A deflection deformation monitoring device for a steel trestle

Abstract

The present application relates to measurement, specifically to the technical field of bridge health monitoring, and discloses a deflection deformation monitoring device for a steel trestle, which comprises a steel truss and a bridge body, the bottom of the bridge body is provided with a control part, the control part is provided with a vibration guide part, the vibration guide part is provided with a deformation monitoring part, the control part is provided with a damping part, the damping part is provided with a distance measuring part, the control part comprises a mounting plate, the mounting plate is mounted at the bottom of the bridge body, a control box is mounted on the mounting plate, one side of the control box is an inclined structure, the vibration guide part comprises a slide, and the slide is mounted on the inclined surface of the control box; the device adopts vibration guide integration, thermal expansion and contraction compensation, and triple design of damping and anti-interference, effectively offsets the interference of concrete bridge body vibration and steel truss thermal deformation on deflection monitoring, avoids misjudgment of the laser displacement sensor, and solves the core problem of data deviation in the prior art.

Description

Technical Field

[0001] This invention relates to measurement, specifically to the field of bridge health monitoring technology, and more specifically to a deflection deformation monitoring device for steel trestle bridges. Background Technology

[0002] Traditional deflection monitoring technologies have many insurmountable limitations. Taking leveling instruments as an example, the operation is cumbersome, requiring surveyors to observe point by point. Total station observations are significantly affected by environmental factors such as weather and lighting, making it difficult to operate normally under adverse weather conditions. The emergence of laser displacement sensors has, to some extent, compensated for the shortcomings of traditional monitoring technologies, offering significant advantages such as high precision, non-contact operation, and fast dynamic response.

[0003] The existing patent CN118746407A discloses a steel trestle deck and a steel trestle deck mid-span deflection monitoring system, which focuses on a solution for monitoring a single deflection parameter and transmitting basic data for early warning. It includes a monitoring box, a housing, a monitoring instrument, a laser displacement sensor, and an antenna installed in the housing. The laser displacement sensor and the antenna are both electrically connected to the monitoring instrument.

[0004] Thermal expansion and contraction is a physical property that almost all materials exhibit. For steel trestle structures, steel has a large coefficient of linear expansion. In areas with significant temperature changes, the expansion and contraction caused by temperature changes cannot be properly released or compensated, which will generate huge temperature stress inside the trestle structure, causing the trestle structure to deform and thus increasing the trestle's deflection.

[0005] Therefore, in the aforementioned patents, laser displacement sensors typically operate based on a fixed measurement benchmark. When the trestle deforms due to thermal expansion and contraction, resulting in deformations that are not part of the monitored target, the sensor will misinterpret these additional deformations as actual deflection changes of the trestle, thus outputting incorrect monitoring data.

[0006] On the other hand, the passage of vehicles is a common source of vibration, which generates dynamic pressure and impact, causing significant vibration of the trestle structure. These vibrations severely interfere with deflection monitoring based on laser displacement sensors, making it difficult for the sensors to accurately capture the static deflection changes of the trestle. Summary of the Invention

[0007] (a) Technical problems to be solved

[0008] To address the shortcomings of existing technologies, this invention provides a deflection deformation monitoring device for steel trestle bridges, which solves the problem of deflection monitoring data deviation caused by thermal expansion and contraction and vibration interference of steel trestle bridges.

[0009] (II) Technical Solution

[0010] To achieve the above objectives, the present invention provides the following technical solution: a deflection deformation monitoring device for a steel trestle bridge, comprising a steel truss and a bridge body, a control unit at the bottom of the bridge body, a vibration guide unit on the control unit, a deformation monitoring unit on the vibration guide unit, a damping unit inside the control unit, and a distance measuring unit on the damping unit. The control unit includes a mounting plate, which is mounted on the bottom of the bridge body. A control box is mounted on the mounting plate, and one side of the control box is an inclined structure. The vibration guide unit includes a slide rail, which is mounted on the inclined surface of the control box. A guide arm is slidably connected to the inner wall of the slide rail. One end of the guide arm is a planar structure and abuts against the bridge body. The other end of the guide arm has a rod groove, in which a guide rod is slidably connected. A support plate is fixedly connected to one end of the guide rod, and a spring is elastically connected between the support plate and the guide arm. A distance sensor is installed on the inner wall of the rod groove, and a vibration sensor is installed at the end of the rod groove. The angle between the guide arm and the support plate is [degrees].

