A hanging basket cantilever box girder end formwork structure free of disassembly

Abstract

This utility model relates to a non-removable formwork structure for the end of a cantilevered box girder, comprising: a precast concrete slab body and positioning bosses; the precast concrete slab body has pre-reserved threaded steel tie rod holes at equal intervals; the precast concrete slab body is divided into a precast concrete slab body casting surface and a precast concrete slab body installation surface, the positioning bosses are evenly spaced around the perimeter of the precast concrete slab body casting surface, and the precast concrete slab body is internally lined with alkali-resistant glass fiber mesh. The beneficial effects of this utility model are: the positioning bosses and the roughened precast concrete slab body casting surface together increase the friction with the box girder concrete, and the threaded steel tie rods welded to the main reinforcement of the box girder improve the connection strength with the main reinforcement, making the formwork, which is a temporary component, a permanent structure, eliminating the impact on the cycle efficiency of the cantilevered segment, and avoiding the deformation of the formwork caused by repeated disassembly and assembly of conventional formwork, which leads to misalignment and deviation of subsequent segment joints.

Description

Technical Field

[0001] This utility model relates to the field of civil engineering bridge construction, and in particular includes a formwork structure for the end of a cantilever box girder that does not require removal. Background Technology

[0002] With the rapid development of my country's transportation industry, the number of bridges being built is increasing daily. Continuous box girder and rigid frame bridges are commonly used bridge structural forms. In the cantilever casting construction of prestressed concrete continuous beam bridges and continuous rigid frame bridges, the installation and removal of end formwork are key aspects affecting construction efficiency and quality. Traditionally, detachable steel or wooden formwork is used at the ends, which presents problems such as cumbersome procedures, risks of concrete damage, and safety hazards associated with working at heights. Therefore, there is an urgent need for a formwork structure that is simple to operate, does not damage the concrete, and has high positioning accuracy. Utility Model Content

[0003] The purpose of this utility model is to overcome the shortcomings of the existing technology and provide a formwork structure for the end of a cantilever box girder that does not require disassembly.

[0004] This type of cantilever box girder end formwork-free structure includes: a precast concrete slab body and positioning bosses; the precast concrete slab body has pre-reserved threaded steel tie rod holes at equal intervals; the precast concrete slab body is divided into a precast concrete slab body casting surface and a precast concrete slab body installation surface, the positioning bosses are equally spaced around the perimeter of the precast concrete slab body casting surface, and the precast concrete slab body is internally lined with alkali-resistant glass fiber mesh.

[0005] Preferably, a threaded steel bar tie rod is inserted through the reserved threaded steel bar tie rod hole, and the main reinforcement of the box girder is provided on one side of the precast concrete slab body casting surface. One end of the threaded steel bar tie rod extends out of the precast concrete slab body casting surface and is welded to the end of the main reinforcement of the box girder. The other end of the threaded steel bar tie rod extends out of the precast concrete slab body installation surface and is fixedly connected to an anchor plate.

[0006] Preferably, the plane formed by the top of several positioning bosses fits into the plane formed by the ends of the main reinforcement bars of the box girder.

[0007] Preferably, the spacing between the pre-reserved threaded steel tie rod holes should match the spacing of the main reinforcement bars of the box girder.

[0008] Preferably, the surface of the precast concrete slab body is rough.

[0009] Preferably, the precast concrete slab body and the positioning boss are an integrated structure.

[0010] The beneficial effects of this utility model are:

[0011] 1) This utility model improves the crack resistance of the precast concrete slab by embedding alkali-resistant glass fiber mesh in the precast concrete slab body; the positioning boss and the roughened casting surface of the precast concrete slab body together increase the friction with the box girder concrete, and at the same time, the threaded steel bar tie rods welded to the main reinforcement of the box girder improve the connection strength with the main reinforcement of the box girder, making the formwork, which is a temporary component, a permanent structure, eliminating the need to remove the end formwork after each pouring, which occupies the critical construction period and affects the cycle efficiency of the cantilevered segment. At the same time, it avoids the deformation of the formwork caused by repeated disassembly and assembly of conventional formwork, which leads to misalignment of subsequent segment joints and deviation of line.

[0012] 2) The precast concrete slab of this utility model has few main body components and a simple structure, and can be mass-produced in the factory, resulting in good economic benefits. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the internal materials of this utility model;

[0014] Figure 2 This is a front view of the present invention;

[0015] Figure 3 This is a side view of the present invention.

[0016] Explanation of reference numerals in the attached drawings: 1. Precast concrete slab body; 2. Reserved threaded steel tie rod hole; 3. Positioning boss; 4. Anchor plate; 5. Main reinforcement of box girder; 6. Threaded steel tie rod; 7. Alkali-resistant glass fiber mesh. Detailed Implementation

[0017] The present invention will be further described below with reference to embodiments. The description of the embodiments below is only for the purpose of helping to understand the present invention. It should be noted that, for those skilled in the art, several modifications can be made to the present invention without departing from the principle of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0018] As one embodiment, a formwork-free end structure for cantilever box girder is proposed, such as... Figure 1-3 As shown, it includes: a precast concrete slab body 1 and positioning bosses 3; the precast concrete slab body 1 has pre-reserved threaded steel tie rod holes 2 at equal intervals; the precast concrete slab body 1 is divided into a precast concrete slab body 1 casting surface and a precast concrete slab body 1 installation surface, the positioning bosses 3 are equally spaced around the perimeter of the precast concrete slab body 1 casting surface, and the precast concrete slab body 1 is internally equipped with alkali-resistant glass fiber mesh 7. By internally equipping the precast concrete slab body with alkali-resistant glass fiber mesh 7, the crack resistance of the precast concrete slab body is improved.

