A Plastic Optical Fiber Sensing System for Bridge Deflection Measurement

Abstract

Deflection is one of the key parameters that reflects the state of a bridge. However, deflection measurement is difficult for a bridge that is under operation. Most existing sensors and measuring techniques often do not meet the requirements for health monitoring for various types of bridges. Therefore, based on changes of optical fiber intensity, a novel sensing system using connected pipes to measure bridge deflection in different positions is proposed in this paper. As an absolute reference, the liquid level position along the structure is adopted for the deflection measurement, and an additional external reference to the ground is not needed in this system. The proposed system consists of three parts: connected pipes to connect the measurement points along the structure, liquid to fill in the connected pipes, and the sensing element to detect the change of level. A plastic optical fiber sensor based on the intensity change is used as the sensing element of the developed system. Then, a set of experimental tests are conducted for performance evaluation purposes. Results show that this system has an accurate linear response and high reliability under various environmental conditions. The deflection of the test beam measured by the sensor agrees with linear variable differential transformer (LVDT) within an error margin of 2.1%. The proposed system shows great potential applicability for future health monitoring of long-span bridges.

Fiber Optic Sensing Technology and Vision Sensing Technology for Structural Health Monitoring

“…The capability and good performance of this DFOS for the long-term monitoring of bridge structures have been confirmed by some fatigue tests [169]. Of course, DFOS can also be useful for bridge deflection monitoring [170], and the latest advancement here has been the use of polymer optical fiber sensing (POFS)-based technology to monitor bridge deflection [171]. Since DFOS is less commonly used in practice on structures outside the laboratory, Novák et al [172] successfully demonstrated the potential of using DFOS to detect and monitor traffic-induced crack development in field experiments on bridges with traffic vibrations.…”

Recent Progress of Fiber-Optic Sensors for the Structural Health Monitoring of Civil Infrastructure

“…However, further work is still needed to explore low-cost, high-sensitivity, and high-stability monitoring technologies. [154].…”

“…The experimental results proved that the monitoring system supervised that the 93.9-m-long part of the optical fiber had detected a small elastic strain in the range of as low as 2 μm/m with a spatial resolution of 20 cm. Subsequently, Dong Yang et al [ 154 ] proposed a deflection measurement for bridges based on the plastic optical fiber sensing (POFS) system. As shown in Figure 15 , the system consists of three parts: a connecting tube for connecting to the measuring point, a liquid for filling the connecting tube, and a new plastic optical fiber liquid level sensor.…”

Instrumentación de edificios para la evaluación del estado estructural en tiempo real

“…Dada la importancia estratégica de los puentes como nexos de unión, se han realizado numerosos estudios en su monitorización, tanto metálicos como de hormigón (Asadollahi, Huang and Li, 2018;Meng et al, 2018;Marchewka, Ziółkowski and Aguilar-Vidal, 2020;Mousavi et al, 2020;Shao et al, 2020;Yang et al, 2020)(Navarro-Henríquez, 2014) (Peng et al, 2020).…”