Shear fatigue of prestressed I-beams with shear reinforcement

In the last decades, increasing traffic loads have led to higher requirements on the bearing capacity of existing and also new bridges. In particular, many bridge structures built in the 1960s and 1970s often contain less web reinforcement than the nowadays required minimum web reinforcement. In this context, the shear resistance under cyclic loading is of special interest. For this reason, experimental tests were conducted on prestressed concrete beams with and without shear reinforcement at the Institute of Structural Concrete of RWTH Aachen University within the last years to investigate the shear fatigue strength. The specimens were able to resist more load cycles than predicted by the approaches implemented in the Eurocodes for bridges. Based on the test results, design models for shear under cyclic loading should be reviewed and improved, especially with regard to the assessment of existing structures. This paper describes the recent tests on 20 I-shaped prestressed beams with web reinforcement.