Bridge hogging moment searching device and method

Abstract

The invention belongs to the technical field of bridge engineering construction, and provides a bridge hogging moment searching device and method. The device comprises a cross beam, walking wheels, a supporting assembly, a vertical sliding vertical plate, an elastic jacking assembly and a guide assembly, the elastic jacking assembly drives the guide assembly to be attached to the bottom of a beam plate in a self-adaptive mode, when the device passes through a tensioning toothed plate, accurate positioning is achieved through downward pressing and rebounding, and the supporting assembly can achieve switching of device moving and positioning locking. The construction method comprises the steps of beam and slab erection, wet joint construction, hogging moment tensioning point searching, prestress tensioning, system conversion and the like, and the device can serve as a tensioning alignment reference after positioning. A worker does not need to enter a high-altitude narrow space for operation, potential safety hazards are reduced, the construction process is simplified, and hogging moment tensioning quality and construction efficiency are improved.

Description

Technical Field

[0001] This invention belongs to the field of bridge engineering construction technology, specifically relating to a device and method for finding negative bending moments in bridges. Background Technology

[0002] Simply supported to continuous beam bridges are currently the most widely used structural form in precast assembled bridge engineering, as shown in the attached figure. Figure 5 and 6 As shown, this method combines the advantages of simple-supported beams (convenient construction, high degree of prefabrication standardization) with continuous beams (superior overall load-bearing performance, smooth driving, and strong structural durability). The construction logic is as follows: First, prefabricated beams are erected in a simply supported state on temporary and permanent supports of the piers. After completing the wet joint reinforcement binding and concrete pouring, the multi-span simply supported beams are converted into a continuous load-bearing structure through the negative moment prestressing tensioning process at the pier top. Finally, the temporary supports are removed to complete the system conversion, achieving uniform load transfer and optimized stress distribution for the entire bridge. The negative moment tensioning toothed plate at the bottom of the beam at the pier top is the core load-bearing node for prestressing tensioning. Its positioning is crucial for ensuring proper prestressing tensioning, avoiding structural load imbalance, and ensuring the quality of the system conversion, directly affecting the overall load-bearing capacity and service life of the bridge.

[0003] Currently, the positioning of bridge negative bending moment tensioning tooth plates mostly relies on traditional methods such as manual exploration and simple tools for positioning, which has the following shortcomings: 1. The negative moment tensioning toothed plate is located below the wet joint at the bottom of the beam and slab. The working space is narrow and the visibility is poor. Traditional manual positioning requires construction workers to bend down or even enter the narrow space at high altitude to touch and explore with their bare hands. This is not only extremely labor-intensive and time-consuming, but also very easy to cause safety accidents such as falls from heights and abrasions. Moreover, there is no feedback mechanism for manual exploration. The position of the toothed plate is judged entirely by the experience of the construction workers. This is very easy to cause positioning deviations and omissions. This directly leads to inaccurate alignment of the subsequent prestressing tensioning, causing quality hazards such as uneven load on the beam and slab and incomplete prestressing tensioning, which affects the durability of the bridge structure.

[0004] 2. Some auxiliary positioning tools can only achieve simple lateral movement and cannot adaptively fit with the bottom curved surface of the beam and slab or the arc transition section of the toothed plate. When passing the position of the tensioned toothed plate, they cannot accurately identify and form obvious positioning feedback, nor can they form obvious positioning marks, which easily leads to missed or incorrect checks.

[0005] 3. After positioning, there is no fixed alignment reference. When the tensioning device is lowered, it still needs to be adjusted for alignment again. During repeated adjustments, the prestressed steel bars and toothed plates are easily bumped, which not only reduces construction efficiency but may also damage the prestressed system. Summary of the Invention

[0006] To address the problems existing in the prior art, a device and method for finding negative bending moments in bridges are proposed.

[0007] The technical solution to the technical problem solved by the present invention is as follows: On the one hand, a bridge negative bending moment finding device is proposed, comprising: a crossbeam spanning between two beams; a traveling wheel is provided at the bottom of the crossbeam, and a support component is provided on the outside of the traveling wheel, the support component being able to lift the crossbeam upward to separate the traveling wheel from the beam; two sets of vertical plates are provided, which are parallel and vertically sliding on the crossbeam; the bottom of the vertical plate passes under the crossbeam and is connected to a guide component, the guide component being able to extend into the bottom of the beam and move along the bottom of the beam; an elastic clamping component is connected to the vertical plate, which can drive the vertical plate to move upward to make the guide component move against the bottom of the beam; when passing the tension tooth plate at the bottom of the beam, it can drive the guide component to move along the arc end of the tension tooth plate and fall back at the vertical end of the tension tooth plate to achieve positioning.

[0008] Preferably, the elastic clamping assembly includes a guide rod fixed on the crossbeam, a crossbeam connected to the top of the vertical plate, a sliding hole on the crossbeam, and the guide rod passing through the sliding hole to guide the crossbeam; a clamping spring is provided on the guide rod, and the two ends of the clamping spring are respectively connected to the bottom of the crossbeam and the crossbeam, and the clamping spring can drive the vertical plate to move upward.

