Bridge end corner testing method based on spherical support

Abstract

The invention discloses a method for testing a bridge end corner based on a spherical support. The method comprises the following steps: step 1, taking an upper support plate in the spherical support on a bridge as a measuring point of the bridge end corner, and fixing a fiber bragg grating tilt angle sensor between the upper support plate and a pier; step 2, converting unknown corner information of the beam end into displacement information of an upper support plate in the spherical support; step 3, converting the displacement information into deformation of the fiber bragg grating by using a fiber bragg grating tilt angle sensor; and 4, transmitting the deformation data of the fiber bragg grating to a fiber bragg grating demodulation mechanism to obtain the wavelength of the fiber bragg grating, and then inversely calculating the beam end rotation angle according to the wavelength of the fiber bragg grating and a beam end rotation angle equation. The device is not easily affected by special environments such as temperature and electromagnetism during beam end corner testing, the beam end corner can be monitored for a long time in a severe environment, the beam end corner can be measured with high precision, and the accuracy of beam end corner measurement can be effectively improved.

Description

Technical Field

[0001] The invention relates to a beam end rotation angle testing method, in particular to a bridge beam end rotation angle testing method based on a spherical bearing. Background Art

[0002] In recent decades, with the continuous advancement of national infrastructure construction, my country's road and railway networks have developed rapidly, and the bridge system as one of the components of public transportation has also been greatly improved. After experiencing large-scale development, my country's bridge construction has transitioned to a new stage of in-depth operation and maintenance management and long-term maintenance as the service life of bridges continues to accumulate. This stage has put forward higher requirements for frequent and comprehensive inspection and evaluation of bridges.

[0003] When a bridge is subjected to external forces, the beam end rotation angle is usually greater than the rotation angle of other sections. Under the same load, the beam end rotation angle and the change after damage are higher than other sections. Therefore, the beam end rotation angle is an important indicator for bridge inspection and evaluation. At present, the existing rotation angle test device is usually used to test the beam end rotation angle, but the existing rotation angle test device has low measurement accuracy and is easily affected by special environments such as temperature and electromagnetics. This will seriously affect the accuracy of the beam end angle test results, and thus seriously affect the safety of bridge use. Summary of the invention

[0004] In order to solve the above deficiencies in the prior art, the present invention aims to provide a method for testing the rotation angle of a bridge beam end based on a spherical bearing, so as to achieve the purpose of improving the accuracy of the beam end angle test results.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is as follows: a method for testing the rotation angle of a bridge beam end based on a spherical bearing, comprising the following steps: step one, using the upper bearing plate in the spherical bearing on the bridge as the measuring point of the rotation angle of the bridge beam end and fixing the fiber grating inclination sensor between the upper bearing plate and the bridge pier; step two, converting the unknown rotation angle information of the beam end into the displacement information of the upper bearing plate in the spherical bearing; step three, using the fiber grating inclination sensor to convert the displacement information in step two into the deformation of the fiber grating; step four, transmitting the deformation data of the fiber grating to the fiber grating demodulation mechanism to obtain the wavelength of the fiber grating, and then inversely calculating the beam end angle based on the fiber grating wavelength and the beam end angle equation.

[0006] As a limitation of the present invention, the fiber grating inclination sensor includes a shell, a connecting member slidably connected to the shell by a sliding mechanism, a height adjustment mechanism arranged at the bottom of the shell for adjusting the height of the shell, a diamond linkage mechanism fixed between the connecting member and the bottom of the shell, a fiber grating fixed on the diamond linkage mechanism, and a temperature compensation fiber grating fixed on the inner wall of the shell.

[0007] As a further limitation of the present invention, the height adjustment mechanism includes a base plate and four threaded rods respectively fixed at four corner positions of the base plate, each threaded rod is slidably connected to the bottom of the shell and is fixedly connected to the bottom of the shell by two limit nuts.

[0008] As a further limitation of the present invention, the diamond-shaped linkage mechanism includes four connecting rods hinged together end to end in sequence.

[0009] As a further limitation of the present invention, the fiber Bragg grating is a femtosecond fiber Bragg grating.

[0010] As a further limitation of the present invention, the equation of the fiber grating wavelength and the beam end angle is: Where L represents half of the length of the upper support plate in the spherical support, l represents the length of the connecting rod in the diamond linkage mechanism, h represents half of the diagonal distance in the vertical direction in the diamond linkage mechanism, Δλ represents the wavelength difference of the fiber Bragg grating, and θ represents the beam end rotation angle.

