Online Deflection Monitoring System for Dafosi Cable-Stayed Bridge

A health monitoring system was designed and installed on Dafosi Bridge, the largest cable-stayed bridge across the Yangtze River in western China. This article briefly describes an online deflection monitoring system, the most important sensing subsystem of the health monitoring system. It can be divided into two major components, one for measurement, and one for control and data processing. The measurement system itself includes two types of deflection sensors to monitor the lateral displacement of the two towers and the flexural and torsional displacement of the main girder. Sensor outputs are pre-processed locally and sent to the host computer at the management center via the Internet. The system design and implementation are reviewed, and the results of data from two kinds of sensors are presented.