Erosion of earth material at bridge pier foundations by flowing water (i.e., scour) is a leading cause of bridge failures worldwide. In the U.S., nearly 21,000 bridges are scour critical, and approximately 60 percent of documented bridge failures have been directly or indirectly caused by scour during 1966 to 2005. This project will assess the risk of scour-induced bridge failures by integrating experimental, numerical, and theoretical research and educational efforts. Specific tasks that will be conducted include: designing a scour sensing system; improving theory on estimating scour hole depths; developing experimentally validated and accurate numerical scour models; and system testing and validation. Five major research tasks that will be accomplished during this three-year project will allow us to quantify the risk of scour-induced bridge failure using direct sensor measurements of scour hole evolution coupled with numerical model updating. First, a "scour net" hardware/software system that can measure scour topography and will optimize them for use in challenging operating environments will be designed. Second, the sensors will be used for measuring jet-induced scour hole evolution and will be used to improve established relationships. Then, fluid-structure models will be implemented, updated using experimental scour topography and bridge dynamic response data, and validated by rigorous experimental testing. The scour net system and numerical models will also be validated through large-scale testing using a unique scour monitoring test bed located in the Hydrotech Research Institute of National Taiwan University. Finally, Monte Carlo simulations and probabilistic methods will be used for assessing the probability of bridge failure due to scouring under various flow and environmental conditions.
This project will result in fundamental methods, technologies, and numerical tools for evaluating the integrity of overwater bridges to scouring. The results will advance sensor technology, structural health monitoring, hydraulic engineering, and structural engineering fields of study. The ability to monitor scouring, model and predict their evolution in time, and measure its impact on entire transportation infrastructure systems will be critical for achieving safe, resilient, next-generation cities that can adapt to global climate changes. Broader impact of research will be in the form of advancing scour monitoring, computational model updating of turbulent fluid flow, scouring, sediment erosion, and substructure degradation, and the integration of experiment and theory for probabilistic failure prediction.
