A formwork for the front support of the main girder of a cable-stayed bridge and a cantilever construction method

Abstract

This invention relates to the field of cable-stayed bridge main girder technology, and in particular to a cable-stayed bridge main girder front support hanging basket and cantilever construction process, including a bearing platform with an adjustable formwork system fixed on both sides of the platform's traveling end. The cable-stayed bridge main girder front support hanging basket of this invention, by installing an electrically controlled suspension system on the bearing platform, can be adapted to different cable-stayed bridge main girders with varying structures through angle and height adjustments, making it highly applicable. The use of a water-bag pre-stressing method for the hanging basket improves the efficiency of loading and unloading, reduces labor input, increases data acquisition accuracy, and lowers construction costs. By adding a hanging basket cantilever and combined platform to the front crossbeam cantilever of the front support hanging basket as a bearing platform for the main girder closure section construction, the closure section construction can be carried out without moving the hanging basket forward, avoiding the need for separate formwork supports for the closure section, ensuring the construction period of the closure section, reducing construction costs, and improving the accuracy of main girder closure.

Description

Technical Field

[0001] This invention relates to the field of cable-stayed bridge main girder technology, and in particular to a hanging basket for the front support of a cable-stayed bridge main girder and a cantilever casting process. Background Technology

[0002] As a type of cable-stayed bridge, cable-stayed bridges have a greater span capacity than beam bridges and possess excellent mechanical properties and economic indicators, making them the most important type of long-span bridge.

[0003] As cable-stayed bridges (including double-tower and single-tower bridges) develop towards larger spans, they all face a very specific problem: excessively long cantilever and excessive weight. Their development has moved in the following three directions: (1) hybrid beam cable-stayed bridges; (2) lightweight concrete beam cable-stayed bridges; (3) cable-stayed bridges using a cooperative system.

[0004] The main girder forms of cable-stayed bridges in my country are as follows: concrete girder bridges primarily use box girder, slab girder, and side-box / center-slab girder types; steel girder bridges mainly use orthotropic steel box girder bridges, with some side-box / center-slab girder types also existing. Concrete cable-stayed bridges are mostly constructed using the cantilever casting method. Cantilever casting has become an effective construction method for building large and medium-span bridges.

[0005] As a key piece of equipment in cantilever construction, the hanging basket plays a crucial role in bridge construction and is favored by construction companies. In my country, the design and manufacturing of hanging baskets have gradually evolved from the initial parallel truss type to a more diversified approach, with increasingly lightweight structures, more rational stress distribution, more convenient construction, and wider applications. With my country's economic development and increased investment in infrastructure, bridges are constantly emerging. Hanging baskets have significant development potential in bridge construction. In the future, hanging basket equipment will tend towards standardization, serialization, and factory production, with high reusability, which will help shorten construction time and save costs.

[0006] The use of front-support cable-stayed bridge main beams for construction with formwork is a mature technology. However, due to the different widths of the main beams, the requirements for the arrangement of the formwork during the cantilever construction process vary. This makes it difficult to quickly adjust the main beams in different states, resulting in complicated operations and limited applicability. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide an improved formwork for the front support of the main girder of a cable-stayed bridge and a cantilever casting process, in order to solve the problem that the current formwork cannot quickly adjust the main girder of the bridge in different states, resulting in complicated operation and low applicability.

[0008] The technical solution adopted by the present invention to solve its technical problem is: a hanging basket for the front support of the main beam of a cable-stayed bridge, including a bearing platform, wherein an adjustable template system is bolted to both sides of the walking end of the bearing platform, and an electrically controlled suspension system is movably assembled on both sides of the bearing platform, wherein a suspended walking device is installed on the top surface of the electrically controlled suspension system.

[0009] The adjustable formwork system includes: a bottom support frame fixed on both sides of the traveling end of the bearing platform, a side box bottom formwork bolted to the upper end of the bottom support frame, a flipping side formwork movably assembled on both sides of the upper surface of the side box bottom formwork, and a first hydraulic strut movably installed between the side box bottom formwork and the flipping side formwork;

[0010] The electrically controlled suspension system includes: lateral extension platforms set on both sides of the load-bearing platform, lateral movable assembly frames fixed on the outer side of the lateral extension platforms, electrically controlled telescopic tilting booms installed inside the lateral movable assembly frames via external shafts, side guide plates fixed on the side walls of the lateral extension platforms, and a second hydraulic strut movably assembled between the side guide plates and the electrically controlled telescopic tilting booms.

