University of Bradford

A numerical method of estimating the strength of masonry arch bridges repaired using near-surface reinforcement is described. The method is based on plasticity theory and, under collapse conditions, the behaviour of the reinforced masonry is assumed to be rigid-perfectly plastic. The steel reinforcement used in the repair is considered as discrete elements in the analysis and the failure mode is idealised as an assemblage of moving rigid blocks separated by zones of displacement discontinuity. Minimisation of the derived collapse load produces the locations and shapes of the fracture or yield zones. Comparisons of the predicted collapse loads and crack patterns at failure show reasonably good agreement with the results obtained from model tests in the laboratory, however, further testing is required to obtain a better estimate of the effectiveness factor for masonry in compression.