Stahlbetonträger mit zweiachsiger Querkraftbeanspruchung

Reinforced Concrete Beams subject to biaxial Shear Forces: strut‐and‐tie models, experiment and design approach Spatial strut‐and‐tie models are developed for the design of reinforced concrete beams subject to biaxial shear forces. They are derived from a resolution of the vector of the resultant shear force and valid for beams with rectangular cross sections. The models consist of tensile struts of stirrups and longitudinal bars, compressive concrete struts directed to each separate area of the longitudinal reinforcement in the cracked part of the cross section as well as compressive struts stiffening the stirrups. They are qualitatively verified by experiments and further elaborated to derive design charts for the design of the stirrups. An example shows the practical application of the charts.     

Ein Bemessungsmodell für durchlaufende Verbundträger mit großen Stegöffnungen

A design model for continuous composite beams with large web openings. Continuous composite beams can be designed according to the plastic hinge theory. The plastic reserves of the cross section and of the system are used to full capacity with this method. The treatment of large web openings was not clarified for the appliance of the plastic hinge theory until now. At the Institute for Concrete Structures and Structural Design at the Kaiserslautern University of Technology a research project, which was supported by the Deutsche Forschungsgemeinschaft (DFG), was executed. Within this project continuous composite beams with openings were experimentally and numerically investigated. Furthermore a design model for calculating those beams according to the plastic hinge theory was developed. In this paper the design model is presented.     

Berechnung der Ersatzwanddicken von Aussteifungselementen mit Öffnungen

Calculation of fictious Wall Thickness of bracing Systems with Openings Regularly special cases of the technical bending theory are emerging in the verification of bracing systems, to whose effects attention is directed here. A reinforcement following the truss modell is recommended under consideration of the shear deformation.     

Experimentelle Validierung von Bemessungsregeln für Stahltrapezprofile mit Öffnungen

Experimental validation of design rules for trapezoidal profiles with openings. Structural design and detailing of trapezoidal steel sheets in Germany currently follows the rules provided by the still valid National Standard DIN 18807‐3 (1987). This Standard is based on the old design concept using one global safety factor and contains references to outdated codes which had been long since withdrawn. Within the framework of transition of design rules from DIN 18807‐3 to the European Standard EN 1090‐4 available provisions for openings in trapezoidal profiles, which exist since 30 years, were brought into question. The investigations regarding background information on these rules revealed a number of open questions concerning their application in practice as well as the mechanical performance of the cover plates. The basic concept for consideration of openings consists of the application of increased loads and verification using the complete cross‐section of trapezoidal profiles. On the one head, several details regarding the application of this method are, however, not clearly specified leaving space for interpretations which may lead to non‐economic results in case of over‐conservative interpretation. On the other hand, non‐safe results may be obtained if neglecting the increased loads while relying on the (non‐existing) strengthening effect of the cover plates.     

Tragverhalten von Einfeldverbundträgern mit Stegöffnungen

Structural behaviour of single‐span composite beams with openings. In the view of few of the available analytical researches on single‐span composite beam with web openings the non‐linear computed results for a test beam with web opening are hire presented. From them some of interest findings can be viewed.     

Besonderheiten von Durchlaufverbundträgern mit Stegöffnungen

Specials of continuous composite beams with web openings. The results of one non‐linear FE‐calculation for a continuous composite beam with a web opening are presented. Thereby some of bearing behaviour and specials can be showed, which should be concerned by designing.