Fusion of Numerical Modeling and Innovative Sensing to Advance Bridge Scour Research and Practice

Download or read book Fusion of Numerical Modeling and Innovative Sensing to Advance Bridge Scour Research and Practice written by Junliang Tao and published by . This book was released on 2013 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bridge scour is the erosion of sediments around bridge piers or abutments due to flowing water. It is the number one cause of bridge failures in the United States. However, the mechanism of bridge scour remains a mystery due to the complex interaction between structures, flow, and sediments; there is also an urgent demand to develop countermeasures reducing the risk caused by bridge scour. This dissertation work aims to provide innovative solutions to address such challenges through highly interdisciplinary efforts. A tremendous effort has also been placed to review and synthesize the existing literature. Computational Fluid Dynamics (CFD) technique is employed to simulate the flow and scour patterns around bridge piers with different geometries. The effects of pier shape, aspect ratio and attack angle on the flow and scour patterns are evaluated. The findings of this work not only further advance the understanding of scour, but also provide insightful practical implications. A numerical simulation framework integrating advanced CFD techniques and a novel sediment transport model is also developed, aiming to model the scour process. The uniqueness of this advanced model is that it incorporates the influence of turbulence, which plays a crucial role in the process of scouring but has been overlooked for decades. To facilitate the characterization of the turbulence at the interface of sediment and river flow, bio-inspired flow sensors are developed. The innovative sensors mimic the function and structure of the hair cells in fish, which is sensitive to turbulence in flow. Smart material (piezoelectric microfiber) is employed to construct the artificial hair cell and the unique patterning of electrodes enables the linear sensitivity as well as the directional sensitivity of the sensor. Three designs are proposed, modeled and optimized. The performance of the prototype sensors is evaluated through laboratory experiments. A field monitoring system is designed and deployed in the field to remotely monitor the evolution of the scour depth around real bridge piers. This system includes an innovative sensor based on Time Domain Reflectometry (TDR) technique and the sensor is proved to be sensitive, durable and cost effective. It also includes a field data acquisition system, which automatically collects the TDR data and transmits the data wirelessly. The scour depth data can be utilized to calibrate the various scour depth prediction equations. It can also be integrated into the bridge risk management system to assist in decision making.