The Research Of Structural Health Monitoring System

In the new period many kinds of new structures & buildings have been designed and many old buildings become much more valuable from the view point of civilization. How to monitor the new structures & buildings and the old preserved buildings becomes an important question for researchers.This paper starts with the concept of structural health monitoring (SHM). The key point of the article is the development of new SHM systems. One of the developed SHM systems is the Wireless Sensor SHM System (WSSHMS) which is mainly used for structural dynamic signals. Another is Fiber Brag Grating SHM System (FBGSHMS) which is mainly used for structural static signals.The WSSHMS consists of accelerometer transducers, wireless transmitting modules, data processing center and customer end computers. The transducers transform the accelerometer signals to voltage signals and the wireless transmitting modules transform the voltage signals to digital signals and transmit them to the data processing center for processing and storing. The customer end computers can send orders to the center to get data and results. Based on the available technology we developed self-organized WSSHMS and WSSHMS based on GPRS&GPS. The paper describes in detail the way of network organizing, data transmitting and system controlling and the circuit diagram of the wireless transmitting module. Both of the WSSHMS have its own controlling software developed by the author. A piece of software based on Natural Excitation Technique (NExT) and Eigensystem Realization Algorithm (ERA) is developed by the author to extract modal parameters from the dynamic signals of the structure.The FBGSHMS uses FBG transducers to get the strain information of the monitored structures. The optical signal will be transformed to digital signal through optical modem and the digital signal will be transmitted to the data processing computer. The paper describes in detail the performance of the FBG transducers, the FBGSHMS framework and the data processing method.Some case studies are proposed in the paper. One is Shanghai great world health monitoring project using WSSHMS and the other is Shanghai Changde Platformsafety monitoring project using FBGSHMS.