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Shear tests on large prestressed concrete t-beams

Abstract:

The experimental results of shear tests on two prefabricated large prestressed concrete T-beams are presented and discussed. The beams were used in previous experiments after which they remained undamaged. The beams are a 1:2 scale model of the approach bridge of the Van Brienenoord bridge in Rotterdam (the Netherlands). However, the reinforcement and prestressing is not an exact scale of the real bridge beams and was designed with requirements of the previous experiments and can be considered as over dimensioned. The beams have a length of 12 m and a depth of 1.3 m. The depth can be considered quite high for laboratory tests especially in terms of the equipment needed to load the beam until failure. Also, when considering a 1:1 scale structure, a beam with this depth could easily have a span of 30 m. Empty ducts in the top flange, used in the previous experiments for transverse prestressing, are filled with high strength cement mortar to prevent a premature flexural failure of the compression zone (crushing). The four shear tests consist of a single point load at a distance of 2.1d from the support. In previous tests a distance of 2.7d was used resulting in a close to shear but ultimately flexural type of failure (Ensink 2015). However, in the previous tests the flexural type of failure was also triggered by the empty ducts. Finally, the results of the shear tests are compared to non-linear 3D finite element analysis and Eurocode design formula using real material properties.