Haicang bridge, which connects Xiaman Island and Haicang District and has been in service for 15 years, is the longest continuous floating steel box girder suspension bridge in Asia and the second longest in the world.The bridge serves as a key joint for state highways and urban transportation. Haicang Bridge represents the crowning achievement of the Chinese bridge construction technology advance in the 20th Century.
In 2015, our self-designed product “High Resolution Distributed Optical Fiber Temperature and Strain Analyzer” was used to conduct the structure health monitoring for Haicang Bridge during the load test.
The measured parameters included temperature and strain distributions and were obtained by the three sensing optical fibers installed on the steel box girders covering the whole length of 1180m of the bridge. The load test were divided into four different working conditions by placing the load trucks at different locations and the corresponding strain distributions along the whole length of the bridge can be found in the above figure(c)
The global and local strain changes of the bridge under different load conditions can reflect the structural condition and provide a strong foundation for the bridge structure health evaluation.
Highway subgrades at Qinghai-Tibet plateau are likely to be damaged by the freezing and thawing cycles due to the capricious climate which leads to serious settlement of the road pavement. This phenomenon causes extra requirements for the construction techniques, maintaining costs and management efforts for the highway.
The Realphotonics' product “High Resolution Distributed Optical Fiber Temperature and Strain Analyzer” has been applied to the condition evaluation and damage detection for the plateau highway. A distributed optical fiber monitorning system was established to demonstrate a rare field monitoring proect of the high altitude plateau highway. With the help of the Realphotonics analyser, studies on online monitoring, data analysis, status evaluation and disaster warning were conducted.
High-precision Optical Fiber Gyro Ring Detection
Optical fiber gyroscope, an orientation-determined device for moving objects, has become an epoch-making high precision instrument, which is widely applied in aerospace, weapon guidance, robotic controls and radar fields.
Optical fiber gyro ring, as the key component of optical fiber gyroscope, directly decide the accuracy of the gyroscope. The “Brillouin distributed multi-parameter testing technology”, proposed by the Realphotonics, can realize a on-line distributed multiple parameters detection, such temperature, strain and birefringence distributions, and can inspect the quality of the optical fiber gyro ring, thus, solving the key problems of the gyroscope precision-improving techniques. The technique will provide instructions for the optical fiber gyro ring manufacturing process, during winding, glue solidifying and temperature controlling, which sigbificantly improves the performance of high-precision optical fiber gyroscope.
Reinforced Beam Strain Monitoring
The Realphotonics' product “High Resolution Distributed Optical Fiber Temperature and Strain Analyzer” has been applied to conducting strain distributions measurement of a reinforced beam under moving load. This demonstration broads the application of the analyser in the structural monitoring of civil engineering field. The technologies and devices we proposed can be applied to the multiple practical monitoring fields such as structural health monitoring, oil pipe leakage monitoring, power line fault monitoring and fire detection.