[0011] The suspended traveling device includes a horizontal guide assembly frame fixed to the inner top surface of the electrically controlled telescopic tilting boom, a support wheel assembly and an electric drive wheel assembly movably installed inside the horizontal guide assembly frame.

[0012] The electrically controlled telescopic tilting boom includes a tilting control arm with external shafts on both sides, an electrically controlled hydraulic strut fixed inside the tilting control arm, and an inverted L-shaped top boom axially fixed to the upper end of the electrically controlled hydraulic strut.

[0013] The bearing platform has side guide assembly slots on both sides at the side guide plate assembly end, and an electrically controlled translation support rod for controlling the extension and retraction of the side guide plate is fixedly mounted on the inner side of the side guide assembly slot.

[0014] An electrically controlled lifting system is installed on the support platform.

[0015] A triangular bottom support frame is welded and fixed to the lower surface of the bearing platform.

[0016] The side guide plate has a strip-shaped storage opening inside, and an electrically controlled flip-type telescopic support frame that cooperates with the triangular bottom support frame is movably assembled inside the strip-shaped storage opening.

[0017] The inner side of the top boom is provided with a strip-shaped telescopic groove, and a longitudinal electrically controlled threaded lifting rod is installed inside the strip-shaped telescopic groove. An internal threaded lifting block is threadedly sleeved on the outer side of the longitudinal electrically controlled threaded lifting rod, and a flip-limiting base plate is elastically assembled on the outer side of the internal threaded lifting block.

[0018] A cantilever construction process for a cable-stayed bridge main girder front support formwork involves fixing the rear end of the formwork to the bottom slab of the already poured girder segment. The stay cables are attached to the front end of the longitudinal beam of the formwork to form the front support point. The tower and the already poured girder segment jointly bear the concrete load of the girder segment to be poured, transforming the cantilever into a supporting structure. This structure changes the stress state of the rear-offset formwork to a simply supported stress state of the front and rear supports. After the formwork is assembled and installed on site, it is pre-stressed to eliminate inelastic deformation, test the load-bearing capacity, design parameters, and construction safety and stability of the formwork, and observe the downward deformation values ​​of the longitudinal and transverse diaphragms of the formwork under test pressure to provide a basis for the pre-camber. A static load test is conducted, with the pre-stressing load arrangement the same as that during concrete pouring. A special pre-stressing water bag is used for pre-stressing. Then, concrete is poured using an adjustable formwork system, followed by concrete curing, prestressing tensioning, grouting, stay cable force conversion, and descent of the formwork and frame.

[0019] The beneficial effects of this invention are:

[0020] (1) The cable-stayed bridge main beam front support hanging basket of the present invention has an electrically controlled suspension system installed on the bearing platform, which can be adapted to the cable-stayed bridge main beam with different structures by adjusting the angle and height as needed, and has a wide range of applications;

[0021] (2) By installing a suspended walking device on the top surface of the electronically controlled suspension system, and with the adjustable angle design, it can be guided and moved on different surfaces, which facilitates subsequent pouring operations.

[0022] (3) By using the structurally adjustable template system, casting can be performed according to the required specifications, making the processing specifications more diverse;

[0023] (4) By setting longitudinal support limit and flip telescopic support mechanism on the electronically controlled suspension system, the structural stability and firmness during suspension can be greatly improved.

[0024] (5) The entire adjustment mechanism adopts a built-in layout design, which greatly improves the space utilization rate;

[0025] (6) The use of water bag preloading baskets improves the construction efficiency of loading and unloading, reduces labor input, improves data collection accuracy, and reduces construction costs;

[0026] (7) By adding a cantilevered hanging basket and a combined platform to the front crossbeam of the hanging basket at the front support point, the main beam closure section construction can be carried out without moving the hanging basket forward, thus avoiding the problem of setting up a separate formwork support for the closure section, ensuring the construction period of the closure section, reducing construction costs, and improving the accuracy of the main beam closure. Attached Figure Description

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0028] Figure 1 This is a schematic diagram of the structure of the present invention.

[0029] Figure 2 This is a schematic diagram of the internal structure of the electronically controlled suspension system in this invention.

[0030] Figure 3 This is a construction flowchart of the present invention. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0032] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0033] Figure 1 and Figure 2 The above-described cable-stayed bridge main beam front support hanging basket includes a bearing platform 1. An adjustable template system is bolted to both sides of the traveling end of the bearing platform 1. An electrically controlled suspension system is movably assembled on both sides of the bearing platform 1. A suspended traveling device is installed on the top surface inside the electrically controlled suspension system.

