On the Structural Safety of Saddling Technique for Strengthening of Masonry Bridges: Design-Oriented Parametric Study and Practical Application

Abstract

ABSTRACT An effective and versatile method for improving the load-bearing capacity of masonry arch bridge is the use of the saddling technique consisting in replacing the existing backfill with in-situ poured concrete. However, this technique is seldom utilized in practice because it can be considered dangerous for the overall stability of the bridge while executed. The primary objective of this research is to evaluate the structural safety of masonry arch bridges with various geometrical configurations during the execution of the saddling technique. To achieve this objective, the study uses a step-by-step simulation approach to analyse the structural safety of the bridge during each stage of the saddling process. The process is in-depth simulated for a reference bridge, and then extended to several configurations to investigate the effect of bridge geometrical parameters on structural safety. The research findings demonstrate that, for conventional masonry bridges, the saddling technique can be safely executed with a high degree of safety. The paper concludes with the practical application of the saddling technique to the Langa de Duero bridge in Spain. The results of this research would promote the wider adoption of the saddling technique as an effective, durable, and safe method for strengthening masonry bridges.