Construction method for steel-concrete combined section of separated single-column cable-stayed bridge

Abstract

The invention relates to the technical field of bridge construction methods, in particular to a construction method for a steel-concrete combined section of a separated single-column cable-stayed bridge. Comprising the following steps: constructing a side span concrete beam in a steel-concrete combined section based on a tower column; a sliding support is built below the steel-concrete combined section; the barge transports the steel box girder in the steel-concrete combined section to the position below the cable crane; hoisting the steel box girder on the barge below the cable crane to a set height by the cable crane; the steel box girder is pulled to the sliding support in the bridge direction in a swinging mode; the steel box girder is driven to move on the sliding support until the steel box girder is in butt joint with the side span concrete beam; and pouring construction is conducted on the joint part between the side span concrete beam and the steel box beam, and construction of the steel-concrete combined section is completed. The construction method for the steel-concrete combined section of the separated single-column cable-stayed bridge is simple and efficient, the construction quality is guaranteed, the construction cost is reduced, and the high risk that a deck crane or a large overwater barge is used on a steep and unstable slope is effectively avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge construction methods, and in particular to a construction method for a steel-concrete combined section of a separated single-column cable-stayed bridge. Background Art

[0002] When erecting steel box girders for large cable-stayed bridges in mountainous areas and complex terrain, and when the bridge site is located in a special geographical environment with steep slopes, far away from deep water areas and extremely high requirements for ecological and environmental protection, traditional steel box girder installation methods - such as cantilever assembly with bridge cranes, slide traction or cable-laying jacking - expose significant limitations and potential risks.

[0003] For example, the cantilever assembly method of the bridge crane can refer to a method for constructing a steel-concrete main beam of a cable-stayed bridge, in which the steel-concrete main beam involved in the method is composed of a concrete side main beam, a steel cross beam and a prefabricated bridge deck; the steel-concrete main beam is constructed in multiple sections, and its construction method includes the following steps: Step 1, a section of concrete side main beam on the main tower and the steel-concrete main beams on both sides of the main tower are cast in situ using brackets; Step 2, the steel-concrete main beams of the remaining cantilever sections in the span are constructed using a front support cable hanging basket; the cantilever hanging basket is assembled on the steel-concrete main beam on one side of the main tower, the steel bars are tied, the steel cross beam is hoisted, and concrete is poured. After the concrete strength reaches the design requirement, the prestressing is applied and the bridge deck is hoisted; Step 3, the cantilever hanging basket is moved forward to the next section, and the construction process in Step 2 is repeated to carry out the construction of the next section; Step 4, the cast-in-situ section of the side span is constructed, and the cast-in-situ section of the side span is constructed using a ground support, and the support adopts a support scheme of pile foundation plus Bailey beam; Step 5, the side span is connected; Step 6, the middle span is connected. This method can be used for rapid construction of steel-concrete main beams in conventional terrain, but for complex terrain, especially on steep and unstable slopes, it is difficult to obtain a stable equipment foundation and operating space, and the safety risks increase dramatically.

[0004] Slide traction requires a large area of flat ground and a long working surface, which is often difficult to achieve in narrow and rugged valleys. It also causes great damage to surface vegetation and is difficult to meet high environmental protection requirements.

[0005] Rope-laying jacking is highly dependent on large barges and other water-based equipment, and cannot be implemented in mountain rivers far away from deep water areas or with turbulent currents. In addition, the jacking process has extremely high requirements for temporary support structures, and its stability is worrying under complex geological conditions.

[0006] Current bridge construction methods are not very suitable for mountainous terrain with large undulating terrain and environmental protection requirements for construction. The complex terrain forces the main beam construction to be installed using a cable hoisting system. Due to the distance between the cable ceiling and the tower top, the hoisted steel beam and concrete beam cannot be directly and accurately hoisted and connected. The construction of the steel-concrete joint section faces special challenges. These factors significantly increase the construction safety risks and the difficulty of quality control. There is an urgent need to develop targeted construction control technologies. Summary of the Invention

[0007] The purpose of this application is to solve the shortcomings of the above-mentioned background technology and provide a construction method for the steel-concrete combined section of a separated single-column cable-stayed bridge.