[0019] like Figure 3As shown, a threaded steel bar tie rod 6 passes through the reserved threaded steel bar tie rod hole 2. A box girder main reinforcement 5 is provided on one side of the precast concrete slab body 1. One end of the threaded steel bar tie rod 6 extends out of the precast concrete slab body 1 and is welded to the end of the box girder main reinforcement 5. The other end of the threaded steel bar tie rod 6 extends out of the precast concrete slab body 1 and is fixedly connected to an anchor plate 4. The plane formed by the tops of several positioning bosses 3 fits against the plane formed by the ends of the box girder main reinforcement 5. The spacing between the reserved threaded steel bar tie rod holes 2 matches the arrangement spacing of the box girder main reinforcement 5. The surface of the precast concrete slab body 1 is rough. The concrete slab body 1 and the positioning boss 3 are an integrated structure; the main reinforcement 5 of the box girder is filled with box girder concrete. The positioning boss 3 and the roughened precast concrete slab body pouring surface together increase the friction with the box girder concrete. At the same time, the threaded steel bar tie rod 6 welded to the main reinforcement 5 of the box girder improves the connection strength with the main reinforcement 5 of the box girder, making the formwork, which is a temporary component, a permanent structure. This eliminates the need to remove the end formwork after each pouring, which takes up critical construction time and affects the cycle efficiency of the cantilevered segment. It also avoids the deformation of the formwork caused by repeated disassembly and assembly of conventional formwork, which can lead to misalignment of subsequent segment joints and deviation in alignment.

[0020] This construction method for the cantilever box girder end formwork structure that does not require removal, such as Figure 1-3 As shown, it includes the following steps:

[0021] Step 1: Fabricate the precast concrete formwork body 1 at the end of the box girder according to the design drawings. The strength grade meets the design requirements. The precast concrete formwork body 1 is filled with Φ6@100mm alkali-resistant glass fiber mesh cloth 7, and the pouring surface of the precast concrete formwork body 1 is roughened.

[0022] Step 2: Set pre-reserved threaded steel bar tie rod holes 2 at a spacing of 300mm×300mm for the precast concrete formwork body 1;

[0023] Step 3: Form positioning bosses 3 around the periphery of the concrete formwork body 1 at 300mm intervals, with their height meeting the requirements of the protective layer thickness, and roughen the surface of the concrete formwork body 1.

[0024] Step 4: After the previous segment is completed, move the hanging basket forward into position and measure and verify the fixation of the outer side of the hanging basket web, bottom plate and top plate;

[0025] Step 5: Carry out the segment reinforcement binding construction according to the design drawings. Only after the inspection and approval can the next construction process be carried out.

[0026] Step 6: After the reinforcement bars of the block are tied, the inner side is installed using steel formwork and manual labor with hand-operated hoists to install the inner side of the hanging basket web.

[0027] Step 7: After the inner template is installed, the end template is installed. The precast concrete slab body 1 is closely attached to the main reinforcement 5 of the box girder, and the threaded steel bar tie rod 6 is passed through the reserved threaded steel bar tie rod hole 2. The inner length of the threaded steel bar tie rod 6 is not less than 200mm and is welded to the main reinforcement 5 of the box girder. The exposed length is not less than 250mm and is fixed with the anchor plate 4.

[0028] Step 8: Concrete pouring can only begin after all templates have been installed and passed inspection. Concrete pouring should be symmetrical and evenly layered.

[0029] Step 9: After the concrete strength meets the requirements, except for the end formwork, all other formwork shall be removed as required, and the hanging basket shall be moved forward to the next segment and placed in place.

Claims

1. A formwork structure for the end of a cantilevered box girder that does not require removal, characterized in that, include: The precast concrete slab body and positioning bosses; the precast concrete slab body has pre-reserved threaded steel tie rod holes at equal intervals; the precast concrete slab body is divided into the precast concrete slab body casting surface and the precast concrete slab body installation surface, the positioning bosses are set at equal intervals around the perimeter of the precast concrete slab body casting surface, and the precast concrete slab body is filled with alkali-resistant glass fiber mesh.

2. The formwork structure at the end of the cantilevered box girder that does not require removal, as described in claim 1, is characterized in that... A threaded steel bar tie rod is inserted through the reserved threaded steel bar tie rod hole. The main reinforcement of the box girder is provided on one side of the precast concrete slab body casting surface. One end of the threaded steel bar tie rod extends out of the precast concrete slab body casting surface and is welded to the end of the main reinforcement of the box girder. The other end of the threaded steel bar tie rod extends out of the precast concrete slab body installation surface and is fixedly connected to the anchor plate.

3. The formwork structure at the end of the cantilevered box girder that does not require removal, as described in claim 2, is characterized in that... The plane formed by the top of several positioning bosses fits into the plane formed by the ends of the main reinforcement bars of the box girder.

4. The formwork structure at the end of the cantilevered box girder that does not require removal, as described in claim 2, is characterized in that... The spacing between the pre-reserved threaded steel tie rod holes should match the spacing of the main reinforcement bars of the box girder.

5. The formwork structure at the end of the cantilevered box girder that does not require removal, as described in claim 1, is characterized in that... The surface of the precast concrete slab is rough.

6. The formwork structure at the end of the cantilevered box girder that does not require removal, as described in claim 1, is characterized in that... The precast concrete slab body and the positioning boss are an integrated structure.

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