Evaluation of strengthening efficiency based on combined global and sectional response of masonry arch bridges

Abstract

The paper is focused on the numerical analysis of the efficiency of strengthening solutions dedicated to masonry arch bridges. An overview of common strengthening methods is described covering the most frequent techniques and their influence on the bridge’s structural behaviour. The numerical study concentrates on the longitudinal behaviour of the arch of single-span bridges. The applied methods are related to the addition of specific structural components on both sides of the arch – extrados and intrados. Two basic solutions are studied based on a rigid or flexible layer corresponding to the most common techniques being applied to these bridges around the world. A comparison of the selected strengthening techniques is given considering their impact on the bridge’s structural behaviour under incremental static loadings. Structural details of the solutions are given as well as their efficiency is evaluated through analytical and numerical analyses. Advanced nonlinear Finite Element models using a meso-modelling technique are presented and selected results showing the mechanical performance of the structure before and after strengthening are provided. The interpretation of the bridge model response parameters, representing the increment of resistance given by the addition of each reinforcement solution, is based on the analysis of the evolution of the structural failure modes up to the maximum load capacity of the bridges, namely in terms of the interaction of internal resistant forces M-N in representative arch cross-sections determined also analytically. Conclusions are formulated to identify optimal reinforcement solutions through the ratios of the maximum load capacity of strengthened and unstrengthened bridge cases, and the ratios between the areas of the M-N interaction diagrams of strengthened and unstrengthened solutions.