Comparative Evaluation of Monitoring Technologies for a Historic Skewed Masonry Arch Railway Bridge

An extensive monitoring installation of a skewed masonry arch railway bridge is presented, where a range of technologies were used to measure the strain and displacement response of the bridge under train loading. Fibre-Bragg Gratings, videogrammetry, vibrating wire strain gauges, crack sensors utilizing potentiometers, and a laser distometer are employed. The objective of the study is to evaluate techniques for measuring the behavior of masonry arch bridges in order to facilitate future monitoring decisions by asset owners. Characteristics and practicalities of each technique are compared, as well as specific monitoring data. While the monitoring data from most methods agrees reasonably well, disagreements do exist due to error or measurement limitations, and the implications of this disagreement for asset owners are discussed. In general, the work also exemplifies the potential of structural health monitoring technologies to provide insight into the dynamic behaviour of masonry arched structures, and in particular heritage structures which may have a complicated history of damage, the progression of which is of interest to their owners.