A device for compensating for loss of prestress of steel strand in a concrete beam

Abstract

The application discloses a concrete beam steel strand prestress loss compensation device, which comprises a jack, a bottom plate and an anchoring disc, the anchoring disc is provided with an anchor hole, the anchor hole is provided with a clamping block, the bottom plate is provided with an avoiding hole, the outer side of the bottom plate is fixedly connected with a plurality of grommets, the bottom plate is fixedly connected with a plurality of guide columns, the guide columns are jointly and slidably connected with a supporting ring, the guide columns are axially and slidably connected with a bidirectional pressing device, the bidirectional pressing device comprises a support plate, the support plate is slidably and rotatably connected with the guide columns, the end of each guide column, which is away from the bottom plate, is provided with a boss, a supporting spring is arranged between the boss and the support plate, one end of the support plate is provided with an elastic hoop plate, one side of the elastic hoop plate is provided with a jacking rod assembly, and the jacking rod assembly is rotatably connected with the support plate. The jacking rod assembly is used for pushing the bottom plate and the grommet towards the clamping block, and the reaction force is used for enabling the support plate to slide away from the clamping block along the guide column, so that the steel strand is pressed and pulled outwards at the same time.

Description

Technical Field

[0001] This invention relates to the field of prestressed bridge construction equipment technology, and in particular to a prestress loss compensation device for steel strands in concrete beams. Background Technology

[0002] A box girder is a modular unit of a bridge deck and a type of beam in bridge engineering. The cross-section of a box girder is approximately trapezoidal, and the interior is hollow. The length varies from tens of meters to hundreds of meters. To ensure the strength of the box girder, steel strands are usually added inside to tighten the box girder along its length. On the construction site, construction workers found that when the jacks were removed, the steel strands would shrink by about 10%, causing them to loosen and reducing the tensioning effect of the box girder.

[0003] Patent document publication number CN111576219A discloses a mechanical prestress loss compensation mechanism for steel strands in a box girder and its usage method, belonging to the technical field of bridge construction equipment. Specifically, it includes an anchor, clamping blocks, steel strands, and a jack. The anchor is fitted onto the steel strand and fixed to it by the clamping blocks. The jack is connected to the end of the steel strand and tightens it. A mechanical clamping block tightening mechanism is provided between the anchor and the jack. By inserting the clamping blocks into the holes of the anchor and clamping them around the steel strand, the insertion action causes the steel strand to push backward, resulting in a retraction effect during the tightening process, thereby weakening the compensation effect. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a prestress loss compensation device for steel strands in concrete beams.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A prestress loss compensation device for steel strands in a concrete beam includes a jack, a base plate, and an anchoring plate. The anchoring plate has anchor holes, and clamping blocks are installed inside the anchor holes. The base plate has clearance holes. Multiple washers are fixedly connected to the outer side of the base plate. Multiple guide columns are fixedly connected to the base plate. The multiple guide columns are slidably connected to a support ring. The guide columns are axially slidably connected to a bidirectional jacking device. The bidirectional jacking device includes a support plate, which is slidably and rotatably connected to the guide columns. Each guide column has a boss at the end away from the base plate. A support spring is installed between the boss and the support plate. An elastic hoop is installed at one end of the support plate. A jacking rod assembly is installed on one side of the elastic hoop. The jacking rod assembly is rotatably connected to the support plate.

[0007] Preferably, the top rod assembly includes a round rod, a polygonal prism, a sleeve, and a clamping rod. The support plate is provided with a rotating hole, and end holes are provided at both ends of the rotating hole. A retaining spring is provided inside the end holes. An annular groove is provided on the outer circle of the round rod, and the retaining spring is provided corresponding to the annular groove.

[0008] One end of the round rod is fixedly connected to a polygonal prism, and the support plate is fixedly connected to a sleeve on one side of the polygonal prism. One end of the clamping rod is provided with a polygonal hole, which is slidably connected to the polygonal prism. One end of the clamping rod is threaded to the inner wall of the sleeve, and the other end of the clamping rod abuts against the base plate.

[0009] Preferably, a clearance cavity is provided in the middle of the rotating hole, a turning wheel is fixedly connected to the middle of the round rod, and the elastic hoop is provided with grooves on the inner and outer sides in a spiral shape. The teeth of the turning wheel are correspondingly provided with the grooves. The inner end of the elastic hoop is fixedly connected to the side of the support plate. The support plate is provided with a through hole, which is connected to the clearance cavity. The outer end of the elastic hoop passes through the through hole.

