Use of multidepth deflectometers and strain gauges to investigate the differential movement at railway bridge approaches

This paper presents findings from on ongoing research study at the University of Illinois focusing on the instrumentation and performance monitoring of railroad bridge approaches using multidepth deflectometers and strain gauges. Different sensors installed at the selected approaches are introduced, and details of the instrumentation activity are explained. Example track settlement data acquired over time is presented to compare the contributions of different substructure layers to the permanent deformation accumulation. Similarly, transient track deformation data gathered for train loading is presented to highlight the contributions of individual track substructure layers towards the total transient deformations. The ballast layers appear to be the primary source of accumulation for both permanent as well as transient deformations.