[0009] Preferably, the guide assembly includes a connecting plate connected to the bottom of the vertical plate, the bottom of the connecting plate extending outward to form a locating plate, and the locating plate moving along the bottom of the beam plate under the action of the elastic clamping assembly.

[0010] Preferably, the bottom of the vertical plate is connected to an inclined slide rail, and the top of the corresponding connecting plate is connected to a slider, which can slide within the slide rail; a baffle is connected to the outer end of the slide rail. The middle of the beam is also vertically connected to the top rod, and the bottom of the top rod can slide between the two connecting plates to tighten the connecting plates so that the outer wall of the connecting plates is pressed against the baffle. The bottom of the top rod is connected to the connecting rod with a pull rope. Pulling the top rod upward can drive the connecting rod to move in the opposite direction so that the locating plate can be pulled out from the bottom of the beam.

[0011] Preferably, a limiting plate is connected to the upper part of the top rod, which can be locked onto the crossbeam to restrict the downward movement of the top rod; a fixing rope is connected to the top of the top rod, and a fixing frame is connected to the top of the corresponding guide rod, so that the fixing rope can be tied to the fixing frame to fix the top rod.

[0012] Preferably, the support assembly includes an upper sleeve and a lower sleeve that can slide relative to each other. The upper sleeve is fixed to the bottom of the crossbeam, and the bottom of the lower sleeve is connected to a support, which is supported on the ground. A return spring is connected between the upper sleeve and the lower sleeve. The side of the upper sleeve is rotatably connected to a first support rod, and the bottom of the lower sleeve is rotatably connected to a second support rod. The ends of the first support rod and the second support rod are hinged to form a linkage mechanism. When the first support rod and the second support rod are aligned in a straight line, they are locked, and the first sleeve and the second sleeve slide in opposite directions, allowing the support assembly to extend and support the beam plate.

[0013] Preferably, the bottom of the second support rod is connected to a lower pedal, and stepping on the lower pedal can drive the second support rod to rotate and achieve support; the bottom of the first support rod is connected to an upper push rod, and pushing the upper push rod can disengage the first support rod from the second support rod.

[0014] On the other hand, a bridge construction method is proposed, including the following steps: S1. Beam and slab erection: The bridge is erected symmetrically onto the temporary and permanent supports of the pier using a bridge erecting machine. The temporary supports are higher than the permanent supports, so that the beam and slab are in a simply supported state. After the erection is completed, several beams and slabs are set in parallel between the two cap beams to form a beam body. The joint between two adjacent beam bodies is a wet joint. S2. Binding of wet joint reinforcement; binding the longitudinal and transverse reinforcement of the wet joint; then inserting the tensioning reinforcement between the tensioning tooth plates of the two adjacent beams, and wrapping the prestressed duct outside the tensioning reinforcement at the wet joint. S3. Wet joint concrete pouring: Use micro-expansion concrete of the same strength grade as the beam body for pouring. After the concrete is poured, cover it with geotextile and spray water for curing. S4. Tensioning point location; using the bridge negative bending moment location device according to any one of claims 1-7 to locate the tensioning tooth plate; S5. Negative moment tensioning: After sequentially placing the anchor plate and anchor wedges on the ends of the tensioning steel bars, lower the tensioning device and the locating device below the beam and slab to perform negative moment tensioning; after tensioning is completed, insert the limiting plate into the tensioning steel bars to complete the negative moment tensioning. S6. Grouting of prestressed ducts; Grouting into the prestressed ducts on the tensioning tooth plate; S7. Remove the locating device; press down the vertical plate to compress the top spring, then lift the top rod upward to detach the locating plate from the bottom of the beam, then release the vertical plate to release the locating device; loosen the support assembly and remove the locating device. S8. Binding and casting between adjacent beams and slabs; after binding the reinforcing bars between adjacent beams and slabs, the concrete is cast to form an integrated beam. S9. System Transformation: Using a symmetrical and synchronous dismantling method, temporary supports are dismantled sequentially to ensure that the beam is placed smoothly on the permanent supports, thus completing the transformation from a simply supported system to a continuous system. Preferably, step S4 includes the following steps: S4.1. Device Placement: Place the locating device between the two beams. First, pull up the top rod to move the connecting rod and the locating plate in opposite directions. Lower the locating device so that the traveling wheels can move along the beams. Press down the vertical plate to compress the top spring. After lowering the locating plate to below the beams, release the top rod. The locating plate will slide into the bottom of the beams. Then release the vertical plate. Under the action of the return spring, the locating plate will be pressed against the bottom of the beams. S4.2. Lateral movement search; push the crossbeam along the beam plate from one end of the wet joint to the other; when it passes the arc end of the tensioning tooth plate, the top spring is gradually compressed, the vertical rod gradually moves downward, and when it reaches the vertical end of the tensioning tooth plate, the vertical rod springs back, which is the tensioning point. S4.3 Device support; Activate the support assembly to support the device on the beam plate, so that the traveling wheels are separated from the beam plate, and the device is positioned.

