Study On Cable Tension Automatic Monitoring System Of Cable-stayed Bridge

The monitoring of the stayed cable tension related to the cable-stayed bridge operational safety and it economic, social is extremely significant. The existing cable testing technology has all kinds of limitations, as well as automatic remote monitoring system is very expensive. Aiming at those problems above, this paper plan on studying automatic monitoring system of fiber bragg grating strain sensor fixed the surface of stayed cable's steel wire and external hanging stayed cable tension display screen .First of all, the principle, applicability and advantage and disadvantage of five measurement methods of stayed cable is analyzed, and their respective use is investigated in this Paper; Secondly, the principle of fiber bragg grating and signal demodulation technique are researched; Thirdly, three function modules of the automatic monitoring system is designed in totally—fiber bragg grating sensor system, fiber bragg grating sensor network analyzer system, optical fiber transmission and display system.Finally,the part triple protection system of cable which is consisted by steel wire's galvanized coating, waterproof glue water layer of encapsulation and PE sleeve layer of repair. The test of installation of sensor approves feasibility that fiber bragg grating strain sensor is fixed the surface of cable. Study the relationship between cable tension F and wavelength's changeΔλB of fiber bragg grating by static load test of bare cable, the fitted equation ( F = aΔλB+ b)of them is gained after it is calibrated, so that measure of cable tension is achieved by fiber bragg grating strain sensor fixed the surface of stayed cable. It is lay the foundation for studying automatic monitoring system of fiber bragg grating strain sensor.The technology of advanced fiber grating sensor is applied to the monitoring of the cable tension in this paper. The measure of cable tension is achieved and the technology of optical fiber sensing which is used in health monitoring of engineering structure by fiber bragg grating strain sensor fixed the surface of cable. They have important academic value and practical significance...