[0010] Preferably, one end of the round rod has a limiting hole, the jack is rotatably connected to a ring, the ring is fixedly connected to a motor, and the output shaft of the motor is provided with a plug rod, which is inserted into the limiting hole.

[0011] Preferably, at least one support plate is fixedly connected to the side rod, and the side rod is provided with an elastic hoop plate and a top rod assembly of the same structure.

[0012] Preferably, the support ring is fixedly connected to at least two side rods, and the end of the side rod away from the support ring is fixedly connected to a cross rod. The cross rod is threadedly connected to a screw rod, and the screw rod is correspondingly set with the anchor plate.

[0013] The advantages of this invention are as follows: The prestress loss compensation device for steel strands in concrete beams provided by this invention pushes the bottom plate through the top rod assembly. On the one hand, it pushes the bottom plate and the pad ring towards the clamping block. On the other hand, the reaction force causes the support plate to slide away from the clamping block on the guide column. This achieves the effect of pressing on one side and pulling the steel strand outward on the other, so that the prestress is additionally compensated after the steel strand is cut, and the prestress loss caused by the retraction of the steel strand due to the removal of the jack is reduced.

[0014] This invention utilizes a rotating rod. On one hand, the threaded connection between the clamping rod and the sleeve causes the clamping rod to move axially, thereby pressing the base plate and pad ring against the clamping block. On the other hand, the rotation of the actuating wheel causes the open end of the elastic hoop to extend into the through hole, tightening the steel strand. Combined with the sliding of the support plate away from the clamping block on the guide post, this achieves the effect of simultaneously clamping and pulling the steel strand outward. This provides additional compensation for the prestress after the steel strand is cut, reducing the prestress loss caused by the retraction of the steel strand due to the removal of the jack. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the basic structure of the present invention;

[0016] Figure 2 This is a schematic diagram of the bidirectional pressing device in this invention;

[0017] Figure 3This is a schematic diagram of the internal structure of the support plate of the bidirectional pressing device in this invention;

[0018] Figure 4 This is a first-person perspective schematic diagram of the usage state of the present invention;

[0019] Figure 5 This is a second-view schematic diagram of the usage state of the present invention;

[0020] Figure 6 yes Figure 5 A magnified view of point E in the image. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0022] Example 1

[0023] like Figures 1-6 As shown, the present invention provides a prestress loss compensation device for steel strands in concrete beams, comprising a jack 1, a base plate 2, and an anchoring plate 3. The anchoring plate 3 is provided with anchor holes 31, and clamping blocks 32 are provided inside the anchor holes 31. The jack 1 and the anchoring plate 3 are conventional structures. Multiple wedge-shaped clamping blocks 32 are provided inside the anchor holes 31. The steel strand passes through the multiple clamping blocks 32. When the clamping blocks 32 are tightened into the anchor holes 31, they clamp the steel strand. The base plate 2 is provided with clearance holes 21 for the steel strand to pass through. Multiple washers 22 are fixedly connected to the outside of the base plate 2. The washers 22 facilitate pressing the clamping blocks 32. 2. Multiple guide columns 23 are fixedly connected, and the multiple guide columns 23 are slidably connected to the support ring 24. The guide columns 23 are axially slidably connected to the bidirectional pressing device 4. The bidirectional pressing device 4 includes a support plate 41. The support plate 41 is slidably and rotatably connected to the guide column 23, so that the support plate 41 can change its angle and can be easily adjusted when the position of the steel strand is offset. Each guide column 23 is provided with a boss 42 at the end away from the bottom plate 2. A support spring 43 is provided between the boss 42 and the support plate 41. An elastic hoop 44 is provided at one end of the support plate 41. A top rod assembly 5 is provided on one side of the elastic hoop 44. The top rod assembly 5 is rotatably connected to the support plate 41.

[0024] The support ring 24 is fixedly connected to at least two side rods 8. The end of the side rod 8 away from the support ring 24 is fixedly connected to a cross rod 81. The cross rod 81 is threadedly connected to a screw 82. The screw 82 is correspondingly set with the anchor plate 3. Before compensation, the pad ring 22 of the base plate 2 is attached to the clamping block 32. The ends of the side rods 8 and cross rods 81 on the side of the support ring 24 are clamped to the side of the anchor plate 3 by the rotation of the screw 82, thus pre-installing the present invention.

