Querkraftermüdung von Spannbetonträgern ohne Querkraftbewehrung

Fatigue of prestressed beams without web reinforcement under cyclic shear

Many existing bridge structures built in the 1960s and 1970s typically feature a high degree of prestressing. They often contain less web reinforcement than the actually required minimum web reinforcement. Therefore, their shear bearing capacity, originally determined based on the principal tensile strength criterion, cannot be verified with the strut and tie models of DIN-Fachbericht 102. Within a research programme, the shear design based on the principal tensile strength criterion has been modified for cyclic shear load (shear fatigue).
The present paper describes the performed fatigue tests on six I-shaped and seven T-shaped prestressed beams without web reinforcement. Based on the resisted load cycles until failure, modified approaches for shear fatigue in terms of GOODMAN-Diagrams based on the principal tensile strength criterion have been developed.