Proposal of an effective modelling strategy for the advanced numerical analysis of masonry arch-bridges

This study investigates the numerical analysis of masonry arch bridges, a process often challenged by various sources of uncertainty that can compromise the reliability of results. A streamlined approach is proposed through the calibration of a simplified finite element model. The San Marcello Pistoiese bridge (Italy) serves as a case study, benefiting from extensive prior documentation, including laboratory testing and dynamic identification, which enables the validation of numerical simulations against experimental data. Two models were developed: a detailed three-dimensional solid model and a simplified shell model. Both employ the Concrete Damage Plasticity (CDP) approach to capture non-linear behaviour, using a bilinear stress-strain relationship up to peak strength, followed by a post-peak softening response in accordance with the Model Code. The shell model was calibrated against the solid model based on modal characteristics and subsequently used for non-linear analyses. Results show that the reduced model effectively reproduces key aspects of the structural response - such as capacity curves and damage patterns - while requiring only 1/500 of the computational time, making it a practical tool for extensive parametric studies under uncertainty.