[0015] Preferably, the tensioning device includes a base plate, on which tensioning jacks are slidably connected laterally. Limiting columns are connected to both ends of the base plate to allow the tensioning jacks to slide out. Fixing plates are also connected to both sides of the base plate. A U-shaped positioning plate is connected to one of the fixing plates. The U-shaped positioning plate can be locked onto the connecting rod and move vertically along the connecting rod. Lifting ropes are connected to the two fixing plates. A crane connects to the lifting ropes to lift the device so that the top of the limiting column is at the bottom of the beam plate, thus stabilizing the entire device.

[0016] Compared with existing technologies, the above technical solution has the following advantages or beneficial effects: 1. This invention enables the device to move laterally as a whole through a crossbeam and traveling wheels. With the help of the elastic clamping component and the guide component, it automatically fits against the bottom of the beam for inspection, eliminating the need for construction personnel to enter the narrow space at the bottom of the beam to work, thus avoiding safety accidents such as bumps and falls.

[0017] 2. The present invention continuously provides upward clamping force through the elastic clamping component, so that the guide component always moves in contact with the bottom of the beam plate. When it passes the arc end of the tension tooth plate, it automatically presses down and quickly rebounds when it reaches the vertical end, forming a clear mechanical positioning feedback, thereby identifying the position of the tooth plate and avoiding missed or incorrect checks.

[0018] 3. This invention features a liftable and lockable support component. During movement, the traveling wheels touch the ground for smooth lateral movement. After positioning, the support component quickly lifts up and locks, preventing device displacement. Simultaneously, in conjunction with the top rod, pull rope, and slide rail slider structure, the guide component can be quickly retracted and extended, simplifying installation and dismantling steps, shortening the positioning process time, accelerating the construction speed of wet joints and negative bending moment tensioning, and shortening the bridge construction cycle.

[0019] 4. After positioning, the device can be temporarily fixed as the alignment reference for the tensioning device. With the limiting structure of the dedicated tensioning device, the tensioning equipment can be lowered and aligned without repeated adjustments. This avoids collisions between the prestressed steel bars and the tensioning tooth plate, protects the integrity of the prestressed system, and further improves the efficiency of negative moment tensioning construction. Attached Figure Description

[0020] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0021] Figure 1 This is a schematic diagram of the locating device.

[0022] Figure 2 yes Figure 1 Enlarged view of the support component at point A in the middle.

[0023] Figure 3 This is a cross-sectional view of the supporting components.

[0024] Figure 4 This is a schematic diagram of the locating device's locating status.

[0025] Figure 5 This is a schematic diagram of a simply supported beam that becomes a continuous beam.

[0026] Figure 6 This is a schematic diagram of the bottom of a simply supported beam that has become a continuous beam.

[0027] Figure 7 This is a schematic diagram showing the coordinated state of the tensioning device and the locating device.

[0028] Figure 8 This is the front view during tensioning.

[0029] Explanation of reference numerals in the attached figures: 1. Crossbeam; 101. Handle; 2. Traveling wheel; 3. Support assembly; 31. Upper sleeve; 32. Lower sleeve; 33. Support; 34. First support rod; 35. Second support rod; 36. Lower pedal; 37. Upper push rod; 38. Return spring; 4. Vertical plate; 41. Slide rail; 42. Rope hole; 43. Baffle; 5. Guide assembly; 51. Connecting plate; 52. Slider; 53. Finding plate; 54. Arc plate; 6. Elastic clamping assembly; 61. Guide rod; 611 62. Fixed frame; 63. Tightening spring; 7. Horizontal plate; 8. Top rod; 9. Limiting plate; 10. Fixing rope; 11. Pull rope; 12. Beam plate; 13. Tensioning toothed plate; 14. Arc end; 15. Vertical end; 16. Prestressed duct; 17. Beam body; 18. Wet joint; 18. Tensioning device; 19. Base plate; 10. Tensioning jack; 111. Limiting column; 112. Fixing plate; 113. U-shaped positioning plate; 114. Lifting rope; 115. Crane. Detailed Implementation

[0030] To clearly illustrate the technical features of this solution, the invention will be described in detail below through specific embodiments and in conjunction with the accompanying drawings. The following disclosure provides many different embodiments or examples for implementing different structures of the invention. To simplify the disclosure of the invention, components and arrangements of specific examples are described below. Furthermore, reference numerals and / or letters may be repeated in different examples. This repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. It should be noted that the components illustrated in the drawings are not necessarily drawn to scale. Descriptions of well-known components and processing techniques and processes are omitted to avoid unnecessarily limiting the invention. Terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0031] Please see Figures 1-8 This embodiment addresses the issue that existing simply supported variable continuous beams lack a positioning device for the tensioning tooth plate 81 during negative bending moment tensioning. Therefore, before tensioning, workers need to locate and position the tensioning tooth plate 81 at the bottom of the beam 8 to determine the position for the subsequent lowering of the tensioning equipment. This prevents the need for repositioning the tensioning equipment due to positional deviations after placement, thus affecting the bridge construction progress. To address this, this embodiment proposes a bridge negative bending moment positioning device. The device includes a crossbeam 1 made of high-strength lightweight alloy profile. Its overall length is adapted to the conventional width of the wet joint 10 between two adjacent beam 8 sections, allowing it to stably span the top of the two beam 8 sections, preventing lateral tilting. Its lightweight design facilitates manual or small-scale equipment handling, reducing on-site construction difficulty. Furthermore, handles 101 are provided at both ends of the crossbeam 1, allowing workers at either end to easily push the device.

