The 6th International Workshop on Advanced Smart Materials and Smart Structures Technology ANCRiSST2011 July 25-26, 2011, Dalian, China Field Study of Bridge Scour Using Imote2.NET-Based Wireless Monitoring System Tzu-Hsuan Lin, Yung-Chi Lu and Shih-Lin Hung Department of Civil Engineering, National Chiao Tung University, Hsinchu, Taiwan ABSTRACT In Taiwan, the typhoon cause great damage on bridge due to Bridge Scour. Hence, the monitoring of Bridge Scour has received considerable interest in the last decade. However, traditional site investigation methods and conventional wired sensing system are expensive and time-consuming and may not always give a complete assessment. Characterized by its low manufacturing costs, low power requirements, miniaturized size, and no need for cabling, the wireless sensor networks (WSN) is an attractive sensing technology for deploying dense distributed sensors in bridge. This study proposed an Imote2.NET-based wireless monitoring system which is deployed in Nioudou Bridge in Taiwan. A field free vibration test was conducted for obtaining dynamic response from wireless sensors. Experimental analysis confirms the high quality of data collection by the proposed reliable data-sensing and transmission protocol. This protocol provided excellent data sensing and transmission quality for determining dynamic structural properties. The field results indicate that the proposed wireless system was a suitable technology for monitoring Bridge Scour. INTRODUCTION In Taiwan, the typhoon cause great damage on bridge due to Bridge Scour. Hence, the monitoring of Bridge Scour has received considerable interest in the last decade. Traditional site investigation methods are expensive and time-consuming and may not always give a complete assessment. Geophysical methods can be used to determine the riverbed profile below the water in a river. A trial of ground penetrating radar (GPR) is a geophysical method that is particularly efficient in determining the sub-bottom geological structure in a shallow freshwater environment. Forde et al. [1] discussed a number of scour surveys using GPR. They concluded that GPR surveys can be effective in determining both the water depth and sub-bottom geological structure near bridge piers and abutments. Yankielun et al. [2] conducted a laboratory experiment using time-domain reflectometry (TDR) for monitoring scour. Their system capable of continuous round-the-clock operation can be used to constantly monitor the extent of scour and can indicate changes in sediment depth of less than 5 cm.