[0025] In this invention, the push rod assembly 5 can be a conventional threaded rod. Through the threaded action of the support plate 41, the base plate 2 and the washer ring 22 are pressed against the clamping block 32, so that the clamping block 32 is inserted into the anchor hole 31 for further anti-retraction. The elastic hoop plate 44 can be a conventional clamp. By clamping the steel strand, the support plate 41 is fixed together with the steel strand. Multiple bidirectional pressing devices 4 are set on the support ring 24 so that all the steel strands can be fixed. After the steel strands are all clamped by the corresponding support plates 41, the push rod assembly 5 pushes against the base plate 2. On the one hand, it pushes the base plate 2 and the washer ring 22 towards the clamping block 32. On the other hand, the reaction force causes the support plate 41 to slide away from the clamping block 32 on the guide column 23. This achieves the effect of pressing while pulling the steel strand outward, so that the prestress is additionally compensated after the steel strand is cut, and the prestress loss caused by the retraction of the steel strand due to the removal of the jack 1 is reduced.

[0026] Example 2

[0027] like Figures 1-6 As shown, in Embodiment 1, the conventional structure of the top rod assembly 5 and the elastic clamp plate 44 results in a small operating space and inconvenience due to the obstruction of the jack 1. Based on this defect, this embodiment discloses a new structure of the top rod assembly 5 and the elastic clamp plate 44. The top rod assembly 5 includes a round rod 51, a polygonal prism 52, a sleeve 53, and a clamping rod 54. The support plate 41 is provided with a rotating hole 55, and end holes 56 are provided at both ends of the rotating hole 55. A retaining spring 57 is provided in the end holes 56. An annular groove is provided on the outer circle of the round rod 51, and the retaining spring 57 is provided corresponding to the annular groove, so that the round rod 51 can only rotate within the rotating hole 55 and will not have axial displacement.

[0028] One end of the round rod 51 is fixedly connected to the polygonal prism 52. The support plate 41 is fixedly connected to the sleeve 53 on one side of the polygonal prism 52. One end of the clamping rod 54 is provided with a polygonal hole, which is slidably connected to the polygonal prism 52. One end of the clamping rod 54 is threadedly connected to the inner wall of the sleeve 53, and the other end of the clamping rod 54 abuts against the base plate 2. When the round rod 51 rotates, the polygonal prism 52 rotates synchronously with the clamping rod 54. Due to the threaded connection between the clamping rod 54 and the sleeve 53, the clamping rod 54 will move axially, thereby enabling the base plate 2 and the washer ring 22 to be pressed against the clamping block 32.

[0029] A clearance cavity 58 is provided in the middle of the rotating hole 55. A turning wheel 59 is fixedly connected to the middle of the round rod 51. The elastic hoop 44 has grooves 591 spaced apart on its inner and outer sides in a spiral shape. The teeth of the turning wheel 59 are correspondingly set with the grooves 591. The inner end of the elastic hoop 44 is fixedly connected to the side of the support plate 41. The support plate 41 is provided with a through hole 592, which is connected to the clearance cavity 58. The outer end of the elastic hoop 44 passes through the through hole 592. The rotation of the round rod 51 causes the turning wheel 59 to rotate. The turning wheel 59 rotates through its teeth and grooves 591, causing the open end of the elastic hoop 44 to extend into the through hole 592. The elastic hoop 44 is a stainless steel sheet with concave and convex features on its inner arc surface corresponding to the steel strand to increase the friction force for clamping the steel strand, so that the elastic hoop 44 clamps the steel strand tightly.

[0030] In this embodiment, by rotating the round rod 51, on the one hand, due to the threaded connection between the clamping rod 54 and the sleeve 53, the clamping rod 54 will move axially, thereby pressing the base plate 2 and the washer ring 22 towards the clamping block 32. On the other hand, due to the rotation of the actuating wheel 59, the open end of the elastic hoop 44 extends into the through hole 592, so that the elastic hoop 44 clamps the steel strand. With the sliding of the support plate 41 away from the clamping block 32 on the guide post 23, it can simultaneously clamp and pull the steel strand outward, so that the prestress after the subsequent steel strand is cut can be additionally compensated, and the prestress loss caused by the retraction of the steel strand due to the departure of the jack 1 can be reduced.

[0031] The rotating rod 51 first tightens the steel strand with the elastic clamp 44. During this process, the support plate 41 slides on the guide post 23, and the support spring 43 plays a buffering role. After the steel strand is tightened, it gradually forms a thrust on the clamping rod 54 to avoid increasing the resistance of the steel strand being pulled outward due to the initial tightening, which would prevent the prestress loss compensation of the steel strand from being achieved.

