Cantilever hanging formwork

Abstract

The utility model discloses a cantilever hanging formwork, which belongs to the technical field of steel-concrete composite beam bridge construction, and comprises a plurality of shear nails mounted at the centers of two sides of a steel beam side wing plate at equal intervals, two first steel pipe upright posts are mounted on the shear nails, a top support is fixedly connected to the top surfaces of the first steel pipe upright posts, and an I-shaped steel main beam is mounted on the top surface of the top support; the ends, extending out of the steel beams, of the I-shaped steel girders are provided with vertically-arranged second steel pipe stand columns, the ends, away from the second steel pipe stand columns, of the I-shaped steel girders are fixedly connected with n-shaped clamping pieces, the sides, close to the second steel pipe stand columns, of the steel beams are provided with bottom cross beams, and the bottom cross beams and the I-shaped steel girders are fixed through fixing screws. The utility model has good strength, rigidity and stability, can meet the pouring of wing plate concrete, is convenient to assemble and disassemble, can be recycled, saves the construction cost, and can effectively reduce the influence on traffic and environment in complex environments such as urban viaducts, transportation hubs and the like.

Description

Technical Field

[0001] This utility model belongs to the field of construction technology of steel-concrete composite beam bridge, and particularly relates to a cantilever formwork frame. Background Technology

[0002] Steel-concrete composite beam bridges, as a highly efficient, economical bridge structure with excellent mechanical properties, have been widely used in bridge engineering in recent years. After the composite beams are erected, the concrete bridge deck needs to be cast in place. For the concrete pouring at the flanges on both sides of the steel box girder, formwork supports need to be erected. Because many of the bridges under construction are located across rivers or roads, requiring navigation and traffic flow, the conditions for erecting full-span scaffolding are not feasible. Utility Model Content

[0003] The purpose of this invention is to provide a cantilever crane mold to solve the problems existing in the prior art.

[0004] To achieve the above objectives, this utility model provides the following solution: This utility model provides a cantilever formwork frame, including multiple shear studs evenly spaced at the center of both sides of the side wing plate of a steel beam. Two first steel pipe columns are installed on the shear studs. A top support is fixed to the top surface of the first steel pipe column. An I-beam main beam is installed on the top surface of the top support. A second steel pipe column is vertically arranged at one end of the I-beam main beam extending outside the steel beam. A Z-shaped fastener is fixed to the end of the I-beam main beam away from the second steel pipe column. A bottom crossbeam is provided on the side of the steel beam close to the second steel pipe column. The bottom crossbeam is fixed to the I-beam main beam by a fixing screw.

[0005] Preferably, the top of the fixing screw is symmetrically provided with a top longitudinal beam, which is located on the top surface of the I-beam main beam.

[0006] Preferably, the distance between the two first steel pipe columns is 1.5m.

[0007] Preferably, the length of the I-beam main beam is 6m and extends 1.5m beyond the steel beam.

[0008] Preferably, the second steel pipe column is provided with two horizontally arranged second steel pipe columns.

[0009] Preferably, the welding length between the zigzag clip and the I-beam main beam is not less than 20cm.

[0010] Preferably, there are two bottom crossbeams, and the distance between the two bottom crossbeams is 1.5m.

[0011] The present invention discloses the following technical effects: The present invention has good strength, rigidity and stability, can meet the requirements of wing plate concrete pouring, is easy to install and dismantle and can be recycled, saving construction costs, and can effectively reduce the impact on traffic and environment in complex environments such as urban overpasses and transportation hubs. Attached Figure Description

[0012] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0013] Figure 1 This is a schematic diagram of the cantilever formwork frame of this utility model.

[0014] In the diagram: 1. First steel pipe column; 2. Top support; 3. I-beam main beam; 4. Fixing bolt; 5. Bottom crossbeam; 6. Top longitudinal beam; 7. Z-shaped fastener; 8. Second steel pipe column; 9. Steel beam; 10. Shear stud; 11. Bridge deck; 12. Square timber. Detailed Implementation

[0015] Steel-concrete composite beam bridges are composite bridge structures that combine the advantages of steel and concrete. They utilize shear connectors to combine steel beams with concrete bridge decks, enabling them to share loads. The following are its key features:

[0016] I. Structural and Design Features

[0017] Composition and Stress Principle: Steel-concrete composite beams consist of steel beams (such as I-beams and box girders) connected to cast-in-place or precast concrete bridge decks via shear keys (studs, channel steel, bent bars, etc.) to form an integral structure. The steel beams bear the main tensile stress, while the concrete bears the compressive stress, effectively improving load-bearing capacity and stiffness.

