Counter-pull supporting device for 0 # box girder cast-in-place construction

Abstract

The utility model discloses a counter-pull supporting device for cast-in-place construction of a 0 # box girder, which relates to the technical field of bridge engineering and comprises a pile foundation, a bearing platform, a pier column, a prestressed tendon, a jacking jack, a construction operation platform, a three-way jack, a 1 # box girder and the 0 # box girder, one end of the prestressed tendon is embedded in the pier column, and the other end of the prestressed tendon is tensioned through the jacking jack. The jacking jack is arranged at the top of the pier column, the construction operation platform is placed at the top of the pier column and supported by the jacking jack, the three-way jack is placed and fixed on the construction operation platform, the 1 # box girder is positioned right above the three-way jack, the 0 # box girder is positioned at the top of the pier column, and the 0 # box girder and the 1 # box girder are tightly attached and connected. The supporting structure has the advantages that the defects of a traditional supporting structure in a large-height bridge and a variable-cross-section pier column are overcome, the repeated utilization rate of equipment is high, the assembly degree is high, and the universality of the equipment is high.

Description

Technical Field

[0001] The utility model relates to the technical field of bridge engineering, and more specifically, it relates to a reverse tension support device for cast-in-place construction of 0# block box girders. Background Art

[0002] Bridge construction is an important part of China's infrastructure construction. As of the end of 2023, there are more than 1 million existing highway bridges in China. The bridge structure includes bridge spans, bearing systems, abutments, piers, and bridge foundations. During the bridge construction process, first, the foundation is treated by burying pile foundations and excavating foundation pits; then the pile cap is poured. After the pile cap construction is completed, the pier columns are poured in layers. Finally, the capping beam is installed on the upper part of the pier column and subsequent pouring is carried out. Before pouring the capping beam, a temporary construction operation platform needs to be set below the capping beam. Since the planar area of the operation platform is much larger than the cross-sectional area of the pier, a support platform needs to be installed for the construction of the capping beam structure.

[0003] The traditional support methods are as follows:

[0004] 1. Scaffold support: Before installing the construction platform, scaffolds are set below it to support the platform. The scaffold is a net structure assembled by multiple members. The members are all made of steel pipes, and the node positions are spherical nodes. The scaffold is a high-order hyperstatic space truss structure with good overall stability, but it has a large amount of work and consumes a lot of materials.

[0005] 2. Steel pipe support: Most steel pipe support frames use one or a few steel pipes. The members are vertically perpendicular and evenly distributed below the construction platform to provide stable vertical force. This kind of support frame needs on-site cutting and welding, which has certain safety hazards and low material reuse rate. And when the height of the structure is too high, the large aspect ratio of the members will lead to an increase in eccentric load, and the safety of this method is low during the construction of high-bridge structures.

[0006] 3. Hoop support: Hoop support is to install hoops on the pier column. The hoops surround the pier column in a circumferential direction. According to the required support force, a reasonable hoop structure or the number of hoops is designed. However, the hoop support is only applicable to cylindrical structures, and the support force of the hoop is greatly affected by the quality of the internal rubber, the friction coefficient, and the hoop tension, with poor stability and high safety risks.

[0007] 4. Embedded support: The embedded support is composed of a steel plate and a steel support. The steel plate has a certain thickness, and there are multiple holes in front of the plate for inserting the steel support frame. There are multiple steel bars welded behind the plate for connecting with the pier column. Before pouring the pier column concrete, the part of the steel bars behind the plate is buried into the pier column. After the concrete is formed, the steel plate and the pier column are connected as a whole, having sufficient support force. Then the steel support is inserted into the holes of the steel plate, and the steel support is supported by the steel plate to provide vertical force for the upper structure construction platform.

[0008] There is currently a construction platform for cast-in-place capping beams or 0# block box girders, where the pier column has a square structure and a flared special-shaped structure at the upper opening, with a maximum height of 27m. The traditional support methods all have certain limitations and need to be improved. Summary of the Invention

[0009] In view of this problem in practical applications, the purpose of the present invention is to propose an anti-pull support device for the cast-in-place construction of 0# block box girders. By embedding prestressed tendons at the top of the pier, placing a steel main beam on the top of the pier, connecting the steel main beams through the embedded prestressed tendons, placing a steel secondary beam above the main beam, and installing a jack above the secondary beam, an anti-pull support device for the cast-in-place construction of 0# block box girders is formed. The construction platform of this anti-pull support device can avoid the deficiencies of traditional support structures in high-height bridges and variable-section pier columns. The specific solutions are as follows:

