Structural Health Monitoring and Model Updating of Aizhai Suspension Bridge

Abstract

A complete structural health monitoring system has been implemented on Aizhai Suspension Bridge for monitoring its health status and assessing its safety for long-term services. This system consists of nearly 112 sensors of various types, including four subsystems: automatic data collection subsystem, artificial maintenance management subsystem, early safety warning and comprehensive assessment subsystem, and centralized database management subsystem. The deployments and functions of this structural health monitoring system are first introduced in this paper. Then, a finite-element model updating method, which combines the substructure method with the response surface model updating method, is proposed to reconstruct the actual working state of this suspension bridge in the early safety warning and comprehensive assessment subsystem. In the remaining part, the temperature fields, strain responses, tension forces of the hangers, longitudinal displacements of the stiffening girder, and the meteorological temperature are analyzed. Through the statistical analysis, the relationship between the temperature fields was found; the temperature fields induced strains of the stiffening girder satisfies the linear relationship. The cumulative probability distribution function of the cycle-index of the same daily stress amplitude follows a Weibull distribution. The monitored relative longitudinal displacements of the stiffening girder are linearly related with the meteorological temperatures. The monitored tension forces of the hangers verify the effects of the suspender-free zones of main cables on the normal hangers for this pylon-girder detached suspension bridge.