[0008] The technical solution of the present application is: a construction method for the steel-concrete joint section of a separated single-column cable-stayed bridge, characterized by comprising the following steps: Concrete beams in the side spans of the steel-concrete composite sections constructed based on tower columns; Build a sliding support under the steel-concrete joint section; The barge transports the steel box girder in the steel-concrete joint section to the bottom of the cable crane; The cable crane lifts the steel box girder on the barge below to the set height; Use the swinging method to pull the steel box girder along the bridge direction to the sliding support; Drive the steel box girder on the sliding bracket until it docks with the side span concrete beam; The joint between the side span concrete beam and the steel box beam is poured to complete the construction of the steel-concrete joint section.

[0009] According to a construction method for a steel-concrete composite section of a separated single-column cable-stayed bridge provided in the present application, the method for constructing the side span concrete beam in the steel-concrete composite section based on the tower column includes: when pouring the side span concrete beam, pre-embedding a lifting ring for swinging the steel box beam at one end of the side span concrete beam facing the steel box beam.

[0010] According to a construction method for a steel-concrete joint section of a separated single-column cable-stayed bridge provided in the present application, the method of building a sliding bracket below the steel-concrete joint section includes: building a sliding bracket below the steel-concrete joint section, building a slide beam arranged along the bridge direction on the sliding bracket, installing a plurality of sliders that can slide along the slide beam on the slide beam, and connecting adjacent sliders on the same slide beam into one through a rigid rod-like structure; and arranging a traction and tensioning structure on the sliding bracket.

[0011] According to a construction method for a steel-concrete joint section of a separated single-column cable-stayed bridge provided in the present application, the method of arranging a traction and tensioning structure on a sliding bracket includes: installing a tensioning jack at one end of the slide beam close to the side span concrete beam, and connecting the tensioning jack to the slider of the same slide beam closest to the tensioning jack with a steel wire rope.

[0012] According to a construction method for the steel-concrete joint section of a separated single-column cable-stayed bridge provided in the present application, the method of lifting the steel box girder on the barge below to a set height with a cable crane includes: the running car of the cable crane moves along the bridge direction toward the side of the tower column to a maximum distance position, and the cable crane lifts the steel box girder on the barge below and rises vertically until the lower end surface of the steel box girder exceeds the set distance from the upper end surface of the sliding bracket.

[0013] According to a construction method for the steel-concrete joint section of a separated single-column cable-stayed bridge provided in the present application, the method of pulling the steel box girder along the bridge direction to the sliding bracket by swinging includes: installing a hand winch at the lifting ring, connecting one end of the lifting belt to the hand winch and the other end to the steel box girder, tightening the lifting belt by the hand winch to cause the steel box girder to shift toward the side span concrete beam until the steel box girder is completely above the sliding bracket, and slowly lowering the steel box girder to the sliding bracket with a cable crane.

[0014] According to a construction method for the steel-concrete joint section of a separated single-column cable-stayed bridge provided in the present application, the method of driving the steel box girder to move on the sliding bracket until it docks with the side span concrete beam includes: using a tensioning jack to pull the steel box girder along the slide beam to a position where it docks with the side span concrete beam, and after sliding into place, arranging multiple three-way jacks between the steel box girder and the sliding bracket, and using the three-way jacks to accurately adjust the elevation, lateral position and longitudinal position of the steel box girder.

[0015] According to a construction method for a steel-concrete joint section of a separated single-column cable-stayed bridge provided in the present application, the method for casting the joint between the side span concrete beam and the steel box beam includes: installing steel bars and prestressed pipes in the steel box beam; arranging a formwork at the joint of the steel box beam and the side span concrete beam; pouring concrete into the formwork; after the concrete at the joint is cured, longitudinally prestressing the steel box beam and the side span concrete beam; after the prestressing is completed, grouting and anchoring the prestressed steel strands.

[0016] According to a construction method for a steel-concrete combined section of a separated single-column cable-stayed bridge provided in the present application, channel steels are provided on both sides of the transverse direction of the slide beam; the vertical portion of the lower end of the channel steel is located on the transverse side of the slide beam, and the horizontal portion of the upper end is fixed to the lower end flange of the slider to limit the transverse and vertical displacement of the slider.

[0017] According to a construction method for a steel-concrete joint section of a separated single-column cable-stayed bridge provided in the present application, a polytetrafluoroethylene plate is installed on the lower end surface of the slider, and a rubber pad is installed on the upper end surface of the slider.