[0034] The adjustable formwork system includes: a bottom support frame 2 fixed on both sides of the walking end of the bearing platform 1, a side box bottom mold 3 bolted to the upper end of the bottom support frame 2, a flipping side mold 4 movably assembled on both sides of the upper surface of the side box bottom mold 3, and a first hydraulic strut 5 movably installed between the side box bottom mold 3 and the flipping side mold 4;

[0035] The electrically controlled suspension system includes: lateral extension platforms 6 set on both sides of the load-bearing platform 1, lateral movable assembly frames fixed on the outer side of the lateral extension platforms 6, electrically controlled telescopic tilting booms installed inside the lateral movable assembly frames via external shafts, side guide plates 7 fixed on the side walls of the lateral extension platforms 6, and a second hydraulic strut 8 movably assembled between the side guide plates 7 and the electrically controlled telescopic tilting booms.

[0036] Both the first hydraulic strut 5 and the second hydraulic strut 8 are electrically controlled for adjustment, and both are existing technologies.

[0037] To facilitate electrically controlled translation, the suspended traveling device includes a horizontal guide assembly frame 9 fixed to the inner top surface of the electrically controlled telescopic tilting boom, a support wheel assembly 10 movably installed inside the horizontal guide assembly frame 9, and an electric drive wheel assembly 11.

[0038] The electric drive wheel assembly 11 is existing technology, consisting of a transverse motor and drive wheels, which are driven to translate by cooperating with the guide rails mounted on the main beam.

[0039] To facilitate lifting and adjustment, the electrically controlled telescopic tilting boom includes a tilting control arm 12 with external shafts on both sides, an electrically controlled hydraulic strut 13 fixed inside the tilting control arm 12, and an inverted L-shaped top boom 14 axially fixed to the upper end of the electrically controlled hydraulic strut 13.

[0040] The electro-hydraulic strut 13 is existing technology, which controls the lifting and lowering of the top boom 14 by telescopic control.

[0041] In order to facilitate the extension and retraction of the side guide plate 7 within the side guide assembly groove 15, the bearing platform 1 has side guide assembly grooves 15 on both sides at the assembly end of the side guide plate 7. Electrically controlled translation support rods 16 for controlling the extension and retraction of the side guide plate 7 are fixedly mounted on the inner side of the side guide assembly groove 15.

[0042] The electrically controlled translation strut 16 is existing technology, which controls the translation of the side guide plate 7 by extending it. This changes the distance between the two electrically controlled telescopic tilting booms, improving adaptability.

[0043] To facilitate the lifting process, an electrically controlled jacking system 17 is installed on the support platform 1.

[0044] The electrically controlled jacking system 17 is existing technology, which performs jacking operations by lifting and lowering.

[0045] To enhance bottom and lateral support, a triangular bottom support frame 18 is welded and fixed to the lower surface of the bearing platform 1.

[0046] To accommodate internal storage and flip-up support limits, a strip-shaped storage opening is provided inside the side guide plate 7. An electrically controlled flip-up telescopic support frame 19 that cooperates with the triangular bottom support frame 18 is movably installed inside the strip-shaped storage opening.

[0047] The electrically controlled flip-and-telescopic support frame 19 is existing technology. It consists of a third hydraulic strut that is movably assembled in the strip-shaped storage opening and a limiting plate that is axially fixed on the telescopic section of the third hydraulic strut. The limiting plate is inserted into the outer limiting groove of the triangular bottom support frame 18 for compression and limiting.

[0048] To facilitate the support and limiting performance at the bottom of the main beam during the pouring process, a strip-shaped telescopic groove 20 is provided on the inner side of the top boom 14. A longitudinally placed electrically controlled threaded lifting rod 21 is installed inside the strip-shaped telescopic groove 20. An internally threaded lifting block 22 is threadedly connected to the outer side of the longitudinally placed electrically controlled threaded lifting rod 21. A flip-limiting base plate 23 is elastically assembled on the outer side of the internally threaded lifting block 22.

