A review of bridge scour: mechanism, estimation, monitoring and countermeasures

Scour of sediments around bridge foundations by the stream is the most significant contributing factor for bridge failures. The scour failures tend to occur without prior warning and have led to fatalities and economic loss every year. A significant amount of work has been conducted on bridge scour. Such efforts can be broadly classified into two major categories, namely science driven and engineering driven. The science-driven research focuses on understanding the scour mechanism and aims to explain the cause of scour due to different factors. Meanwhile, engineering-driven research focuses on the estimation, monitoring and countermeasures of bridge scour. This paper presents a comprehensive and up-to-date literature review of bridge scour research and practice. Firstly, a brief introduction is given which includes recent cases of failures caused by bridge scour. Then, both scientific and technical research on bridge scour is reviewed, which are categorized into four aspects: macroscopic and microscopic mechanism, scour depth prediction carried out by experimental and field data, direct and remote monitoring methods and active and passive countermeasures. Finally, a summary is provided covering both experimental and computational methods for scour research. Discussion is also provided on emerging ideas to investigate bridge scour from both science and engineering perspectives.