Während das Biegetragverhalten von Betonbauteilen sehr genau beschrieben werden kann, ist das Querkrafttragverhalten schubschlanker Bauteile noch immer Gegenstand kontroverser Diskussionen. Für die Bemessungspraxis sind Modelle notwendig, die einfach anwendbar sind und dennoch ausreichend genaue und damit wirtschaftliche Vorhersagen erlauben. Das hier gezeigte einheitliche Querkraftmodell ermöglicht bei der Bemessung einen stetigen Übergang zwischen Bauteilen ohne und mit Querkraftbewehrung. Der Vergleich mit den ACI‐DAfStb‐Querkraftdatenbanken belegt, dass das vorgeschlagene Modell für Bauteile mit Querkraftbewehrung zu deutlich geringeren Streuungen und gleichzeitig einem besseren Sicherheitsniveau im Vergleich zum aktuellen EC2 führt. Insbesondere für Bauteile mit geringen Querkraftbewehrungsgraden ergeben sich hierdurch höhere Tragfähigkeiten, was z.B. für die Nachrechnung von Bestandsbauwerken wie Brücken von Vorteil ist. Die beispielhafte Nachrechnung einer Bestandsbrücke bestätigt die deutliche Steigerung der rechnerischen Querkrafttragfähigkeit für Spannbetonbrücken mit geringen Querkraftbewehrungsgraden.
Uniform Shear Design Method for Existing Reinforced and Prestressed Concrete Briges
While the flexural bending behavior of concrete structures can be described accurately, the shear behavior of slender beams still is subject of controversial discussions. For design praxis, easy to use and at the same time precise models are necessary to ensure economical design. The proposed uniform shear design procedure provides a continuous transition between beams without and with shear reinforcement. The comparison with the shear databanks of the ACI‐DAfStb confirms that the proposed model provides a strongly reduced coefficient of variation as well as a higher degree of safety in comparison to the current model of EC2. Especially for beams with small amounts of shear reinforcement, higher shear capacities result which is beneficiary for the recalculation of existing structures like bridges. The exemplary recalculation of an existing bridge confirms a notable increase of the shear capacity for prestressed concrete bridges with small amounts of shear reinforcement.
Abstract:Increasing traffic loads and changes in code provisions lead to deficits in shear and flexural capacity of many existing highway bridges. Therefore, a large number of structures are expected to require refurbishment and strengthening in the future. This projection is based on the current condition of many older road bridges. Different strengthening methods for bridges exist to extend their service life, all having specific advantages and disadvantages. By applying a thin layer of carbon textile-reinforced mortar (CTRM) to bridge deck slabs and the webs of pre-stressed concrete bridges, the fatigue and ultimate strength of these members can be increased significantly. The CTRM layer is a combination of a corrosion resistant carbon fiber reinforced polymer (CFRP) fabric and an efficient mortar. In this paper, the strengthening method and the experimental results obtained at RWTH Aachen University are presented.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.