Angle limiting stress compensation device for folded line pretensioning method and use method thereof

Abstract

The application discloses a kind of angle limiting stress compensation devices and use methods for fold line pre-tensioning method, including horizontal pressure plate, horizontal connecting plate, vertical limiting connecting plate, vertical limiting connecting plate is vertically set multiple first roller groups;Vertical compensation connecting plate is set in vertical limiting connecting plate middle, and two ends are respectively set pull plate, guide plate, and vertically set multiple second roller groups;Jack is set on horizontal pressure plate, and output end is provided with tensioning nut;Tensioning rod, one end passes through pull plate and is fixed by connecting nut, the other end is sequentially connected with tensioning nut and passes out to pressure plate and jack;Guide shaft, one end is fixed with guide plate, the other end passes out connecting plate outside.The compensation structure is tensile structure, and the structural stability is high, safe and reliable, solves the problem of insufficient stability of compensation compression structure, and realizes mechanical self-locking of compensation structure by using locking nut, and the compensation force is effectively guaranteed.

Description

Technical Field

[0001] This invention belongs to the field of bridge technology, specifically relating to an angle-limiting stress compensation device and its usage method for the zigzag pre-tensioning method. Background Technology

[0002] Prestressed systems are classified into pre-tensioning and post-tensioning methods based on the sequence of concrete pouring and tensioning. Pre-tensioning offers advantages such as simple construction procedures, uniform prestress distribution at all points on the prestressing tendons, and reduced steel consumption (no anchor heads at the anchoring ends), leading to its widespread use. To improve construction efficiency, existing pre-tensioning methods typically employ a multi-beam prefabrication and construction process. However, the use of multiple bending devices (W) on multiple beams generates significant friction, resulting in a substantial reduction in prestress at the non-tensioning ends. Patent "CN107575031A" discloses a stress-relief pre-tensioning compensation device and its application in pre-tensioning multi-beam reinforcement construction. By installing the compensation device between two beams, it solves the problem of excessive stress loss in the intermediate beam during the simultaneous prefabrication and tensioning of multiple beams. However, this patented technology still has the following drawbacks:

[0003] 1. The device uses a jacking method to provide stress compensation. The bogie is a compression structure. In order to prevent the bogie from becoming unstable or tipping over, an additional guide rail is added. However, the guide rail is a cantilever beam structure with poor bending resistance, which leads to poor stability of the bogie structure.

[0004] 2. Simultaneously, the bending angle of the steel strand at the guide frame is large, twice the designed bending angle, resulting in high stress concentration and a high risk of breakage. Specifically, as shown below... Figure 1 As shown.

[0005] The information disclosed in the above background section is only intended to enhance the understanding of the overall background of the present invention, and should not be construed as an admission or implication in any way that such information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] To address the above shortcomings, this patent develops an angle-limiting stress compensation device and its usage method for the zigzag pre-tensioning method. The compensation structure is a tension structure, which has high structural stability and is safe and reliable, thus solving the problem of insufficient stability of the compensation compressive structure.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A stress compensation device for angle limiting in a zigzag pretensioning method includes: a stress compensation frame comprising a transverse bearing plate and a transverse connecting plate, both having a central hole; the two ends of the transverse bearing plate and the transverse connecting plate being connected by a vertical limiting connecting plate; and multiple sets of first roller groups arranged at vertical intervals along the vertical direction on the vertical limiting connecting plate; and a vertical compensation connecting plate disposed between the two vertical limiting connecting plates, with tensioning points respectively provided at both ends of the vertical compensation connecting plate facing the transverse bearing plate and the transverse connecting plate. The system includes a plate, a guide plate, and a vertical compensation connecting plate with multiple sets of second rollers spaced vertically along its length; a jack with a through hole in its axial direction, which is fixed to the transverse bearing plate by a support foot, and a tension nut on its output end; a tension rod with external threads at both ends, one end of which passes through the tension plate and is fixed by a connecting nut, and the other end passes through the through hole of the bearing plate and the jack to connect with the tension nut; and a guide shaft with one end fixed to the guide plate and the other end passing through the center hole of the connecting plate.

[0009] Specifically, the second roller assembly includes two rollers arranged in the horizontal direction along the vertical compensation connecting plate 12.

