Internal and external combined pushing system for horizontal pushing of continuous rigid frame bridge

Abstract

The utility model relates to the technical field of bridge construction, and discloses an internal and external combined pushing system for horizontal pushing of a continuous rigid frame bridge, which comprises a plurality of pushing counter-force frames, one ends of the pushing counter-force frames are arranged on the end faces of web plates of cantilever beam sections on two sides of a midspan closure section, the other ends of the pushing counter-force frames are abutted against jacks, and the jacks push the cantilever beam sections through the pushing counter-force frames; the stiff frameworks are used for being installed on box girder top plates and bottom plates at the ends of cantilever beam sections on the two sides of a midspan closure section, the top plate and the bottom plate of the first side box girder are fixedly connected with one ends of the stiff frameworks, and after the jack is pushed in place, the top plate and the bottom plate of the second side box girder are correspondingly and temporarily locked with the other ends of the stiff frameworks; the internal pushing counter-force frame and the jack are adopted for pushing, the force transmission mechanism is clear, no additional bending moment is generated, and stress on the box girder of the closure section is facilitated; the external stiff framework is adopted for temporary locking, and the pushing reaction frame can be detached after locking, so that the cracking risk of subsequent steel beam tensioning is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of bridge construction, in particular to a body and an outside combined jacking system for horizontal jacking of a continuous rigid frame bridge. Background Art

[0002] The shrinkage and creep of the concrete in the upper structure of the prestressed concrete continuous rigid frame bridge causes the pier top to shift toward the middle of the span. Especially for the short pier and long span continuous rigid frame bridge, due to the large rigidity of the pier, the excessive displacement of the pier top will cause a large permanent bending moment at the pier top and pier bottom, which greatly reduces the stability of the pier. Therefore, before the closure of the middle span, a set of horizontal thrusts are applied to the ends of the cantilever beam sections on both sides of the closure section, so that the main pier top will produce a certain amount of pre-deflection to both sides, generating a bending moment and displacement opposite to the shrinkage and creep of the concrete, which is used to offset part of the permanent internal force and displacement generated by the shrinkage and creep of the concrete after the bridge is completed, thereby improving the force and stability of the pier body. The jacking and temporary locking of the closure section of the continuous rigid frame bridge generally adopts a rigid support structure (also known as a rigid skeleton). After the jacking is completed, the rigid skeleton is promptly connected and locked, and then the closure section concrete is poured.

[0003] In the early days, the rigid skeleton was mostly internal, that is, the rigid skeleton and the jacking device were installed in the concrete pouring surface of the box girder. After the concrete of the closing section was poured, the rigid skeleton was completely contained in the rigid skeleton, and the rigid skeleton was retained in the box girder as a permanent structure. However, due to the influence of the cross-sectional width of the box girder, the rigid skeleton is easy to interfere with the position of the corrugated pipe and the steel bars in the box girder. When the steel strands of the closing section of the middle span are tensioned, the internal rigid skeleton will absorb most of the compressive stress from the prestressed steel strands, resulting in a decrease in the compressive stress reserve of the concrete in the closing section, increasing the risk of cracking.

[0004] In view of the above reasons, in recent years, the rigid skeleton has mostly adopted an external type, that is, the rigid skeleton and the jacking device are located outside the concrete pouring surface. After the concrete pouring of the closing section is completed, it needs to be removed. It is a temporary component and does not participate in the force of the beam body. Its characteristics are that it does not interfere with the positioning and binding of the corrugated pipe and ordinary steel bars in the closing section, and the construction is convenient; it does not share the compressive stress from the prestressed steel strands, and the compressive stress reserve of the closing section concrete is sufficient. However, when pushing externally, it is necessary to embed the jacking base in advance. When designing the jacking base, due to the small thickness of the top and bottom plates of the box beam (generally 25cm to 35cm), there is a problem of insufficient depth when directly burying anchors such as steel plate bolts, so the thickness of the top and bottom plates needs to be partially increased. This scheme has the following defects: First, the structure and force transmission mechanism are complicated. The longitudinal thrust is first transmitted to the embedded steel plate through the rigid support, then transmitted to the top and bottom plate thickening blocks through the embedded steel plate, and finally transmitted to the beam concrete; Second, the resultant force point of the jacking action does not coincide with the center of gravity of the box beam section, the additional bending moment is large, and vertical displacement and torsional deformation are easily generated. Utility Model Content

[0005] In view of the shortcomings of the prior art, the purpose of the utility model is to provide an internal and external combined jacking system for horizontal jacking of a continuous rigid frame bridge. By adopting an internal jacking reaction frame and a jack for jacking, the force transmission mechanism is clear, no additional bending moment is generated, and it is beneficial to the stress of the box girder in the closing section; an external rigid frame is used for temporary locking, and the jacking reaction frame can be disassembled after locking, thereby reducing the risk of cracking during subsequent steel bundle tensioning.

