Using a phase difference detection technique for monitoring the structural health of bridge piers

摘要

In this study, a new technique for monitoring the structural health of bridge piers, from the point of view of earthquake-induced damage, is introduced and then simulated and evaluated using a scaled model of a typical bridge. This system uses the detection of phase difference between two synchronous receiver nodes, connected through a wireless sensor network, and utilizes an array of inexpensive, high-frequency oscillator circuits (4 GHz) as wireless transmitters, placing them at the important structural positions of the bridge piers, and then receiving and analyzing the signals sent by these transmitters to the two receiver nodes. The proposed monitoring system measures the changes in phase difference between two synchronous receiver nodes before and after damage (displacement or deformation); it shows an accuracy of a tenth of a millimeter in the simulations, and it also has high reliability in monitoring the structural heath of the bridge because it provides a real-time report of the status of each transmitter (activated, deactivated, and damaged). The proposed system is low in price compared to other structural health monitoring (SHM) methods and also entails a much lower volume and complexity of data processing than similar techniques. This study did not carry out any field trials, but a complete simulation using an array of six transmitters (TX) and two receivers (RX) was conducted for a scaled model with six piers, and mathematical and geometrical principles and signal processing and simulation details were thoroughly examined. Copyright © 2015 John Wiley & Sons, Ltd.