[0049] The longitudinally mounted electrically controlled threaded lifting rod 21 is existing technology. It controls the lifting of the internal threaded lifting block 22 inside the strip-shaped telescopic groove 20 by rotating the lead screw driven by a longitudinally mounted motor. The flip-limiting base plate 23 is elastically connected to the outside of the internal threaded lifting block 22 through the inner side spring piece and reset. It is movably mounted on the outside of the internal threaded lifting block 22 by the movable frames on both sides.

[0050] like Figure 3 The diagram illustrates a cantilever construction process for a cable-stayed bridge main girder with a front support formwork. The rear end of the formwork is offset to the bottom slab of the already poured girder segment. The stay cables are attached to the front end of the longitudinal beams of the formwork, forming a front support point. The pylon and the already poured girder segment jointly bear the concrete load of the girder segment to be poured, transforming the cantilever structure into a supporting structure. This structure changes the stress state of the rear-offset formwork to a simply supported stress state with front and rear supports. After the formwork is assembled and installed on-site, it undergoes pre-stressing to eliminate inelastic deformation, verify the formwork's load-bearing capacity, design parameters, and construction safety and stability, and observe the downward deformation values ​​of the longitudinal and transverse diaphragms under test pressure to provide a basis for the pre-camber. A static load test is conducted, with the pre-stressing load arrangement the same as during concrete pouring. A special pre-stressing water bag is used for pre-stressing. Concrete is then poured using an adjustable formwork system, followed by curing, prestressing tensioning, grouting, stay cable force conversion, and the lowering of the formwork and frame.

[0051] A box-section is adopted with added stiffening plates to improve its cross-sectional properties; Q345 steel is used in the steel design to reduce self-weight while meeting the same stress requirements; according to the location and number of anchor points, different cross-sectional heights are adopted for the front, middle, and rear crossbeams to reduce self-weight, taking into account their stress requirements. For example, the front crossbeam uses a 2.5m high rectangular cross-section, the middle crossbeam uses a 2m high rectangular cross-section, and the rear crossbeam uses a 1m high rectangular cross-section.

[0052] The shear key adopts the method of reaction seat + shear groove, that is, the reaction seat is set at the fixed position of the main longitudinal beam of the hanging basket, and the shear groove is reserved at the bottom plate of each segment of the concrete main beam, and the embedded steel plate is added to meet the stress requirements of resisting the longitudinal component of the stay cable, ensuring the stress stability and structural safety during the construction process of the three-sheet hanging basket.

[0053] The method of first sliding the basket horizontally, then lifting it vertically with a crane, and finally moving it longitudinally to install the hanging basket effectively avoids the problems of narrow working areas at the bridge site and conflicts between the hanging basket installation position and the river embankment, reduces interference with the surrounding environment, greatly improves construction efficiency, and saves construction time.

[0054] A complete set of ultra-wide front support cable-stayed formwork installation technology has been developed, which effectively solves the problem of integral installation of large-tonnage components. In particular, the design of reusable integrated formwork lifting tooling has greatly improved the efficiency of formwork lifting construction.

[0055] This invention provides a cable-stayed bridge main girder front support hanging basket. By installing an electrically controlled suspension system on the bearing platform 1, it can adapt to different cable-stayed bridge main girder structures through angle and height adjustments, making it highly versatile. A suspended walking device is installed on the top surface of the electrically controlled suspension system, with an adjustable angle design, allowing it to be guided and moved across different surfaces, facilitating subsequent pouring operations. The adjustable template system allows for casting according to specific requirements, resulting in more diverse processing specifications. Furthermore, the electrically controlled suspension system is equipped with longitudinal support limits and a tilting telescopic support. The support mechanism greatly enhances the structural stability and firmness during suspension; the entire adjustment mechanism adopts a built-in layout design, significantly improving space utilization; the use of water bag pre-stressing of the hanging basket improves the efficiency of loading and unloading, reduces labor input, increases data acquisition accuracy, and lowers construction costs; by adding a hanging basket cantilever and combined platform to the front crossbeam cantilever of the front support hanging basket as a load-bearing platform for the main beam closure section construction, the closure section construction can be carried out without moving the hanging basket forward, avoiding the problem of setting up a separate formwork support for the closure section, ensuring the construction period of the closure section, reducing construction costs, and improving the accuracy of main beam closure.