[0018] The advantages of the present application are as follows: 1. The construction method of the present application is applicable to bridge construction in complex mountainous terrain with large undulating terrain, effectively avoiding the high risk of using a bridge crane or a large water barge (such as required for cable laying and pushing) on steep and unstable slopes. By adopting a swinging method to connect the cable crane and the sliding support, the problem that the cable crane cannot directly transfer the steel box girder to the sliding support is solved, which greatly reduces the difficulty and safety risks of direct lifting and docking at high altitude, provides a stable and controllable operating platform, ensures the rapid construction of the entire steel-concrete joint section, reduces the difficulty of the entire bridge construction, improves construction efficiency, combines safety and economy, and is suitable for large-scale promotion and application. 2. This application pre-installs lifting rings on the side span concrete beams, using the lifting rings as the fulcrum for subsequent swinging. This allows the entire steel box girder to be pulled and swung along the bridge direction using simple tools, significantly improving the efficiency of steel box girder hoisting, reducing construction difficulty, and resolving the issue of cable hoisting blind spots preventing the steel box girder from being hoisted and moved. 3. This application builds a sliding bracket at the steel-concrete joint section. The sliding bracket has a simple structure and can be connected to a cable crane to quickly connect the steel box girder with the side span concrete beam. The connection process between the steel box girder and the side span concrete beam becomes simpler and the construction operation is more convenient. 4. This application installs a tensioning jack on the slideway beam to tension the steel box beam on the slideway beam through the tensioning jack, which makes the butt joint construction of the steel box beam very simple, and the equipment used is of conventional structure, with very low cost and easy operation; 5. The method of lifting the steel box girder with a cable crane in this application is very simple. The cable crane only needs to perform vertical lifting and does not require subsequent lateral adjustment. The initial lifting work can be completed by lifting the steel box girder beyond the sliding bracket. The operation is very simple. 6. This application uses a hand chain hoist to achieve the movement of the steel box girder along the bridge direction through a precisely calculated short-distance swing movement, solving the problem that the cable crane cannot move along the bridge direction to lift the steel box girder onto the sliding bracket. The entire construction method is simple, low in construction cost, easy to operate, and the construction accuracy and safety are controllable. 7. This application uses a three-way jack installed on a sliding bracket to precisely adjust the steel box girder, so that the steel box girder can be accurately docked with the side span concrete beam. The adjustment method is simple and easy to operate. The equipment and tools used are all conventional structures, and the construction cost is low. 8. This application relies on sliding brackets to support the steel box beam. After the steel box beam is aligned and adjusted, the side span concrete beam can be butted together by building a formwork and pouring concrete. This is simple to construct and easy to operate, greatly reducing the difficulty of butt-jointing the steel box beam and the side span concrete beam. 9. The slider and slideway beam constructed in this application have a simple structure. By setting the channel steel to limit the slider in the transverse and vertical directions of the bridge, the sliding of the steel box beam on the slideway beam is more stable, and the safety of construction is greatly improved; 10. This application sets a PTFE plate at the lower end of the slider, which can effectively reduce the friction between the slider and the slide beam, making the sliding adjustment of the steel box beam smoother. A rubber pad is set at the upper end of the slider to make the connection between the steel box beam and the slider tighter and more stable.

[0019] The construction method of the steel-concrete composite section of the separated single-column cable-stayed bridge applied in this application is simple and efficient, ensures construction quality, reduces construction costs, and effectively avoids the high risk of using bridge cranes or large water barges on steep and unstable slopes. It is suitable for bridge construction under complex and harsh conditions such as steep terrain in mountainous areas, far away from deep water areas, and sensitive ecological environments. It can effectively solve the problem of high-precision installation of the steel-concrete composite section when there is a lifting blind spot in the cable lifting system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 : Schematic diagram of the construction process of the steel-concrete combined section of the cable-stayed bridge of this application; Figure 2 : Schematic diagram of the steel box girder swing structure of the present application; Figure 3 : Schematic diagram of the lifting ring arrangement structure of this application; Figure 4 : Schematic diagram of steel box girder traction of this application; Figure 5 : Schematic diagram of the arrangement structure of the slider, channel steel and slide beam of the present application; Among them: 1—side span concrete beam; 2—steel box beam; 3—sliding bracket; 4—lifting ring; 5—cable crane; 6—slide beam; 7—sliding block; 8—tensioning jack; 9—wire rope; 10—hand hoist; 11—lifting belt; 12—channel steel. DETAILED DESCRIPTION

