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

摘要

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