[0018] Design Advantages

[0019] Material efficiency: The amount of steel used is reduced by about 30% compared to pure steel structures, and the amount of concrete used is reduced compared to traditional bridges, resulting in a more economical overall cost.

[0020] Stiffness and stability: The moment of inertia of the composite beam section can reach 1.64 times that of the pure steel beam, significantly reducing deflection and making it suitable for long-span bridges (such as 60-480 meters).

[0021] Convenient construction: Steel beams and bridge decks can be prefabricated, reducing on-site formwork procedures and shortening the construction period (such as the Nanjiemen Yangtze River Rail Bridge, which uses prefabricated bridge decks + cast-in-place wet joints).

[0022] Key technologies

[0023] Shear connectors: studs are the most commonly used, while channel steel is suitable for applications with lower welding quality requirements, but shear strength and fatigue performance must be considered.

[0024] Variable cross-section design: Steel beams near the central pier are often thickened to cope with sudden changes in bending moment and shear force. The cross-sectional matching between the steel beam and the bridge deck needs to be adjusted parametrically using software (such as CSiBridge).

[0025] II. Construction Technology and Challenges

[0026] Steel beams are mostly prefabricated in factories (such as Q345B steel), transported to the site, and then hoisted in sections, connected by welding or bolts to form a whole. For example, the steel beams of the Chongqing Nanjimen Bridge adopt a longitudinal and transverse beam system, with standard segments being 10.5 meters long. They are hoisted by masts and assembled symmetrically using cantilever methods.

[0027] Bridge deck construction

[0028] Precast + Cast-in-place: Wet joints are poured after the precast bridge deck is installed, or it can be cast directly on the steel beam (requires special casting equipment to reduce formwork support).

[0029] Construction techniques in frigid regions: A bridge in Harbin used suspended formwork made of high-strength threaded steel bars to avoid full-span scaffolding and controlled the concrete pouring time to reduce deformation due to temperature differences.

[0030] Special working conditions response

[0031] Construction across existing roads: For example, the Qijiazhuanggou Grand Bridge in Beijing uses a suspension-disc-locking combined support system to avoid occupying main traffic arteries while protecting the appearance of the weathering steel beams.

[0032] Shrinkage and creep control: The effects of long-term concrete deformation are offset by pre-camber design (such as the camber of a bridge in Aksu, which is 10-11 mm).

[0033] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0034] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] Reference Figure 1As shown, this embodiment provides a cantilever formwork frame, including multiple shear studs 10 evenly spaced on the center of both sides of the side wing plate of the steel beam 9. Two first steel pipe columns 1 are installed on the shear studs 10. A top support 2 is fixed to the top surface of the first steel pipe column 1. An I-beam main beam 3 is installed on the top surface of the top support 2. A second steel pipe column 8 is provided at one end of the I-beam main beam 3 extending outside the steel beam 9. A Z-shaped fastener 7 is fixed to the end of the I-beam main beam 3 away from the second steel pipe column 8. A bottom crossbeam 5 is provided on the side of the steel beam 9 close to the second steel pipe column 8. The bottom crossbeam 5 is fixed to the I-beam main beam 3 by a fixing screw 4.

[0036] The rigid connection between shear studs 10 and the side flanges of steel beam 9 ensures uniform load distribution, preventing lateral displacement caused by localized stress concentration during concrete pouring. The combination of the first steel pipe column 1 and the top support 2 forms a vertical support system, which, together with the cantilever design of the I-beam main beam 3, effectively disperses the load on the cantilever flanges. The second steel pipe column 8 and the bottom crossbeam 5 form a lateral stability frame through fixing bolts 4, significantly improving the formwork's anti-overturning capacity. This structural design ensures the stiffness of the cantilever end (6m long I-beam main beam, 1.5m cantilever) while enabling rapid installation, dismantling, and reuse, making it particularly suitable for space-constrained scenarios such as urban viaducts.

[0037] This utility model has good strength, rigidity and stability, can meet the requirements of wing plate concrete pouring, is easy to install and dismantle and can be recycled, saving construction costs. In complex environments such as urban overpasses and transportation hubs, it can effectively reduce the impact on traffic and the environment.

[0038] To further optimize the design, a top longitudinal beam 6 is symmetrically provided at the top of the fixing screw 4, and the top longitudinal beam 6 is located on the top surface of the I-beam main beam 3.

[0039] The top longitudinal beams 6 are symmetrically arranged on top of the fixing bolts 4, further enhancing the lateral stiffness of the I-beam main beam 3. This design uses double longitudinal beams to constrain the lateral deformation of the I-beam, preventing excessive deflection at the cantilever end due to uneven load during concrete pouring.

