In this paper, a novel modelling approach based on the discrete element method for the simulation of backfill material in masonry arch bridges has been proposed. According to the method, bricks in the barrel vault are represented as an assembly of distinct blocks separated by zero thickness interfaces at each mortar joint while backfill is represented as an assemblage of densely packed discrete irregular deformable particles. A series of computational models were developed and their results are compared against full scale experimental test results. A good agreement between the experimental and the numerical results was obtained which demonstrates the huge potential of this novel modelling approach proposed. One of the major advantages of th...