[0010] An anti-pull support device for the cast-in-place construction of 0# block box girders includes a pile foundation, a bearing platform, and a pier column, and also includes prestressed tendons, jacks for lifting, a construction operation platform, three-way jacks, a 1# block box girder, and a 0# block box girder. One end of the prestressed tendon is buried into the pier column, and the other end is tensioned through the jack for lifting. The jacks for lifting are arranged at the top of the pier column. The construction operation platform is placed on the top of the pier column and supported by the jacks for lifting. The three-way jacks are placed and fixed on the construction operation platform. The 1# block box girder is positioned directly above the three-way jacks. The 0# block box girder is located at the top of the pier column, and the 0# block box girder is closely attached and connected to the 1# block box girder.

[0011] Further, the construction operation platform is composed of a steel main beam and a secondary beam. The steel main beam is placed on both sides near the edge at the top of the pier column, and the secondary beam is placed on the steel main beam.

[0012] Further, the prestressed tendons are arranged at the four corner points at the top of the pier column to provide tensile reaction forces for the construction operation platform.

[0013] Further, the jacks for lifting are arranged at the four corner points at the top of the pier column to provide upward lifting forces for the steel main beam and tensile reaction forces for the prestressed tendons.

[0014] Further, the three-way jacks are placed and bolt-fixed on the secondary beam for the linear adjustment of the 1# block box girder.

[0015] Further, the 1# block box girders are located on both sides of the 0# block box girder.

[0016] Further, it also includes a temporary construction scaffold. The temporary construction scaffold is located on the construction operation platform and on both sides of the 0# block box girder for the casting construction of the flange plate of the 0# block box girder;

[0017] Among them: The temporary construction scaffolding is connected to the steel pipes assembled in sections by bolts.

[0018] Furthermore, horizontal prestressed steel bars are buried between the No. 1 block box girder and the No. 0 block box girder.

[0019] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0020] (1) The present utility model can be applied to ultra-high pier columns with a height exceeding 20m, and is suitable for pier columns with an inclined outer surface, providing a solution for the construction of box girder structures above large-height and special-shaped pier columns.

[0021] (2) The mechanical jacks at the top of the pier column serve as the support points for the operation platform, eliminating the need to erect large-scale scaffolding and steel pipe support columns, simplifying the construction process, reducing the construction space, and cutting down the construction cost.

[0022] (3) After the box girder is poured, when removing the jacks and the steel support brackets, only by lowering the height of the jacks can the formwork be removed. The removal process is simple and will not cause permanent damage to the bridge pier columns.

[0023] (4) Using two jacks to provide vertical support force for the operation platform reduces the consumption of steel and cuts down the construction cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is the front elevation schematic view of the present utility model;

[0025] Figure 2 is the side elevation schematic view of the present utility model.

[0026] Reference numerals: 1, pile foundation; 2, bearing platform; 3, pier column; 4, prestressed steel bar; 5, jack for lifting; 6, construction operation platform; 7, three-way jack; 8, No. 1 block box girder; 9, No. 0 block box girder; 10, temporary construction scaffolding. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments.

[0028] As Figure 1-2 shown, an anti-pulling support device for cast-in-place construction of the No. 0 block box girder includes a pile foundation 1, a bearing platform 2, and a pier column 3. The pile foundation 1 is buried underground, and the bearing platform 2 and the pier column 3 are successively poured on the pile foundation 1. Specifically, during construction, first, the pile foundation 1 is buried underground, the foundation is treated by excavating the foundation pit, and then the bearing platform 2 is poured. After the construction of the bearing platform 2 is completed, the pier column 3 is poured in layers.

[0029] To solve the problem of the limitations of the existing technology in the construction of the 0# block box girder, in this application, prestressed tendons 4 are embedded at the top of the pier, a construction working platform is placed on the top of the pier column 3, and the construction operation platform 6 is connected to the embedded prestressed tendons 4 through jacking jacks 5 to form an inverted tension support device for the in-situ casting of the 0# block box girder. At the same time, three-way jacks 7 that can move in three directions are installed on the construction operation platform 6. The three-way jacks 7 are symmetrically distributed at four positions on the top surface of the pier column 3 to form a pouring support system and a construction platform for the 0# block box girder 9.

