DESIGN AND REALIZATION OF STRUCTURAL DAMAGE ALARMING SYSTEM FOR LONG-SPAN CABLE-SUPPORTED BRIDGES

Structural health monitoring and damage diagnosis for long-span cable-supported bridges are becoming one of the most attractive research topics in recent years. The principal achievements in the design and realization of online structural damage alarming systems for the Runyang Suspension Bridge and the Sutong Cable-stayed Bridge are presented in this paper. The real-time damage alarming technique is established based on energy variations of wavelet packet energy spectrums (WPES) decomposed from the structural dynamic responses. In the first stage, the WPES of the bridge is extracted from the measured dynamic responses under ambient excitations. The second stage is to formulate the correlation models describing the seasonal relationship between WPES and temperature and the third stage is to classify the measured changes of WPES due to environmental temperature or structural damage using novelty detection technique based on statistical process control. The software, developments of structural damage alarming systems for the Runyang Suspension Bridge and the Sutong Cable-stayed Bridge are presented in detail in the paper together with the typical analysis results obtained from the online damage alarming system.