THE INFLUENCE OF MORTAR PROPERTIES ON THE SYSTEM BEHAVIOR OF MASONRY ARCH BRIDGES

Four half-scale arches have been constructed in the laboratory and tested to simulate the response of masonry arch bridges to moving loads. The arches were built using lime mortar with 17 voussoirs and span length of 1.22 m. The loads varied from 115 kg to 910 kg and were obtained by hanging steel weights from the center-of-gravity of the voussoirs. A data acquisition system was used to record the displacements normal to the voussoirs at 16 points around the extrados. Results from the experiments show that the lime mortar affects the system behavior of a masonry arch. The mortar joints exhibit significant plastic behavior with the first few cycles of loading, then behave in a more elastic fashion when the magnitude of load and load cycles increase. When applying moving loads across the arch ring, two distinct types of deformation are noticed; elastic deflections of the voussoirs along the extrados and plastic deformations that accumulate in the mortar joints. (A)