Tragfähigkeit von Lochleibungsverbindungen vorgespannter Glasscheiben zur Ausbildung von Anschlüssen im Konstruktiven Glasbau

Strength of bearing connections in toughened glass plates for the structural use. In steel structures due to their “infinite'” ductility the bearing connections are standard components of joints. Their design rules are based on simple engineering models. However if analogous bearing connections are subject of glazing structures the requirements on the materials' ductility cannot be met. Therefore interlayers out of mortar etc. in the hole surrounding the bolt have to be introduced such that a ductile load deformation behaviour can be reached reducing stress peaks and avoiding steel‐glass‐contact. On this basis design rules are to be established to predict the load carrying capacity of bolts in glass bearings. The following investigations describe the experimental and theoretical works to derive an engineering model for this purpose.     

FE‐Untersuchungen zur Interaktion von Biegedrillknicken und plastischem Querschnittsversagen bei Durchlaufträgern

Finite element analysis of the interaction between lateral torsional buckling and cross‐section yielding of continuous beams. Continuous beams can be regarded as economically designed, if lateral torsional buckling and yielding occur simultaneously. In order to predict the exact failure mechanism and to adopt necessary measures, the various interactions can be examined by means of the finite element method. Another advantage of FE analysis is that asymmetrical crosssections, beams with web stiffeners or openings as well as arbitrary supports can be examined. Goal of this paper is to point out which aspects have to be considered when developing a suitable computational model, beginning with the FE discretization and the choice of the time step up to the introduction of imperfections. Further, guidelines for the interpretation of FE results, e.g. of load displacement curves, are provided.     

Untersuchungen über das Trag‐ und Dehnungsverhalten des Betongurtes bei Verbundanschlüssen

Investigations about the load bearing‐ and strain behavior of the concrete slab in the range of composite connections. Due to the rising cost pressures in the construction industry, it is particularly important to choose efficient design methods to achieve economic structures. The use of the plastic hinge theory may lead to good results within the steel and composite construction industry because cross section‐ and system reserves can almost fully used. This means for the normal composite beam a redistribution of the bending moment from the support section to the field section. This redistribution causes an increase of the rotation at the composite connection. The presented tests show the influence of the reinforcement (type of reinforcement and reinforcement ratio) to the rotation capacity of the connection. The increased rotation requirements of composite connections in the area of plastic hinges should already be take in to account at planning state.     

Untersuchungen zur Wiederverwendung von Spundwänden

Insbesondere in den letzten Jahren wird das Thema Nachhaltigkeit und ressourcenschonender Umgang mit der Umwelt immer stärker in Politik und Gesellschaft diskutiert. Auch in der Geotechnik ist viel Potential vorhanden, nachhaltig mit den Rohstoffen umzugehen. In diesem Beitrag wird hierzu auf die Möglichkeiten der Wiederverwendung von Stahlspundwänden eingegangen. Dabei wird ein wesentliches Augenmerk auf die Möglichkeiten des Recyclings des Spundwandstahls gelegt. Weiterhin erfolgt eine ausführliche Diskussion bezüglich des Ziehens von Spundwänden und den hierbei auftretenden Problemen. So ist häufig ein Anstieg des Herausziehwiderstands über die Zeit feststellbar. Anhand verschiedener Finite‐Elemente‐Untersuchungen wird dieser Zuwachs des Herausziehwiderstands numerisch untersucht, und es können verschiedene Faktoren herausgearbeitet werden, die dem zugrunde liegen. Investigations regarding the re‐use of sheet‐piles. Especially in recent years the topic sustainability and careful handling of environment are discussed more and more in politics and society. In geotechnical engineering there is great potential to deal more sustainable with the used resources. In this contribution, the possibilities of re‐using steel sheet‐piles are discussed. A main scope is set on the possibilities of recycling of the steel. Furthermore, the pull‐out process of sheet‐piles is discussed and problems during the pull‐out process are described. In‐situ often an increase of pull‐out forces over time can be noticed. Several numerical investigations using finite element method are presented to investigate the possible factors which influence the increase in pull‐out forces.     

Durchknöpftragfähigkeit der Verbindungen von Aluminiumtrapezprofilen und Aluminiumwellprofilen bei Befestigung im anliegenden Gurt

Pull‐through resistance of connections of trapezoidal and corrugated sheeting made of aluminium. Pull‐through failure of connections of trapezoidal and corrugated sheeting made of aluminium differs from the pull‐trough failure of comparable connections with steel sheeting. The reasons for this different behaviour and the consequences are explained. Based on the observed failure modes and some general aspects, a new approach for the calculation of the pull‐through resistance of connections is presented and verified by more than 1000 test results which without loss of safety significantly improves the prediction of pull‐through failure loads compared to DIN 18807‐6.     

Dauerhaftigkeit der Verschlüsse von Schleusen und Wehranlagen

Durability of the gates of locks and weir plants. Hydraulic steel constructions are special steel structures. They have a high relevance for the operability and bearing capacity of a water‐structural plant and are subject to special requirements and operating conditions. Therefore high demands are made on their durability. Due to the immersion medium “Water” the steel structures of the gates of shiplocks and movable weirs are exposed to corrosion hazards exceedingly. Gates of ship locks are stresses by fatigue additionally. Concerning the steel structures of weirs corrosive, abrasive and/or hydrodynamic effects dominate. An overview will be given which methods and possibilities are used to achieve an appropriate durability during the intended service life under these circumstances. In this context the importance of a regular structure‐maintenance will be shown too. Furthermore new innovative gate structures may offer advantages with regard to fatigue strength, simplified maintenance and inspection possibilities and favorable corrosion protection characteristics.