Railway-crossing small prefabricated concrete box girder wet joint structure

Abstract

The utility model discloses a railway-crossing small prefabricated concrete box girder wet joint structure, which belongs to the technical field of prefabricated box girder wet joints and comprises a prefabricated box girder, pre-embedded U-shaped anchor bars, tie bars, pre-embedded supporting templates, connecting U-shaped supporting anchor bars, permanent templates, connecting bars and a wet joint concrete layer. The embedded U-shaped anchor bars are connected with the tie bars to form a reliable steel bar network system, after the prefabricated box girder is installed, the permanent formwork is connected with the embedded supporting formwork in a welding mode, the U-shaped supporting anchor bars are welded and connected every 1.5 meters, a stable integral structure is formed, and the deformation resistance of the steel plate is effectively enhanced. Compared with the prior art, the utility model not only solves the potential problems of complex construction, high difficulty, high labor cost, large hidden danger coefficient and the like, but also gives consideration to attractive appearance, safety and practical performance.

Description

Technical Field

[0001] The utility model relates to the technical field of wet joints of prefabricated box girders, in particular to a wet joint structure of a small prefabricated concrete box girder spanning a railway. Background Art

[0002] With the rapid economic development of my country in recent years, the construction of bridge infrastructure has continued to increase. For some special bridges, such as those spanning hills, ravines, and railways, prefabricated box girders are erected using bridge erection machines during construction. However, due to the unreasonable structure of the cast-in-place rebar and other factors during wet joint construction, the erection, assembly, and disassembly of the hanging formwork is time-consuming and labor-intensive, resulting in relatively slow construction speeds. The high height below the abutments and the lack of any protective measures pose a high risk. Insecure anchoring can cause falling objects, affecting normal traffic on the railway below. This creates a complex construction environment with a high risk factor. Summary of the Invention

[0003] The purpose of the utility model is to solve the problems raised in the background technology and to provide a wet joint structure of a small prefabricated concrete box girder across a railway.

[0004] The technical solution of the utility model to achieve the above purpose is as follows:

[0005] A wet joint structure of a small prefabricated concrete box girder across a railway comprises a prefabricated box girder and a wet joint construction groove located between adjacent prefabricated box girders, wherein horizontal tie bars are fixed in the prefabricated box girder, and the tie bars extend from the ends of the beam flange plates of the prefabricated box girder to the wet joint construction groove; embedded U-shaped anchor bars are fixed at positions near the ends of the beam flange plates in the prefabricated box girder, and the embedded U-shaped anchor bars are fixedly connected to the tie bars; embedded support templates are fixed to the bottoms of the beam flange plates of the prefabricated box girder, and the embedded support templates extend from the ends of the beam flange plates to the wet joint construction groove, and the embedded support templates are fixedly connected to the bottoms of the embedded U-shaped anchor bars; adjacent The wet joint construction groove between the prefabricated box girders is provided with connecting U-shaped support anchor bars, and connecting bars are fixed on the U-shaped support anchor bars, and the two ends of the connecting bars are respectively fixedly connected to the tie bars extending from the ends of the beam flange plates of the two prefabricated box girders; the bottom of the connecting U-shaped support anchor bars is fixedly connected to the permanent formwork, and the two ends of the permanent formwork are respectively fixedly connected to the embedded support formwork extending from the ends of the beam flange plates of the two prefabricated box girders; a wet joint concrete layer is poured in the wet joint construction groove, and the extended part of the tie bars, the extended part of the embedded support formwork, the U-shaped support anchor bars, the permanent formwork and the connecting bars are all poured in the wet joint concrete layer.

[0006] Preferably, a bridge deck concrete cast-in-place layer is provided on the upper surface of the wet joint concrete layer, and an asphalt concrete surface is provided above the bridge deck concrete cast-in-place layer.

[0007] Preferably, the embedded supporting formwork extends 80 mm beyond the beam edge of the prefabricated box beam.

[0008] Preferably, the embedded support formwork and the permanent formwork are made of galvanized steel plates.

[0009] Preferably, the connection between the connecting reinforcement and the tie reinforcement is wrapped with a steel bar lap tube.

