Simple Cost-effective Scour Sensor

Local bridge scour is caused by the interference of bridge piers with the flow of water and is characterized by the formation of scour holes. Local scour occurs at a bridge pier when the local flow field is strong enough to remove bed materials. Several variables affect the scour depth including the flow intensity, the relative flow depth, the pier-width, and the properties of the river bed materials. This study developed a fiber optic scour sensor capable of monitoring and providing quantitative characteristics of both scour depth and flow processes, i.e. rate. The proposed fiber optic scour sensor will include a single Fiber Optic Bragg Grating (FBG) sensor embedded inside a rod cantilevered into the river bed. The sensor will allow for better monitoring of scour and therefore better bridge maintenance. Research results proved that the simple concept for the development of a very low cost sensor with only one sensing element is sound. The simplicity of the sensor allows for widespread implementation in myriads of scour critical bridges. Field experimentations have been limited to few tests; however, and the system has not been thoroughly tested under flood situations. Further experiments are necessary to accurately determine the sensor resolution and repeatability under field conditions and to further establish the software for more sophisticated and user-friendly remote monitoring applications. The contents of this report reflect the view of the author, who is responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the Illinois Center for Transportation, the Illinois Department of Transportation, or the Federal Highway Administration. This report does not constitute a standard, specification, or regulation. Trademark or manufacturers' names appear in this report only because they are considered essential to the object of this document and do not constitute an endorsement of product by the Federal Highway Administration, the Illinois Department of Transportation, or the Illinois Center for Transportation. ii EXECUTIVE SUMMARY Local bridge scour is caused by the interference of bridge piers with the flow of water and is characterized by the formation of scour holes. Local scour occurs at a bridge pier when the local flow field is strong enough to remove bed materials. Several variables affect the scour depth including the flow intensity, the relative flow depth, the pier-width, and the properties of the river bed materials. This study developed a fiber …