Shear resistance of existing prestressed concrete bridges under static and cyclic loading

The demands on the load-carrying capacity of bridges have increased over the last decades due to higher traffic volume. In the future, an even further increase of traffic loads is expected. Many ex- isting bridge structures in Germany built in the 1960s and 1970s were designed for lower traffic loads applying the principal tensile stress criterion for shear. These structures typically feature a high degree of prestressing and low shear reinforcement ratios. In addition to the verification of the shear strength under static loading in the ultimate limit state, the shear fatigue resistance under ser- vice loads must be proved to account for the increased fatigue loads. This paper presents alternative design approaches developed at the Institute of Structural Concrete at RWTH Aachen University for the static and fatigue verification considering the provided shear reinforcement. The application to a typical bridge structure of the German road network is presented.