[0006] In order to achieve the above purpose, the utility model is implemented through the following technical solutions:

[0007] A combined internal and external jacking system for horizontal jacking of a continuous rigid frame bridge, comprising:

[0008] A plurality of jacking reaction frames, one end of which is arranged on the end surface of the web of the cantilever beam section on both sides of the mid-span closure section, and the other end is abutted against the jack, and the jack pushes the cantilever beam section through the jacking reaction frame;

[0009] Several rigid frames are used to be installed on the top and bottom plates of the box beam at the ends of the cantilever beam sections on both sides of the mid-span closure section. The top and bottom plates of the box beam on the first side are fixedly connected to one end of the rigid frame. After the jack is pushed into place, the top and bottom plates of the box beam on the second side are temporarily locked with the other end of the rigid frame respectively. Several rigid frames are arranged in parallel.

[0010] As a further implementation method, the thrust reaction frame is welded by an I-beam and a tie plate, and steel pads are provided at both ends of the I-beam.

[0011] As a further implementation, the steel plate at the first end is embedded in the end surface of the web, and the steel plate at the second end is used to abut against the jack.

[0012] As a further implementation method, the rigid frame is welded by I-beams and tie plates, and the top plate and bottom plate surfaces at the ends of the cantilever beam section are pre-embedded with steel plates, which are used for welding connection with the rigid frame.

[0013] As a further implementation method, the steel pad is embedded in the end surface of the web by anchoring steel bars.

[0014] As a further implementation method, the steel plate is embedded in the top plate and bottom plate surfaces of the box beam at the end of the cantilever beam section by anchoring steel bars.

[0015] As a further implementation, the rigid frame and the thrust reaction frame are arranged in parallel.

[0016] As a further implementation method, an anchor steel mesh is pre-embedded in the end surface of the web of the cantilever beam section, and the anchor steel mesh is located at the position of the anchor steel bars on the steel pad.

[0017] As a further implementation, the thrust reaction frames at the web end surfaces on the cantilever beam section are arranged at the same height.

[0018] As a further implementation, the rigid skeleton is provided at least at two locations on the top plate and the bottom plate.

[0019] The beneficial effects of the above utility model are as follows:

[0020] 1. The utility model adopts an internal jacking reaction frame and a jack for jacking, and the force transmission mechanism is clear, and no additional bending moment is generated, which is beneficial to the force of the box girder in the closing section; an external rigid frame is used for temporary locking, and the jacking reaction frame can be disassembled after locking, thereby reducing the risk of cracking during subsequent steel bundle tensioning.

[0021] 2. The jacking system of the utility model has little interference with the construction of the closing section, is easy to construct, and does not affect the stress reserve of the concrete of the closing section; the temporary locking rigid frame and the jacking reaction frame can be reused, saving costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention.

[0023] Figure 1 It is a cross-sectional structural schematic diagram of a combined internal and external jacking system for horizontal jacking of a continuous rigid frame bridge in an embodiment of the utility model;

[0024] Figure 2 It is a schematic diagram of the horizontal elevation structure of a combined internal and external jacking system for horizontal jacking of a continuous rigid frame bridge in an embodiment of the utility model;

[0025] Figure 3 It is a schematic diagram of the structure of the rigid skeleton in the embodiment of the utility model;

[0026] Figure 4 It is a structural schematic diagram of a top push reaction frame in an embodiment of the utility model;

[0027] Figure 5 It is a schematic structural diagram of the anchored steel mesh in an embodiment of the utility model.

[0028] In the figure: the distances or sizes between parts are exaggerated to show the positions of various parts, and the schematic diagram is for reference only.

[0029] Among them: 101. Rigid frame, 102. Thrust reaction frame, 103. Jack, 104. Steel plate, 105. Steel pad, 106. Anchor steel bars, 107. Anchor steel mesh, 108. I-beam, 109. Tie plate. DETAILED DESCRIPTION

[0030] It should be noted that the following detailed descriptions are all illustrative and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0031] Embodiment 1

[0032] In a typical implementation of the present invention, reference is made to Figure 1-Figure 5 As shown, a combined internal and external jacking system for horizontal jacking of a continuous rigid frame bridge includes cantilever beam sections on both sides of an uncast middle span closure section, a plurality of jacking reaction frames 102, a plurality of rigid frames 101, jacks 103, steel plates 104, steel pads 105, anchoring steel bars 106, steel mesh under the anchor 107, I-beams 108, and tie plates 109.

