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In order to simulate the specific load-carrying behavior of masonry arch bridges, nonlinear finite element analyses may be carried out. To that end, an associated analysis concept is proposed in this paper. The applied smeared crack model allows one to realistically reproduce characteristic damage patterns observed at existing bridge structures of this type. By using the proposed analysis concept, load-bearing reserves may be revealed and possible causes for existing damage may be identified. The concept includes appropriate failure criteria and corresponding safety margins. The latter approximately conform to valid design codes, but also account for the specifics of nonlinear analyses. In parametric studies, the objectivity of the analysis results and influences of different material parameters on the load-bearing behavior were investigated. Furthermore, two examples of the safety evaluation of existing masonry arch bridges are presented. In both cases, observed damage patterns could be reproduced in the numerical simulations. Destructive load tests at a disused bridge provided an additional opportunity to validate the proposed analysis concept.

Safety evaluation of a masonry arch bridge by nonlinear finite element simulationsUsing the example of a railway bridge, a procedure for the safety evaluation of existing masonry arch bridges is presented. The investigated bridge was to be preserved and utilized under increased usage requirements. A conventional framework based analysis was not considered to be a promising approach for this particular problem. By nonlinear finite element simulations, however, it was possible to reveal an additional load-carrying capacity. In order to simulate the mechanical behavior of the structure as realistic as possible, the adjacent soil was incorporated in the finite element model. Nonlinear material laws were used for both masonry and soil. For the masonry, the smeared crack approach of nonlinear fracture mechanics has been adopted. The curved bridge axis, lateral loads, and eccentricities of the vertical loads required a 3D modeling. The simulation results allowed to prove structural safety even under exceptional traffic loads anticipated for the future. In addition, possible causes for the existing damage pattern could be identified.