A long-span bridge deck deformation monitoring device and monitoring method

Abstract

The present invention discloses a long-span bridge deck deformation monitoring device and monitoring method, specifically relating to the field of bridge monitoring technology. The device includes a mounting device, a laser, and a light spot recognition device. The laser and the light spot recognition device are mounted on the mounting device in back-to-back relationship. The monitoring device also includes a protective cover. A plurality of heat dissipation guide tubes are fixedly mounted inside the protective cover. A heat dissipation air pump is also provided inside the protective cover. A blow hood and an air suction hood are provided on the protective cover. The bottom end of the heat dissipation guide tube is docked with the air outlet of the heat dissipation air pump, and the top end of the heat dissipation guide tube is docked with the blow hood. The blow hood forms an airflow from top to bottom on the surface of the protective lens. The present invention uses the heat dissipation air pump to form a circulating airflow in the heat dissipation guide tube, reduce the temperature gradient of the air temperature inside and outside the protective lens, avoid the refraction problem caused by the excessive difference in air temperature inside and outside the protective lens, and further improve the accuracy of the monitoring device.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge monitoring, and more particularly to a device and method for monitoring deformation of a bridge deck of a long-span bridge. Background Art

[0002] During the construction and actual commissioning of bridges, parts of the bridge structure may deform due to many factors such as external loads, environmental factors, and the materials and structures themselves. Due to the large size of the bridge system, in order to monitor the bridge more accurately and safely, it is usually necessary to use multiple detection methods for multi-parameter monitoring, such as settlement monitoring, deflection monitoring, crack monitoring, and tilt monitoring.

[0003] Deflection monitoring of bridge beam structures (including box girders and the top deck) is a crucial factor in assessing bridge safety performance. It primarily detects the degree of bending deformation in the beam structure, specifically the displacement of a point in the structure perpendicular to its original position. Current bridge deflection monitoring methods primarily rely on video surveillance to determine the degree of vertical deformation at monitoring points, but this approach offers limited accuracy. Therefore, existing technologies based on laser imaging and photoelectric imaging utilize laser projection to calculate the deflection and displacement of the target, driven by movement or deformation. This is done by using the relative displacement of the projected light spot to improve both accuracy and detection speed.

[0004] In the above detection scheme, a fixed structure is mainly set up at the bridge pier or on the ground, the laser is set in the fixed structure, and a corresponding target structure is set on the beam. Then, a light spot recognition device (a visual recognition camera or directly using a CMOS image sensor) is placed in the target. The light beam of the laser sensor is obtained through the target, and the position of the light spot projection in the light spot recognition device is determined. When the beam is deformed, the relative deviation displacement of the light spot projection can be detected, and the left and right and up and down deformation of the beam can be synchronously judged.

[0005] In the above scheme, due to the limited power of the laser, the actual effective laser detection range is restricted. Therefore, at a larger detection distance, for example, especially during long-distance use, the laser beam is easily affected by environmental factors, such as dust, water vapor or other substances in the air, causing attenuation or scattering of the laser signal, affecting the measurement accuracy and other problems. Therefore, in the case of a bridge with a single beam span that is too large (i.e., a large span with a large distance between the two piers), as the distance between the target and the fixed structure becomes farther and farther, the accuracy of the laser signal transmission will eventually decrease, which is not conducive to the accurate monitoring of the bridge structure.

[0006] Therefore, in the prior art, by integrating the laser and the light spot recognition device into one monitoring device and setting the two back to back, the monitoring device has both laser emission and laser recognition functions, and the monitoring device is distributed on the bridge in sequence according to the corresponding detection points.

[0007] By adopting the above method, by using multiple groups of lasers, the problems caused by the long laser beam length can be avoided, ensuring that the laser beam energy received by each spot recognition device can be accurately identified and judged. At the same time, multiple points on the large-span beam can also be detected, thereby effectively performing high-precision monitoring.

[0008] Among them, in order to protect the light spot recognition equipment and laser, a protective structure is needed to effectively seal the equipment to prevent external dust and water vapor from damaging or affecting the equipment, especially to prevent the dust layer from blocking and covering the sensor in the light spot recognition equipment, thereby ensuring the accurate and safe use of the equipment. At the same time, the protective equipment is provided with a light-transmitting structure for allowing the laser to pass through, thereby achieving comprehensive protection.

[0009] Since the laser generates heat during actual use, the heat generated by the laser will not have an impact on monitoring situations with short intervals and single use times. However, when long-term cyclic detection is required, or the single detection time is long, the use of the laser will cause the overall temperature inside the protective structure to rise, which in turn leads to a large temperature difference between the inside and outside of the equipment, and then to uneven air density distribution. In severe cases, it will cause the laser beam to produce a certain degree of refraction, which will affect the recognition accuracy of the laser beam on the spot recognition equipment, which is not conducive to the collection of more accurate monitoring data. Summary of the Invention

[0010] The present invention provides a large-span bridge deck deformation monitoring device and monitoring method, which aims to solve the problem that when existing bridge monitoring equipment is used for a long time, the use of the laser will cause the overall temperature inside the protective structure to rise, which in turn leads to a large temperature difference between the inside and outside of the equipment, and thus leads to uneven air density distribution. In severe cases, it will cause the laser beam to produce a certain degree of refraction, thereby affecting the recognition accuracy of the laser beam on the light spot recognition equipment, which is not conducive to the collection of more accurate monitoring data.