[0032] Two traveling wheels 2 are installed at the bottom of both ends of the crossbeam 1. The traveling wheels 2 are made of wear-resistant rubber wheels, which are adapted to the rough construction surface of the top of the beam 8. They roll smoothly and will not scratch the precast surface of the beam 8, enabling the entire device to move laterally along the length of the beam 8, replacing the manual bending and probing method. Support components 3 are installed on the outer side of the traveling wheels 2. The support components 3 are initially in a retracted state, so as not to interfere with the rolling of the traveling wheels 2. After positioning, the entire crossbeam 1 can be lifted upwards, so that the traveling wheels 2 are completely separated from the top surface of the beam 8, preventing displacement after positioning and ensuring that the positioning benchmark is fixed.

[0033] The support assembly 3 specifically includes an upper sleeve 31 and a lower sleeve 32 that can slide relative to each other. The top of the upper sleeve 31 is fixedly welded or bolted to the bottom of the crossbeam 1, and the bottom of the lower sleeve 32 is fixedly connected to an anti-slip support 33. The bottom of the support 33 can fit against the top surface of the beam plate 8 to improve the stability of the support. A return spring 38 is built between the upper sleeve 31 and the lower sleeve 32. The return spring 38 is initially in a stretched state, which drives the upper and lower sleeves 32 to the retracted position. The side of the upper sleeve 31 is rotatably connected to the first support rod 34 through a pivot, and the bottom of the lower sleeve 32 is rotatably connected to the second support rod 35 through a pivot. The ends of the first support rod 34 and the second support rod 35 are hinged to each other to form a lockable linkage mechanism. When the construction workers bend the first support rod 34 and the second support rod 35 to the same straight line, the linkage mechanism achieves rigid locking, the upper and lower sleeves 32 slide in opposite directions, the support component 3 extends as a whole, and the crossbeam 1 is steadily lifted. In the locked state, it will not retract on its own without external force intervention, and the support stability is strong. The bottom of the second support rod 35 is fixedly connected to the lower pedal 36. Stepping on the lower pedal 36 can easily drive the linkage mechanism to unfold and lock. The operation does not require the use of tools, simplifying the construction steps. The bottom of the first support rod 34 is connected to the upper push rod 37. When the device is removed, pushing the upper push rod 37 can break the straight locking state of the linkage mechanism. The return spring 38 retracts and drives the support component 3 to retract, quickly releasing the support and improving the disassembly and assembly efficiency.

[0034] Two sets of vertical plates 4 are parallel and vertically slidingly installed on the crossbeam 1. The two sets of vertical plates 4 are symmetrically distributed, and vertical grooves are opened on the surface of the crossbeam 1 accordingly. The top of the vertical plate 4 is inserted into the groove to ensure that it does not shift or shake during the vertical sliding process. The bottom of the vertical plate 4 passes through the connecting guide component 5 located below the crossbeam 1. The guide component 5 can penetrate into the narrow space below the wet joint 10 at the bottom of the beam slab 8 and move smoothly along the bottom curved surface of the beam slab 8 to complete the exploration of the tensioning toothed plate 81.

[0035] Each set of vertical plates 4 is equipped with a set of elastic clamping components 6. The elastic clamping components 6 include a guide rod 61 fixed to the top surface of the crossbeam 1, and a horizontal plate 63 fixedly connected to the top of the vertical plate 4. The surface of the crossbeam 63 has a sliding hole adapted to the guide rod 61. The guide rod 61 passes vertically through the sliding hole to guide the vertical sliding of the crossbeam 63 and the vertical plate 4 as a whole, preventing lateral displacement. A clamping spring 62 is sleeved on the outside of the guide rod 61. The two ends of the clamping spring 62 are fixedly connected to the bottom of the crossbeam 63 and the top surface of the crossbeam 1, respectively. The clamping spring 62 is always in a pre-compressed state, continuously providing an upward clamping force to the vertical plate 4 and the guide components 5, ensuring that the guide components 5 are tightly attached to the bottom of the beam plate 8 throughout the entire process, and there will be no situation of suspension or missed inspection.

