Capacity assessment of ancient masonry arch bridge : A case study

Most masonry arch railway bridges in the world are servicing the communities well beyond their intended design lives. However, these bridges would have undergone numerous deteriorations over the period of several decades of service life. The asset owners of these bridges are confronted with the decision over whether to continue servicing or decommissioning these bridges. Such decisions are critical from safety and economic points of views, and it can be addressed only by conducting a proper investigation of such structures. This paper presents the capacity assessment of typical in-service masonry arch bridges based on properties of masonry obtained through core testing. The bridges were modeled and analyzed for the ultimate capacity through limit state analysis method. Important parameters such as influence of backfill properties, strength of masonry, and span-to-rise ratio are discussed. The results indicate that the investigated bridges can sustain the current operating loads with a reasonable margin of safety index.