[0011] Preferably, a monitoring box is installed inside the control box, a laser displacement sensor is installed on one side of the monitoring box, and a T-shaped slide is installed on the monitoring box.

[0012] Preferably, the deformation monitoring unit includes a boom, which is fixedly connected to one side of the inner wall of the control box. A rotating arm is rotatably connected to the boom, and a swing rod is fixedly connected to one end of the swing arm. A steel ring is sleeved on the end of the swing rod. A positioning frame and a pressure sensor are installed on the outer wall of the control box, and an arc-shaped contact plate is installed on the detection end of the pressure sensor.

[0013] Preferably, the outer wall of the control box has a swing hole with the same shape as the positioning frame, the end of the swing rod is slidably connected to the inner wall of the swing hole, the arc-shaped contact piece contacts the steel ring, and the rotation point of the rotating arm and the boom is equipped with an angle sensor.

[0014] Preferably, the end of the rotating arm is provided with a groove, a connecting arm one is fixedly connected to the guide arm, a connecting arm two is hinged to the connecting arm one, and the connecting arm two is hinged in the groove.

[0015] Preferably, the shock absorption unit includes a damper, one end of which is installed on the inclined inner wall of the control box, and a first rod sleeve is fixedly connected to the other end of the damper. A second rod sleeve is fixedly connected to the outer wall of the first rod sleeve, and the ports of the first rod sleeve and the second rod sleeve are perpendicular to each other.

[0016] Preferably, a sliding rod is slidably connected to the inner wall of the second sleeve, a rod head is fixedly connected to one end of the sliding rod, a tension spring is elastically connected between the rod head and the second sleeve, and a wedge plate is fixedly connected to the other end of the sliding rod, the wedge surface of the wedge plate is in contact with the outer wall of the swing rod.

[0017] Preferably, the ranging unit includes a positioning plate, which is mounted on a steel truss. A steel arm is mounted on the positioning plate, the steel arm is perpendicular to the bridge body and its top extends into the control box, and the top of the steel arm is a sloping structure.

[0018] Preferably, a sliding rod two is slidably connected to the inner wall of the first rod sleeve, and a support arm is fixedly connected to the end of the second sliding rod. A tension spring two is elastically connected between the support arm and the first rod sleeve. A distance measuring plate is installed on the top of the support arm, and one side of the distance measuring plate is an inclined structure that contacts the inclined surface of the steel arm.

[0019] Preferably, a T-shaped slider is installed on one side of the ranging plate, the T-shaped slider is slidably connected to the T-shaped groove, and the sensing end of the laser displacement sensor is aligned with the vertical surface of the ranging plate.

[0020] (III) Beneficial Effects

[0021] Compared with the prior art, the present invention provides a deflection deformation monitoring device for steel trestle bridges, which has the following beneficial effects:

[0022] 1. The deflection deformation monitoring device for steel trestle bridges adopts a triple design of vibration guidance integration, thermal expansion and contraction compensation, and shock absorption and anti-interference, which effectively counteracts the interference of concrete bridge vibration and steel truss thermal deformation on deflection monitoring, avoids misjudgment by laser displacement sensors, and solves the core problem of data deviation in existing technologies.

[0023] 2. This deflection deformation monitoring device for steel trestle bridges adopts a multi-dimensional data fusion mode that uses a laser displacement sensor for core measurement and pressure, vibration, and angle sensors for auxiliary correction. Combined with the precise transmission and trajectory constraint of the mechanical structure, it significantly improves the accuracy and reliability of deflection measurement.

[0024] 3. This deflection deformation monitoring device for steel trestle bridges uses an installation plate and a positioning plate to adapt to the installation requirements of concrete bridge bodies and steel trusses respectively. It can cope with complex working conditions such as open-air, high temperature, and multiple vibrations, and is suitable for deflection monitoring scenarios of various steel trestle bridges.

[0025] 4. The deflection deformation monitoring device for steel trestle bridges adopts the synergistic action of the damper and elastic components of the shock absorption unit to buffer vibration impact, ensure the linkage stability of each mechanical component, avoid structural loosening or measurement deviation under severe working conditions, and extend the service life of the device.

