AE Monitoring and Numerical Simulation of a Two‐span Model Masonry Arch Bridge Subjected to Pier Scour

Abstract

Abstract: A scaled model of a two‐span masonry arch bridge has been built to investigate the effect of the central pile settlement because of riverbank erosion. The bridge geometry and the structural details, included the masonry bricks and mortar joints, are realized in the scale 1 : 2. The model bridge has been equipped with different Non‐Destructive Testing (NDT) instruments, including accelerometers, displacement transducers LVTD, strain gages, optic fibres strain sensors and Acoustic Emissions (AE) transducers. The model bridge has been subjected to incremental settlement of the pile, which was sustained on a mobile support. The exact mechanism and temporal evolution of the pier scour has been investigated numerically and experimentally by mean of a hydraulic model. In this article, a detailed description of AE data and damage localization is provided. During the first stage of the settlement, the AE counting has been recorded. Based on the interpretation of the AE rate, it is possible to monitor the criticality of the ongoing process. In addition, thanks to the AE equipment, it has been possible to localize the main damaged zones. The statistical properties AE time series have been analysed using an estimation of the b‐value of the Gutenberg‐Richter (GR) law permitting to determine the damage level reached in the model. The damage evolution has been also interpreted numerically with the aid of a finite element programme able to predict the nucleation and propagation of fracture. In this way, some criteria for the monitoring and interpretation of full‐scale structure cracking are provided for the assessment in presence of riverbank erosion phenomena.