Innovative Monitoring Techniques on the Cables of Cable-Stayed Bridges (II)−Considering Measuring Efficiency and Wind-Rain Weather Condition

This paper describes how, in order to evaluate the cable tensions of a cable-stayed bridge, conventionally piezoelectric sensors or force-balanced sensors are applied to measure the vibration signal spectrum of cables. Connected to a signal analyzer (such as a PC) through electrical wires in parallel, those sensors are tied-up to the cable-tendon to be measured. However, with limited sensors and signal channels, the measurements of all cable vibration could only be implemented part by part. Practically, it is difficult to measure all cable vibration simultaneously. For overcoming the mentioned difficulties, an innovative optic-fiber health monitoring system on the cables of a cable-stayed bridge is designed in this article. Herein this paper will not only introduce the mechanism of the new system but also the application to a real cable-stayed bridge. With the new device, it becomes possible to monitor all cables of a cable-stayed bridge economically, simultaneously, and regularly, even in wind-rain weather condition.