[0033] like Figure 2 As shown, it is a schematic diagram of the cross-elevation structure of a combined internal and external jacking system for horizontal jacking of a continuous rigid frame bridge. The middle area needs to be poured with concrete later to form a mid-span closure section, and both sides are cantilever beam sections. Before the mid-span closure is carried out, a group of horizontal thrusts are applied to the ends of the cantilever beam sections on both sides of the closure section. The jacks push the end faces of the cantilever beam sections to both sides through the jacking reaction frame 102, so that the top of the main pier produces a certain amount of pre-deflection to both sides, generating bending moment and displacement opposite to the shrinkage and creep of concrete, which are used to offset part of the permanent internal force and displacement caused by the shrinkage and creep of concrete after the bridge is completed, thereby improving the force and stability of the pier body.

[0034] like Figure 3 As shown, the rigid frame 101 is welded by two parallel arranged I-beams 108 and a gusset plate 109, the gusset plate 109 is welded to one side flange plate of the I-beam 108, thereby fixing the two I-beams 108 together, and the other side flange plates of the two I-beams 108 are used to be welded to the steel plate 104 as a whole.

[0035] like Figure 1 , Figure 2 , Figure 3 As shown, the steel plate 104 is used to be pre-buried in advance at the top plate and bottom plate plane of the box beam at the ends of the cantilever beam sections on both sides. A plurality of anchoring steel bars 106 are welded at the bottom of the steel plate to improve the anchoring strength of the steel plate 104. The top surface of the steel plate 104 is exposed on the top plate and bottom plate surface, and is used to be welded and fixed to the other side flange plates of the two I-beams 108.

[0036] like Figure 4As shown, the push reaction frame is welded by two I-beams 108 and a gusset plate 109, and the flange plates on both sides of the two I-beams 108 are welded to the gusset plate 109 to form an integrated structure. During the construction process, both ends of the I-beam need to be welded with the steel pad 105.

[0037] like Figure 1 As shown, two jacking points are arranged on the end faces of the two webs of the cantilever beam sections on both sides of the mid-span closure section, and the two jacking points have the same height and are located in the middle position in the height direction of the webs.

[0038] like Figure 1 and Figure 2 As shown, during construction, the steel pad 105 needs to be pre-buried at the end surface of the web, and the first end of the push reaction frame 102 is used to be welded to the steel pad 105 through the gusset plate 109. The steel pad at the second end of the push reaction frame 102 is used to abut the jack.

[0039] The steel plate is embedded in the end face of the web through anchoring steel bars 106 to improve the strength. At the same time, in order to prevent the web from being cracked at the pushing point when the box beam is pushed to both sides by a jack, an anchor steel mesh 7 is embedded in advance at this position of the web of the box beam to improve the strength. Specifically, an anchor steel mesh is embedded in the end face of the web of the cantilever beam section, and the anchor steel mesh is located at the position of the anchor steel bars 106 on the embedded steel plate 105.

[0040] The thrust reaction frame 102 at the web end face on the cantilever beam section is set at the same height, and one side of the embedded steel pad 105 is flush with the web end face to facilitate welding with the supporting plate 109 on the end face of the thrust reaction frame 102 as a whole.

[0041] This embodiment requires the use of four groups of thrust reaction frames 102. In the box girders on the left and right sides, the web end faces on the same side are connected to one group of thrust reaction frames 102 through pre-buried steel pads. Jacks can be installed between the two groups of thrust reaction frames 102. Therefore, two groups of jacks are provided. The two groups of jacks can push the box girder to the left and right sides to produce a certain amount of pre-bias.

[0042] like Figure 1 and Figure 2 As shown, the rigid frame 101 is used to be installed on the top plate and bottom plate of the box beam at the ends of the cantilever beam sections on both sides of the mid-span closure section. The top plate and bottom plate of the first side box beam are fixedly connected to one end of the rigid frame 101. After the jack 103 is pushed into place, the top plate and bottom plate of the second side box beam are temporarily locked with the other end of the rigid frame 101.

[0043] This embodiment is provided with four sets of rigid frames 101 arranged in parallel, the four sets of rigid frames 101 are arranged along the length direction of the box beam, and the rigid frames 101 and the thrust reaction frames 102 are arranged in parallel.

[0044] like Figure 1 As shown, the rigid frame 101 is arranged at two locations on the top plate and the bottom plate, the rigid frame 101 is arranged close to the web, and the steel plate 104 is embedded in the top plate and the bottom plate surface of the box beam at the end of the cantilever beam section through the anchor steel bar 106.