[0036] The guide component 5 includes a connecting plate 51 horizontally fixed to the bottom of the vertical plate 4. The bottom of the connecting plate 51 extends horizontally outward to form an integrated locating plate 53. The end of the locating plate 53 is rounded to form an arc plate 54 to prevent scratching the bottom concrete and prestressed ducts of the beam slab 8 during the probing process. Under the tightening action of the elastic clamping component 6, the locating plate 53 always moves close to the bottom of the beam slab 8. When it passes the position of the tensioning toothed plate 81, the arc-shaped transition section of the toothed plate will push the locating plate 53 downward, causing the vertical plate 4 to move downward synchronously and compress the clamping spring 62. When the locating plate 53 moves to the position of the vertical end 812 of the toothed plate, the clamping spring 62 rebounds instantly, causing the locating plate 53 and the vertical plate 4 to move upward quickly, generating obvious vibration and displacement feedback. Construction personnel can intuitively perceive the precise position of the toothed plate without the need for experience judgment, avoiding positioning deviations and missed inspections.

[0037] A slanted slide rail 41 is fixedly connected to the bottom outer side of the vertical plate 4, and a slider 52 is fixedly connected to the top of the connecting plate 51. The slider 52 is engaged within the slide rail 41 and can slide slantably along the slide rail 41, enabling the locating plate 53 to be extended and retracted slantably, facilitating the locating plate 53 to slide into the bottom of the beam plate 8 for locating. A baffle 43 is fixedly connected to the outer end of the slide rail 41, limiting the sliding stroke of the slider 52 to prevent the slider 52 from slipping off the slide rail 41 and ensuring the structural stability of the guide assembly 5 during movement.

[0038] A vertical sliding top rod 7 is connected to the middle of the crossbeam 1. It can slide into the gap between the two connecting plates 51, tighten the connecting plates 51 on both sides, and make the outer wall of the connecting plates 51 close to the baffle 43, locking the exploration position of the locating plate 53. Pull ropes 73 are connected between the bottom of the top rod 7 and the two connecting plates 51 on both sides. When the vertical plate 4 is pressed down first, the locating plate 53 is moved downward. When the top rod 7 is pulled up, the pull ropes 73 simultaneously pull the two connecting plates 51 on both sides to move diagonally opposite along the slide rail 41, so that the locating plate 53 can be quickly pulled out from the bottom of the beam plate 8, realizing the rapid dismantling of the device. At the same time, in order to improve the passage of the pull rope 73, rope holes 42 are opened at the positions where the connecting plates 51 and the vertical plate 4 are in contact with the top rod 7, so that the pull rope 73 can pass through the rope holes 42 when it is pulled upward. The top rod 7 is fixedly connected to the upper part of the limiting plate 71, which can be snapped onto the top surface of the crossbeam 1 to limit the excessive downward movement of the top rod 7; the top of the top rod 7 is connected to the fixing rope 72, and the top of the guide rod 61 is fixedly connected to the fixing frame 611. After positioning, the fixing rope 72 is tied inside the fixing frame 611 to fix the position of the top rod 7, thereby locking the entire guide assembly 5 and fixing the device directly above the toothed plate as the alignment reference for the subsequent tensioning device 11.

[0039] This embodiment replaces manual entry into confined spaces at heights for unauthorized inspection, reducing safety accidents such as falls from heights and abrasions, lowering the labor intensity of construction workers, and avoiding positioning deviations and omissions caused by manual experience judgment, thus improving the positioning accuracy of the tensioning toothed plate 81. The elastic clamping component 6 enables the guide component 5 to self-adaptively fit with the bottom of the beam 8, eliminating the need for manual adjustment of the fit. The mechanical rebound feedback from the arc end 811 to the vertical end 812 when passing through the tensioning toothed plate 81 is intuitive and obvious, allowing construction workers to quickly identify the positioning point without professional skills, resulting in a high construction error tolerance rate. The support component 3 works in conjunction with the traveling wheels 2. During the movement phase, the traveling wheels 2 ensure smooth horizontal movement, and during the positioning phase, the support component 3 quickly locks and lifts up, ensuring a firm and secure device that can be directly used as a tensioning alignment benchmark, avoiding secondary positioning and adjustment, and improving construction efficiency.

[0040] Continue reading Figures 1-8 This embodiment also proposes a bridge construction method using a locating device, including the following steps: S1. Beam slab 8 erection: Using a bridge erecting machine, the precast beam slab 8 is smoothly erected sequentially onto the temporary supports 33 and permanent supports 33 of the piers. The height of the temporary supports 33 is controlled to be slightly higher than that of the permanent supports 33, so that the beam slab 8 is in a standard simply supported state, avoiding premature stress that could lead to structural cracking. After erection, multiple beam slabs 8 are laid parallel between adjacent cap beams to form an integral beam body 9. A standard width wet joint 10 is reserved between adjacent beam slabs 8 to provide space for subsequent reinforcement binding, concrete pouring, and negative moment tensioning.

[0041] S2. Binding of reinforcement bars at wet joint 10: According to the construction drawings, bind the longitudinal reinforcing bars and transverse structural reinforcing bars of wet joint 10 in sequence to ensure that the spacing and lap length of the reinforcing bars meet the specifications. After the reinforcement bars are bound, prestressed tensioning bars are inserted between the tensioning tooth plates 81 of two adjacent beams 8. The tensioning bars are fitted with sealed prestressed pipes to prevent grout from entering the pipes and clogging the ducts during subsequent concrete pouring, and to protect the prestressed reinforcing bars from contamination.