[0010] This invention also discloses a method for using an angle-limiting stress compensation device in the broken-line pre-tensioning method, comprising the following steps:

[0011] S1: Steel strand threading:

[0012] The steel strand passes under the first roller group and over the second roller group;

[0013] S2: Steel strand tensioning: Tension the steel strands from the outer ends of the pre-tensioned beams L1 on both sides as required until the tension force is F1;

[0014] S3: Stress compensation:

[0015] Loosen the locking nut and apply tension force F0 to the jack to compensate the tension force F2 of the inner end steel strand of the pre-tensioned beam L1 to the tension force F1; tighten the locking nut and press it against the end face of the pressure plate; the jack piston retracts and the tension force F0 is transferred to the locking nut;

[0016] S4: Unloading and releasing the steel strand:

[0017] After the pre-tensioned beam L1 is poured and reaches its strength, the jack applies tension to F0; the locking nut is loosened; the jack piston returns to unload; then the steel strands at the outer end of the pre-tensioned beam L1 are released and unloaded.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. In the simultaneous prefabrication of multiple beams using the zigzag pretensioning method, this invention employs an angle-limiting stress compensator at the middle position to compensate for the tension force at the non-tensioned end of the beam and to allow for the release of tension in the steel strands. It utilizes a self-balancing structure combining angle limiting and stress compensation, reducing the stress requirements on the foundation. The compensation structure is a tension structure, exhibiting high structural stability and reliability, thus solving the problem of insufficient stability in compressive structures.

[0020] 2. After stress compensation, the stress compensation device of the present invention uses a locking nut to achieve mechanical self-locking of the compensation structure, which effectively ensures the compensation force and solves the problem of unstable hydraulic self-locking of the jack; during the self-locking process, the jack can be removed, which improves the utilization rate of the equipment.

[0021] 3. The compensation position of this invention adopts a double-row roller structure, which results in a small bending angle of the steel strand and low stress at the bending point. This solves the problem of stress concentration at the bending point of the steel strand in existing compensation structures and improves structural safety. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the bending angle of a pre-tensioned compensation device for unloading force in the prior art.

[0023] Figure 2 This is a schematic diagram of an angle-limiting stress compensation device for a zigzag pre-tensioning method according to Example 1.

[0024] Figure 3 This is a schematic diagram of the bend angle of the steel strand in the stress compensation device in Example 1.

[0025] Figure 4 This is a schematic diagram illustrating the assembly method of an angle-limiting stress compensation device for the zigzag pre-tensioning method in Example 1.

[0026] Figure 5 This is a schematic diagram of an angle-limiting stress compensation device for a zigzag pre-tensioning method according to Example 2.

[0027] In the diagram: A - steel strand; B - pre-tensioning compensation device; W - bending device; X - steel strand bending angle; 2X - steel strand bending angle at the pre-tensioning compensation device; L1 - pre-tensioning beam; L2 - pre-tensioning beam; F1 - tension force of steel strand on the outer end face of pre-tensioning beam L1; F2 - tension force of steel strand on the inner end face of pre-tensioning beam L1; F0 - compensation tension force; 1 - tension nut; 2 - tension rod; 3 - jack; 4 - support foot; 5 - locking nut; 6 - connecting nut; 7 - transverse bearing plate; 8 - vertical limiting connecting plate; 9 - first roller; 10 - first pin; 11 - tension plate; 12 - vertical compensation connecting plate; 13 - second roller; 14 - second pin; 15 - guide plate; 16 - transverse connecting plate; 17 - guide shaft. Detailed Implementation

[0028] To illustrate the technical content, objectives, and effects of this invention in detail, the following description is provided in conjunction with embodiments and accompanying drawings. It should be understood that in the description of these embodiments, terms indicating orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings and are used only for the convenience of describing this embodiment and simplifying the description. They are not intended to 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 this invention.

[0029] Example 1

[0030] In the prior art, reference Figure 1 As shown, the bogie with its polygonal reinforcement and compression structure is characterized by a compression member. According to the principles of material mechanics, when a compression member is under compression and the pressure reaches a critical pressure or force, the linear equilibrium of the member becomes unstable and transitions to a curved equilibrium. This loss of linear equilibrium and transition to curved equilibrium is called instability. After instability, even a small increase in pressure will cause a significant increase in bending deformation, and the member will lose its load-bearing capacity. Failure caused by instability can lead to damage to the entire structure. Therefore, compression structures require the addition of stabilizing structures to prevent instability or collapse.