[0045] Working principle: Anchor steel bars 106 are welded to embedded steel plates 104 and steel pads 105. Steel plates 104, steel pads 105 and anchor steel mesh 107 are pre-embedded at the ends of the largest cantilever beams on both sides of the mid-span closure section according to the predetermined positions. Two I-beams are welded to form a rigid skeleton 101 and a top thrust reaction frame 102 through a tie plate.

[0046] When closing the top push, the top push reaction frame 102 is welded to the steel pad 105 at the web, and the steel pad 105 is welded to the other end of the top push reaction frame 102. One end of the rigid frame 101 is welded to the embedded steel plate 104, and the other end is temporarily kept free to move.

[0047] The jack 103 is placed between the jacking reaction frames 102, and the jacking force is loaded in stages according to the jacking force requirements. After the jacking is in place, the free end of the rigid frame 101 is welded to the embedded steel plate 104 in time for temporary locking.

[0048] After the temporary locking of the rigid frame 101 is completed, the jack 103 can be unloaded and the top push reaction frame 102 can be removed. The closing section of the box girder undergoes processes such as formwork erection, steel bar binding, and concrete pouring. When the concrete strength of the closing section reaches the design requirements, the rigid frame 101 is cut and removed, and the steel strands of the closing section are tensioned to complete the closing of the entire bridge.

[0049] The above-mentioned jacking system of this embodiment has a simple structure, a clear force transmission mechanism, and does not generate additional bending moment, which is beneficial to the force of the box girder in the closing section; it has little interference with the construction of the closing section, is convenient for construction, and does not affect the stress reserve of the concrete in the closing section. In addition, the temporary locking rigid frame and the jacking reaction frame can be reused, saving costs.

[0050] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A combined internal and external jacking system for horizontal jacking of a continuous rigid frame bridge, characterized in that: include: A plurality of jacking reaction frames, one end of which is arranged on the end surface of the web of the cantilever beam section on both sides of the mid-span closure section, and the other end is abutted against the jack, and the jack pushes the cantilever beam section through the jacking reaction frame; Several rigid frames are used to be installed on the top and bottom plates of the box beam at the ends of the cantilever beam sections on both sides of the mid-span closure section. The top and bottom plates of the box beam on the first side are fixedly connected to one end of the rigid frame. After the jack is pushed into place, the top and bottom plates of the box beam on the second side are temporarily locked with the other end of the rigid frame respectively. Several rigid frames are arranged in parallel.

2. The internal and external combined jacking system for horizontal jacking of a continuous rigid frame bridge according to claim 1 is characterized in that: The thrust reaction frame is welded by an I-beam and a tie plate, and steel pads are arranged at both ends of the I-beam.

3. The internal and external combined jacking system for horizontal jacking of a continuous rigid frame bridge according to claim 2 is characterized in that: The steel plate at the first end is pre-buried at the end surface of the web, and the steel plate at the second end is used to abut against the jack.

4. The internal and external combined jacking system for horizontal jacking of a continuous rigid frame bridge according to claim 1 is characterized in that: The rigid frame is welded by I-beams and tie plates, and the top plate and bottom plate surfaces at the ends of the cantilever beam sections are pre-embedded with steel plates, which are used for welding connection with the rigid frame.

5. The internal and external combined jacking system for horizontal jacking of a continuous rigid frame bridge according to claim 3 is characterized in that: The steel pad is pre-embedded at the end surface of the web through anchoring steel bars.

6. The internal and external combined jacking system for horizontal jacking of a continuous rigid frame bridge according to claim 4 is characterized in that: The steel plates are pre-embedded in the top plate and bottom plate surfaces of the box beam at the ends of the cantilever beam sections through anchored steel bars.

7. The internal and external combined jacking system for horizontal jacking of a continuous rigid frame bridge according to claim 1 is characterized in that: The rigid frame and the thrust reaction frame are arranged in parallel.

8. The internal and external combined jacking system for horizontal jacking of a continuous rigid frame bridge according to claim 5 is characterized in that: An anchor steel mesh is pre-embedded in the end surface of the web of the cantilever beam section, and the anchor steel mesh is located at the position of the anchor steel bars on the steel pad.

9. The internal and external combined jacking system for horizontal jacking of a continuous rigid frame bridge according to claim 1 is characterized in that: The thrust reaction frames at the end faces of the webs on the cantilever beam sections are arranged at the same height.

10. The internal and external combined jacking system for horizontal jacking of a continuous rigid frame bridge according to claim 1 is characterized in that: The rigid frame is arranged at least at two locations on the top plate and the bottom plate.

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