[0026] 5. This deflection and deformation monitoring device for steel trestle bridges adopts the simultaneous acquisition of multiple types of data such as deflection, vibration, and thermal deformation. It can not only output the true load deflection value, but also provide comprehensive data support for the health status assessment of steel trestle bridges, and assist in subsequent maintenance decisions. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall structure of a deflection deformation monitoring device for steel trestle bridges proposed in this invention.

[0028] Figure 2 This is a diagram showing the assembly of the steel truss and bridge body of the present invention;

[0029] Figure 3 This is a schematic diagram of the control unit of the present invention;

[0030] Figure 4 This is a schematic diagram of the internal structure of the control box of the present invention;

[0031] Figure 5 This invention relates to the cooperation between the pressure sensor and the control box.

[0032] Figure 6 This is a cross-sectional view of the guide arm of the present invention;

[0033] Figure 7 This is a diagram showing the fit between the monitoring box and the vibration guide of the present invention;

[0034] Figure 8 For the present invention Figure 7 Enlarged view of A in the middle;

[0035] Figure 9 This is a diagram showing the fit between the shock-absorbing part and the distance measuring part of the present invention.

[0036] In the diagram: 1. Steel truss; 2. Bridge body; 3. Control unit; 31. Mounting plate; 32. Control box; 33. Monitoring box; 34. Laser displacement sensor; 35. T-shaped chute; 4. Vibration guide unit; 41. Slide rail; 42. Guide arm; 43. Rod groove; 44. Guide rod; 45. Support plate; 46. Spring; 47. Distance sensor; 48. Vibration sensor; 49. Connecting arm one; 410. Connecting arm two; 5. Deformation monitoring unit; 51. Boom; 52. Swing arm; 53. Swing rod; 54. Steel ring; 55. Positioning frame; 56. Pressure sensor; 57. Arc-shaped contact plate; 58. Angle sensor; 6. Shock absorber; 61. Damper; 62. Rod sleeve one; 63. Rod sleeve two; 64. Slide rod one; 65. Rod head; 66. Tension spring one; 67. Wedge plate; 7. Distance measuring part; 71. Positioning plate; 72. Steel arm; 73. Support arm; 74. Tension spring two; 75. Distance measuring plate; 76. T-shaped slider. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Please see Figure 1 - Figure 9 This invention provides a deflection deformation monitoring device for a steel trestle bridge, comprising a steel truss 1 and a bridge body 2. The bridge body 2 is made of concrete. A control unit 3 is located at the bottom of the bridge body 2, a vibration guide unit 4 is located on the control unit 3, a deformation monitoring unit 5 is located on the vibration guide unit 4, a shock absorber unit 6 is located inside the control unit 3, and a distance measuring unit 7 is located on the shock absorber unit 6. The control unit 3 serves as the overall mounting and core load-bearing foundation of the device, and includes a mounting plate 31. The mounting plate 31 is installed at the bottom of the bridge body 2, and a control box 32 is mounted on the mounting plate 31. One side of the control box 32 is an inclined structure. The control box 32 is equipped with a monitoring box 33. The monitoring box 33 adopts the steel trestle plate and steel trestle plate mid-span deflection monitoring system disclosed in the existing patent CN118746407A. Its principle mainly relies on the laser displacement sensor 34 to measure the flexural deformation at the mid-span of the bridge. It contains a processor and other systems, which will not be described in detail here. The monitoring box 33 is equipped with a laser displacement sensor 34, which is compatible with the SICK triangular principle photoelectric distance sensor. The monitoring box 33 is equipped with a T-shaped slide 35.

[0039] In this invention, the vibration guide 4 receives the dispersed vibration of the concrete bridge body 2, including a slide 41. The slide 41 is installed on the inclined surface of the control box 32. A guide arm 42 is slidably connected to the inner wall of the slide 41. One end of the guide arm 42 is a planar structure and abuts against the bridge body 2. The other end of the guide arm 42 is provided with a rod groove 43. A guide rod 44 is slidably connected in the rod groove 43. A support plate 45 is fixedly connected to one end of the guide rod 44. A spring 46 is elastically connected between the support plate 45 and the guide arm 42. A distance sensor 47 is installed on the inner wall of the rod groove 43, with the model VOLFAKR-100-V2 electronic ruler as the adapter. A vibration sensor 48 is installed at the end of the rod groove 43, with the model industrial-grade temperature and vibration sensor as the adapter. The angle between the guide arm 42 and the support plate 45 is 90 degrees.