[0011] To achieve the above-mentioned object, the present invention provides the following technical solution: a long-span bridge deck deformation monitoring device, comprising a mounting device, a laser, and a light spot recognition device, wherein the laser and the light spot recognition device are mounted on the mounting device in back-to-back relation;

[0012] The monitoring device also includes a protective cover, in which the laser and the light spot recognition device are both located. The protective cover is provided with light-transmitting windows at positions corresponding to the laser and the light spot recognition device, and protective lenses are installed in the light-transmitting windows.

[0013] Multiple sets of heat dissipation guide tubes are fixedly installed inside the protective cover, a heat dissipation air pump is also provided inside the protective cover, a blow hood and an air suction hood are provided on the protective cover, the bottom end of the heat dissipation guide tube is connected to the air outlet of the heat dissipation air pump, the top end of the heat dissipation guide tube is connected to the blow hood, and the air suction hood is connected to the exhaust port of the heat dissipation guide tube. When the heat dissipation air pump is working, the blow hood forms an airflow from top to bottom on the surface of the protective lens.

[0014] In a preferred embodiment, the mounting device includes a fixed pile and a mounting plate, a fixed frame is fixedly mounted on the fixed pile, the laser and the light spot recognition device are both mounted on the fixed frame, and an attitude adjuster is installed between the laser and the fixed frame and between the light spot recognition device and the fixed frame. The attitude adjuster consists of a lifting adjuster and a pitch adjuster. The attitude adjuster is used to adjust the height and angle of the laser and the light spot recognition device.

[0015] In a preferred embodiment, a shielding cover is provided at a position corresponding to the light-transmitting window on the outside of the protective cover, and a slit guide is provided on the outside of the protective lens. The slit guide is slidably installed in the shielding cover, and the slit guide is slidably arranged in a direction parallel to the protective lens. A wind guide plate is provided on the side of the slit guide corresponding to the protective lens, and the wind guide plate is arranged corresponding to the air outlet of the blowing cover. The bottom of the wind guide plate is inclined toward the side close to the protective lens, and a gap is provided between the bottom of the wind guide plate and the protective lens.

[0016] In a preferred embodiment, a slide groove structure is provided on both sides of the shielding cover, and the end of the slit guide passes through the slide groove structure and slides with the slide groove structure. A pull-back reel is installed on the top of the outer side of the shielding cover for rotation, and a pull-back rope is installed on the pull-back reel. The pull-back rope is fixedly connected to the part of the slit guide passing through the slide groove structure. A torsion elastic part is provided between the pull-back reel and the shielding cover, and a heater is fixedly installed at the bottom end of the air guide plate.

[0017] In a preferred embodiment, the bottom of the protective cover is directly fixedly connected to the mounting plate, the heat dissipation air pump is fixedly mounted on the mounting plate, the top of the protective cover is fixedly socketed with the fixing pile, and a shock-absorbing pad structure is provided between the protective cover and the fixing pile and between the bottom of the protective cover and the mounting plate.

[0018] In a preferred embodiment, the upper and lower ends of the heat dissipation guide tube are fixedly connected to the side walls of the protective cover through a fixing plate. The heat dissipation guide tube adopts an elastic pipe structure. A counterweight structure is fixedly installed in the middle of the heat dissipation guide tube. The counterweight structure is a plurality of metal disc structures arranged in sequence in the upper and lower parts, so that the heat dissipation guide tube and the counterweight structure form a tuned mass damper.

[0019] In a preferred embodiment, an extension frame is fixedly mounted on the fixing frame, the extension frame extends toward the light-transmitting window of the protective cover, the protective lens is fixedly mounted on the extension frame, a flexible cover is arranged around the protective lens, and the flexible cover is fixedly connected to the inner wall of the protective cover.

[0020] In a preferred embodiment, a movable lens is slidingly fitted on the outer side of the protective lens, the flexible cover is fixedly connected to the edge of the movable lens, a protruding fixing seat is fixedly installed at the position of the inside of the protective cover corresponding to the flexible cover, the protruding fixing seat extends into the inner cavity of the protective cover, the flexible cover is fixedly installed on the protruding fixing seat, and the protruding fixing seat supports the flexible cover to form an inward stretch, thereby causing the flexible cover to form an elastic pulling force on the edge of the movable lens.

[0021] In a preferred embodiment, the movable lens is an elastic light-transmitting structure, and the protective lens is provided with a vent hole that passes through the protective lens and communicates with the area between the movable lens and the flexible cover. The vent hole is provided with a connecting tube that is connected to the suction pump structure.

[0022] A method for monitoring deformation of a bridge deck of a long-span bridge comprises the following steps:

[0023] Step 1: Install the devices. Fix each set of monitoring devices to the corresponding position on the beam according to the installation point. One set of monitoring devices is fixed on the bridge pier. The laser of one set of monitoring devices corresponds to the spot recognition device of the other set.

[0024] Step 2: Record the initial point position, turn on each set of monitoring devices, and make the laser beam of the laser in the previous set of detection equipment shoot towards the light spot recognition device in the next set of monitoring devices, and let the light spot recognition device identify the projected light spot position of the laser beam;

[0025] Step 3: Continuous detection, real-time recording of the detection data of each group of monitoring devices, using the detection point of the monitoring device at the bridge pier as the benchmark, detecting the detection displacement value of each monitoring device, and calculating the actual displacement value of each detection point in a superimposed manner.

