Assessment of Multispan Masonry Arch Bridges. II: Examples and Applications

Modern approaches to multispan masonry bridges are approximate in many ways: load distribution, masonry degradation, fill-to-barrel, span-to-span, and span-to-pier interaction are taken into account by means of approximate models or are neglected. At the end of the assessment procedure, the approximation to the load carrying capacity of the bridge cannot be easily quantified. In Part I of this paper, an extension of the classical approach to masonry arches was formulated taking into account the nonlinear response of masonry, a limit to compressive inelastic strains, and assuming simplifying but conservative assumptions. The procedure allows the analysis of multispan masonry bridges considering the nonlinear response of arches and barrels and the mutual interaction. The response of two- and three-span prototypes is compared to that of a single arch; then the procedure is applied to a six- 18.5-m span in-service viaduct. A detailed comparison with the single-span-bridge approach is discussed. Specific attention is paid to the evolution of the collapse mechanism and to the effect of load distribution, addressing the concentrated loads versus distributed equivalent loads problem and showing how the limit to compressive inelastic strains, i.e., to masonry ductility, may be of great importance to the structural analysis of masonry bridges.