Bridge line shape detection system based on optical fiber sensing and detection method thereof

Abstract

The invention discloses a bridge line shape detection system based on optical fiber sensing and a detection method thereof. The detection system comprises a water tank (5), a fiber grating interrogator (6), a data processing device (7) and fiber grating water pressure gauges (2) arranged on a plurality of detection points (23) on the surface (1) of a bridge girder, wherein the fiber grating waterpressure gauges (2) are connected with the water tank (5) through water pipes (4); the fiber grating interrogator (6) is connected with the data processing device (7); the water tank (5) is arranged in a tower column of a bridge to be measured; a measuring datum point (22) is arranged in the tower column; and the fiber grating water pressure gauges (2) are installed on the measuring datum point (22). The detection method comprises the following steps: calculating the wavelength change of a first grating (15) and a second grating (16) in the fiber grating water pressure gauges (2) of each detection point (23); and calculating the vertical deflection value of each detection point (23). Static measurement and dynamic measurement of a large-span bridge line shape can be satisfied.

Description

technical field [0001] The invention relates to a detection system, more specifically to a bridge alignment detection system based on optical fiber sensing and a detection method thereof, and belongs to the technical field of optical fiber sensing detection. Background technique [0002] In recent years, with the continuous development of computer technology, communication technology, sensor detection and other technologies, the use of computer Internet of Things for automatic health detection has become the main method for bridge detection. Among the various parameters detected, bridge alignment detection is an important part of bridge detection and an important indicator of bridge safety evaluation. Bridge alignment detection is mainly realized by bridge deflection detection. Deflection is the longitudinal displacement of the centroid at a certain section on the main girder in the direction perpendicular to the axis, which directly reflects the vertical overall stiffness o...

AI Technical Summary

Problems solved by technology

[0003] At present, the existing bridge deflection measurement methods mainly include theodolite method, level instrument method, dial indicator method, total station method, laser measurement method, GPS measurement method, connecting pipe measurement method, inclination measurement method, fiber optic gyroscope measurement method, etc. Among them, the theodolite method, the level method, the dial indicator method and the total station method are only suitable for manual periodic inspection, and the traffic needs to be closed during the measurement; although the laser measurement method has high measurement accuracy, it is easily affected by weather and environmental changes. Not suitable for long-term continuous measurement; although GPS has global, all-weather, continuous three-dimensional navigation and positioning capabilities, but its cost is high, the calculation is complicated, and the measurement accuracy is not high

The fiber optic gyroscope is a rapid detection method of bridge alignment that has emerged in recent years. It installs the measurement system on the detection vehicle. When the detection vehicle passes the bridge to be inspected, the linear curve of the bridge can be obtained; the advantages of this measurement method It is simple and fast, but the disadvantage is that the measurement accuracy is not high, and it is not suitable for online detection

The measurement method based on the inclinometer is used for the alignment measurement of long-span bridges, but with the increase of measurement points, the measurement error continues to accumulate, and the measurement accuracy is difficult to meet the requirements

The connecting pipe deflection measurement method is the main bridge alignment detection method currently used, and has been widely used in bridge structural health detection; however, the electromagnetic pressure transmitter mainly used in this method has some problems in actual measurement, such as large-span In bridge measurement, firstly, the pressure measurement range requirements must be met, and the measurement accuracy will inevitably be sacrificed; in dynamic measurement, due to the limitation of networking technology, the synchronization of data collection is difficult to meet the requirements; in addition, electromagnetic sensors need power supply, are susceptible to interference, etc. Its long-term stability is poor

Images