Development and commissioning of FBG sensors for impact test of rockfall protective barrier

Purpose Protective barriers have been effectively applied to intercept and stop rocks from falling onto railway tracks. Determination of exact stress and deformation values during impact tests for key components of the protective barrier form important criteria for quality control of these barriers. Monitoring changes in force along the protective barrier when deployed in field application allows for real-time disaster warning for collapse and falling rocks. Based on Fiber Bragg Grating (FBG) sensing technology, this paper presents an effective sensing detection system for the protective barrier. Design/methodology/approach In this paper, we propose a monitoring strategy for key components of a protective barrier. During performance tests, dynamic force and strain were measured for the steel strands and supporting I-beam, respectively. Design of a special elastic structure for the force transducer based on finite element analysis and tensile tests has been discussed here. Two types of FBG force transducers were manufactured based on the elastic structure. Four FBG force transducers and four FBG strain sensors were used for impact verification testing of a new rigid protective barrier with a design protection level of 25KJ. Findings Dynamic force and strain responses were obtained during an impact of free-falling block with kinetic energy of 25 KJ. Originality/value The FBG monitoring scheme can be extremely valuable for optimized design of the barrier and can provide real-time disaster warning in regions of collapse and falling rocks.