[0026] The beneficial effects of the present invention are as follows: the present invention can judge the overall deformation of the bridge by judging the actual displacement of each detection point. When facing a large-span bridge, more accurate monitoring data can be obtained. At the same time, it also solves the problem of insufficient laser power and difficulty in adapting to large-distance monitoring scenarios. At the same time, with the help of a heat dissipation air pump, a circulating airflow is formed in the heat dissipation guide pipe to form a temperature exchange with the inner cavity of the protective cover, thereby reducing the air temperature difference inside and outside the protective cover, and reducing the temperature gradient of the air temperature inside and outside the protective lens, that is, avoiding the refraction problem caused by the large difference in air temperature inside and outside the protective lens, further improving the accuracy of the monitoring device, and the airflow blown out by the blow hood flows through the protective lens, which can reduce the adhesion of objects such as dust, rain and snow, reduce the influence of external debris on detection, and improve the safety and accuracy of the monitoring device. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the main structure of the monitoring device of the present invention.

[0028] Figure 2 Schematic diagram of the overall structure of the monitoring device of the present invention.

[0029] Figure 3 Schematic diagram of the internal structure of the protective cover of the present invention.

[0030] Figure 4 This is a schematic diagram of the monitoring device of the present invention when it is installed above the bridge deck.

[0031] Figure 5 It is a schematic diagram of the detection status between two adjacent groups of monitoring devices of the present invention.

[0032] Figure 6 This is a schematic diagram of the present invention using a visual recognition camera as a light spot recognition device.

[0033] Figure 7 Schematic diagram of the airflow state formed outside the protective lens of the present invention.

[0034] Figure 8 This is a schematic diagram of the present invention after a slit guide is provided outside the protective lens.

[0035] Figure 9 Schematic diagram of the pull-back scheme of the slit guide of the present invention.

[0036] Figure 10 This is a structural diagram of the present invention when the heat dissipation guide tube is improved into a damper.

[0037] Figure 11 This is a schematic diagram of an improved solution for the connection between the protective lens and the protective cover after the heat dissipation guide tube is improved in the present invention.

[0038] Figure 12For the present invention Figure 11 A magnified view of the structure of part A.

[0039] Figure 13 This is a schematic diagram of a further improved solution for the connection between the protective lens and the protective cover according to the present invention.

[0040] Figure 14 For the present invention Figure 13 Enlarged view of the B structure.

[0041] Figure 15 Flow chart of the monitoring method of the present invention.

[0042] The accompanying drawings are marked as follows: 1. Installation device; 11. Fixed pile; 12. Mounting plate; 13. Fixed frame; 14. Extension frame; 2. Laser; 3. Spot recognition equipment; 31. Visual recognition camera; 32. Laser beam receiving plate; 4. Attitude adjuster; 41. Lift adjuster; 42. Pitch adjuster; 5. Protective cover; 51. Shielding cover; 52. Blowing cover; 53. Suction cover; 6. Protective lens; 61. Flexible cover; 62. Movable lens; 63. Protruding fixing seat; 64. Vent; 7. Heat dissipation guide pipe; 71. Heat dissipation air pump; 72. Fixed plate; 73. Counterweight structure; 8. Slit guide; 81. Wind guide plate; 82. Heater; 83. Retracting reel. DETAILED DESCRIPTION

[0043] The present application is described in further detail below in conjunction with the accompanying drawings. It is necessary to point out that the following specific implementation methods are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Technicians in this field can make some non-essential improvements and adjustments to the present application based on the above application content.

[0044] Refer to the instruction manual Figures 1 to 14, a long-span bridge deck deformation monitoring device, including an installation device 1, a laser 2 and a light spot recognition device 3, wherein the installation device 1 includes a fixed pile 11 and a mounting plate 12. In actual use, the mounting plate 12 is fixed to the corresponding structure on the bridge by embedded bolts or other fixing structures. The laser 2 and the light spot recognition device 3 are installed on the fixed pile 11 back to back, wherein a fixing frame 13 is fixedly installed on the fixed pile 11, and the laser 2 and the light spot recognition device 3 are both installed on the fixing frame 13, and an attitude adjuster 4 is installed between the laser 2 and the fixing frame 13 and between the light spot recognition device 3 and the fixing frame 13. The attitude adjuster 4 is used to adjust the height and angle of the laser 2 and the light spot recognition device 3. Specifically, the attitude adjuster 4 is composed of a lifting adjuster 41 and a pitch adjuster 42. For example, the lifting adjuster 41 is a vertical sliding guide structure, and the pitch adjuster 42 is a rotating structure. It can be manually adjusted and fixed with a buckle or a set screw, or it can be directly automatically adjusted by a driving device such as a linear drive or a rotary drive.

[0045] The monitoring device also includes a protective cover 5, which is fixedly mounted on the outside of the mounting device 1. The laser 2 and the light spot recognition device 3 are both located inside the protective cover 5, thereby forming a closed protective space with the help of the protective cover 5. The protective cover 5 is provided with light-transmitting windows at positions corresponding to the laser 2 and the light spot recognition device 3. A protective lens 6 is installed in the light-transmitting window, and a shielding cover 51 is provided outside the light-transmitting window for shielding and protecting the protective lens 6.

[0046] In actual use, multiple groups of monitoring devices are fixedly installed at corresponding monitoring positions on the bridge deck through the mounting plates 12, wherein at least one group of monitoring devices is fixedly installed at the bridge piers or other fixed areas known not to be deformed, and the specific number of monitoring devices is determined according to the actual length of the beam structure to be monitored, and each monitoring device is set in a fixed direction, that is, in two adjacent groups of monitoring devices, the laser 2 of one group of monitoring devices corresponds to the light spot recognition device 3 of the other group of monitoring devices, and the monitoring devices can also be installed at the bridge deck, the side of the bridge or the bottom of the bridge according to actual conditions. When installed at the bottom of the bridge, the monitoring device can be protected to a certain extent by the help of the bridge body, but it is not conducive to the maintenance and installation of the device. Therefore, refer to the appendix of the instruction manual. Figure 4 In this embodiment, the monitoring device is preferably installed above the beam, that is, on the bridge deck. While monitoring the beam, the bridge deck can also be monitored preferentially.

