstellende impulsförmige Druck‐/Sog‐Belastung betrachtet und die zu erwartende Lebensdauer der Konstruktion rechnerisch prognostiziert. Die experimentellen Untersuchungen werden in der Form von Dauerschwingversuchen mit bis zu 5 Mio. Lastspielen durchgeführt. Die dynamische Belastung wird in realitätsnaher Größe durch einen servohydraulischen Zylinder aufgebracht und die Reaktionen der Lärmschutzwandsteher werden über die gesamte Versuchsdauer messtechnisch dokumentiert. Es wurden unterschiedliche Typen von Lärmschutzwandstehern getestet und die Auswirkungen von Ausführungsmängeln auf die Dauerhaftigkeit experimentell untersucht. Die Ergebnisse der durchgeführten Ermüdungsversuche werden umfassend dargelegt und diskutiert.

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Die in Bauwerken mit zyklischen oder nicht vorwiegend ruhenden Beanspruchungen eingesetzten Schraubverbindungen werden gezielt vorgespannt, um die Beanspruchbarkeit und Steifigkeit der Anschlüsse zu erhöhen. Die bereits nach der Montage in den geschraubten Verbindungen auftretenden Vorspannkraftverluste sind idealerweise bei der Bemessung und Ausführung der Konstruktion realistisch abzuschätzen und implizit zu berücksichtigen, damit die rechnerisch angesetzte Vorspannkraft während der Nutzungsdauer des Bauwerks in der Verbindung verbleibt. Im Rahmen des IGF‐Forschungsvorhabens 18711 BG „Vorspannkraftverluste ermüdungsbeanspruchter vorgespannter Schraubverbindungen” wurden hierzu systematische Untersuchungen an vorgespannten geschraubten Verbindungen der Kategorien B/C und E nach DIN EN 1993‐1‐8 vom Institut für Metall‐ und Leichtbau der Universität Duisburg‐Essen (IML) in Kooperation mit der Fraunhofer‐Einrichtung für Großstrukturen in der Produktionstechnik in Rostock (IGP) durchgeführt. Hierbei wurden Vorspannkraftverluste aus Setzen und infolge Ermüdungsbeanspruchung experimentell ermittelt und auf die geplante Lebensdauer logarithmisch extrapoliert. Die Untersuchungen erfolgten an M20‐Schraubengarnituren mit verschiedenen Verbindungsmitteln/Anziehverfahren sowie Klemmlängenverhältnissen und Oberflächenausführungen der Prüfteile.

The design rules for cylindrical shells subjected to uniform external pressure can be found in corresponding codes and recommendations, e.g. in EN 1993‐1‐6 (2007) or European Recommendation ECCS EDR5 (2008). Although the buckling strength of thin‐walled shells is highly dependent on the imperfections caused by various fabrication or manufacturing processes, the sensitivity of the buckling resistance of an imperfect shell to the amplitude of the geometric imperfections is not taken into account in design rules of standards. This paper investigates in detail the effect of boundary conditions and cylinder length on the linear buckling behaviour of cylindrical shells subjected to uniform external pressure. Following this, a comprehensive computational study is performed using geometrically nonlinear analyses on imperfect cylindrical shells with two‐imperfection types: (i) eigenmode‐affine form and (ii) longitudinal eigenmode‐affine pattern. Based on the numerical results obtained from eigenvalue analyses, the existing formulae of EN 1993‐1‐6 for the external pressure buckling factor Cβs of short cylindrical shells are modified to provide a more accurate prediction of the elastic critical circumferential buckling stress. The effects of geometric nonlinearity and imperfection sensitivity on the buckling strength are also briefly explored.

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Stainless steel material is a suitable choice for modern steel constructions as it has a high resistance to corrosion combined with high material strength and ductility. Furthermore, its use leads to significant reductions in maintenance. In this frame, bolted connections made of stainless steel components become more and more important to enhance the application of stainless steel not only to small parts of steel structures but also to complex structures. Whereas non preloaded stainless steel bolted connections are already widely used, according to EN 1090-2, the application of preloaded stainless steel bolting assemblies is not allowed unless otherwise specified. If they shall be used, they shall be treated as special fasteners and a procedure test is mandatory. Also EN 1993-1-4 requires that their acceptability in a particular application has to be demonstrated from test results. These restrictions are mainly caused by two facts: firstly, the viscoplastic deformation behaviour of stainless steel which might result in not negligible preload losses in the bolting assemblies themselves and secondly, the gap of knowledge regarding suitable tightening parameters and procedures for stainless steel bolting assemblies to secure a required preload in the bolting assemblies and to avoid galling. To solve these questions, research activities have been carried out in the frame of the European RFCS-research project "Execution and reliability of slip resistant connections for steel structures using CS and SS" SIROCO. The present contribution gives an initial insight into the viscoplastic deformation behaviour of stainless steel bolting assemblies which were achieved in SIROCO which shows that preloaded bolted stainless steel connections can be treated similar to those made of carbon steel.

The use of stainless steel components can lead to a significant reduction of maintenance costs compared to a structure executed in carbon steel. Because of its high material strength, ductility and corrosion resistance stainless steels are becoming more and more popular as a construction material in both building and civil engineering structures. Consequently slip-resistant bolted connections made of stainless steel are becoming more important. Slip-resistant bolted connections are used in joints where slip is not acceptable (because they are subject to reversal of shear load or any other reason) or in joints that are subject to cyclic shear load (to improve the fatigue class of the connecting plates). Existing design codes/standards do not specify slip factors for surface treatments of stainless steel grades, the minimum values of slip factors for common surface treatments/coatings that are specified in EN 1090-2 are exclusively valid for carbon steels. One of the reasons for this is that stainless steel alloys are thought to suffer more than carbon steels from time dependent behaviour (creep and relaxation) at room temperature. This could lead to higher preload losses and consequently to lower slip factors than used for carbon steels with comparable surface treatment. However, no evidence of this can be found in literature. Creep and relaxation are stress dependant phenomena and the stresses in the components of preloaded bolted connections are locally highly non-uniform. Therefore, slip factors of different stainless steel grades have to be determined by experiments to investigate the effects of time dependant material behaviour. In this paper the results of slip factor tests on four stainless steel grades are presented and the influence of surface treatments and the preload level on the slip factor of stainless steel slip-resistant connections is discussed.