[0030] Specifically, the inverted tension support device for the in-situ casting construction of the 0# block box girder further includes prestressed tendons 4, jacking jacks 5, construction operation platform 6, three-way jacks 7, 1# block box girder 8, and 0# block box girder 9.

[0031] Among them: The prestressed tendons 4 are arranged at the four corner points of the top of the pier column 3 to provide a tension reaction force for the construction operation platform 6 of the 0# block box girder 9, forming an inverted suspension support platform. Preferably, the prestressed tendons 4 are 8 prestressed steel bars of ø40mm, with a strength grade of 835 / 1050. One end of the prestressed tendons 4 is buried into the pier column 3, and the other end is tensioned through the jacking jack 5.

[0032] The jacking jacks 5 are arranged on the top of the pier column 3. Preferably, the jacking jacks 5 are 100T jacks. Similarly, the jacking jacks 5 are arranged at the four corner points of the top of the pier column 3 to provide an upward jacking force for the construction operation platform 6, tension the prestressed tendons 4 embedded at the top of the pier, and provide a tension reaction force.

[0033] The construction operation platform 6 and the three-way jacks 7 form a support system. The support system serves both as a load-bearing structure for the box girder construction and as an operation platform. It mainly adopts a space steel frame structure, which is spliced by steel materials, can effectively disperse and bear the loads from all directions, provide a stable and safe working space for the construction, carry the equipment and materials required for the construction, and ensure the smooth progress of the construction process.

[0034] The construction operation platform 6 is placed on the top of the pier column 3 and supported by the jacking jacks 5. Specifically, the construction operation platform 6 is composed of a main steel beam and secondary beams (not shown in the figure). The main beam adopts H762 steel and is placed on both sides near the edge of the top of the pier column 3 as the main load-bearing member of the construction operation platform 6 for the pouring of the 0# block box girder 9; the secondary beam adopts I61 I-beam, and the secondary beam is placed on the main steel beam as an integral part of the pouring construction support platform and operation platform for the 0# block box girder 9. Among them, the main beam is located above the jacking jack 5, and the jacking jack 5 provides an upward jacking force for the main beam to realize the provision of an upward jacking force for the construction operation platform 6.

[0035] The three-way jack 7 is placed and fixed on the construction operation platform 6. The three-way jack 7 is a 25T three-way movable jack, mainly used for the linear adjustment of the 1# block box girder 8, and can adjust the height, longitudinal and transverse horizontal displacements of the box girder. It is connected to the secondary beam by bolts.

[0036] The 1# block box girder 8 is positioned directly above the three-way jack 7. The 1# block box girder 8 is preferably prefabricated, and preferably there are two. The two 1# block box girders 8 are located on both sides of the 0# block box girder 9.

[0037] The 0# block box girder 9 is located at the top of the pier column 3, and the 0# block box girder 9 is closely attached and connected to the 1# block box girder 8.

[0038] During installation, the two 1# block box girders 8 on both sides are connected to the 0# block box girder 9 through the prestress tension of the three-way jack 7.

[0039] See Figure 2 , the anti-pull support device further includes a temporary construction scaffold 10. The temporary construction scaffold 10 is located on the construction operation platform 6 and on both sides of the 0# block box girder 9, and is used for the casting construction of the flange plate of the 0# block box girder 9. Among them: the temporary construction scaffold is connected to the segmented and assembled steel pipes by bolts (not shown in the figure) to ensure the stability and bearing capacity of the support.

[0040] Horizontal prestressed steel bars are buried between the 1# block box girder 8 and the 0# block box girder 9 to fix the 1# block box girder 8 and the 0# block box girder 9.

[0041] In addition, it should be noted that the anti-pull support device of the present application is applicable to pier columns 3 with large height and special-shaped structures. In this embodiment, the pier column 3 is a special-shaped structure with a height exceeding 20m and a trumpet-shaped upper part.

[0042] The specific construction steps of this embodiment are as follows:

[0043] First, pre-embed the prestressed tendons 4: First, bind the vertical steel bars in the pier column 3, and pre-embed the prestressed tendons 4 during the construction of the lower structure of the pier column 3. The pre-embedding process adopts the pouring method;

[0044] Secondly, install the jacking jacks 5: After pouring, 4 jacking jacks 5 are symmetrically installed at the four corner points of the top of the pier column 3. The jacking jacks 5 can provide vertical support force for the construction operation platform 6 directly above it;