[0047] In the above solution, the laser 2 can be an ordinary laser device, and the spot recognition device 3 can directly use a CMOS image sensor. After the laser beam is irradiated on the CMOS image sensor, the irradiation position of the laser beam can be directly identified. This solution is small in size and low in power consumption. However, in order to avoid excessive laser beam energy, a certain light-shielding lens needs to be set (for example, the protective lens 6 can be directly set as a filter lens). In addition, the spot recognition device 3 can also use a visual recognition system, for example, refer to the attached manual. Figure 6 The light spot recognition device 3 is composed of a visual recognition camera 31 and a laser beam receiving plate 32. The laser beam receiving plate 32 is a filter light curtain (the filter light curtain uses a square colored organic glass with the deflection measurement range as the side length). The laser is irradiated on the laser beam receiving plate 32 to form a light spot. The visual recognition camera 31 uses the visual recognition system to identify the specific position of the light plate behind the laser beam receiving plate 32. However, whether the CMOS image sensor or the visual recognition camera 31 is directly used, the principle is to visually identify the actual projection position of the laser beam and obtain the corresponding position parameters. When the detection point is displaced, the actual projection position of the laser beam changes, and then by identifying the change, the actual displacement change of the detection point can be identified.

[0048] During actual monitoring, the laser 2 in each group of monitoring devices is controlled to turn on and emit a laser beam. The laser beam is irradiated to the light spot recognition device 3 in the next group of monitoring devices, and the light spot recognition device 3 identifies the position of the light spot. Since the actual position of the laser 2 set at the bridge pier or other fixed position is relatively fixed, the detection point is regarded as the base point. When the beam structure deforms, the monitoring device at the corresponding detection point will undergo relative displacement. Therefore, the position of the light spot of the laser beam emitted by the previous group of monitoring devices irradiating the light spot recognition device 3 of the monitoring device in the group will also undergo a certain displacement, and the actual displacement of the detection point can be determined. Since each detection point shifts, the laser 2 at the detection point will also shift along with the light spot recognition device 3. Therefore, the actual displacement of the next group of monitoring devices needs to be superimposed on the displacement of the previous group of monitoring devices. Then, by determining the actual displacement of each detection point, the overall deformation of the bridge can be determined. When facing long-span bridges, more accurate monitoring data can be obtained. At the same time, it also solves the problem of insufficient laser power and difficulty in adapting to long-distance monitoring scenarios.

[0049] It should be noted that the above-mentioned coordination of the laser 2 and the light spot recognition device 3, as well as the specific recognition and judgment of the light spot by the light spot recognition device 3 and the related data processing, are all mature existing technologies. Therefore, this embodiment will not be explained in detail without changing its actual detection and deformation judgment principles. Each monitoring device can choose the setting and monitoring mode according to cost requirements. For example, in the case of sufficient cost, each monitoring device can be directly fixed on the bridge for a long time and only requires regular maintenance. For scenarios with limited costs, a reserved installation port can be set at the corresponding position on the bridge, and the bridge can be monitored by regular inspection. When inspection is required, the monitoring device can be installed at the corresponding position, so that the monitoring device can be freely configured and can adapt to multiple bridges.

[0050] In the above embodiment, if fixed long-term monitoring is adopted and the monitoring device is set above the bridge deck, due to the complexity of the external environment, it is necessary to provide more effective protection for the monitoring device. Figure 3 A plurality of heat dissipation guide tubes 7 are fixedly installed inside the protective cover 5. The heat dissipation guide tubes 7 are heat-conducting structures, such as metal tubes. A heat dissipation air pump 71 is also provided inside the protective cover 5. A blowing hood 52 is provided at a position above the protective lens 6 on the protective cover 5. A suction hood 53 is provided at an area below the protective lens 6 on the protective cover 5. The air outlet of the blowing hood 52 is arranged parallel to the protective lens 6. The bottom end of the heat dissipation guide tube 7 is connected to the air outlet of the heat dissipation air pump 71 through a multi-head pipe, the top end of the heat dissipation guide tube 7 is connected to the blowing hood 52 through a multi-head pipe, and the suction hood 53 is connected to the exhaust port of the heat dissipation guide tube 7 through a pipeline.

[0051] By adopting the above scheme, with the help of the heat dissipation air pump 71, a circulating airflow is formed in the heat dissipation guide pipe 7, and then, under the premise of ensuring the relative sealing of the protective cover 5 and ensuring that external water, dust layer and other substances do not enter the interior of the protective cover 5, a temperature exchange is formed in the inner cavity of the protective cover 5, thereby reducing the internal temperature of the protective cover 5, especially the air after absorbing heat in the protective cover 5 is blown downward from the blowing hood 52 and flows through the surface of the protective lens 6. At this time, the air temperature inside the protective lens 6 is appropriately cooled, and the airflow blown out by the heat dissipation guide pipe 7 is heated to a certain extent, but is still lower than the temperature of the air inside the protective lens 6. Therefore, the air blown to the surface of the protective lens 6 by the blowing hood 52 can reduce the temperature difference gradient of the air temperature inside and outside the protective lens 6, that is, avoid the refraction problem caused by the excessive difference in air temperature between the inside and outside of the protective lens 6, and further improve the accuracy of the monitoring device.