[0042] S3. Wet Joint 10 Concrete Pouring: Micro-expansion concrete of the same strength grade as the precast beam slab 8 is used for wet joint 10. During pouring, a vibrator is used for thorough compaction to avoid quality defects such as honeycomb, pitting, and voids, ensuring a tight bond between wet joint 10 and the precast beam slab 8. After concrete pouring, geotextile is promptly covered and water is sprayed regularly for curing. The curing time meets the design specifications. Subsequent negative moment tensioning operations can only be carried out after the concrete strength reaches the design strength to prevent concrete cracking.

[0043] S4. Finding the tension point; S4.1. Device Placement: Place the selected negative bending moment locating device stably between the two beam slabs 8. The construction personnel first pull up the top rod 7, and through the pull rope 73, drive the connecting plates 51 on both sides to move obliquely upward and in opposite directions along the slide rail 41, so that the locating plate 53 retracts to the storage state; then lower the entire device so that the traveling wheel 2 lands stably on the top surface of the beam slab 8, and push the device to test run to confirm that the traveling wheel 2 rolls smoothly; press down the vertical plate 4 to compress the top tension spring 62, and lower the locating plate 53 to the space below the wet joint 10 at the bottom of the beam slab 8. Release the top rod 7, and the connecting plate 51 slides along the slide rail 41 under the action of gravity, and the locating plate 53 extends into the bottom of the beam slab 8. Then release the vertical plate 4, and under the action of the top tension spring 62, the locating plate 53 automatically fits into the bottom of the beam slab 8, completing the device debugging.

[0044] S4.2. Lateral movement for exploration and positioning: Construction personnel slowly push the crossbeam 1 along the length of the beam 8, causing the device to move at a constant speed from one end of the wet joint 10 to the other end. During the movement, the device should be kept stable without violent shaking. When the locating plate 53 passes through the arc transition section of the tensioning toothed plate 81, the toothed plate pushes the locating plate 53 downward, and the vertical plate 4 moves downward simultaneously to compress the tensioning spring 62. When the locating plate 53 moves to the vertical end 812 of the tensioning toothed plate 81, the tensioning spring 62 rebounds instantly, causing the locating plate 53 to move upward quickly, generating obvious vibration feedback. This is the tensioning point.

[0045] S4.3. Device positioning and locking: Press down on the lower pedal 36 of the support assembly 3 to extend the linkage mechanism to the linear locking state. The support assembly 3 extends and lifts the entire crossbeam 1, and the traveling wheel 2 is completely separated from the top surface of the beam plate 8. Tighten the locking bolts of the vertical plate 4 and tie the fixing rope 72 to the fixing frame 611 to fix the top rod 7, thus completing the overall locking of the device. The device remains fixed throughout the process and serves as the alignment reference for the subsequent tensioning device 11.

[0046] S5. Negative moment tensioning; The anchor plates and anchor clips of the tensioning device 11 are sequentially fitted onto the ends of the tensioning steel bars. This is the work that requires workers to reach the bottom of the beam slab 8 during this construction. The tensioning device 11 adopts a special device that is compatible with this locating device. U-shaped positioning plates 115 are set on both sides of the bottom plate 111 of the tensioning device 11, which can be directly snapped onto the device connecting rod. It is lowered vertically along the laser spot to the bottom of the beam slab 8 without repeated adjustment and alignment. The tensioning jack 112 is started, and the negative moment prestressing is completed symmetrically and synchronously according to the design tensioning stress and tensioning sequence. The stress and deformation are monitored in real time during the tensioning process. After the tensioning is in place, the limiting plate 71 is fitted into the tensioning steel bar to complete the anchoring and ensure that the prestressing is tensioned in place without any load eccentricity. S6. Grouting of prestressed ducts 82: After tensioning is completed and accepted, cement grout is injected into the prestressed ducts 82 on the tensioning tooth plate 81 using a grouting machine. The cement grout mix ratio meets the design requirements. The grouting process ensures fullness, density and no voids. After completion, the grouting port and grout outlet are sealed in time to protect the prestressed steel bars from corrosion and improve the durability of the structure. S7. Remove the locating device; press down the vertical plate 4 to compress the top spring 62, then lift the top rod 7 upward to disengage the locating plate 53 from the bottom of the beam plate 8, then release the vertical plate 4 to release the locating device; release the support assembly 3 to remove the locating device. S8. Binding and pouring between adjacent beams and slabs 8; after binding the reinforcing bars between adjacent beams and slabs 8, pouring is carried out to form an integrated beam body 9; S9. System Transformation: Using a symmetrical and synchronous dismantling method, the temporary supports 33 are dismantled in sequence to ensure that the beam 9 is stably placed on the permanent supports 33, thus completing the transformation from a simply supported system to a continuous system.