[0040] The design was further optimized, with the spacing between the two first steel pipe columns 1 being 1.5m. The height was determined based on the pouring thickness of the bridge deck 11 and the construction space requirements. PVC sleeves were installed on the outside of the first steel pipe columns 1 for easy removal and extraction later. The first steel pipe columns 1 were made of φ48 steel pipes, and a 25# I-beam main beam 3 was installed inside the top support 2.

[0041] The 1.5m spacing of the first steel pipe columns is based on the optimized mechanical properties of the steel-concrete composite beam, which can meet the uniformly distributed load requirements (approximately 3-5 kN / m) during the pouring of the wing plate concrete. 2 This avoids both congestion of construction space caused by excessively dense columns.

[0042] The design was further optimized so that the length of the I-beam main beam 3 is 6m and extends 1.5m beyond the steel beam 9. Vertical and horizontal φ48 second steel pipe columns 8 are welded to the ends of the I-beam main beam 3 to serve as protective railings for construction.

[0043] To further optimize the design, two horizontally arranged second steel pipe columns 8 are provided on the second steel pipe column 8.

[0044] The transverse double-column arrangement of the second steel pipe column 8 forms a "portal frame," significantly improving the torsional resistance of the formwork in the cantilever direction. This design is particularly suitable for stability control under wind loads or dynamic construction loads (such as pump truck vibration).

[0045] Further optimization of the design ensures that the welding length between the U-shaped clamp 7 and the I-beam main beam 3 is no less than 20cm. Based on the height, dimensions, and position of the I-beam main beam 3, U-shaped clamps are fabricated using φ16 round steel and welded to the installed steel box girder to fix the I-beam main beam 3. The welding length is no less than 20cm, and the weld should be full to ensure welding quality. The welding length of the U-shaped clamp 7 to the I-beam main beam 3 is ≥20cm, ensuring the shear strength of the joint area (up to 1.2 times the weld design strength). This highly reliable connection method avoids the loosening defects of traditional bolted connections.

[0046] The design was further optimized by installing two bottom crossbeams 5, with a spacing of 1.5m between the two bottom crossbeams 5.

[0047] The main I-beam 3 and the bottom crossbeam 5 of the formwork frame are fixed at the elevation by two M16 bolts at 1.5m intervals as the lifting structure for the cast-in-place concrete formwork of the flange. The bottom crossbeam 5 is made of two No. 10 channel steels arranged horizontally at a distance of 1.5m and fixed by fixing bolts 4. 10*10cm square timber 12@30cm is laid up the bridge as the formwork support.

[0048] In the description of this utility model, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0049] The embodiments described above are merely preferred embodiments of the present utility model and are not intended to limit the scope of the present utility model. Various modifications and improvements made to the technical solutions of the present utility model by those skilled in the art without departing from the spirit of the present utility model should fall within the protection scope defined by the claims of the present utility model.

Claims

1. A cantilever formwork support, characterized in that: The structure includes multiple shear studs (10) evenly spaced on both sides of the center of the side wing plate of the steel beam (9). Two first steel pipe columns (1) are installed on the shear studs (10). A top support (2) is fixed to the top surface of the first steel pipe column (1). An I-beam main beam (3) is installed on the top surface of the top support (2). A second steel pipe column (8) is vertically arranged at one end of the I-beam main beam (3) extending outward from the outside of the steel beam (9). A Z-shaped fastener (7) is fixed to one end of the I-beam main beam (3) away from the second steel pipe column (8). A bottom crossbeam (5) is provided on the side of the steel beam (9) close to the second steel pipe column (8). The bottom crossbeam (5) is fixed to the I-beam main beam (3) by a fixing screw (4).

2. The cantilever formwork frame according to claim 1, characterized in that: The top of the fixing screw (4) is symmetrically provided with a top longitudinal beam (6), which is located on the top surface of the I-beam main beam (3).

3. The cantilever formwork frame according to claim 1, characterized in that: The distance between the two first steel pipe columns (1) is 1.5m.

4. The cantilever formwork frame according to claim 1, characterized in that: The length of the I-beam main beam (3) is 6m and extends 1.5m beyond the steel beam (9).

5. The cantilever formwork frame according to claim 1, characterized in that: The second steel pipe column (8) is provided with two horizontally arranged second steel pipe columns (8).

6. The cantilever formwork frame according to claim 1, characterized in that: The welding length between the zigzag clamp (7) and the I-beam main beam (3) shall not be less than 20cm.

7. The cantilever formwork frame according to claim 1, characterized in that: There are two bottom crossbeams (5), and the distance between the two bottom crossbeams (5) is 1.5m.

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