[0031] This embodiment provides an angle-limiting stress compensation device for the pre-tensioning method using a broken line, specifically as follows: Figures 2-4 As shown, it mainly includes: a stress compensation frame, a vertical compensation connecting plate 12, a jack 3, a tension rod 2, and a guide shaft 17. The stress compensation frame includes horizontal bearing plates 7 and horizontal connecting plates 16 arranged parallel to each other. The two ends of the horizontal bearing plates 7 and horizontal connecting plates 16 are connected to form a rectangular frame by parallel vertical limiting connecting plates 8. Both the horizontal bearing plates 7 and horizontal connecting plates 16 are provided with a central hole, which can serve as a guide.

[0032] The vertical compensation connecting plate 12 is located in the middle of the two vertical limiting connecting plates 8. The two ends of the vertical compensation connecting plate 12 facing the horizontal bearing plate 7 and the horizontal connecting plate 16 are respectively fixed with a pull plate 11 and a guide plate 15.

[0033] The jack 3 is fixed to the horizontal pressure plate 7 by the support foot 4 and the output end faces the outside of the rectangular frame. The jack 3 has a through hole in the axial direction. The output end of the jack 3 is provided with a tension nut 1. The tension nut 3 can bear pressure on the piston output front end of the jack 3. The tension nut 1 is coaxial with the through hole.

[0034] Both ends of the tension rod 2 are set with external threads. One end is inside the rectangular frame and is fixed to the tension plate 11 by the connecting nut 6. The other end passes through the through hole of the bearing plate 7 and the jack 3 and is connected to the tension nut 1.

[0035] One end of the guide shaft 17 is fixed to the guide plate 15, and the other end passes through the center hole of the connecting plate 16.

[0036] Multiple sets of first roller groups are arranged at vertical intervals along the vertical limit connecting plate 8. Each first roller group includes a first roller 9, which is rotatably mounted on the vertical limit connecting plate 8 via a first pin 10.

[0037] Multiple sets of second rollers are arranged at vertical intervals on the vertical compensation connecting plate 12; the second roller set includes a second roller 13, which is rotatably mounted on the vertical compensation connecting plate 12 via a second pin 14.

[0038] In this embodiment, during the simultaneous prefabrication of multiple beams using the zigzag pretensioning method, steel strands are rotatably overlapped sequentially with the first roller 9 on the left, the second roller 13 in the middle, and the first roller 9 on the right. An angle-limiting stress compensator is then used at the middle position. The compensation structure is designed as a tie-rod type tension structure, which reduces the application of auxiliary structures, eliminates the need for additional instability prevention structures, reduces the possibility of instability, and eliminates concerns about the slight increase in pressure from the cantilever beam structure causing a significant amplification of bending deformation. This ensures safe and reliable use, and allows the tension of the entire structure to reach the prestressing standard, solving the problem of insufficient stability of the compensation compression structure in the prior art.

[0039] As a preferred embodiment, the second roller group includes two second rollers 13 arranged in the horizontal direction along the vertical compensation connecting plate 12. Figure 3 As shown, the bending angle of the steel strand in the double-row roller structure is half that of the steel strand in the single-row roller structure, and the bending stress of the steel strand is also half that of the single-row roller structure, resulting in higher safety of the steel strand.

[0040] The method of using the angle-limiting stress compensation device in the broken-line pre-tensioning method of this embodiment is as follows: Figure 4 As shown, the specific steps include the following:

[0041] S1: Steel strand threading:

[0042] Steel strand A passes under the first roller group and over the second roller group;

[0043] S2: Tensioning of steel strand A: Tension the steel strand from the outer ends of the pre-tensioned beams L1 on both sides as required until the tension force is F1;

[0044] S3: Stress compensation:

[0045] Loosen the locking nut 5 and apply tension force F0 to the jack 3 to compensate the tension force F2 of the inner end steel strand of the pre-tensioned beam L1 to the tension force F1; tighten the locking nut 5 and press it on the end face of the pressure plate 7; the piston of the jack 3 retracts and the tension force F0 is transferred to the locking nut 5;

[0046] S4: Unloading and releasing the steel strand:

[0047] After the pre-tensioned beams L1 and L2 are poured and reach their strength, jack 3 applies tension to F0; the locking nut 5 is loosened; the piston of jack 3 returns to unload; then the outer end of the pre-tensioned beam L1 is tensioned and unloaded by releasing the steel strand A.

