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

Abstract

This invention relates to the technical field of bridge construction methods, specifically to a construction method for a steel-concrete composite section of a separated single-column cable-stayed bridge. The method includes the following steps: constructing the side span concrete beam of the steel-concrete composite section based on the tower column; erecting a sliding support frame below the steel-concrete composite section; transporting the steel box girder of the steel-concrete composite section by barge to below the cable crane; lifting the steel box girder from the barge below to a set height by the cable crane; using a swinging method to pull the steel box girder along the bridge direction to the sliding support frame; driving the steel box girder to move on the sliding support frame until it connects with the side span concrete beam; and pouring the joint between the side span concrete beam and the steel box girder to complete the construction of the steel-concrete composite section. The construction method for the steel-concrete composite section of a separated single-column cable-stayed bridge presented in this application is simple and efficient, ensures construction quality, reduces construction costs, and effectively avoids the high risks associated with using bridge deck cranes or large barges on steep and unstable slopes.

Description

Technical Field

[0001] This invention relates to the technical field of bridge construction methods, specifically to a construction method for a steel-concrete composite section of a separated single-column cable-stayed bridge. Background Technology

[0002] When erecting large cable-stayed bridge steel box girders in mountainous and complex terrain conditions, especially when the bridge site is located on a steep slope, far from deep water areas, and in a special geographical environment with extremely high requirements for ecological and environmental protection, traditional steel box girder installation methods—such as cantilever assembly with bridge deck cranes, traction by sliding tracks, or cable-pushing—expose significant limitations and potential risks.

[0003] For example, the cantilever assembly method using a bridge deck crane can refer to a construction method for a cable-stayed bridge steel-concrete main girder. This method involves a steel-concrete main girder composed of concrete side main girders, steel crossbeams, and precast bridge deck panels. The steel-concrete main girder is constructed in multiple segments, and the construction method includes the following steps: Step 1, the concrete side main girder on the main tower and the steel-concrete main girders on both sides of the main tower are constructed using cast-in-place scaffolding; Step 2, the remaining cantilever segments of the steel-concrete main girder in the middle span are constructed using front-support cable-stayed formwork; the cantilever formwork is assembled on the steel-concrete main girder on one side of the main tower, the reinforcing bars are tied, the steel crossbeams are hoisted, and concrete is poured. After the concrete strength reaches the design requirements, prestressing is applied, and the bridge deck panels are hoisted; Step 3, the cantilever formwork is moved forward to the next segment, and the construction procedures in Step 2 are repeated for the next segment; Step 4, the side span is constructed using cast-in-place scaffolding, which uses a pile foundation plus Bailey beam support scheme; Step 5, the side span is closed; Step 6, the middle span is closed. This method allows for rapid construction of steel-concrete main beams in conventional terrain, but it is difficult to obtain stable equipment foundations and operating space in complex terrain, especially on steep and unstable slopes, which greatly increases safety risks.

[0004] The tobogganing system 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 the surface vegetation and is difficult to meet high environmental protection requirements.

[0005] Cable-assisted jacking relies heavily on large barges and other watercraft, making it impossible to implement in mountainous rivers or areas far from deep water or with rapid currents. Furthermore, the jacking process places extremely high demands on temporary support structures, raising concerns about stability under complex geological conditions.

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

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

[0008] The technical solution of this application is: a construction method for a steel-concrete composite section of a separated single-column cable-stayed bridge, characterized by the following steps: Based on the side span concrete beams in the steel-concrete composite section of the tower column construction; A sliding support structure was erected below the steel-concrete composite section; The barge transports the steel box girder from the steel-concrete composite section to below the cable crane. The cable crane lifted the steel box girder from the barge below to the set height; The steel box girder was pulled along the bridge direction to the sliding support by a swing-slip method. Drive the steel box girder to move on the sliding support until it connects with the side span concrete beam; The joint between the side span concrete beam and the steel box girder was poured to complete the construction of the steel-concrete joint section.

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

[0010] According to the construction method of the steel-concrete composite section of a separated single-column cable-stayed bridge provided in this application, the method of constructing a sliding support under the steel-concrete composite section includes: constructing a sliding support under the steel-concrete composite section; constructing a sliding beam arranged along the longitudinal direction of the bridge on the sliding support; installing several sliders that can slide along the sliding beam on the sliding beam; connecting adjacent sliders on the same sliding beam into a whole by a rigid rod-like structure; and arranging a traction tensioning structure on the sliding support.