[0021] The embodiments of the present application are described in detail below, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0022] In the description of this application, it should be understood that the terms "longitudinal", "transverse", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0023] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0024] The present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] The present application relates to a method for constructing a steel-concrete composite section of a detached, single-column, cable-stayed bridge. The construction method of the present application is suitable for bridge construction in complex and harsh conditions such as steep mountainous terrain, areas far from deep water, and areas with sensitive ecological environments. It can effectively solve the problem of high-precision installation of steel-concrete composite sections when there are blind spots in the cable hoisting system. The entire construction method is simple, safe, reliable, and easy to operate, ensuring construction quality and reducing construction costs. It effectively avoids the high risk of using a bridge crane or a large water barge (such as required for cable laying and jacking) on steep and unstable slopes, greatly reduces the difficulty and safety risks of direct lifting and docking at high altitudes, and provides a stable and controllable operating platform.

[0026] Specifically, such as Figures 1 to 5 As shown, the construction method of the steel-concrete composite section of a separated single-column cable-stayed bridge of the present application is carried out according to the following steps: S1, side span concrete beam 1 in the steel-concrete composite section based on tower column construction; The side span concrete beam 1 is close to the river bank and can be cast by building a support or relying on a tower column; S2. Build a sliding support 3 below the steel-concrete joint section; The purpose of building the sliding bracket 3 is to support the steel box girder 2, and to facilitate the subsequent adjustment of the steel box girder 2 and the docking with the side span concrete beam 1; S3, transporting the steel box girder 2 in the steel-concrete joint section by barge to the bottom of the cable crane 5; The steel box girder 2 refers to the steel box girder 2 segment that is connected to the side span concrete girder 1. The steel box girder 2 is a large structure. For areas with complex terrain, transporting the steel box girder 2 by barge is the most convenient operation method. S4, the cable crane 5 lifts the steel box girder 2 on the barge below to the set height; The cable crane 5 can directly lift the steel box girder 2 on the barge. However, due to the complex terrain and interference from other buildings, when the cable crane 5 moves to its maximum distance along the bridge, there is still a certain distance between it and the side span concrete girder 1. In other words, it is impossible to move the steel box girder 2 to the position where it connects with the side span concrete girder 1 by relying solely on the cable crane 5. S5. Pull the steel box girder 2 along the bridge direction onto the sliding support 3 by swinging. The steel box girder 2 is pulled by swinging. At this time, the steel box girder 2 is suspended by the cable crane 5. Only a small force needs to be applied to the steel box girder 2 to pull the steel box girder 2 along the bridge direction to the position where it connects with the side span concrete beam 1. The operation is very simple and solves the problem that the cable crane 5 cannot be directly lifted into place. S6, driving the steel box girder 2 to move on the sliding support 3 until it docks with the side span concrete beam 1; After the steel box girder 2 is transferred to the sliding bracket 3, it is adjusted on the sliding bracket 3 so that the steel box girder 2 can be accurately aligned with the side span concrete beam 1. The steel box girder 2 is first pulled along the bridge on the sliding bracket 3 to a position close to the side span concrete beam 1, and then adjusted in three directions: vertically, transversely, and along the bridge until it is accurately aligned with the side span concrete beam 1. S7, pouring construction on the joint between the side span concrete beam 1 and the steel box beam 2 to complete the construction of the steel-concrete joint section; After the steel box girder 2 is precisely aligned with the side span concrete beam 1, the formwork can be installed to cast the concrete joint connecting the steel box girder 2 and the side span concrete beam 1.

[0027] In some embodiments of the present application, this embodiment optimizes the above-mentioned step S1. The specific method of constructing the side span concrete beam 1 in the steel-concrete combined section based on the tower column is: when the side span concrete beam 1 is cast, a lifting ring 4 for swinging the steel box beam 2 is pre-embedded at one end of the side span concrete beam 1 facing the steel box beam 2.

[0028] The lifting ring 4 is the fulcrum for subsequently pulling the steel box girder 2 to swing along the bridge direction. In this embodiment, by pre-embedding the lifting ring 4 at the end of the side span concrete beam 1, it is convenient for subsequent construction personnel to swing the steel box girder 2 based on the lifting ring 4 on the side span concrete beam 1.

[0029] The arrangement structure of the lifting ring 4 is as follows Figures 2 and 3 As shown, in this embodiment, lifting rings 4 are provided on both sides of the transverse bridge at one end of the side span concrete beam 1 near the steel box beam 2. Specifically, two sets of lifting rings 4 are provided at the end of the side span concrete beam 1. During the swinging operation of the steel box beam 2, the two sets of lifting rings 4 work together to conveniently transfer the steel box beam 2 to the sliding support 3. The simultaneous action of the two sets of lifting rings 4 provides a more stable structure, preventing deflection or oscillation during the swinging process, thereby ensuring construction safety.