[0047] The tensioning device 11 in this method includes a base plate 111, on which a tensioning jack 112 is slidably connected laterally. Limiting columns 113 are connected to both ends of the base plate 111 to prevent the tensioning jack 112 from slipping out. Fixing plates 114 are also connected to both sides of the base plate 111. A U-shaped positioning plate 115 is connected to one of the fixing plates 114. The U-shaped positioning plate 115 can be locked onto the connecting rod and move vertically along the connecting rod. Lifting ropes 116 are connected to the two fixing plates 114. A crane 117 is connected to the lifting ropes 116 to lift the device so that the limiting columns 113 are pressed against the bottom of the beam plate 8 to achieve overall stability of the device.

[0048] When using this device, first adjust the tensioning jack 112 to correspond to the position of the bottom prestressed duct 82 and fix the tensioning jack 112 on the base plate 111. Then, use the crane 117 to lift the base plate 111 and its components, place it between the two beams 8 along its length, and then rotate it to ensure that the base plate 111 is approximately parallel to the crossbeam 1. Then, move the tensioning device 11 close to the locating device and observe the U-shaped positioning plate 115 gradually adhering to the connecting plate 51. When the U-shaped positioning plate 115 is aligned with the connecting plate 51, move the tensioning device 11 upwards using the crane 117 so that the limiting column 113 is against the bottom of the beam 8. Then, control the crane 117 to move towards the locating device so that the tensioned steel bar can be accurately placed into the tensioning jack 112 for tensioning. This device, combined with the locating device, allows the tensioning device 11 to be positioned, and workers can see whether it is aligned on the beam 8, making construction convenient and quick.

[0049] Although the specific embodiments of the invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the invention. Based on the technical solutions of the invention, various modifications or variations that can be made by those skilled in the art without creative effort are still within the scope of protection of the invention.

Claims

1. A bridge negative bending moment finding device, characterized in that, include: A crossbeam (1) spans between two beams (8); a traveling wheel (2) is provided at the bottom of the crossbeam (1), and a support component (3) is provided on the outside of the traveling wheel (2). The support component (3) can lift the crossbeam (1) upward to separate the traveling wheel (2) from the beam (8); Two sets of vertical plates (4) are set on the crossbeam (1) in parallel and vertically sliding manner; the bottom of the vertical plate (4) passes under the crossbeam (1) and is connected to the guide component (5), which can extend into the bottom of the beam plate (8) and move along the bottom of the beam plate (8); The elastic clamping component (6) is connected to the vertical plate (4) and can drive the vertical plate (4) to move upward so that the guide component (5) moves to fit the bottom of the beam plate (8); when it passes the tension tooth plate (81) at the bottom of the beam plate (8), it can drive the guide component (5) to move along the arc end (811) of the tension tooth plate (81) and fall back at the vertical end (812) of the tension tooth plate (81) to achieve positioning.

2. The bridge negative bending moment finding device according to claim 1, characterized in that: The elastic clamping assembly (6) includes a guide rod (61) fixed on the crossbeam (1), a crossbeam (63) connected to the top of the vertical plate (4), a sliding hole on the crossbeam (63), the guide rod (61) passing through the sliding hole to guide the crossbeam (63); a clamping spring (62) is provided on the guide rod (61), the two ends of the clamping spring (62) are respectively connected to the bottom of the crossbeam (63) and the crossbeam (1), and the clamping spring (62) can drive the vertical plate (4) to move upward.

3. A bridge negative bending moment finding device according to claim 1 or 2, characterized in that: The guide assembly (5) includes a connecting plate (51), which is connected to the bottom of the vertical plate (4). The bottom of the connecting plate (51) extends outward to form a locating plate (53), which moves along the bottom of the beam plate (8) under the action of the elastic clamping assembly (6).

4. The bridge negative bending moment finding device according to claim 3, characterized in that: The bottom of the vertical plate (4) is connected to an inclined slide rail (41), and the top of the corresponding connecting plate (51) is connected to a slider (52). The slider (52) can slide inside the slide rail (41); the outer end of the slide rail (41) is connected to a baffle (43). The middle part of the crossbeam (1) is also vertically connected to the top rod (7). The bottom of the top rod (7) can slide between the two connecting plates (51) to tighten the connecting plate (51) so that the outer wall of the connecting plate (51) is pressed against the baffle (43). The bottom of the top rod (7) is connected to the connecting rod with a pull rope (73). Pulling the top rod (7) upward can drive the connecting rod to move in opposite directions so that the locating plate (53) can be pulled out from the bottom of the beam plate (8).

5. A bridge negative bending moment finding device according to claim 5, characterized in that: The top rod (7) is connected to a limiting plate (71) at the top. The limiting plate (71) can be locked on the crossbeam (1) to restrict the downward movement of the top rod (7). The top of the top rod (7) is connected to a fixing rope (72), and the top of the corresponding guide rod (61) is connected to a fixing frame (611). The fixing rope (72) can be tied into the fixing frame (611) to fix the top rod (7).

