Sensing and Analysis of Concrete Pavement Vibration Field Based on Distributed Optical Fiber

Vibration-driven services arc an cffcctivc tool for smart roads, providing multi¬functional services such as structural health monitoring, wheel tracking, and risk warning for intelligent transportation systems. The key is the sensing and analysis of pavement vibration. In this study, a distributed sensing system for vibration of a concrete pavement was developed by optimizing the design and layout of the sensing units based on distributed optical fiber. Analysis methods were proposed for space-time features and space-frequency features of the vibration field. using signal analysis methods such as short-term energy and power spectrum analyses. An analytical method for the vibration space-time response characteristics and global vibration characteristics was then proposed. Finally∗ a full-scale vibration test was conducted at Tongji University. Results showed: ® The load position significantly affects the spatiotemporal distribution of the short-term energy. The coordinates of the short-term energy peak can sensitively reflect changes in the load position. Compared with a linear optical cable∗ the sensing system composed of an optical fiber ring has higher spatial resolution and positioning accuracy (0. 35 m). ② With the same load excitation, the distributed vibration sensing system has similar test results to commercial accelerometers (frequency error 0.9), and shows high stability under repeated testing. ③ The elastic modulus of the concrete pavement slab significantly affects the global power spectral density field. The larger the modulus, the greater the natural frequencies of the first four orders, with the increase becoming more significant with increasing order. This trend agrees with theoretical analysis. The results indicate that the distributed vibration sensing system can accurately and stably measure the time, space, and frequency domain information of the concrete pavement vibration field. It also proves that the analysis methods for space-time response characteristics and global vibration characteristics of the vibration field are effective and reliable. © 2022 Xi'an Highway University. All rights reserved.