[0030] In a further embodiment of the present application, the present embodiment optimizes the above-mentioned step S2. Specifically, the method of building the sliding support 3 below the steel-concrete combined section is as follows: the steel-concrete combined section is close to the shore, so the sliding support 3 can be built based on the shore terrain or on the tower column. The sliding support 3 can be a full-height support structure, or other support structure forms can be adopted, as long as it meets the support and positioning function of the steel box girder 2; A sliding bracket 3 is built below the steel-concrete joint section, and a slide beam 6 arranged along the longitudinal direction of the bridge is built on the sliding bracket 3. In this embodiment, multiple slide beams 6 are arranged on the upper end face of the sliding bracket 3. The multiple slide beams 6 are arranged at intervals along the transverse direction of the bridge, and the slide beams 6 themselves are arranged along the longitudinal direction of the bridge; a number of sliders 7 that can slide along the slide beams 6 are installed on the slide beams 6, and adjacent sliders 7 on the same slide beam 6 are connected as a whole through a rigid rod-like structure; a traction and tensioning structure is arranged on the sliding bracket 3.

[0031] like Figure 5 As shown, in this embodiment, channel steels 12 are provided on both sides of the slide beam 6 in the transverse direction. The channel steels 12 include transverse side plates and vertical side plates. The transverse side plates are fixed on the lower flange of the slider 7, and the vertical side plates are located on the transverse side of the slide beam 6. The channel steels 12 are structures used to limit the slider 7. The slider 7 is an I-beam structure. The lower flange of the slider 7 is slidably connected to the upper end face of the slide beam 6. The transverse side plates extending horizontally from the upper end of the channel steel 12 are fixed to the upper end face of the lower flange of the slider 7. The channel steels 12 on both sides can effectively limit the relative displacement of the slider 7 in the transverse and vertical directions, so that the slider 7 can move stably along the slide beam 6. Such a structure can effectively improve the sliding stability of the steel box girder 2 and avoid offset.

[0032] Furthermore, a polytetrafluoroethylene (PTFE) plate is installed on the lower end surface of the slider 7. The PTFE plate can effectively reduce the frictional resistance between the slide beam 6 and the slider 7, making the slide of the slider 7 on the slide beam 6 smoother and reducing the traction required for the sliding of the steel box girder 2. In addition, a rubber pad is installed on the upper end surface of the slider 7 of this embodiment. The rubber pad can enable the steel box girder 2 to sit more stably on the slider 7, allowing the steel box girder 2 to rest more stably on the slider 7, making the connection between the two tighter, making the steel box girder 2 less likely to overturn, and making the sliding process of the steel box girder 2 along the slide beam 6 safer.

[0033] In other embodiments of the present application, this embodiment optimizes the above-mentioned method of arranging the traction and tensioning structure on the sliding bracket 3, and installs a tensioning jack 8 at one end of the slide beam 6 close to the side span concrete beam 1, and connects the tensioning jack 8 to the slider 7 of the same slide beam 6 closest to the tensioning jack 8 with a steel wire rope 9.

[0034] like Figure 4As shown, the tensioning jack 8 is a traction structure installed on the slide beam 6. The slide beam 6 is provided with a reaction seat. The tensioning jack 8 is fixed to the reaction seat and connected to the slider 7 of the same group via a steel wire rope 9. When the steel box girder 2 needs to be pulled, the tensioning jack 8 applies a force to the slider 7 along the bridge direction toward the side span concrete beam 1. The steel box girder 2 follows the slider 7 along the slide beam 6 until it moves to the docking position with the side span concrete beam 1. In actual application, multiple tensioning jacks 8 work together to enable the steel box girder 2 to move stably and accurately to the docking position.