[0052] At the same time, the circulation of the heat dissipation air pump 71 can also prevent the temperature inside the protective cover 5 from being too high, which may cause the temperature of the laser 2 or the light spot recognition device 3 to be too high and affect the operation, and also form a certain protection mechanism for the laser 2 and the light spot recognition device 3. At the same time, the airflow blown out by the blowing hood 52 flows through the protective lens 6, and the suction hood 53 forms an exhaust airflow in the area below the protective lens 6, which comprehensively forms an airflow from top to bottom on the surface of the protective lens 6, and the exhaust of the suction hood 53 can increase the airflow intensity on the surface of the protective lens 6. Due to the existence of the airflow, dust, rain, snow and other objects are not easy to stay on the protective lens 6, thereby keeping the protective lens 6 relatively clean. In winter, it can also prevent the surface of the protective lens 6 from fogging or frost and ice, thereby improving the safety and accuracy of the monitoring device.

[0053] Furthermore, in order to ensure the heat exchange effect of the heat dissipation guide tube 7, it is necessary to ensure that the air hood 52 has sufficient air output. Therefore, the actual air flow intensity blown out by the air hood 52 is limited. For this purpose, this embodiment also provides the following technical solutions. For details, refer to the attached manual. Figure 8 and Figure 9 The slit guide 8 is provided on the outer side of the protective lens 6, and the slit guide 8 is slidably installed in the shielding cover 51, and the slit guide 8 is slidably arranged in the direction parallel to the protective lens 6. The slit guide 8 is provided on the side of the protective lens 6 corresponding to the slit guide 8, and the wind guide plate 81 is provided corresponding to the air outlet of the blowing cover 52. The bottom of the wind guide plate 81 is inclined toward the side close to the protective lens 6, and a gap, i.e., a slit, is provided between the bottom of the wind guide plate 81 and the protective lens 6. Therefore, in actual use, the airflow blown out of the blowing cover 52 will enter the inner space of the wind guide plate 81. Due to the inclined setting of the wind guide plate 81, the airflow is finally blown out from the gap between the wind guide plate 81 and the protective lens 6 through the guidance of the wind guide plate 81, and then with the help of the slit between the wind guide plate 81 and the protective lens 6, the airflow strength is enhanced, so that the attachments on the protective lens 6 can be blown away more forcefully.

[0054] Among them, since the air guide plate 81 is also pushed by the air flow while guiding the air flow, before the monitoring device is turned on, the slit guide 8 can be placed at the top near the blowing hood 52. When the device is turned on, the cooling air pump 71 is gradually started slowly, and the air flow intensity blown out by the blowing hood 52 begins to slowly increase, and then gradually blows the slit guide 8 downward, thereby strengthening the air flow intensity on the surface of the protective lens 6 with the help of the air guide plate 81, and can also automatically drive the slit guide 8 to move downward gradually, so that the strong air flow at the slit of the air guide plate 81 can gradually pass through all areas of the protective lens 6. In order to facilitate the resetting of the slit guide 8, the present invention also provides the following retraction scheme for the slit guide 8. Specifically, a slide groove structure is provided on both sides of the shielding cover 51, and the end of the slit guide 8 passes through the slide groove structure and slides with the slide groove structure. The rotation of the top of the outer side of the shielding cover 51 is installed with a retraction reel 83, and a retraction rope is installed on the retraction reel 83. The retraction rope is passed through the slit guide 8. The part of the sliding groove structure is fixedly connected, wherein the pull-back reel 83 has a rotational power for winding the pull-back rope and lifting the slit guide 8 and pulling it back. For example, a rotation drive structure can be set to automatically rotate the pull-back reel 83, or the pull-back reel 83 can be manually controlled to rotate. In this embodiment, the pull-back reel 83 preferably has a torsion elastic member (torsion spring). However, the torsion elastic member provides a torsion force on the pull-back reel 83, and the pulling force on the slit guide 8 is less than that on the blowing hood 5. The thrust of the blown airflow on the air guide plate 81 is such that before each startup (or before the cooling air pump 71 needs to be turned on), the slit guide 8 is automatically located at the highest position under the retraction of the reel 83. When the machine is started (or when the cooling air pump 71 needs to be turned on), the airflow blown out by the blow hood 52 can gradually push the air guide plate 81 downward. In this process, the elastic torque of the retracting reel 83 can also form a movement damping for the downward movement of the slit guide 8, thereby preventing the slit guide 8 from being blown down quickly all at once.

[0055] It should be noted that the above is only a simple driving solution for the slit guide 8 provided in this embodiment. If necessary, an automatic driving and moving solution can also be set up. For example, a driving device such as a linear motor is set up to drive the slit guide 8 to move automatically, and the driving time of the slit guide 8 is automatically selected according to demand. Since this embodiment mainly relies on the guidance of the wind guide plate 81 to enhance the airflow intensity on the surface of the protective lens 6 to clean the protective lens 6, the slit guide 8 does not contact the protective lens 6 throughout the process, so it will not cause scratches or damage to the slit guide 8.

