Bridge reassessment in Germany: shear capacity computation based on arch action model

Structural reassessments of existing older German road bridges based on current German standards often uncover substantial deficits, particularly in terms of the required shear reinforcement in the main girders in longitudinal direction. In the case of many thousands of bridges built in the 1950s/1960s, the ratio of the required to the existing shear reinforcement amount can vary by factor of 2–3 or even exceed these values. These shear deficits are only partly due to increases in traffic loads. Most of these are attributed to the evolution of structural shear capacity calculation models and are particularly due to disregarding a substantial concrete contribution to shear capacity. As a result of these imprecise calculation models, unnecessary cost-intensive strengthening measures might have been executed in many cases. To gain more information about the shear load-bearing capacity of prestressed continuous concrete beams, large-scale experiments have been executed at the Technical University of Dortmund. The overall aim was to verify an analytical arching model to offer a more precise shear reassessment approach for existing bridge structures. This model can help to conserve and preserve existing concrete bridges that form part of the built environment and which form part of the engineering heritage of societies.