Experimental/Feasibility Study of Radio Frequency Tracers for Monitoring Sediment Transport and Scour around Bridges

The scour occurring around bridge piers in sandbed rivers can greatly affect the life of the pier, and overall structural integrity. Few methods exist for tracing sand particles due to the difficulty in reproducing particles that mimic the geometric properties and specific gravity of sand particles. The focus of this research is to develop a tracing technique for sand particles focusing on using artificial coarse sand particles and a Radio Frequency Identification (RFID) system. An RFID system consists of programmed transponders and a corresponding reader that communicate using radio waves. This communication provides the ability to track individual particles with embedded transponders (from here on referred to as seeded particles) allowing for an estimate of scour. RFID has many potential benefits over other tracing technologies. However, there are still challenges facing RFID technology before it can be implemented as a replacement to other tracing technologies, such as unknown performance in aquatic environments and the relationship between transponder particle movement and actual scour. To address these issues, an RFID system was built in a laboratory setting to measure the parameters (e.g. maximum burial depth, signal interference due to turbulence, etc.) that must be known for field implementation and to develop a relationship between particle movement and scour. A matrix of desirable individual parameters, including scour, were tested in a sandbed flume. Initial testing has revealed mixed results about the viability of the system, as the maximum unburied detection range has been small, the casing material has shown a potential for significant interference, and transponder orientation as had a large effect on read range. Some of this issues can be addressed with alterations to the system (more power, different antenna), which will require further testing.