Mechanical Behavior of Brickwork Multi-ring Masonry Arch Bridges Constructed with Different Bond Types

The aim of this paper is to assess the mechanical behavior of brickwork multi-ring masonry arch bridges constructed with different bond types. Based on the Discrete Element Method (DEM), a series of two-dimensional numerical models of masonry arch bridges were developed and validated against experimental results obtained from the literature. A parametric analysis was then performed to investigate the effect of: (a) multi-ring arch barrel; (b) backfill properties; and (c) bond properties of mortar joints on the failure mechanism and load-carrying capacity (Ul) of masonry arch bridges. The results demonstrated that an increase in the elastic modulus of the backfill material decreased the deformability of the soil, which further limited the deformation of the arch barrel and led to a reduced Ul. Nevertheless, the effect of Poisson’s ratio of backfill material was found to be insignificant. However, the thickness of the arch barrel considerably affected the Ul of the masonry arch bridge. In particular, an increase of the arch thickness led to an exponential increase of the Ul. Among the parameters investigated in the parametric analysis, the bond strength of the unit-to-mortar interface had the most significant influence on the ultimate strength of masonry arch bridges. Moreover, both the four-hinge and ring-separation failure mechanisms were captured by the numerical model. The results presented in the study can be used towards assisting the understanding of the soil-structure interaction and failure mechanisms that occur in brickwork masonry arch bridges.