Finite-element analysis of masonry arch bridges

This paper describes a method of assessing the load-carrying capacity of masonry arch bridges using the general-purpose finite-element (FE) package LUSAS, Good agreement was found, in terms of collapse loads and load-deflection characteristics, between the FE analysis adopted here and the experimental data. Three bridges were assessed: Bridgemill (actual collapse load 361 kN/m, FE collapse load 362 kN/m), Strathmashie (actual collapse load 228 kN/m, FE collapse load 226 kN/m) and Barlae (actual collapse load 296 kN/m, FE collapse load 302 kN/m), These values were based on cases where the material properties were well documented, which will not always be the case for other less well-researched arches, and therefore a parametric study involving the arch's elastic modulus, its compressive strength, its tensile strength and the backfill's load dispersal angle was carried out, The progressive development of cracking in the arch ring due to the application of live loading was also analysed, The method adopted was found to be a viable assessment tool for those bridges where the cost of potential repair/maintenance justifies what can be time-consuming FE work.