[0010] The utility model provides a wet joint structure of a small precast concrete box girder across a railway, which has the following beneficial effects:

[0011] Through its structural design, this device pre-buries a pre-buried support template at the end of the beam flange plate of the prefabricated box beam in advance during the production of the prefabricated box beam (the prefabricated box beam at the edge is only equipped with one on the inner flange plate), and the pre-buried support template is welded to the pre-buried U-shaped anchor bar, and the pre-buried U-shaped anchor bar is welded to the tie bar to form a reliable steel network system. After the prefabricated box beam is installed, the permanent template is used to cover the two pre-buried support templates to form a semi-enclosed space, and the middle permanent template is connected to the pre-buried support templates on both sides by welding, so as to ensure that no sliding and cracks will occur. The gaps and grout are prevented from leaking. Finally, U-shaped support anchor bars are welded on the permanent formwork at intervals of 1.5 meters. The tie bars extending from the prefabricated box beams are welded with connecting bars, and it is ensured that the connecting bars and the connecting U-shaped support anchor bars are also firmly welded to form a stable overall structure, which effectively enhances the deformation resistance of the steel plate. The connection between the connecting bars and the tie bars is wrapped with a steel lap tube to enhance the strength of the connection. After the prefabricated box beam is installed, the wet joint concrete layer can be poured, and the bridge deck concrete cast-in-place layer and the asphalt concrete surface are poured on the wet joint concrete layer to complete the construction. Compared with the existing technology, the utility model not only solves potential problems such as complex and difficult construction, high labor costs, and a large hidden danger coefficient, but also takes into account aesthetics, safety, and practical performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a partial front view of the wet joint structure of the utility model.

[0013] Figure 2 It is a top view of a bridge deck using the wet joint structure of the present invention (not cast).

[0014] Figure 3 It is a schematic diagram of the explosion structure of the wet joint structure of the utility model.

[0015] Figure 4 It is a cross-sectional view of a bridge body adopting the wet joint structure of the present invention.

[0016] Figure 5 This is a main view of a bridge body adopting the wet joint structure of the utility model.

[0017] In the figure: 1. Prefabricated box girder; 2. Embedded U-shaped anchor bars; 3. Protective device; 4. Tie bars; 5. Embedded support formwork; 6. Rebar lap tube; 7. Connecting U-shaped support anchor bars; 8. Permanent formwork; 9. Connecting bars; 10. Cast-in-place concrete layer of bridge deck; 11. Asphalt concrete surface; 12. Wet joint construction trough; 13. Wet joint concrete layer; 301. Concrete guardrail; 302. Column; 303. Anti-throw net. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0019] In the description of this utility model, it should be noted that the terms "upper / lower end," "inner," "outer," "front end," "rear end," "both ends," "one end," "the other end," and the like, indicating positions or relationships, are based on the positions or relationships shown in the accompanying drawings and are intended solely to facilitate the description of this utility model and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0020] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "set / mounted," "sleeved," "connected," etc., should be understood in a broad sense. For example, "connected" may refer to a fixed connection, a detachable connection, or an integral connection; it may refer to a mechanical connection or an electrical connection; it may refer to a direct connection or an indirect connection through an intermediate medium; it may refer to internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0021] See also Figure 1-5The present embodiment provides a technical solution: a wet joint structure of a small precast concrete box girder across a railway, comprising a precast box girder and a wet joint construction groove 12 located between adjacent precast box girders 1; a horizontally arranged tie bar 4 is fixed in the precast box girder 1, and the tie bar 4 extends from the end of the beam flange plate of the precast box girder 1 to the wet joint construction groove 12; a pre-embedded U-shaped anchor bar 2 is fixed at a position near the end of the beam flange plate in the precast box girder 1; a pre-embedded support template 5 is fixed at the bottom of the beam flange plate of the precast box girder 1, and the pre-embedded support template 5 extends from the end of the beam flange plate to the wet joint construction groove 12, and the pre-embedded support template 5 is fixedly connected to the bottom of the pre-embedded U-shaped anchor bar 2; adjacent precast box girders 1 is provided with a U-shaped support anchor bar 7, and a connecting bar 9 is fixed on the U-shaped support anchor bar 7. The two ends of the connecting bar 9 are respectively fixedly connected to the tie bars 4 extending from the ends of the beam flange plates of the two prefabricated box girders 1; the bottom of the U-shaped support anchor bar 7 is fixedly connected with a permanent formwork 8, and the two ends of the permanent formwork 8 are respectively fixedly connected to the embedded support formwork 5 extending from the ends of the beam flange plates of the two prefabricated box girders 1; a wet joint concrete layer 13 is poured in the wet joint construction groove 12, and the extended part of the tie bar 4, the extended part of the embedded support formwork 5, the U-shaped support anchor bar 7, the permanent formwork 8, and the connecting bar 9 are all poured in the wet joint concrete layer 13.