[0056] Furthermore, in some cold environments, such as winter, ice easily forms on the surface of objects, especially on the surface of the protective lens 6. Although the airflow blown out by the soft blowing hood 52 reduces the adhesion of debris and reduces fogging and icing on the surface of the protective lens 6, for monitoring devices that need to be turned on and tested regularly, ice easily forms on the surface of the protective lens 6 during the off period. At this time, it is difficult to directly remove the ice by relying solely on the airflow of the blowing hood 52 when the device is turned on. Therefore, a heater 82 (such as a resistance heater) can be fixedly installed at the bottom end of the air guide plate 81. Before the laser 2 and the spot recognition device 3 are officially turned on, the cooling air pump 71 is turned on first, and the slit is heated with the help of the heater 82. Since the heater 82 only heats locally, and while heating, it is blown by the airflow, the corresponding part of the protective lens 6 can be cleaned and de-iced. As the slit guide 8 gradually moves downward, all the cleaning work can be completed. Since the area of ​​the protective lens 6 is no longer heated after the blowing hood 52 moves downward, grouting can be used to cool it down. Therefore, the overall temperature of the protective lens 6 will not increase, and the normal passage of the laser beam will not be affected.

[0057] In the above embodiment, since the bridge is usually higher than the ground, especially in the case of a long-span bridge, the height of the bridge deck from the ground increases significantly. As the height increases, the wind speed will generally increase, because the lower atmosphere is more affected by ground friction, while the upper atmosphere is less affected by this resistance. Since the monitoring device is mainly installed on the beam, the monitoring device will often be affected by wind (especially crosswinds that are prone to occur on the bridge deck), causing vibrations. In particular, the shielding cover 51 is mainly used to cover and protect devices such as the laser 2 and the light spot recognition device 3. Therefore, it itself is mainly a thin-walled structure. When affected by external wind, the shielding cover 5 is prone to vibration, which in turn easily causes the monitoring device as a whole to vibrate greatly. The displacement caused by this vibration will affect the displacement detection accuracy of the laser 2 and the light spot recognition device 3 itself for the detection point. Therefore, in order to reduce the vibration impact on the laser 2 and the light spot recognition device 3, this embodiment also provides the following solution. For details, please refer to the attached manual. Figures 10 to 14 First, a shock-absorbing structure is provided between the protective cover 5 and the mounting device 1. For example, the bottom of the protective cover 5 is directly fixedly connected to the mounting plate 12, and the heat dissipation air pump 71 is also fixedly mounted on the mounting plate 12, thereby forming a direct connection between the slit guide 8 and the heat dissipation air pump 71 and the bridge, reducing its vibration impact on the fixed pile 11, and the top of the protective cover 5 can also be fixedly connected to the fixed pile 11, but a shock-absorbing pad structure (rubber pad) needs to be provided at the connection part. At the same time, a shock-absorbing pad structure (rubber pad) is also provided between the bottom of the protective cover 5 and the mounting plate 12. Furthermore, since multiple groups of heat dissipation guide tubes 7 are provided in the inner wall of the protective cover 5, it can also be improved with the help of the heat dissipation guide tubes 7 to improve the vibration reduction effect of the protective cover 5. Refer to the attached manual. Figure 10 The upper and lower ends of the heat dissipation guide tube 7 are fixedly connected to the side walls of the protective cover 5 through a fixing plate 72, so that the heat dissipation guide tube 7 forms a suspended area arranged above and below, wherein the heat dissipation guide tube 7 is made of elastic pipe fittings, for example, the heat dissipation guide tube 7 uses a thin-walled metal tube (aluminum alloy or stainless steel thin-walled tube, etc.), and a counterweight structure 73 is fixedly installed in the middle of the heat dissipation guide tube 7. The counterweight structure 73 is a plurality of metal disc structures arranged in sequence above and below, and then with the help of the counterweight of the counterweight structure 73, the heat dissipation guide tube 7 and the counterweight structure 73 form a tuned mass damper. When the protective cover 5 is vibrated by external excitation, the counterweight structure 73 will elastically move in the opposite direction to offset part of the vibration energy, thereby reducing the actual vibration intensity of the protective cover 5. In addition, the counterweight structure 73 uses a metal disc structure, which can directly increase the contact area with the air inside the protective cover 5, improve the efficiency of heat conduction to the air flow inside the heat dissipation guide tube 7, and thus improve the heat exchange effect.

[0058] Furthermore, since the laser 2 and the light spot recognition device 3 are mainly installed on the fixed pile 11, and the fixed pile 11 is mainly directly connected to the bridge structure, it is possible to effectively avoid the laser 2 and the light spot recognition device 3 from moving and displacing due to factors other than the deformation of the beam body, thereby improving the monitoring and measurement accuracy. The protective cover 5 itself can effectively reduce the vibration intensity caused by external factors, but it will still produce a certain amount of vibration. Therefore, in order to avoid the protective lens 6 of the external vibration belt from generating irregular vibration and forming a tilt error, which will cause additional refraction error to the laser beam, the protective lens 6 should not be directly fixedly connected to the protective cover 5, and the connection method between the two needs to be improved. For example, refer to the attached manual. Figure 11 and Figure 12 An extension frame 14 is fixedly mounted on the fixed frame 13, and the extension frame 14 is extended toward the light-transmitting window of the protective cover 5. The protective lens 6 is fixedly mounted on the extension frame 14. A flexible cover 61 is arranged around the protective lens 6. The flexible cover 61 is a flexible structure, such as a rubber structure. The flexible cover 61 is fixedly connected to the inner wall of the protective cover 5. Therefore, since the protective lens 6 is directly connected to the fixed frame 13 and is relatively fixed to the laser 2 and the light spot recognition device 3, when the protective cover 5 vibrates, the vibration is absorbed by the flexible cover 61 and will not be transmitted to the protective lens 6, thereby effectively avoiding the vibration of the protective lens 6 and affecting the monitoring accuracy.