6. The bridge negative bending moment finding device according to claim 1, characterized in that: The support assembly (3) includes an upper sleeve (31) and a lower sleeve (32) that can slide relative to each other. The upper sleeve (31) is fixed to the bottom of the crossbeam (1), and the bottom of the lower sleeve (32) is connected to a support (33), which is supported on the ground. A return spring (38) is connected between the upper sleeve (31) and the lower sleeve (32). The side of the upper sleeve (31) is rotatably connected to the first support rod (34), and the bottom of the lower sleeve (32) is rotatably connected to the second support rod (35). The ends of the first support rod (34) and the second support rod (35) are hinged to form a linkage mechanism. When the first support rod (34) and the second support rod (35) are aligned in a straight line, the first sleeve and the second sleeve slide in opposite directions, and the support assembly (3) extends and supports the beam plate (8).

7. A bridge negative bending moment finding device according to claim 6, characterized in that: The bottom of the second support rod (35) is connected to the lower pedal (36). Stepping on the lower pedal (36) can drive the second support rod (35) to rotate to achieve support. The bottom of the first support rod (34) is connected to the upper push rod (37). Pushing the upper push rod (37) can disengage the first support rod (34) from the second support rod (35).

8. A bridge construction method, characterized in that, Includes the following steps: S1. Beam (8) erection: The beam (8) is erected symmetrically on the temporary support (33) and permanent support (33) of the pier using a bridge erecting machine. The temporary support (33) is higher than the permanent support (33), so that the beam (8) is in a simply supported state. After the erection is completed, several beams (8) are set in parallel between the two cap beams to form a beam body (9). The two adjacent beam bodies (9) are wet joints (10). S2. Binding of reinforcement bars in wet joint (10); Binding of longitudinal and transverse reinforcement bars in wet joint (10); then inserting tension reinforcement bars between tensioning tooth plates (81) of two adjacent beams (9), and installing prestressed ducts on the outside of the tension reinforcement bars at the wet joint (10). S3. Wet joint (10) concrete pouring: Use micro-expansion concrete of the same strength grade as the beam (9) for pouring. After the concrete is poured, cover it with geotextile and spray water for curing. S4. Tensioning point location; using the bridge negative bending moment location device according to any one of claims 1-7 to locate the position of the tensioning tooth plate (81); S5. Negative moment tensioning; After the anchor plate and anchor wedge are successively placed on the end of the tensioning steel bar, the tensioning device (11) is placed under the beam (8) with the locating device attached to it to perform negative moment tensioning; After the tensioning is completed, the limiting plate (71) is placed into the tensioning steel bar to complete the negative moment tensioning; S6. Grouting of prestressed ducts (82); Grouting into the prestressed ducts (82) on the tensioning toothed plate (81); S7. Remove the locating device; press down the vertical plate (4) to compress the top spring (62), then lift the top rod (7) upward to make the locating plate (53) detach from the bottom of the beam plate (8), then release the vertical plate (4) to release the locating device; release the support assembly (3) to remove the locating device; S8. Binding and pouring between adjacent beams and slabs (8); After binding the steel bars between adjacent beams and slabs (8), pour the concrete to form an integrated beam body (9). S9. System transformation: Using a symmetrical and synchronous dismantling method, the temporary supports (33) are dismantled in sequence to ensure that the beam (9) is placed smoothly on the permanent supports (33) and the transformation from a simple supported system to a continuous system is completed.

9. A bridge construction method according to claim 8, characterized in that, Step S4 includes the following steps: S4.

1. Device placement; Place the locating device between the two beams (8), first pull up the top rod (7) to drive the connecting rod and the locating plate (53) to move in opposite directions; lower the locating device so that the traveling wheel (2) can move along the beam (8); press down the vertical plate (4) to compress the top spring (62), lower the locating plate (53) to below the beam (8), then release the top rod (7), and after the locating plate (53) slides into the bottom of the beam (8), release the vertical plate (4), and under the action of the return spring (38), the locating plate (53) presses against the bottom of the beam (8); S4.

2. Lateral movement search; push the crossbeam (1) along the beam plate (8) from one end of the wet joint (10) to the other end; when it passes the arc end (811) of the tensioning tooth plate (81), the top spring (62) is gradually compressed, the vertical rod gradually moves downward, and when it reaches the vertical end (812) of the tensioning tooth plate (81), the vertical rod springs back, and this is the tensioning point; S4.3 Device support; start the support assembly (3) to support the device on the beam plate (8), so that the walking wheel (2) is separated from the beam plate (8) and the device is positioned.

10. A bridge construction method according to claim 8, characterized in that: The tensioning device (11) includes a base plate (111), on which a tensioning jack (112) is slidably connected laterally. Limiting columns (113) are connected to both ends of the base plate (111) to prevent the tensioning jack (112) from slipping out. Fixing plates (114) are also connected to both sides of the base plate (111). A U-shaped positioning plate (115) is connected to one of the fixing plates (114). The U-shaped positioning plate (115) can be locked on the connecting rod and move vertically along the connecting rod. Lifting ropes (116) are connected to the two fixing plates (114). The crane (117) is connected to the lifting ropes (116) to lift the device so that the limiting column (113) is pressed against the bottom of the beam plate (8) to achieve overall stability of the device.

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