Development of a cyber-based automated structural health monitoring (SHM) system for steel bridges

Abstract

This paper presents an automated structural health monitoring (SHM) system based on wireless sensor network for real-time condition assessment of civil infrastructures. The system consists of a new wireless accelerometer sensor and MATLAB-based data management and data analysis toolboxes. In the first part, the process of the wireless sensor development is presented, which was especially designed to meet the requirements of low-amplitude vibration measurements and sudden event monitoring of civil infrastructures. Then, the multipurpose MATLAB-based toolbox is introduced, which is able to manage and synchronize time-series data, process the monitoring data, evaluate modal parameters using time and frequency domain System Identification (SI) techniques, compare the modal parameters from various SI methods, and identify any abnormalities as structural damage. In order to validate the performance of the wireless sensor nodes in terms of sensitivity, time synchronization and event-triggered sampling mode, a series of shaking table tests was conducted on a steel bridge model at Structures Laboratory, Auckland University of Technology. Also, the system was installed on the Newmarket Viaduct to evaluate the performance of the monitoring system in an outdoor environment. The laboratory test results showed that the developed wireless sensor system is able to provide promising performance for low-to-high amplitude vibration measurements. In addition, the dynamic characteristics of the full-scale bridge measured using the vibration data were consistent in comparison to the previous ambient vibration tests conducted on the full-scale structure, showing the reliability of the system in terms of data recording and data analysis for an accurate SHM system.