[0059] Furthermore, this embodiment also provides a solution for further improving the connection between the protective lens and the protective cover. Figure 13 and Figure 14The outer side of the protective lens 6 is slidably fitted with a movable lens 62, and the flexible cover 61 is fixedly connected to the edge of the movable lens 62. A protruding fixing seat 63 is fixedly installed at the position of the flexible cover 61 inside the protective cover 5, and the protruding fixing seat 63 extends toward the inner cavity of the protective cover 5. The flexible cover 61 is fixedly installed on the protruding fixing seat 63, and the protruding fixing seat 63 supports the flexible cover 61 to form an inward stretch, thereby causing the flexible cover 61 to form an elastic tension on the edge of the movable lens 62. In actual use, if the protective cover 5 vibrates and produces relative displacement with the protective lens 6, the flexible cover 61 will drive the movable lens 62 to move relative to the protective lens 6, but will not cause the protective lens 6 to vibrate, and under the action of the elastic tension of the flexible cover 61, the movable lens 62 can be kept in close contact with the protective lens 6. Therefore, when the protective cover 5 vibrates, the micro-vibration of the movable lens 62 can be retained to further prevent the adhesion of debris.

[0060] In addition, the movable lens 62 itself can also adopt an elastic light-transmitting structure, such as a plastic sheet, and the protective lens 6 is provided with a vent 64 that penetrates the protective lens 6 and is connected to the area between the movable lens 62 and the flexible cover 61. The vent 64 is provided with a connecting pipe, which is connected to the suction pump structure. In an area with long-term cold, if ice appears on the surface of the protective lens 6, air can be inflated between the movable lens 62 and the flexible cover 61 through the vent 64, thereby causing the movable lens 62 to bulge relatively (that is, to bend and deform), thereby helping to fall off the ice. After de-icing is completed, air is extracted from the vent 64 to make the movable lens 62 fit the protective lens 6 again.

[0061] It should be noted that the solution provided in this embodiment is mainly based on the principles of laser imaging and photoelectric imaging for basic detection. If necessary, other monitoring structures or detection sensors can be added to enrich the detection data and reduce detection errors. For example, an inclination sensor can be set on the laser 2 and the light spot recognition device 3 to detect the angle change of the laser 2 and the light spot recognition device 3 when the bridge is deformed, so as to calculate the error value caused by the angle change and compensate for it.

[0062] Refer to the instruction manual Figure 5 Based on the above monitoring device, the present invention also provides a method for monitoring deformation of a bridge deck of a long-span bridge, comprising the following steps:

[0063] Step 1: Install the monitoring devices. Install each set of monitoring devices at the corresponding position on the beam according to the installation point. One set of monitoring devices is fixedly installed at a relatively fixed bridge pier. The laser 2 of one set of monitoring devices corresponds to the light spot recognition device 3 of the other set.

[0064] Step 2: Record the initial point position, turn on each set of monitoring devices, and direct the laser beam of the laser 2 in the previous set of detection devices to the light spot recognition device 3 in the next set of monitoring devices. The light spot recognition device 3 recognizes the projected light spot of the laser beam, processes it with the image processor, records the light spot position information, and uses the point position of the monitoring device at the bridge pier as the zero point to record the detection values ​​of the remaining monitoring device points;

[0065] Step 3: Continuous detection, real-time recording of the detection data of each group of monitoring devices, taking the detection point of the monitoring device at the bridge pier as the benchmark, detecting the detection displacement value of each monitoring device, and calculating the actual displacement value of each detection point in a superimposed manner (that is, the actual displacement value of the monitoring point where the next monitoring device is located is the actual displacement value of the detection point where the previous monitoring device is located plus the detection value of the next monitoring device).

[0066] It should be noted that in the above step 3, the detection point of the monitoring device at the bridge pier is used as the reference point to determine the relative displacement of the monitoring device at the second, third, fourth, and nth detection points in sequence. The displacement of the n+1th detection point can be based on the nth detection point. The detection results of the detection structure between the n+1th and nth detection points are superimposed to obtain the actual displacement value of the n+1th detection point. The specific calculation formula is as follows:

[0067] Right now:

[0068] Where:

[0069] D n : The actual displacement of the nth detection point (relative to the reference point);

[0070] Δ n : The relative displacement between the nth and n-1th detection points;

[0071] The above-described embodiments merely illustrate several implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that variations and improvements are possible without departing from the scope of the present invention, and these variations and improvements are fully within the scope of protection of the present invention.

Claims

1. A long-span bridge deck deformation monitoring device, characterized by: It comprises a mounting device (1), a laser (2) and a light spot recognition device (3), wherein the laser (2) and the light spot recognition device (3) are mounted on the mounting device (1) in opposite directions; The monitoring device further comprises a protective cover (5), wherein the laser (2) and the light spot recognition device (3) are both located within the protective cover (5), and the protective cover (5) is provided with light-transmitting windows at positions corresponding to the laser (2) and the light spot recognition device (3), wherein a protective lens (6) is installed within the light-transmitting window; A plurality of heat dissipation guide tubes (7) are fixedly installed inside the protective cover (5), a heat dissipation air pump (71) is also provided inside the protective cover (5), a blowing cover (52) and an air suction cover (53) are provided on the protective cover (5), the bottom end of the heat dissipation guide tube (7) is connected to the air outlet of the heat dissipation air pump (71), the top end of the heat dissipation guide tube (7) is connected to the blowing cover (52), and the air suction cover (53) is connected to the air extraction port of the heat dissipation guide tube (7), and when the heat dissipation air pump (71) is working, the blowing cover (52) forms an airflow from top to bottom on the surface of the protective lens (6).

