Application Of A High-speed High-precision Optical Sensor Technology In Bridge Monitoring

At present,national public transport has made rapid development.There are also many problems to be solved,such as traffic congestion, facility quality and intelligent monitoring and so on. Bridges and related facilities as an important part of the transportation hub,because of its long-term in the heavy-duty carry and harsh environment, can easily lead to traffic accidents. Thus, the health monitoring has been paid more and more attention.In the United States, an important transportation hub bridge in Minneapolis, Minnesota, near the collapse phenomenon, in which13people were killed the this accident in2007. If that used optical fiber sensor technology on the bridge, they would avoid this tragedy.This project, a high-speed high-precision optical sensor technology in bridge monitoring, and make full use of optical fiber sensing technology, electronic technology and computer network technology. Improved circuit of an ADC high speed and precision to solve the problem of the accuracy of the monitoring system successly; again Mach-Zehnder interferometer technology for data transmission and reception of experimental fiber, greatly improving the rate of the system; finally, combine computer software and network technology with more than technology, and design a complete set of optical fiber sensing monitoring bridge health status program.The theory describes the principle of optical fiber sensors and optical fiber sensing technology features, mainly to solve the circuit of Pipelined ADCs circuit of the front end of the sample-and-hold improvements. In principle, accuracy can be improved from10bit to13bit, sampling frequency up to100MHz. Through improved bootstrap switch circuit, the sleeve-type gain, switched capacitor feedback circuit from the theory of this topic.In practice, describes the background and practical significance of the bridge health monitoring project. Then about the composition of the entire system:the sensor subsystem, application of fiber Bragg grating sensors, the use of distributed or quasi-distributed architecture, through the optical fiber multiplexing into the next level circuit; data collection and transmission subsystem, mainly depends on the fiber performance of transmission, the use of server storage or signal processing of the signal collected by the fiber; data analysis and evaluation system for signal processing, higher server upload the data to conclude that, in accordance with the specification. The data analysis process, the successful application of software technology and digital signal processing techniques, to judge the health status of the bridge, and the results via the Internet to achieve long-distance transmission.Finally, the construction of the bridge sensor case analysis, rational distribution of sensors in accordance with the structure of the bridge, and the actual data.Application prospects at home and abroad have more emphasis on the construction of road infrastructure, especially the safety issue. Applied research in this subject, or a combination of domestic and foreign leading technology, and achieved certain results in the public transport bridge monitoring. This technology is based on sensor technology and computer network technology, if they can be technically a breakthrough to achieve the monitoring of over500km, to develop more meaningful sensors and reduce operating costs. Its investment will in a large market, but also to ensure that the bridge facilities, safe and reliable operation in the daily production and people’s lives.