[0022] In this embodiment, a bridge deck concrete cast-in-place layer 10 is provided on the upper surface of the wet joint concrete layer 13, and an asphalt concrete surface 11 is provided above the bridge deck concrete cast-in-place layer 10; in order to ensure the strength and durability of the wet joint construction groove 12, the wet joint concrete layer 13 uses a special concrete with a higher strength grade than the bridge deck concrete cast-in-place layer 10, and a micro-expansion agent is specially added to enhance the concrete's crack resistance, density and bonding strength with the wet joint interface.

[0023] In this embodiment, the embedded supporting formwork 5 exceeds the beam edge of the prefabricated box beam 1 by 80 mm, ensuring sufficient overlap length and enhancing the integrity of the structure.

[0024] In this embodiment, the embedded support formwork 5 and the permanent formwork 8 are made of galvanized steel plates. The galvanized steel plates have good anti-corrosion properties and extend the service life of the present invention.

[0025] In this embodiment, the connection between the connecting reinforcement 9 and the tie reinforcement 4 is wrapped with a reinforcement lap tube 6 to enhance the strength of the connection.

[0026] In the embodiment, a protective device 3 is installed on the prefabricated box girder 1 located at the edges of both sides of the bridge body. The protective device 3 includes a concrete guardrail 301, a column 302, and an anti-throwing net 303. The concrete guardrail 301 is fixedly connected to the prefabricated box girder 1, the column 302 is fixedly connected to the concrete guardrail 301, and the anti-throwing net 303 is fixedly connected to the column 302. The safety of the construction workers is ensured by pouring the concrete guardrail 301 in the protective device 3 to the outside of the prefabricated box girder 1. The concrete guardrail 301 is equipped with a column 302 to support the anti-throwing net 303 to prevent materials and other items during construction from falling under the bridge, thereby ensuring construction safety.

[0027] In this embodiment: the construction of the utility model is divided into five steps;

[0028] 1. Pre-embedded supporting steel plate 5:

[0029] During factory fabrication, pre-embedded support formwork 5 is embedded within the precast box girder 1. Pre-embedded U-shaped anchor bars 2 are welded onto the pre-embedded support formwork 5 and connected to the tie bars 4 within the precast box girder 1, forming a reliable reinforcement network. This enhances the pre-embedded support formwork 5's deformation resistance and ensures that the loads are synergistically applied to the entire precast box girder 1. The pre-embedded support formwork 5 is located at the bottom of the beam flange plate of the precast box girder 1 and extends 80mm beyond the beam edge. The pre-embedded support formwork 5 is then cast in the wet joint with the permanent formwork 8 as a permanent bottom form.

[0030] 2. Support positioning and installation:

[0031] Before construction, construction workers should clean the slag and gravel from the cap on site, ensuring that there is no debris, gravel, or other debris remaining on the cap surface. After determining the location and drawing the positioning lines, the bearings are precisely placed in the designated position, ensuring that the contact surface between the bearing and the cap is flat and without offset. High-strength expansion bolts are used to secure the shock-absorbing bearings. The centerline of the bearings is further determined and marked. This step is crucial for the subsequent precise docking and overall stability of the bridge structure.

[0032] 3. Hoisting and positioning of prefabricated box beam 1:

[0033] After the prefabricated box girder 1 is transported to the construction site, its appearance and quality are inspected, and it is transferred to the beam transport flat car behind the abutment by a gantry crane. The beam transport flat car is towed by a loader, and the prefabricated box girder 1 is transported to the rear span of the bridge erection machine. The transport flat car is fixed and waits for the bridge erection machine to lift and install it. (The installation and use of the gantry crane must be approved and calibrated by the relevant departments, and the calibration report of the gantry crane must be submitted separately.); According to the actual line center line and pier center line, the center position and the bottom contour line of the precast box girder 1 are measured on the cap beam support pedestal concrete and the shock-absorbing support, and the bottom edge points of each beam slab are determined on the horizontal line of the beam end position of the precast box girder 1 to prepare for the installation of the precast box girder 1. A protective device 3 is installed on the outside of the precast box girder 1 at the edge to ensure the construction safety of the construction workers. The safety of the construction workers is ensured by pouring the concrete guardrail 301 in the protective device 3 on the outside of the precast box girder 1. The concrete guardrail 301 is equipped with columns 302 to support the anti-throw net 303 to prevent materials and other items during construction from falling under the bridge, thereby ensuring construction safety.

