Safety Assessment of Masonry Railway Arch Bridges in Australia: A Simplified Tier-1 Approach Using Strain Rating Method

ABSTRACT Assessing the safety of aged masonry arch bridges is a challenging task due to lack of information on their material properties, inherent variability, and construction details. The safety of two railway masonry arch bridges were evaluated subjected to regular train passages through field measurements in this study. Out of two assessed bridges, one bridge was evaluated for the mechanical properties of brick masonry using extracted cores that have been tested under compression and indirect tension. The mechanical properties of both bridges were further evaluated through Flat Jack tests and expert-based qualitative approaches. Serviceability strains at the crown, support and quarter regions of the selected arches were determined using noncontact digital image correlation (DIC) method. The tangential and radial strain levels measured in bridges were found lower than the failure strain of the masonry used in the arch barrels. A simplified method of specifying the rating of masonry arch bridges using strain measurement is proposed for serviceability and ultimate state assessments. The strain rating factors for the assessed arches were found safe. The proposed simplified strain rating method is simple to use for the real-time field strain data and can be used as a tier-1 assessment to screen the bridges, which incorporates the material and construction variations, and dynamic effects in the masonry arch bridges.