[0045] Then, install the main beam, secondary beam, and three-way jack 7 support system: Install the main beam and secondary beam in sequence to form the construction operation platform 6, and install the three-way jacks 7 at the four corner points of the construction operation platform 6 and fix them with bolts. The three-way jacks 7 are located directly below the 1# block box girder 8 to adjust the vertical, transverse, and longitudinal positions of the 1# block box girder 8, and form the support system of the box girder in sequence;

[0046] Next, after the three-way jack 7 is symmetrically installed on both sides, install the 1# block box girders 8 on both sides. The 1# block box girders 8 on both sides are installed simultaneously. After being hoisted to the target position by a crane, they are accurately positioned by the three-way jack 7 to prevent gaps from occurring between the 1# block box girder 8 and the adjacent 0# block box girder 9, and temporary steel bars are tied on the construction platform to fix the 1# block box girder 8;

[0047] After that, set up a temporary construction scaffold 10 for the casting construction of the flange plate of the 0# block box girder 9; the temporary construction scaffold 10 is connected to the segmented assembled steel pipes by bolts to ensure the stability and bearing capacity of the support;

[0048] Then, carry out in-situ casting construction on the 0# block box girder 9 at the top of the pier column 3. First, install the formwork to ensure the accuracy and precision of the main girder installation, that is, install the steel bar framework on the pier column 3, and then carry out the pouring work. During pouring, horizontal prestressed steel bars are buried between the 1# block box girder 8 and the 0# block box girder 9; after the concrete is formed and the strength reaches 40 MPa, the prestressed steel bars are tensioned to fix the 1# block box girder 8 and the 0# block box girder 9;

[0049] Finally, after the prestressed grouting strength reaches 100% of the design requirements, by unloading the reaction force of the jack 5 for lifting, the support system is separated from the main structure of the box girder, and then the temporary construction platform and the anti-pull support device are removed to complete the construction of the box girder.

[0050] The above is only the preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions falling within the idea of the present invention belong to the protection scope of the present invention. It should be noted that for those of ordinary skill in the art in this technical field, several improvements and refinements made without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. An inverted tension support device for cast-in-place construction of 0# block box girders, comprising a pile foundation, a bearing platform, and a pier column, characterized in that, It also includes prestressed tendons, jacks for jacking up, construction operation platforms, three-way jacks, box girders of Block 1, and box girders of Block 0. One end of the prestressed tendons is embedded into the pier column, and the other end is tensioned by the jacks for jacking up. The jacks for jacking up are arranged at the top of the pier column. The construction operation platform is placed on the top of the pier column and supported by the jacks for jacking up. The three-way jacks are placed and fixed on the construction operation platform. The box girders of Block 1 are positioned directly above the three-way jacks. The box girders of Block 0 are located at the top of the pier column, and the box girders of Block 0 are closely attached and connected to the box girders of Block 1.

2. The anti-tension support device for in-situ casting construction of the 0# block box girder according to claim 1, wherein, The construction operation platform is composed of main steel beams and secondary beams. The main steel beams are placed on both sides near the edge at the top of the pier column, and the secondary beams are placed on the main steel beams.

3. The anti-tensile support device for in-situ casting construction of the 0# block box girder according to claim 1, wherein The prestressed tendons are arranged at the four corner points at the top of the pier column and are used to provide tension reaction forces for the construction operation platform.

4. The anti-pulling support device for in-situ casting construction of the 0# block box girder according to claim 2, wherein, The jacks for jacking up are arranged at the four corner points at the top of the pier column and are used to provide upward jacking forces for the main steel beams and tension reaction forces for the prestressed tendons.

5. The anti-pulling support device for in-situ casting construction of the 0# block box girder according to claim 2, characterized in that, The three-way jacks are placed and bolt-fixed on the secondary beams and are used for the linear adjustment of the box girders of Block 1.

6. The anti-pulling support device for in-situ casting construction of the 0# block box girder according to claim 1, characterized in that, The box girders of Block 1 are located on both sides of the box girders of Block 0.

7. The anti-pulling support device for in-situ casting construction of the 0# block box girder according to claim 1, characterized in that, It also includes a temporary construction scaffolding. The temporary construction scaffolding is located on the construction operation platform and on both sides of the box girders of Block 0 and is used for the casting construction of the flange plates of the box girders of Block 0. Wherein: The temporary construction scaffolding is connected to the steel pipes assembled in sections by bolts.

8. The anti-pulling support device for in-situ casting construction of the 0# block box girder according to claim 1, characterized in that Transverse prestressed steel bars are buried between the box girders of Block 1 and the box girders of Block 0.

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