[0034] 4. Laying of permanent formwork 8:

[0035] The cast-in-place bridge deck wet joints utilize 8mm galvanized steel sheeting as permanent formwork 8. The permanent base formwork 8 is laid promptly using the skylight points and initially secured to the pre-embedded support formwork 5 pre-installed in the wet joint between the two precast box girders 1 by spot welding. After this initial securing step, a thorough inspection is performed to ensure that no gaps exist along the entire wet joint. The edges connecting the pre-embedded support formwork 5 to the permanent formwork 8 are welded using a full-weld process to ensure a secure connection. After welding, an anti-corrosion paint is applied. After drying, a fire-retardant coating is sprayed on the weld, and any weld slag that may have fallen is thoroughly removed. U-shaped support anchor bars 7 are welded to the center of the permanent formwork 8 at 1.5-meter intervals. Connecting bars 9 of the same type are used to connect the tie bars 4 extending from the precast box girders 1 in the wet joints. These connecting bars 9 are also securely welded to the U-shaped support anchor bars 7, forming a stable overall structure and effectively enhancing the deformation resistance of the permanent formwork 8. The joints are then wrapped with steel lap tubes 6 to enhance the strength of the joints.

[0036] 5. Pouring and maintenance of wet joints:

[0037] After the prefabricated box girder 1 is installed, a wet joint concrete layer 13 is first poured into the wet joint construction groove 12. Then, a bridge deck concrete cast-in-place layer 10 and an asphalt concrete surface 11 are laid on top of the wet joint concrete layer 13. To ensure the strength and durability of the joint area, the wet joint concrete layer 13 is made of special concrete with a higher strength grade than the bridge deck concrete cast-in-place layers 10 on both sides of the joint. A micro-expansion agent is also added to enhance the concrete's crack resistance, density, and bond strength with the joint interface. For special locations such as railway viaducts, due to safety and environmental restrictions, it is difficult to directly sprinkle water on top. To prevent cracks from early shrinkage, a moist geotextile is promptly covered and maintained after the concrete has initially set. The permanent formwork 8 used does not require demoulding after the wet joint has finally set.

[0038] It should be noted that, as used herein, the terms "comprise," "include," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, the phrase "comprising an element defined by..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

[0039] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A wet joint structure for a small precast concrete box girder across a railway, comprising a precast box girder and a wet joint construction groove (12) located between adjacent precast box girders (1), characterized in that: A horizontally arranged tie bar (4) is fixed in the prefabricated box beam (1), and the tie bar (4) extends from the end of the beam flange plate of the prefabricated box beam (1) to the wet joint construction groove (12); a pre-buried U-shaped anchor bar (2) is fixed at a position near the end of the beam flange plate in the prefabricated box beam (1); a pre-buried support template (5) is fixed at the bottom of the beam flange plate of the prefabricated box beam (1), and the pre-buried support template (5) extends from the end of the beam flange plate to the wet joint construction groove (12), and the pre-buried support template (5) is fixedly connected to the bottom of the pre-buried U-shaped anchor bar (2); a connecting U-shaped support anchor bar (7) is provided in the wet joint construction groove (12) between adjacent prefabricated box beams (1), and the U-shaped support anchor bar (7) is fixed to the bottom of the prefabricated box beam (1). ) is fixed with a connecting bar (9), and the two ends of the connecting bar (9) are respectively fixedly connected to the tie bars (4) extending from the ends of the beam flange plates of the two prefabricated box beams (1); the bottom of the U-shaped support anchor bar (7) is fixedly connected to the permanent formwork (8), and the two ends of the permanent formwork (8) are respectively fixedly connected to the embedded support formwork (5) extending from the ends of the beam flange plates of the two prefabricated box beams (1); a wet joint concrete layer (13) is poured in the wet joint construction groove (12), and the extended part of the tie bar (4), the extended part of the embedded support formwork (5), the U-shaped support anchor bar (7), the permanent formwork (8), and the connecting bar (9) are all poured in the wet joint concrete layer (13).

2. The wet joint structure of a small precast concrete box girder across a railway according to claim 1 is characterized in that: A bridge deck concrete cast-in-place layer (10) is provided on the upper surface of the wet joint concrete layer (13), and an asphalt concrete surface (11) is provided above the bridge deck concrete cast-in-place layer (10).

3. The wet joint structure of a small precast concrete box girder across a railway according to claim 1 is characterized in that: The embedded supporting formwork (5) extends 80 mm beyond the beam edge of the prefabricated box beam (1).

4. The wet joint structure of a small precast concrete box girder across a railway according to claim 1, characterized in that: The embedded support formwork (5) and the permanent formwork (8) are made of galvanized steel plates.

5. The wet joint structure of a small precast concrete box girder across a railway according to claim 1, characterized in that: The connection between the connecting reinforcement (9) and the tie reinforcement (4) is wrapped with a reinforcement lap tube (6).

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