Refined modelling methods of structural reinforcements in the analysis of masonry bridges

Abstract

Masonry arch bridges constitute a large part of today’s Italian architectural heritage. Italy has the highest percentage in Europe of masonry railway bridges with respect to the total. Due to the processes of degradation and to the increased levels of the loads and of the safety requirements, rehabilitation and retrofitting of these bridges is required. Among the available reinforcement techniques, the use of reinforcements with mortar/cement matrix fiber nets has gained great popularity due to the advantages shown over traditional techniques in terms of strength and durability. The FRCM, acronym of “Fiber Reinforced Cementitious Matrix” is a valid reinforcement alternative to the use of polymeric matrix reinforcements, due to its greater compatibility with the masonry support. The Italian technical standards suggest a simplified method for the design of the reinforcement based on empirical coefficients that increase the mechanical properties of the masonry materials, disregarding the consideration of the complex crisis mechanisms occurring, especially in more complex systems like the multi-arch bridges.The object of this work is the definition of a more refined and efficient method for the numerical modeling of FRCM reinforcement in the structural analysis of multi-span masonry arch bridge. Specifically, an equivalent reduced nets embedded in a mortar continuum determined with the area equivalence principle.The model is calibrated based on experimental characterization tests carried out on PBO-Mesh, and on the constituents. A validation test of the model is performed with reference to arch models reinforced with PBO-Mesh experimentally tested.The effectiveness of the proposed approaches is verified analyzing the seismic behavior of a masonry multi-span bridge, also considering the soil-structure interaction.