[0035] In some embodiments of the present application, the present embodiment optimizes the above-mentioned step S4. Specifically, the cable crane 5 lifts the steel box girder 2 on the lower barge to a set height by: the running gear of the cable crane 5 moves along the bridge direction toward the tower column to the maximum distance position, which is actually the position closest to the tower column, so as to reduce the amplitude of the steel box girder 2 swinging along the bridge direction; the cable crane 5 lifts the steel box girder 2 on the lower barge and rises vertically until the lower end surface of the steel box girder 2 exceeds the upper end surface of the sliding bracket 3 by a set distance. The set distance in this embodiment is 1000mm~2000mm, that is, the cable crane 5 lifts the steel box girder 2 until the lower end surface of the steel box girder 2 exceeds the upper end surface of the sliding bracket 3 by 1000mm~2000mm, ensuring that when the steel box girder 2 swings to the top of the sliding bracket 3, the lower end surface of the steel box girder 2 exceeds the upper end surface of the sliding bracket 3 by more than 500mm, so as to avoid the steel box girder 2 from colliding with or interfering with other structures during the swinging process. It is also possible to make the steel box girder 2 finally fall onto the slider 7 stably.

[0036] In a further embodiment of the present application, this embodiment optimizes the above-mentioned step S5. Specifically, the method of pulling the steel box girder 2 along the bridge to the sliding bracket 3 by swinging is as follows: a hand winch 10 is installed at the lifting ring 4, one end of the sling 11 is connected to the hand winch 10, and the other end is connected to the steel box girder 2, and the sling 11 is tightened by the hand winch 10 to make the steel box girder 2 offset to the side of the side span concrete beam 1 until the steel box girder 2 is completely above the sliding bracket 3, and the cable crane 5 slowly lowers the steel box girder 2 to the sliding bracket 3.

[0037] The hand chain hoists 10 on the two lifting rings 4 work together to apply a pulling force to the steel box girder 2 along the bridge direction toward the side span concrete beam 1. At this time, the steel box girder 2 is suspended by the cable hoist 5. Therefore, the force required to drive the steel box girder 2 along the bridge direction does not need to be too large, and the conventional hand chain hoists 10 can achieve the swinging operation. The entire swinging process is simple to operate and convenient to construct.

[0038] After the steel box girder 2 is completely swung to the top of the sliding bracket 3, the cable crane 5 slowly lowers the steel box girder 2. At this time, the hand hoist 10 is in a tensioned state until the steel box girder 2 slowly falls on the slider 7. After the steel box girder 2 is stably placed on the slider 7, the connection between the cable crane 5 and the sling 11 is removed.

[0039] In other embodiments of the present application, this embodiment optimizes the above-mentioned step S6. Specifically, the method of driving the steel box girder 2 to move on the sliding bracket 3 until it is docked with the side span concrete beam 1 is: using the tensioning jack 8 to pull the steel box girder 2 along the slide beam 6 to the position where it is docked with the side span concrete beam 1, and after sliding into place, arranging multiple three-way jacks between the steel box girder 2 and the sliding bracket 3, and using the three-way jacks to accurately adjust the elevation, lateral position and longitudinal position of the steel box girder 2.

[0040] Multiple three-way jacks are arranged between the steel box girder 2 and the sliding bracket 3. The multiple three-way jacks work together to adjust the position of the steel box girder 2. The adjustment can be repeated multiple times by adjusting the elevation first, then adjusting the position along the bridge, and finally adjusting the position across the bridge until the docking accuracy requirements are met.

[0041] The three-way jack is adjusted in conjunction with the slider 7, that is, the three-way jack is lower than the upper end surface of the slider 7 when retracted. After the three-way jack is adjusted once, the steel box girder 2 can be dropped back onto the slider 7, and then repeated many times until the steel box girder 2 completes the precise alignment operation.

[0042] In a preferred embodiment of the present application, this embodiment optimizes the above-mentioned step S7. Specifically, the method for pouring construction of the joint between the side span concrete beam 1 and the steel box beam 2 is: install steel bars and prestressed pipes in the steel box beam 2, and install the lower steel cell longitudinal steel bars from bottom to top, install the upper steel cell longitudinal steel bars from bottom to top, and install the joint section cross beam steel bars and box beam connecting steel bars from bottom to top; arrange the formwork at the joint of the steel box beam 2 and the side span concrete beam 1, adopt a "helping bottom" between the inclined bottom plate bottom formwork and the bottom formwork, and stick a layer of sponge strips on the side of the bottom formwork to prevent leakage at the bottom mouth. When installing the inclined bottom plate bottom formwork and the outer side formwork, support them firmly to prevent the formwork from displacement when pouring concrete. At the same time, the overlap length of the inclined bottom plate bottom formwork, the outer side formwork and the joint section wall panel along the bridge direction is not less than 10 cm, and they are sealed with sponge strips. Block to ensure the construction quality of the joint section; pour concrete into the formwork, and use self-compacting C55 slightly expansive concrete with good fluidity. After selecting the concrete material, cross-tests should be carried out to determine the optimal concrete construction mix ratio that meets the construction requirements. The pouring should be carried out in the order of "reserved section box beam bottom plate, lower steel grid, beam bottom, joint section and reserved section (inner and outer) inclined bottom plate (height difference ≤ 30cm), middle of beam, reserved section web, reserved section box beam top plate, upper steel grid, beam top"; after the concrete pouring is completed, it should be covered and insulated for maintenance immediately, with a maintenance period of not less than 7 days. After the concrete curing at the joint is completed, the steel box beam 2 and the side span concrete beam 1 should be longitudinally prestressed; the prestressed pipe should be grouting and anchored as soon as possible within 24 hours after the steel bundle is tensioned.

