Monitoring Substructure Movements during Slide-In Bridge Construction

Abstract

To reduce disruption to traffic during bridge replacement, accelerated bridge replacement (ABR) methodologies are being developed. One of the ABR methodologies being implemented is slide-in bridge construction (SIBC), which reduces the total duration of traffic disruption to less than one or two weekends. Because the SIBC activities are new, the system response is unknown. Quantification of the loads acting on permanent and temporary structures during the slide operation is required to develop recommendations for standardizing SIBC. With this purpose, substructure movements were monitored during an SIBC project in Michigan, USA, and the forces acting on the substructure during the slide operation were back-calculated. Theoretically, forces develop in the sliding direction because of friction, and in the vertical direction because of superstructure weight. However, the analysis results indicated that a force couple developed due differential friction at the sliding surfaces, and resulted in rotating the superstructure and pushing the substructure in the horizontal direction transverse to the slide. Therefore, it is recommended to include monitoring as a task in the project special provisions until the process is standardized.