Abstract

This lecture presents multi-level FE modelling strategies developed within the Computational Structural Mechanics group at Imperial College London for nonlinear simulation of masonry bridges. Most masonry bridges and viaducts were built more than a century ago and are still in use, representing critical components of roadway and railway infrastructure systems in different countries worldwide. Material deterioration and increased traffic loading have led to the progressive development of damage and cracking in the brick/blockwork, potentially leading to substandard performance. Accurate assessment is required to evaluate structural safety and guide the implementation of effective strengthening measures. It should be based on a realistic representation of the complex interaction among the components, including arch barrel, spandrel walls, backfill and piers in multi-span bridges. The developed 3D and 2D mesoscale and macroscale models for masonry bridges are based on different scales of representation to model material nonlinearity in masonry. Backfill materials are modelled by elastoplastic continuum descriptions, allowing for their inherent cohesive and frictional characteristics. At the same time, the physical interfaces between the different masonry parts and the backfill are represented by nonlinear interfaces, enabling separation and sliding between the connected parts. Detailed mesoscale models enable separate descriptions for masonry units and mortar joints, providing a high-fidelity representation of the material response and incorporating existing damage and cracking. More efficient macroscale models guarantee a reduced computational cost. They still allow for the typical 3D response of masonry bridges but require detailed calibration of the model material parameters. Numerical examples comprising comparisons against the results from physical experiments on full-scale specimens and monitoring data on realistic bridges are presented to critically appraise the developed multi-level modelling strategies for masonry arch bridges.