[0043] In actual application, the following method can be used: construct the side span concrete beam 1 in the steel-concrete combination section based on the tower column, and pre-embed a lifting ring 4 for swinging the steel box beam 2 at one end of the side span concrete beam 1 facing the steel box beam 2 when pouring the side span concrete beam 1; build a sliding bracket 3 under the steel-concrete combination section, build a slide beam 6 arranged along the bridge direction on the sliding bracket 3, install a number of sliders 7 that can slide along the slide beam 6 on the slide beam 6, and the adjacent sliders 7 on the same slide beam 6 They are connected as a whole by a rigid rod-like structure; a tensioning jack 8 is installed at one end of the slide beam 6 close to the side span concrete beam 1, and the tensioning jack 8 is connected to the slider 7 of the same slide beam 6 closest to the tensioning jack 8 by a steel wire rope 9; the carriage of the cable crane 5 moves along the bridge direction toward the tower column to the maximum distance position, and the cable crane 5 lifts the steel box girder 2 on the barge below and rises vertically until the lower end surface of the steel box girder 2 exceeds the set distance of the upper end surface of the sliding bracket 3; at the lifting ring 4 Install the hand chain hoist 10, connect one end of the lifting belt 11 to the hand chain hoist 10 and the other end to the steel box girder 2, tighten the lifting belt 11 by the hand chain hoist 10 to make the steel box girder 2 offset to the side span concrete beam 1 until the steel box girder 2 is completely above the sliding bracket 3, and the cable crane 5 slowly lowers the steel box girder 2 to the sliding bracket 3; use the tensioning jack 8 to pull the steel box girder 2 along the slide beam 6 to the position where it docks with the side span concrete beam 1, and after sliding into place, the steel box girder 2 and the sliding bracket are connected. A plurality of three-way jacks are arranged between the frames 3, and the elevation, transverse position and longitudinal position of the steel box girder 2 are precisely adjusted by using the three-way jacks; after the alignment is completed, the steel bars and prestressed pipes are installed in the steel box girder 2; the formwork is arranged at the junction of the steel box girder 2 and the side span concrete beam 1; concrete is poured into the formwork; after the concrete curing of the junction is completed, the steel box girder 2 and the side span concrete beam 1 are longitudinally prestressed; after the prestressing is completed, the prestressed steel strands are grouted and anchored.

[0044] like Figure 2 As shown, the bridge direction of this application is Figure 2 The left and right directions in this application refer to the horizontal bridge direction. Figure 2 The vertical direction of the paper in this application refers to Figure 2 The up and down directions in .

[0045] The above shows and describes the basic principles, main features, and advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present application. Various changes and improvements may be made to the present application without departing from the spirit and scope of the present application. Such changes and improvements are intended to fall within the scope of the present application. The scope of protection claimed in this application is defined by the appended claims and their equivalents.

Claims

1. A construction method for the steel-concrete joint section of a separated single-column cable-stayed bridge, characterized by: The following steps are involved: Concrete beams on the side spans of the steel-concrete composite section based on the tower column construction (1); Build a sliding support (3) below the steel-concrete joint section; The barge transports the steel box girder (2) in the steel-concrete joint section to the bottom of the cable crane (4); The cable crane (4) lifts the steel box girder (2) on the barge below to a set height; The steel box girder (2) is pulled along the bridge direction onto the sliding support (3) by swinging; Driving the steel box girder (2) to move on the sliding bracket (3) until it docks with the side span concrete beam (1); The joint between the side span concrete beam (1) and the steel box beam (2) is cast to complete the construction of the steel-concrete joint section.

