THE DESIGN AND REALIZATION OF THE ONLINE MODAL SYSTEM FOR THE RUN YANG SUSPENSION BRIDGE

摘要

In this paper, Run Yang suspension bridge is taken as the engineering background to study the design and realization for the online modal identification system, including design strategy, structure, sensor placement, locations optimization and method of modal identification. Based on analysis for the dynamics of the bridge, an optimal sensor points system is put forward. Some important improvements on modal identification are made and used for realization of the online modal identification. Most importantly, a method to identify modal parameters is put forward, which takes advantage of girder vibration mode functions to optimize modal parameters derived by peak picking method. Comparing the identification results from online modal system with those from field measurement, the resulted modal frequencies and modal shapes are considerably consistent. Run Yang suspension bridge online modal identification system has been completed and operated over one year, which provides a large amount of parameters for analyzing the dynamics and evaluating the state of the bridge.