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

[0012] According to the construction method of the steel-concrete composite section of the separated single-column cable-stayed bridge provided in this application, the method of the cable crane lifting the steel box girder on the barge below to a set height includes: the trolley of the cable crane moves along the bridge direction toward the tower column to the maximum distance position, and the cable crane lifts the steel box girder on the barge below vertically until the lower end face of the steel box girder exceeds the upper end face of the sliding support by a set distance.

[0013] According to the construction method of the steel-concrete composite section of the separated single-column cable-stayed bridge provided in this application, the method of traction of the steel box girder to the sliding support along the bridge direction by swinging includes: installing a hand-operated hoist at the lifting ring, connecting one end of the hoist to the hand-operated hoist and the other end to the steel box girder, and using the hand-operated hoist to tension the hoist to shift the steel box girder to the side of the concrete beam of the side span until the steel box girder is completely above the sliding support, and then slowly lowering the steel box girder to the sliding support by the cable crane.

[0014] According to the construction method of the steel-concrete composite section of the separated single-column cable-stayed bridge provided in this application, the method of driving the steel box girder to move on the sliding support until it is connected with the side span concrete beam includes: using tension jacks to pull the steel box girder along the sliding beam to the position where it is connected with the side span concrete beam; after sliding into place, arranging multiple three-way jacks between the steel box girder and the sliding support, and using the three-way jacks to precisely adjust the elevation, lateral position and longitudinal position of the steel box girder.

[0015] According to the construction method of the steel-concrete composite section of a separated single-column cable-stayed bridge provided in this application, the method for pouring the joint between the side span concrete beam and the steel box girder includes: installing reinforcing bars and prestressing ducts inside the steel box girder; arranging formwork at the joint between the steel box girder and the side span concrete beam; pouring concrete into the formwork; after the concrete at the joint has cured, longitudinally prestressing the steel box girder and the side span concrete beam; and grouting and anchoring the prestressing steel strands after tensioning.

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

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

[0018] The advantages of this application are as follows: 1. The construction method of this application is applicable to bridge construction in complex mountainous terrain with large topographic relief. It effectively avoids the high risks of using bridge deck cranes or large barges on steep and unstable slopes (such as those required for cable-stayed jacking). By adopting a swing-and-slide method to connect the cable crane and the sliding support, it solves the problem that the cable crane cannot directly transfer the steel box girder to the sliding support. It greatly reduces the difficulty and safety risks of direct high-altitude hoisting and docking, provides a stable and controllable operating platform, ensures the rapid construction of the entire steel-concrete composite section, reduces the difficulty of the entire bridge construction, improves construction efficiency, and combines safety and economy. It is suitable for widespread promotion and application. 2. This application pre-installs lifting rings on the concrete beam of the side span, using the lifting rings as the force points for subsequent swinging. This allows for the traction and swinging of the entire steel box girder along the bridge direction using simple tools, which greatly improves the efficiency of steel box girder hoisting, reduces construction difficulty, and solves the problem of not being able to hoist and move the steel box girder in the blind area of ​​the cable hoist. 3. This application constructs a sliding support structure in the steel-concrete composite section. The sliding support structure is simple and can be connected to the cable crane, enabling the steel box girder to be quickly connected to 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 simplifies the connection construction of the steel box girder by installing tension jacks on the slide beam and tensioning and pulling the steel box girder on the slide beam. The equipment used is of conventional structure, with very low operating cost and easy operation. 5. The cable crane method for hoisting steel box girders in this application is very simple. The cable crane only needs to perform vertical lifting and does not need to perform subsequent lateral adjustment. The initial hoisting work can be completed once the steel box girder is hoisted above the sliding support. The operation is very simple. 6. This application uses a hand-operated hoist to move the steel box girder along the bridge direction by precisely calculated short-distance swinging, which solves the problem that cable cranes cannot move the steel box girder along the bridge direction to the sliding support. The whole construction method is simple, the construction cost is low, the operation is convenient, and the construction accuracy and safety are controllable. 7. This application uses three-way jacks installed on the sliding support to precisely adjust the steel box girder, so that the steel box girder can be accurately connected with the side span concrete beam. The adjustment method is simple and easy to operate. The equipment and tools used are all of conventional structure, and the construction cost is low. 8. This application relies on sliding supports to support the steel box girder. After the steel box girder is aligned and adjusted, the connection with the side span concrete beam can be completed by building a formwork and pouring concrete. The construction is simple and the operation is convenient, which greatly reduces the difficulty of the connection construction between the steel box girder and the side span concrete beam. 9. The slider and slide beam structure constructed in this application is simple. By setting channel steel to limit the slider in the horizontal and vertical directions, the sliding of the steel box girder on the slide beam is more stable, and the safety of construction is greatly improved. 10. This application provides 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 provided 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 for the steel-concrete composite section of the separated single-column cable-stayed bridge proposed in this application is simple and efficient, ensures construction quality, reduces construction costs, and effectively avoids the high risks of using bridge deck cranes or large barges on steep and unstable slopes. It is suitable for bridge construction under complex and harsh conditions such as steep mountainous terrain, areas far from deep water, and sensitive ecological environments. It can effectively solve the problem of high-precision installation of the steel-concrete composite section when there are blind spots in the cable hoisting system. Attached Figure Description

