Serviceability and Strength Assessment of Old Railway Masonry Arch Bridges in Australia
摘要
There are significant numbers of colonial period masonry arch railway bridges that are still in operation in Australia. Severability of these bridges are paramount, as they are part of critical railway network. This paper summarises a work carried out to assess the serviceability and loadbearing capacity of two 110+ years old railway masonry arch bridges in Australia. The serviceability strains and displacements were monitored at support, quarter points and crown of the arch of each bridge using a digital image correlation method, while the train passes over these bridges. The radial (perpendicular) and tangential (parallel) deflections and strain levels were found under elastic limits with maximum magnitudes recorded as 0.5 mm and 110 microstrain, respectively. The serviceability stress in the brick masonry piers of both bridges was determined using flat jack apparatus. On an average the mean in-situ stress of 1.2 MPa was recorded. The compressive strength of these masonry bridges was characterised using the core samples taken from piers of one of the bridges. The core samples were tested with capping on top and bottom and the mean strength of 10.6 MPa for old masonry material was obtained. The measured in-situ stress and ultimate strength of masonry was considered safe, and the magnitudes of deflection and strain were within the allowed limits.