[0040] In this embodiment, the deformation monitoring unit 5 receives the mechanical movement of the vibration guide unit 4 and includes a boom 51, which is fixedly connected to one side of the inner wall of the control box 32. A rotating arm 52 is rotatably connected to the boom 51, and a swing rod 53 is fixedly connected to one end of the swing rod 52. A steel ring 54 is fitted onto the end of the swing rod 53. A positioning frame 55 and a pressure sensor 56 (compatible model Honeywell X129981-13U) are installed on the outer wall of the control box 32. The detection end of the pressure sensor 56 is mounted on... The control box 32 is equipped with an arc-shaped contact piece 57. The outer wall of the control box 32 has a swing hole with the same shape as the positioning frame 55. The end of the swing rod 53 is slidably connected to the inner wall of the swing hole. The arc-shaped contact piece 57 contacts the steel ring 54. An angle sensor 58 is installed at the rotation point of the rotating arm 52 and the boom 51. The adapter model is MPSMAQ600A. The end of the rotating arm 52 has a groove. A connecting arm 49 is fixedly connected to the guide arm 42. A connecting arm 410 is hinged to the connecting arm 49. The connecting arm 410 is hinged in the groove.

[0041] It is worth noting that the shock absorption unit 6 buffers the overall vibration and impact within the control box 32, including a damper 61. One end of the damper 61 is installed on the inclined inner wall of the control box 32, and a first rod sleeve 62 is fixedly connected to the other end of the damper 61. A second rod sleeve 63 is fixedly connected to the outer wall of the first rod sleeve 62. The ports of the first rod sleeve 62 and the second rod sleeve 63 are perpendicular to each other. A first sliding rod 64 is slidably connected to the inner wall of the second rod sleeve 63. A rod head 65 is fixedly connected to one end of the first sliding rod 64. A tension spring 66 is elastically connected between the rod head 65 and the second rod sleeve 63. A wedge plate 67 is fixedly connected to the other end of the first sliding rod 64. The wedge surface of the wedge plate 67 contacts the outer wall of the swing rod 53.

[0042] It is worth noting that the ranging unit 7 includes a positioning plate 71, which is mounted on the steel truss 1. A steel arm 72 is mounted on the positioning plate 71. The steel arm 72 is perpendicular to the bridge body 2, and its top extends into the control box 32. The top of the steel arm 72 is a sloping structure. A sliding rod 2 is slidably connected to the inner wall of the first sleeve 62. A support arm 73 is fixedly connected to the end of the sliding rod 2. A tension spring 2 74 is elastically connected between the support arm 73 and the first sleeve 62. A ranging plate 75 is mounted on the top of the support arm 73. One side of the ranging plate 75 is a sloping structure, and the sloping surface connects to the sloping surface of the steel arm 72. A T-shaped slider 76 is installed on one side of the ranging plate 75, and the T-shaped slider 76 is slidably connected to the T-shaped groove 35. The sensing end of the laser displacement sensor 34 is aligned with the vertical surface of the ranging plate 75. Taking the steel truss 1 as a reference, the steel arm 72 is fixed by the positioning plate 71, which converts the bending deformation of the steel truss 1 into the downward movement of the steel arm 72. With the cooperation of the inclined surface of the steel arm 72 and the ranging plate 75, the downward movement is converted into the translation of the ranging plate 75, providing the laser displacement sensor 34 with a measurable distance change, and realizing the accurate acquisition of the core deflection data.

[0043] Working principle: Vehicle traffic, wind load, etc. will cause the bridge body 2 to generate scattered and disordered vibrations. The scattered vibrations of the concrete bridge body 2 are directly transmitted to the guide arm 42. The vibration is constrained by the slide rail 41 into unidirectional sliding along the inclined direction, completing the integration of disordered vibrations into ordered oblique motion. When the guide arm 42 slides along the slide rail 41, the vibration sensor 48 synchronously collects the integrated oblique vibration data. At the same time, the spring 46 elastically connected between the guide arm 42 and the support plate 45 buffers the instantaneous impact of vibration, avoiding severe vibration from interfering with the subsequent deflection measurement components. When the guide arm 42 slides, the connecting arm 1 49 fixed on its side wall pulls the hinged connecting arm 2 410, thereby driving the rotating arm 52 to rotate around the boom 51. The swing rod 53 fixed at the other end of the rotating arm 52 slides along the swing hole of the control box 32 with the rotating arm 52, providing a motion basis for the subsequent thermal expansion and contraction compensation data collection.

