ANALYSIS OF MULTI-RING BRICKWORK ARCH BRIDGES

Multi-ring brickwork arches have inherently different performance characteristics to those of voussoir arches. This is because the mortar joints between rings form potential planes of weakness. Often the unit-mortar adhesion bonding rings together will be weak or non-existent; in other cases it will normally be very difficult to quantify the magnitude of the shear forces which can be sustained at the interfaces between adjacent rings. It may therefore often be sensible to ignore it altogether, the arch barrel then being treated as comprising a number of unbonded blocks. A discrete rigid block, mechanism, method of analysis suitable for analysing such assemblages of masonry units is developed in the paper. This is subsequently used as a tool to investigate the behaviours of a series of large-scale model arches and arch bridges built in the laboratory. The programme of laboratory tests have showed not only that arches containing barrels with initially debonded rings were significantly weaker than those with more securely bonded rings, but that it was possible for mortar bonded arch rings to become debonded during loading. This also had serious consequences with regard to carrying capacity. (A)