[0011] Due to the adoption of the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0012] (1) The present invention converts the unknown rotation angle information of the beam end into the displacement information of the support plate on the spherical support and uses a fiber grating inclination sensor to convert the displacement information into the deformation of the fiber grating. Finally, a fiber grating demodulation mechanism is used to obtain the wavelength of the fiber grating. Then, the beam end rotation angle is inversely calculated based on the fiber grating wavelength and the beam end rotation angle equation. In the process of testing the beam end rotation angle, the fiber grating inclination sensor used is not easily affected by special environments such as temperature and electromagnetics, is durable, and can be used in environments that require long-term monitoring and harsh environments. In addition, the fiber grating inclination sensor has high measurement accuracy, which can effectively improve the accuracy of beam end angle measurement.

[0013] (2) The fiber Bragg grating inclination sensor of the present invention has a reasonable structure and low manufacturing cost. When the bridge is deformed by load, the unknown rotation angle information of the beam end is converted into the displacement information of the upper support plate in the spherical support. The connecting member and the sliding mechanism in the fiber Bragg grating inclination sensor cooperate with each other to convert the displacement information of the upper support plate into the displacement information of the diamond linkage mechanism. The fiber Bragg grating fixed on the diamond linkage mechanism will move with the diamond linkage mechanism to realize the conversion of the displacement information of the diamond linkage mechanism into the deformation of the fiber Bragg grating. The fiber Bragg grating demodulation mechanism can be used to obtain the wavelength of the fiber Bragg grating. Then, the beam end rotation angle can be inversely calculated according to the fiber Bragg grating wavelength and the beam end rotation angle equation. The measurement accuracy of the fiber Bragg grating inclination sensor is 5.212×10 -5°, compared with the test method of testing the beam end angle using the existing angle test device, the fiber grating inclination sensor in the present invention has high measurement accuracy, which can effectively improve the accuracy of the beam end angle test results. At the same time, the fiber grating inclination sensor in the present invention can not only measure the static inclination of the beam end, but also measure the dynamic inclination of the beam end, which is more practical. In addition, the fiber grating as the sensitive element of the fiber grating inclination sensor has the advantage that it has strong corrosion resistance and is not easily affected by temperature and electromagnetic interference, which can effectively improve the stability and reliability of the present invention when used.

[0014] (3) The fiber Bragg grating inclination sensor in the present invention has a height adjustment mechanism. By adjusting the height of the height adjustment mechanism, the rotation angle of the spherical support at different heights can be tested. This makes the fiber Bragg grating inclination sensor highly flexible and adaptable, which can effectively improve the practicality of the present invention.

[0015] (4) The fiber Bragg grating in the present invention adopts a femtosecond fiber Bragg grating. Compared with ordinary fiber Bragg gratings, femtosecond fiber Bragg gratings can withstand greater strain and higher temperature, which makes the fiber Bragg grating inclination sensor more durable and less susceptible to the influence of ambient temperature during use, which can effectively improve the reliability and stability of the structure of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0017] Figure 1 It is a flowchart of a method for testing the rotation angle of a bridge beam end based on a spherical bearing in an embodiment of the present invention;

[0018] Figure 2 A schematic diagram of the installation position of the fiber Bragg grating inclination sensor in the embodiment of the present invention when in use;

[0019] Figure 3 A schematic diagram of the structure of a fiber Bragg grating inclination sensor according to an embodiment of the present invention;

[0020] Figure 4 Schematic diagram of the connection relationship among the connecting member, the slider, the slide rail, the fixing block and the diamond-shaped connecting rod mechanism in the embodiment of the present invention;

[0021] Figure 5 is a schematic structural diagram of a first hinge component in an embodiment of the present invention;

[0022] In the figure: 1, shell; 2, connecting member; 3, slider; 4, slide rail; 5, first rod; 6, second rod; 7, third rod; 8, fourth rod; 9, first pin; 10, second pin; 11, first hinge member; 12, second hinge member; 13, fiber Bragg grating; 14, temperature compensation fiber Bragg grating; 15, bottom plate; 16, threaded rod; 17, limit nut; 18, fixing block; 19, bridge; 20, spherical bearing; 21, bridge pier; 22, fiber Bragg grating inclination sensor; 110, third pin; 111, first circular block; 112, first strip groove. DETAILED DESCRIPTION

[0023] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and understand the present invention, and are not used to limit the present invention.