[0048] While traditional jacks can only be locked by hydraulic pressure, the hydraulic valves cannot achieve mechanical locking, thus failing to maintain stable hydraulic pressure and consequently causing a decrease in the compensating force. This embodiment employs a locking nut to achieve mechanical self-locking of the compensating structure, effectively ensuring the compensating force and resolving the issue of unstable hydraulic pressure self-locking, thereby maintaining stable compensating force. Simultaneously, the jack can be removed, allowing for its full and efficient utilization.

[0049] Example 2

[0050] The difference between this embodiment and Embodiment 1 is that the angle limiting stress compensation device is placed in the opposite direction, and the steel strand is threaded through the cable: the steel strand passes over the first roller group and under the second roller group; the rest of the process is the same as in Embodiment 1. Stress compensation tensioning can also be achieved, therefore the device in this embodiment is also convenient to use.

[0051] Although the present invention has been described in detail above with specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A stress compensation device for angle limiting in the broken-line pre-tensioning method, comprising: The stress compensation frame includes a transverse bearing plate (7) and a transverse connecting plate (16). Both the transverse bearing plate (7) and the transverse connecting plate (16) are provided with a central hole. The two ends of the transverse bearing plate (7) and the transverse connecting plate (16) are connected by a vertical limiting connecting plate (8). Multiple sets of first roller groups are arranged at vertical intervals on the vertical limiting connecting plate (8). The first roller group includes a first roller (9) which is rotatably mounted on the vertical limiting connecting plate (8) through a first pin (10). A vertical compensation connecting plate (12) is set between two vertical limiting connecting plates (8). The vertical compensation connecting plate (12) is provided with a pull plate (11) and a guide plate (15) at both ends facing the horizontal bearing plate (7) and the horizontal connecting plate (16), respectively. Multiple sets of second roller groups are arranged at vertical intervals on the vertical compensation connecting plate (12). The second roller group includes a second roller (13), which is rotatably mounted on the vertical compensation connecting plate (12) through a second pin (14). The second roller group includes two second rollers (13) arranged in the horizontal direction of the vertical compensation connecting plate (12). Jack (3) has a through hole in its axial direction. The jack is fixed on the transverse bearing plate (7) by the support foot (4), and a tension nut (1) is provided on the output end. Tensioning rod (2), both ends of tensioning rod (2) are set with external threads. One end passes through the tension plate (11) and is fixed by the connecting nut (6). The other end passes through the center hole of the transverse bearing plate (7) and the through hole of the jack (3) and is connected to the tensioning nut (1). The guide shaft (17) is fixed at one end to the guide plate (15) and the other end passes through the center hole of the transverse connecting plate (16).

2. The method of using the angle-limiting stress compensation device for the pre-tensioning method according to claim 1, characterized in that, Includes the following steps: S1: Steel strand threading: The steel strand passes under the first roller group and over the second roller group; S2: Steel strand tensioning: Tension the steel strands from the outer ends of the pre-tensioned beams L1 on both sides as required until the tension force is F1; S3: Stress compensation: Loosen the locking nut (5) and apply tension force F0 to the jack (3) to compensate the tension force F2 of the inner end steel strand of the pre-tensioned beam L1 to the tension force F1; tighten the locking nut (5) and press it on the end face of the transverse bearing plate (7); the piston of the jack (3) retracts and the tension force F0 is transferred to the locking nut (5); S4: Unloading and releasing the steel strand: After the pre-tensioned beam L1 is poured and reaches its strength, the jack (3) applies tension to F0; the locking nut (5) is loosened; the piston of the jack (3) returns to unload; then the steel strands of the pre-tensioned beams L1 and L2 are released and unloaded.

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