2. The long-span bridge deck deformation monitoring device according to claim 1, characterized in that: The mounting device (1) comprises a fixing pile (11) and a mounting plate (12), a fixing frame (13) is fixedly mounted on the fixing pile (11), the laser (2) and the light spot recognition device (3) are both mounted on the fixing frame (13), and a posture adjuster (4) is installed between the laser (2) and the fixing frame (13) and between the light spot recognition device (3) and the fixing frame (13), the posture adjuster (4) is composed of a lifting adjuster (41) and a pitch adjuster (42), and the posture adjuster (4) is used to adjust the height and angle of the laser (2) and the light spot recognition device (3).

3. The long-span bridge deck deformation monitoring device according to claim 2, characterized in that: A shielding cover (51) is provided on the outside of the protective cover (5) at a position corresponding to the light-transmitting window, a slit guide (8) is provided on the outside of the protective lens (6), the slit guide (8) is slidably mounted in the shielding cover (51), and the slit guide (8) is slidably arranged in a direction parallel to the protective lens (6), a wind guide plate (81) is provided on a side of the slit guide (8) corresponding to the protective lens (6), the wind guide plate (81) is arranged corresponding to the air outlet of the blowing cover (52), the bottom of the wind guide plate (81) is inclined toward a side close to the protective lens (6), and a gap is provided between the bottom of the wind guide plate (81) and the protective lens (6).

4. The long-span bridge deck deformation monitoring device according to claim 3 is characterized in that: Both sides of the shielding cover (51) are provided with a slide groove structure, and the end of the slit guide (8) passes through the slide groove structure and slides with the slide groove structure. A retraction reel (83) is installed on the top of the outer side of the shielding cover (51) for rotation, and a retraction rope is installed on the retraction reel (83). The retraction rope is fixedly connected to the part of the slit guide (8) passing through the slide groove structure. A torsion elastic member is provided between the retraction reel (83) and the shielding cover (51), and a heater (82) is fixedly installed on the bottom end of the air guide plate (81).

5. The long-span bridge deck deformation monitoring device according to claim 4 is characterized in that: The bottom of the protective cover (5) is directly fixedly connected to the mounting plate (12), the heat dissipation air pump (71) is fixedly mounted on the mounting plate (12), the top of the protective cover (5) is fixedly sleeved with the fixing pile (11), and a shock-absorbing pad structure is provided between the protective cover (5) and the fixing pile (11) and between the bottom of the protective cover (5) and the mounting plate (12).

6. The long-span bridge deck deformation monitoring device according to claim 5, characterized in that: The upper and lower ends of the heat dissipation guide tube (7) are fixedly connected to the side wall of the protective cover (5) through a fixing plate (72). The heat dissipation guide tube (7) is selected to have an elastic pipe structure. A counterweight structure (73) is fixedly installed in the middle of the heat dissipation guide tube (7). The counterweight structure (73) is a structure of multiple metal discs arranged in sequence at intervals in the upper and lower parts, so that the heat dissipation guide tube (7) and the counterweight structure (73) form a tuned mass damper.

7. The long-span bridge deck deformation monitoring device according to claim 6, characterized in that: An extension frame (14) is fixedly mounted on the fixing frame (13), and the extension frame (14) is extended toward the light-transmitting window of the protective cover (5). The protective lens (6) is fixedly mounted on the extension frame (14), and a flexible cover (61) is provided around the protective lens (6), and the flexible cover (61) is fixedly connected to the inner wall of the protective cover (5).

8. The long-span bridge deck deformation monitoring device according to claim 7, characterized in that: The outer side of the protective lens (6) is slidably fitted with a movable lens (62), the flexible cover (61) is fixedly connected to the edge of the movable lens (62), and a protruding fixing seat (63) is fixedly installed at a position corresponding to the flexible cover (61) inside the protective cover (5), the protruding fixing seat (63) extends into the inner cavity of the protective cover (5), the flexible cover (61) is fixedly installed on the protruding fixing seat (63), and the protruding fixing seat (63) supports the flexible cover (61) to form an inward stretch, thereby allowing the flexible cover (61) to form an elastic pulling force on the edge of the movable lens (62).

9. The long-span bridge deck deformation monitoring device according to claim 8, characterized in that: The movable lens (62) is an elastic light-transmitting structure, and the protective lens (6) is provided with a vent hole (64) that penetrates the protective lens (6) and communicates with the area between the movable lens (62) and the flexible cover (61). The vent hole (64) is provided with a connecting pipe that is connected to the suction pump structure.

10. A monitoring method based on the long-span bridge deck deformation monitoring device according to claim 9, characterized in that: The following steps are involved: Step 1: Install the device. Each group of monitoring devices is fixedly installed at a corresponding position on the beam body according to the installation point. One group of monitoring devices is fixedly installed at the bridge pier. The laser (2) of one group of monitoring devices corresponds to the light spot recognition device (3) of the other group. Step 2: Record the initial point position, start each group of monitoring devices, and make the laser beam of the laser (2) in the previous group of detection devices shoot toward the light spot recognition device (3) in the next group of monitoring devices, and let the light spot recognition device (3) recognize the projection light spot position of the laser beam; Step 3: Continuous detection, real-time recording of the detection data of each group of monitoring devices, using the detection point of the monitoring device at the bridge pier as the benchmark, detecting the detection displacement value of each monitoring device, and calculating the actual displacement value of each detection point in a superimposed manner.

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