Structural health monitoring using distributed fiber optic sensors

• Main Author: Chong, Richard Hong Leong.
• Other Authors: Yang Yaowen
• Format: Final Year Project
• Language: English
• Published: 2010
• Subjects: DRNTU::Engineering::Civil engineering::Structures and design
• Online Access: http://hdl.handle.net/10356/40953
• Institution: Nanyang Technological University

Structural Health Monitoring is important in preventing failure of structures which might lead to major catastrophes. Various methods of SHM are available and one such method is the distributed fiber optic sensing techniques based on Brillouin scattering. This method, which uses optical fiber as the sensor, is capable of capturing accurate information of a wide range of parameters such as temperature, strain, pressure, electrical voltage and even deformation in the in-service structure. Due to the bare optical fiber’s fragility, it is a challenge to install it directly in real life application without packaging, so reliable packaging technique for optical fiber is essential and critical to ensure reliable sensing in structures using BOTDR technology, especially in rough construction conditions or harsh environments. If BOTDR optic fiber sensing is chosen as the main monitoring system for the underground structure, the material of the optical fiber used as well as the packaging technique is extremely critical in order to withstand the rough underground condition. Selection of installation method is of great important as well, in order to achieve high reliability and accuracy in the monitoring results and data analysis. This project seeks to investigate the reliability and degree of accuracy of various optical fibers with different packaging method. Compressive tests with load increment are conducted on a steel specimen with strain gauges and optical fibers installed along its web. The second part of the project focuses on the micro model experiment which is used as a real life simulation of the possible installation at the Jurong underground cavern (JRC). It seeks to investigate the degree of accuracy in strain variation and displacement shape using this sensing technique as compared to the traditional method of strain gauges measurement.