[0032] Example 3

[0033] like Figures 1-6 As shown, one end of the round rod 51 has a limiting hole 6, and the jack 1 is rotatably connected to the ring 61. The ring 61 is fixedly connected to the motor 62, and the output shaft of the motor 62 is provided with a plug rod 63, which is inserted into the limiting hole 6. The ring 61 rotates freely, and the plug rod 63 of the motor 62 is coaxial with the round rod 51. The plug rod 63 axially extends and retracts to cooperate with the clamp of the motor 62, so that the plug rod 63 of the motor 62 can drive the corresponding round rod 51 to rotate, so that all the bidirectional pressing devices 4 are tightened, thereby realizing the synchronous prestress loss compensation of all steel strands.

[0034] Example 4

[0035] like Figures 1-6 As shown, at least one support plate 41 is fixedly connected to the side rod 7, and the side rod 7 is provided with an elastic hoop plate 44 and a top rod assembly 5 of the same structure, as shown. Figure 1 and Figure 5 For structures with multiple steel strands (one or more at the center of the anchor plate or multiple along the edges), this allows adjacent steel strands in the diameter direction to overlap, facilitating the fastening of multiple steel strands.

[0036] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A prestress loss compensation device for steel strands in a concrete beam, comprising a jack (1), a base plate (2), and an anchoring plate (3), wherein the anchoring plate (3) is provided with anchor holes (31), and clamping blocks (32) are provided in the anchor holes (31); the base plate (2) is provided with clearance holes (21); multiple washers (22) are fixedly connected to the outside of the base plate (2); multiple guide columns (23) are fixedly connected to the base plate (2); and multiple guide columns (23) are slidably connected to a support ring (24), characterized in that: The guide column (23) is axially slidingly connected to the bidirectional top-pressing device (4); The bidirectional pressing device (4) includes a support plate (41), which is slidably and rotatably connected to the guide column (23). Each guide column (23) has a boss (42) at one end away from the bottom plate (2). A support spring (43) is provided between the boss (42) and the support plate (41). An elastic hoop (44) is provided at one end of the support plate (41). A top rod assembly (5) is provided on one side of the elastic hoop (44). The top rod assembly (5) is rotatably connected to the support plate (41). The support ring (24) is fixedly connected to at least two side rods (8). The end of the side rod (8) away from the support ring (24) is fixedly connected to a cross rod (81). The cross rod (81) is threadedly connected to a screw (82). The screw (82) is correspondingly set with the anchor plate (3). Before compensation, the pad ring (22) of the base plate (2) is attached to the clamping block (32). The ends of the side rods (8) and cross rods (81) on the side of the support ring (24) are clamped to the side of the anchor plate (3) by the rotation of the screw (82).

2. The prestress loss compensation device for steel strands in a concrete beam according to claim 1, characterized in that: The top rod assembly (5) includes a round rod (51), a polygonal prism (52), a sleeve (53) and a clamping rod (54). The support plate (41) is provided with a rotating hole (55). The rotating hole (55) is provided with end holes (56) at both ends. A retaining spring (57) is provided inside the end holes (56). The outer circle of the round rod (51) is provided with an annular groove. The retaining spring (57) is provided corresponding to the annular groove. One end of the round rod (51) is fixedly connected to the polygonal prism (52), and the support plate (41) is fixedly connected to the sleeve (53) on one side of the polygonal prism (52). One end of the clamping rod (54) is provided with a polygonal hole, which is slidably connected to the polygonal prism (52). One end of the clamping rod (54) is threadedly connected to the inner wall of the sleeve (53), and the other end of the clamping rod (54) abuts against the base plate (2).

3. The prestress loss compensation device for steel strands in a concrete beam according to claim 2, characterized in that: A clearance cavity (58) is provided in the middle of the rotating hole (55), and a turning wheel (59) is fixedly connected in the middle of the round rod (51). The elastic hoop (44) has a groove (591) spaced on its inner and outer sides in a spiral shape. The teeth of the turning wheel (59) are correspondingly set with the groove (591). The inner end of the elastic hoop (44) is fixedly connected to the side of the support plate (41). The support plate (41) is provided with a through hole (592). The through hole (592) is connected to the clearance cavity (58). The outer end of the elastic hoop (44) passes through the through hole (592).

4. A prestress loss compensation device for steel strands in a concrete beam according to claim 2, characterized in that: The circular rod (51) has a limiting hole (6) at one end, the jack (1) is rotatably connected to the ring (61), the ring (61) is fixedly connected to the motor (62), the output shaft of the motor (62) is provided with a plug rod (63), and the plug rod (63) is inserted into the limiting hole (6).

5. A prestress loss compensation device for steel strands in a concrete beam according to claim 4, characterized in that: At least one support plate (41) is fixedly connected to a side rod (7), and the side rod (7) is provided with an elastic hoop plate (44) and a top rod assembly (5) of the same structure.

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