Research Of Bridge Deflection Measurement Based On Wireless Inclination Sensors

Bridge is an important component of modern transportation network, and plays an important role in the persistent development of our economy. Along with the economy development and technology improvement, people are paying more and more attention to the bridge SHM (Structural Health Monitoring). The bridge SHM ensures the bridge safety, protects people's lives and property.Deflection measurement is not only an important part of the bridge SHM, but also an important way to measure the bridge. Based on the analyzing of the advantages and disadvantages of various bridge deflection measurement ways,this paper presents the obliquity deflection measurement method using the developed wireless inclinometer.Firstly, according to the simple beam model,the force situation in the static load condition and the deflection curve equation are analyzed. The improved obliquity deflection measurement method is introduced, base on the research of deflection measurement theory. Secondly, the wireless sensor network(WSN) is introduced briefly.The wireless inclination deflection measurement system is designed, the hardware and software parts are introduced particularly. The low-power wireless inclination sensor is designed with modularized method. The TI's MAC protocol stack has been researched, which is loaded by the sensor node. The node is capable of networking and sending data, measures the angle value and sends data to the coordinator. The coordinator sends data to computer through the serial port, then the deflection curve is displayed after data processing. Lastly, we carry out a serial of experiments on the simple beam, measuring the deflection of the beam, comparing with the laser displacement measurement result. The experiment result indicated that the precision of inclination method is very good. In the experiment, the relative error is less than 5%.The measurement error was analyzed.In conclusion,it is proved that this method is capable of measuring deflection effectively and conveniently, which is usefulness and reliability, has great prospect of application.