Based On The New Type Of Fiber Bragg Grating Sensing Technology Of Urban Viaduct Health Monitoring Technology Research

With the cities developing faster and faster in China, demands of urban viaducts increase rapidly. Once put into use, city viaducts’ material properties will keep degenerating and aging in the course of its long-term operations. Meanwhile, they can also be affected by natural disasters and man-made factors, such as geological disasters, climate, car accidents, overloading operators, fire and so on. Then they will lead to natural cumulative damage and sudden damage with different degrees to the structure or components, and result in reduced performance. Most of the viaducts are built in the city and some of them even close to people’s living area. So, damages happened to them will threaten people’s lives and property safety directly. Undoubtedly, we must focus on construction. At the same time, more attention should be given to the safety, reliability, durability and normal function during the operation. Therefore, it is particularly necessary to monitor the construction health of special viaducts in cities.Sensors are the "tentacles" for people to perceive the world and access information. They can replace people to obtain the required information in harsh environment that humans can not adapt to. Sensing technology is one of the core technologies in modern technology competition. As a sensor that gradually developed recently, fiber optic sensor has many advantages. Such as light weight, small size, passive operation, low-power, anti-electromagnetic interference, high sensitivity, wide bandwidth, strong tolerance of environment and so on. What’s more, it has more obvious advantages in simultaneous measurement of multiple parameters, distributed or multiplexed sensing and intelligent structure and other aspects, and thus has good potential for development. Moreover, with the development of price, quality and other aspects of the constituent elements of fiber optic sensor, its advantages are becoming more and more obvious compared with traditional sensors. Currently, the developed fiber optic sensors and related systems have been widely used to the measurement of angle, acceleration, pressure, gas, vibration, temperature, displacement, strain and so on.Fiber Bragg grating sensing technology has advantages that traditional sensor technology unmatched and cannot alternative, so it is very meaningful for the application to combine this kind of new technology with modern geotechnical health monitoring.This paper focuses on the combination of modern urban viaduct health monitoring with new fiber Bragg grating sensors, then contact to the engineering practice. Some research works are carried out, such as the force mode of main beam of large cantilever’s cover, the stress analysis and control during construction phase of the beam, the optimization of capping beam’s structure, and evaluation of the suitability of a bridge. It has solved some practical problems that exist in the project implementation process, and achieved good social and economic benefits.