[0024] Embodiment A method for testing the rotation angle of a bridge beam end based on a spherical bearing

[0025] like Figure 1 As shown, this embodiment includes the following steps:

[0026] Step 1: Figure 2 As shown, the upper support plate in the spherical support 20 on the bridge 19 is used as the measuring point of the angle of the beam end of the bridge 19, and the fiber grating inclination sensor 22 is fixed between the upper support plate and the bridge pier 21;

[0027] Step 2: convert the unknown rotation angle information of the beam end into the displacement information of the upper bearing plate in the spherical bearing 20;

[0028] Step 3: using the fiber Bragg grating inclination sensor 22 to convert the displacement information in step 2 into the deformation of the fiber Bragg grating 13;

[0029] Step 4: Transmit the deformation data of the fiber Bragg grating 13 to the fiber Bragg grating demodulation mechanism to obtain the wavelength of the fiber Bragg grating 13, and then inversely calculate the beam end angle according to the fiber Bragg grating wavelength and the beam end angle equation.

[0030] like Figure 3 , Figure 4As shown, the fiber Bragg grating inclination sensor 22 includes a shell 1, a connecting member 2 slidably connected to the shell 1 through a sliding mechanism, a height adjustment mechanism arranged at the bottom of the shell 1 for adjusting the height of the shell 1, a diamond connecting rod mechanism fixed between the connecting member 2 and the bottom of the shell 1, a fiber Bragg grating 13 fixed on the diamond connecting rod mechanism, and a temperature compensation fiber Bragg grating 14 fixed on the inner wall of the shell 1, wherein the connecting member 2 is a rectangular rod, the top of the shell 1 is provided with a rectangular through hole adapted to the rectangular rod, the rectangular rod is inserted into the rectangular through hole and the rectangular rod can slide in the rectangular through hole, the sliding mechanism includes a slide rail 4 fixed on the inner wall of the shell 1 and a slider 3 slidably connected to the slide rail 4, and the slider 3 is fixed on the connecting member 2. The fiber Bragg grating 13 adopts the existing femtosecond fiber Bragg grating. When in use, one end of the fiber Bragg grating 13 needs to be electrically connected to the fiber Bragg grating demodulation mechanism, and one end of the temperature compensation fiber Bragg grating 14 needs to be electrically connected to the fiber Bragg grating demodulation mechanism to transmit the deformation data of the fiber Bragg grating 13 to the fiber Bragg grating demodulation mechanism and obtain the wavelength of the fiber Bragg grating. It should be explained that the temperature compensation fiber Bragg grating 14 is a force-free fiber Bragg grating, which can supplement the temperature of the fiber Bragg grating 13, thereby eliminating the influence of temperature on the measurement accuracy.

[0031] like Figure 4 As shown, the diamond linkage mechanism includes four links hinged together end to end. Specifically, in this embodiment, the two links located at the top are defined as the first rod 5 and the second rod 6 from left to right, and the two links located at the bottom are defined as the third rod 7 and the fourth rod 8 from left to right, wherein the first rod 5 and the second rod 6 are hinged together by a first pin 9, the end of which is fixed on the connecting member 2, and the third rod 7 and the fourth rod 8 are hinged together by a second pin 10, which is fixed on the side wall of the housing 1 through a fixing block 18. The first rod 5 and the third rod 7 are hinged together by a first hinge member 11, as shown in FIG. Figure 5 As shown, the first hinged component 11 includes a third pin 110 and a first circular block 111 fixed at the end of the third pin 110, and the first circular block 111 is provided with a first strip groove 112. The second rod 6 and the fourth rod 8 are hinged together through the second hinged component 12, wherein the second hinged component 12 includes a fourth pin and a second circular block fixed at the end of the fourth pin, and the second circular block is provided with a second strip groove. The optical fiber Bragg grating 13 is fixed on the first strip groove 112 and the second strip groove.