2. The method for constructing the steel-concrete joint section of a separated single-column cable-stayed bridge according to claim 1, characterized in that: The method for constructing a side span concrete beam (1) in a steel-concrete combined section based on a tower column comprises: pre-embedding a lifting ring (4) for swinging the steel box beam (2) at one end of the side span concrete beam (1) facing the steel box beam (2) when the side span concrete beam (1) is cast.

3. The method for constructing the steel-concrete joint section of a separated single-column cable-stayed bridge according to claim 1, characterized in that: The method for constructing a sliding bracket (3) below the steel-concrete joint section comprises: constructing a sliding bracket (3) below the steel-concrete joint section, constructing a slideway beam (6) arranged along the bridge direction on the sliding bracket (3), installing a plurality of sliders (7) on the slideway beam (6) that can slide along the slideway beam (6), and connecting adjacent sliders (7) on the same slideway beam (6) into one body through a rigid rod-shaped structure; and arranging a traction tensioning structure on the sliding bracket (3).

4. The method for constructing the steel-concrete joint section of a separated single-column cable-stayed bridge according to claim 3, characterized in that: The method for arranging a traction tensioning structure on a sliding support (3) comprises: installing a tensioning jack (8) at one end of a slideway beam (6) close to a side span concrete beam (1), and connecting the tensioning jack (8) to a slider on the same slideway beam (6) closest to the tensioning jack (8) using a steel wire rope (9).

5. The method for constructing the steel-concrete joint section of a separated single-column cable-stayed bridge according to claim 1, characterized in that: The method for the cable crane (5) to lift the steel box girder (2) on the lower barge to a set height comprises: the running vehicle of the cable crane (5) moves along the bridge direction toward the tower column to a maximum distance position, and the cable crane (5) lifts the steel box girder (2) on the lower barge and rises vertically until the lower end surface of the steel box girder (2) exceeds the set distance of the upper end surface of the sliding bracket (3).

6. The method for constructing the steel-concrete joint section of a separated single-column cable-stayed bridge according to claim 2, characterized in that: The method for pulling the steel box girder (2) along the bridge to the sliding bracket (3) by swinging includes: installing a hand winch (10) at the lifting ring (4), connecting one end of a lifting belt (11) to the hand winch (10) and the other end to the steel box girder (2), tightening the lifting belt (11) by the hand winch (10) to cause the steel box girder (2) to shift toward the side span concrete beam (2) until the steel box girder (2) is completely above the sliding bracket (3), and slowly lowering the steel box girder (2) to the sliding bracket (3) by a cable crane (5).

7. The method for constructing the steel-concrete joint section of a separated single-column cable-stayed bridge according to claim 4, characterized in that: The method for driving the steel box girder (2) to move on the sliding bracket (3) until it docks with the side span concrete beam (1) comprises: using a tensioning jack (8) to pull the steel box girder (2) along the slide beam (6) to a position where it docks with the side span concrete beam (1); after sliding into place, arranging a plurality of three-way jacks between the steel box girder (2) and the sliding bracket (3); and using the three-way jacks to accurately adjust the elevation, transverse position and longitudinal position of the steel box girder (2).

8. The method for constructing the steel-concrete joint section of a separated single-column cable-stayed bridge according to claim 1, characterized in that: The method for pouring the joint between the side span concrete beam (1) and the steel box beam (2) comprises: installing steel bars and prestressed pipes in the steel box beam (2); arranging a template at the joint between the steel box beam (2) and the side span concrete beam (1); pouring concrete into the template; after the concrete at the joint is cured, longitudinally prestressing the steel box beam (2) and the side span concrete beam (1); and after the prestressing is completed, grouting and anchoring the prestressed steel strands.

9. The method for constructing the steel-concrete joint section of a separated single-column cable-stayed bridge according to claim 3, characterized in that: Channel steels (12) are provided on both sides of the transverse direction of the slide beam (6); the vertical portion of the lower end of the channel steel (12) is located on the transverse side of the slide beam (6), and the horizontal portion of the upper end is fixed to the lower end flange of the slider (7) to limit the transverse and vertical displacement of the slider (7).

10. The method for constructing the steel-concrete joint section of a separated single-column cable-stayed bridge according to claim 9, characterized in that: The lower end surface of the slider (7) is installed with a polytetrafluoroethylene plate, and the upper end surface of the slider is installed with a rubber pad.

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