Monitor system of cable tension with fiber Bragg grating

Abstract

ABSTRACT Measuring cable-stayed bridge’s cable tension in real time is very worthiness in construction control, cable replacing and bridge’s health monitoring. A novel distributed cable tension fiber Bragg grating vibrate measuring system is designed in this paper. Utilizing the relationship between tension and frequency to measure the cable tension indirectly based on theory of string vibration. Double fi ber Bragg grating micro accelerometer is de signed to improve measuring sensitivity and resolution. Using continues wave tunable frequency technique to demodulate the distributed grating vibrating measuring system and applying the system in tensional stress control when build the bridge. The experiment results and theory indicate that the monitoring system has a simple structure with good stability, linear response capacity, and wide measurable range of the cable tension. It is can satisfy the n eeds for long term monitoring of cable-stayed bridge, as well as provide continuous an d accurate information. Keywords: cable-stayed bridges; cable tension mon itoring; fiber Bragg gr ating; accelerometer