[0044] The core of the deflection deformation of the steel trestle is caused by the bending of the steel truss 1. Its deformation is transmitted to the laser displacement sensor 34 through the mechanical structure to achieve accurate measurement. When the steel truss 1 is subjected to the weight of the vehicle and the self-weight of the structure and undergoes bending deformation, the positioning plate 71 fixed on the steel truss 1 bends synchronously with the steel truss 1, thereby causing the steel arm 72 vertically connected to the positioning plate 71 to sink downward.

[0045] As the steel arm 72 sinks, the thrust of its inclined plane on the distance measuring plate 75 along the inclined plane gradually disappears, forcing the distance measuring plate 75 to slide along the T-shaped slide groove 35 via the T-shaped slider 76 on the side wall. The sliding direction is away from the direction of the laser displacement sensor 34 by the tension of the tension spring 74. The sensing end of the laser displacement sensor 34 is aligned with the vertical surface of the distance measuring plate 75. The sliding distance of the distance measuring plate 75 is directly converted into the change in the laser sensing distance. This change is the actual deflection deformation caused by the bending of the steel truss 1, thus completing the core deflection data acquisition.

[0046] The steel ring 54, fitted onto the end of the swing rod 53, is made of the same material as the steel truss 1 and has the same coefficient of thermal expansion. Its design purpose is to counteract the interference of thermal expansion and contraction on deflection measurement. When the ambient temperature changes, the steel truss 1 undergoes non-load deformation due to thermal expansion and contraction, elongating at high temperatures and contracting at low temperatures. The steel ring 54 undergoes thermal expansion and contraction of the same amplitude simultaneously. The steel ring 54 is always in contact with the arc-shaped contact piece 57 at the detection end of the pressure sensor 56. When the steel ring 54 expands thermally, the compressive force on the arc-shaped contact piece 57 increases, and when it contracts, the compressive force decreases. The pressure sensor 56 converts the pressure change into an electrical signal and, combined with the formula for the coefficient of thermal expansion of steel, calculates the amount of thermal deformation of the steel ring 54, that is, the amount of thermal deformation of the steel truss 1.

[0047] The thermal deformation data of the pressure sensor 56 is combined with the vibration data of the vibration sensor 48. The distance sensor 47 in the guide arm 42 monitors the relative position of the guide rod 44 and the rod groove 43 to help capture minute displacements. The original deflection value collected by the laser displacement sensor 34 is triple-corrected to eliminate errors caused by non-load deformation of the steel truss 1 due to thermal expansion and contraction and vibration of the concrete bridge body 2. Finally, the true load deflection value of the steel trestle bridge is output. At the same time, the angle sensor 58 at the rotation point of the swing arm 52 and the boom 51 monitors the rotation angle of the swing arm 52 to help verify the influence of thermal deformation and vibration on the deflection data and further improve the correction accuracy.

[0048] The damping unit 6 inside the control box 32 is used to weaken the impact of extreme vibrations on the measurement system. When the vibration amplitude of the concrete bridge body 2 is large, the damper 61 buffers the overall vibration impact inside the control box 32. At the same time, when the swing rod 53 slides, it squeezes the wedge plate 67, causing the slide rod 64 to slide along the sleeve 63. The tension spring 66 between the end of the slide rod 64 and the sleeve 63 undergoes elastic deformation, absorbing the vibration energy of the swing rod 53, avoiding the contact deviation between the steel arm 72 and the measuring plate 75 caused by severe vibration, and ensuring the stability of the core measurement link.