[0032] The height adjustment mechanism includes a base plate 15 and four threaded rods 16 respectively fixed at four corner positions of the base plate 15, each threaded rod 16 is slidably connected to the bottom of the shell 1 and is fixedly connected to the bottom of the shell 1 by two limit nuts 17. Specifically, in the present embodiment, the base plate 15 is a rectangular plate, the limit nuts 17 are hexagonal nuts, and a circular through hole is respectively opened at the four corner positions of the bottom of the shell 1. The size of the circular through hole is adapted to the size of the threaded rod 16 so that the threaded rod 16 can slide in the circular through hole, each threaded rod 16 is slidably connected to the corresponding circular through hole, and the two limit nuts 17 on each threaded rod 16 are respectively pressed against the top surface and the bottom surface of the bottom of the shell 1 to fix the threaded rod 16 to the bottom of the shell 1.

[0033] The principle of testing the beam end angle of the present invention is as follows: when the bridge 19 is deformed by load, the unknown beam end angle information is converted into the displacement information of the upper support plate in the spherical support 20, and the connection member 2 in the fiber grating inclination sensor 22 cooperates with the sliding mechanism to convert the displacement information of the upper support plate into the displacement information of the diamond linkage mechanism, and the fiber grating 13 fixed on the diamond linkage mechanism will move with the diamond linkage mechanism to realize the conversion of the displacement information of the diamond linkage mechanism into the deformation of the fiber grating 13, and then cooperate with the fiber grating demodulation mechanism to obtain the wavelength of the fiber grating 13. After obtaining the wavelength of the fiber grating 13, the beam end angle can be inversely calculated using the fiber grating wavelength and the beam end angle equation, wherein the fiber grating wavelength and the beam end angle equation are:

[0034] Wherein L represents half the length of the support plate on the spherical support, l represents the length of the connecting rod in the diamond linkage mechanism, h represents half the diagonal distance in the vertical direction of the diamond linkage mechanism, that is, half the vertical distance between the first pin 9 and the second pin 10 in the diamond linkage mechanism, Δλ represents the wavelength difference of the fiber grating 13, and θ represents the beam end angle.

[0035] It should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the above embodiments, those skilled in the art can still modify the technical solutions described in the above embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for testing the rotation angle of a bridge beam end based on a spherical bearing, characterized in that: The following steps are involved: Step 1: Use the upper bearing plate in the spherical bearing on the bridge as the measuring point of the bridge beam end angle and fix the fiber grating inclination sensor between the upper bearing plate and the bridge pier; Step 2: convert the unknown rotation angle information of the beam end into the displacement information of the upper bearing plate in the spherical bearing; Step 3: using a fiber Bragg grating inclination sensor to convert the displacement information in step 2 into a deformation of the fiber Bragg grating; Step 4: Transmit the deformation data of the fiber Bragg grating to the fiber Bragg grating demodulation mechanism to obtain the wavelength of the fiber Bragg grating, and then inversely calculate the beam end angle according to the fiber Bragg grating wavelength and the beam end angle equation.

2. A method for testing the rotation angle of a bridge beam end based on a spherical bearing according to claim 1, characterized in that: The fiber Bragg grating inclination sensor comprises a shell, a connecting member slidably connected to the shell through a sliding mechanism, a height adjustment mechanism arranged at the bottom of the shell for adjusting the height of the shell, a diamond connecting rod mechanism fixed between the connecting member and the bottom of the shell, a fiber Bragg grating fixed on the diamond connecting rod mechanism, and a temperature compensation fiber Bragg grating fixed on the inner wall of the shell.

3. A method for testing the rotation angle of a bridge beam end based on a spherical bearing according to claim 2, characterized in that: The height adjustment mechanism comprises a bottom plate and four threaded rods respectively fixed at four corner positions of the bottom plate, each threaded rod is slidably connected to the bottom of the shell and is fixedly connected to the bottom of the shell through two limit nuts.

4. A method for testing the rotation angle of a bridge beam end based on a spherical bearing according to claim 3, characterized in that: The diamond-shaped connecting rod mechanism comprises four connecting rods which are hinged together end to end in sequence.

5. A method for testing the rotation angle of a bridge beam end based on a spherical bearing according to any one of claims 2 to 4, characterized in that: The fiber grating is a femtosecond fiber grating.

6. A method for testing the rotation angle of a bridge beam end based on a spherical bearing according to claim 5, characterized in that: The equation of the fiber Bragg grating wavelength and the beam end rotation angle is: Where L represents half of the length of the upper support plate in the spherical support, l represents the length of the connecting rod in the diamond linkage mechanism, h represents half of the diagonal distance in the vertical direction in the diamond linkage mechanism, Δλ represents the wavelength difference of the fiber Bragg grating, and θ represents the beam end rotation angle.

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