[0056] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A formwork for the front support of the main girder of a cable-stayed bridge, comprising a load-bearing platform (1), characterized in that: The carrying platform (1) has an adjustable template system bolted to both sides of its walking end. The carrying platform is equipped with an electrically controlled suspension system on both sides. The electrically controlled suspension system has a suspended walking device installed on its top surface. The adjustable formwork system includes: a bottom support frame (2) fixed on both sides of the walking end of the bearing platform (1), a side box bottom mold (3) bolted to the upper end of the bottom support frame (2), a flip side mold (4) movably assembled on both sides of the upper surface of the side box bottom mold (3), and a first hydraulic strut (5) movably installed between the side box bottom mold (3) and the flip side mold (4). The electrically controlled suspension system includes: a lateral extension platform (6) set on both sides of the load-bearing platform (1), a lateral movable assembly frame fixed on the outer side of the lateral extension platform (6), an electrically controlled telescopic tilting boom installed inside the lateral movable assembly frame by an external shaft, a side guide plate (7) fixed on the side wall of the lateral extension platform, and a second hydraulic strut (8) movably assembled below the side guide plate (7) and between the electrically controlled telescopic tilting boom. The electrically controlled telescopic tilting boom includes a tilting control arm (12) with external shafts on both sides, an electrically controlled hydraulic strut (13) fixed inside the tilting control arm (12), and an inverted L-shaped top boom (14) axially fixed to the upper end of the electrically controlled hydraulic strut (13). The suspended traveling device is installed on the top surface inside the inverted L-shaped top boom (14).

2. The formwork for the front support of the main girder of a cable-stayed bridge according to claim 1, characterized in that: The suspended walking device includes a horizontal guide assembly frame (9) fixed on the top surface of the top arm (14) of the inverted L-shaped structure, a support wheel assembly (10) and an electric drive wheel assembly (11) movably installed inside the horizontal guide assembly frame (9).

3. The formwork for the front support of the main girder of a cable-stayed bridge according to claim 1, characterized in that: The bearing platform (1) has side guide assembly grooves (15) on both sides at the assembly end of the side guide plate (7). The inner side of the side guide assembly groove (15) is fixedly equipped with an electrically controlled translation support rod (16) for controlling the extension and retraction of the side guide plate (7).

4. The formwork for the front support of the main girder of a cable-stayed bridge according to claim 1, characterized in that: An electrically controlled lifting system (17) is installed on the carrying platform (1).

5. A formwork for the front support of the main girder of a cable-stayed bridge according to claim 3, characterized in that: A triangular bottom support frame (18) is welded and fixed to the lower surface of the bearing platform (1).

6. A formwork hanging basket at the front support of the main girder of a cable-stayed bridge according to claim 5, characterized in that: The side guide plate (7) has a strip-shaped storage opening inside, and an electrically controlled flip-type telescopic support frame (19) that cooperates with the triangular bottom support frame (18) is movably assembled inside the strip-shaped storage opening.

7. A formwork hanging basket at the front support of the main girder of a cable-stayed bridge according to claim 1, characterized in that: The top boom (14) has a strip-shaped telescopic groove (20) on its inner side. A longitudinal electrically controlled threaded lifting rod (21) is installed inside the strip-shaped telescopic groove (20). An internal threaded lifting block (22) is threaded onto the outer side of the longitudinal electrically controlled threaded lifting rod (21). A flip-limiting base plate (23) is elastically assembled on the outer side of the internal threaded lifting block (22).

8. A cantilever casting process for the front support formwork of the main girder of a cable-stayed bridge as described in claim 1, characterized in that: The bearing platform (1) includes longitudinal beams, longitudinal diaphragm beams and transverse diaphragm beams. The rear end of the hanging basket is anchored to the bottom plate of the cast beam segment. The inclined cable is attached to the front end of the longitudinal beam of the hanging basket to form a front support point. The tower and the cast beam segment jointly bear the concrete load of the beam segment to be cast, turning the cantilever into a supporting structure. With such a structure, the cantilever stress state of the rear anchor hanging basket can be changed to the simple support stress state of the front and rear supports. After the hanging basket is assembled and installed on site, it needs to be pre-stressed to eliminate inelastic deformation, test the bearing capacity, design parameters and construction safety stability of the hanging basket, and observe the deformation values ​​of the longitudinal diaphragm beam and transverse diaphragm beam under the test pressure state to provide a basis for the construction pre-camber. A static load test is adopted. The pre-stressing load arrangement is the same as that when pouring concrete. A special pre-stressing water bag is used for pre-stressing. Then, concrete is poured in the adjustable formwork system. Then, the concrete is cured, prestressed, grouted, and the cable force of the inclined cable is converted. The hanging basket and frame are lowered.

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