[0049] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A deflection deformation monitoring device for a steel trestle bridge, comprising a steel truss (1) and a bridge body (2), characterized in that: A control unit (3) is provided at the bottom of the bridge body (2). A vibration guide unit (4) is provided on the control unit (3). A deformation monitoring unit (5) is provided on the vibration guide unit (4). A damping unit (6) is provided inside the control unit (3). A distance measuring unit (7) is provided on the damping unit (6). The control unit (3) includes a mounting plate (31). The mounting plate (31) is installed at the bottom of the bridge body (2). A control box (32) is installed on the mounting plate (31). One side of (32) is an inclined structure. The vibration guide (4) includes a slide (41). The slide (41) is installed on the inclined surface of the control box (32). A guide arm (42) is slidably connected to the inner wall of the slide (41). One end of the guide arm (42) is a planar structure and abuts against the bridge body (2). The other end of the guide arm (42) is provided with a rod groove (43). A guide rod (44) is slidably connected in the rod groove (43). One end of the guide rod (44) is fixedly connected to... A support plate (45) is attached, and a spring (46) is elastically connected between the support plate (45) and the guide arm (42). A distance sensor (47) is installed on the inner wall of the rod groove (43), and a vibration sensor (48) is installed at the end of the rod groove (43). The angle between the guide arm (42) and the support plate (45) is 90 degrees. The deformation monitoring unit (5) includes a boom (51), which is fixedly connected to one side of the inner wall of the control box (32). The boom (51) has... A rotating arm (52) is rotatably connected, and a swing rod (53) is fixedly connected to one end of the rotating arm (52). A steel ring (54) is sleeved on the end of the swing rod (53). A positioning frame (55) and a pressure sensor (56) are installed on the outer wall of the control box (32). An arc-shaped contact piece (57) is installed on the detection end of the pressure sensor (56). The arc-shaped contact piece (57) contacts the steel ring (54). The steel ring (54) is made of the same material as the steel truss (1) and has the same coefficient of thermal expansion.

2. The deflection deformation monitoring device for steel trestle bridges according to claim 1, characterized in that: The control box (32) is equipped with a monitoring box (33), a laser displacement sensor (34) is installed on one side of the monitoring box (33), and a T-shaped slide (35) is installed on the monitoring box (33).

3. The deflection deformation monitoring device for steel trestle bridges according to claim 2, characterized in that: The outer wall of the control box (32) is provided with a swing hole with the same shape as the positioning frame (55). The end of the swing rod (53) is slidably connected to the inner wall of the swing hole. An angle sensor (58) is installed at the rotation point of the rotating arm (52) and the boom (51).

4. The deflection deformation monitoring device for steel trestle bridges according to claim 3, characterized in that: The end of the rotating arm (52) is provided with a groove, and a connecting arm one (49) is fixedly connected to the guide arm (42). A connecting arm two (410) is hinged to the connecting arm one (49), and the connecting arm two (410) is hinged in the groove.

5. The deflection deformation monitoring device for steel trestle bridges according to claim 3, characterized in that: The shock absorption unit (6) includes a damper (61). One end of the damper (61) is installed on the inclined inner wall of the control box (32). A first rod sleeve (62) is fixedly connected to the other end of the damper (61). A second rod sleeve (63) is fixedly connected to the outer wall of the first rod sleeve (62). The port of the first rod sleeve (62) and the port of the second rod sleeve (63) are set perpendicular to each other.

6. The deflection deformation monitoring device for steel trestle bridges according to claim 5, characterized in that: The inner wall of the second sleeve (63) is slidably connected to a first slide rod (64). One end of the first slide rod (64) is fixedly connected to a rod head (65). A tension spring (66) is elastically connected between the rod head (65) and the second sleeve (63). A wedge plate (67) is fixedly connected to the other end of the first slide rod (64). The wedge surface of the wedge plate (67) is in contact with the outer wall of the swing rod (53).

7. The deflection deformation monitoring device for steel trestle bridges according to claim 5, characterized in that: The ranging unit (7) includes a positioning plate (71), which is mounted on a steel truss (1). A steel arm (72) is mounted on the positioning plate (71). The steel arm (72) is perpendicular to the bridge body (2) and the top of the steel arm (72) extends into the control box (32). The top of the steel arm (72) is a sloping structure.

8. The deflection deformation monitoring device for steel trestle bridges according to claim 7, characterized in that: The inner wall of the first sleeve (62) is slidably connected to a second slide rod, and the end of the second slide rod is fixedly connected to a support arm (73). The support arm (73) and the first sleeve (62) are elastically connected by a second tension spring (74). A distance measuring plate (75) is installed on the top of the support arm (73). One side of the distance measuring plate (75) is a slope structure and contacts the slope of the steel arm (72) through the slope.

9. A deflection deformation monitoring device for steel trestle bridges according to claim 8, characterized in that: A T-shaped slider (76) is installed on one side of the ranging plate (75), and the T-shaped slider (76) is slidably connected to the T-shaped groove (35). The sensing end of the laser displacement sensor (34) is aligned with the vertical surface of the ranging plate (75).

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