[0020] Figure 1 This application provides a schematic diagram of the construction process for the steel-concrete composite section of a cable-stayed bridge. Figure 2 : Schematic diagram of the swaying structure of the steel box girder in this application; Figure 3 : A schematic diagram of the lifting ring arrangement structure in this application; Figure 4 : A schematic diagram of the steel box girder traction in this application; Figure 5 : A schematic diagram of the arrangement structure of the slider, channel steel, and slide beam in this application; Wherein: 1—Side span concrete beam; 2—Steel box girder; 3—Sliding support; 4—Lifting ring; 5—Cable hoist; 6—Slide beam; 7—Sliding block; 8—Tension jack; 9—Wire rope; 10—Hand-operated hoist; 11—Lifting strap; 12—Channel steel. Detailed Implementation

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

[0022] In the description of this application, it should be understood that the terms "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "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 application and simplifying the description, 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 application.

[0023] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

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

[0025] This application relates to a construction method for a steel-concrete composite section of a separated single-column cable-stayed bridge. This method is applicable to bridge construction under complex and demanding conditions such as steep mountainous terrain, locations far from deep water areas, and sensitive ecological environments. It effectively solves the challenge of high-precision installation of the steel-concrete composite section when there are blind spots in the cable-stayed system. The entire construction method is simple, safe, reliable, and convenient to operate, ensuring construction quality and reducing construction costs. It effectively avoids the high risks associated with using bridge cranes or large barges on steep and unstable slopes (such as those required for cable-laying and pushing), significantly reducing the difficulty and safety risks of direct high-altitude hoisting and docking, and providing a stable and controllable operating platform.

[0026] Specifically, such as Figures 1-5 As shown, the construction method of the steel-concrete composite section of a separated single-column cable-stayed bridge according to this application is carried out according to the following steps: S1, Concrete beam 1 of the side span in the steel-concrete composite section based on tower column construction; The side span concrete beam 1 is close to the riverbank, and can be constructed by building a support frame or relying on the tower column; S2. Construct a sliding support 3 below the steel-concrete composite section; The purpose of setting up the sliding support 3 is to support the steel box girder 2, and to facilitate the subsequent adjustment of the steel box girder 2 and its connection with the side span concrete beam 1. S3, the steel box girder 2 in the steel-concrete composite section transported by barge to below the cable crane 5; Steel box girder 2 refers to the steel box girder segment 2 that is connected to the side span concrete beam 1. The steel box girder 2 has a huge structure. For areas with complex terrain, transporting the steel box girder 2 by barge is the most convenient means of operation. S4. Cable crane 5 lifts the steel box girder 2 from the barge below to the set height; Cable crane 5 can directly lift the steel box girder 2 from the barge. However, due to the complex terrain and other interference, when cable crane 5 moves the maximum distance along the bridge, there is still a certain distance between it and the side span concrete beam 1. In other words, if cable crane 5 is used alone, it is impossible to move the steel box girder 2 to the position where it is connected with the side span concrete beam 1. S5. The steel box girder 2 is pulled along the bridge direction to the sliding support 3 by a swinging motion. 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 it along the bridge direction to the position where it connects with the side span concrete beam 1. The operation is very simple and also solves the problem that the cable crane 5 cannot be directly lifted into place. S6. Drive the steel box girder 2 to move on the sliding support 3 until it connects with the side span concrete beam 1. After the steel box girder 2 is transferred to the sliding support 3, it is adjusted on the sliding support 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 direction to a position close to the side span concrete beam 1 on the sliding support 3, and then adjusted in three directions: vertical, transverse and longitudinal, until it is accurately aligned with the side span concrete beam 1. S7. Construct the joint between the side span concrete beam 1 and the steel box girder 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 and the concrete joint connecting the steel box girder 2 and the side span concrete beam 1 can be poured.

[0027] In some embodiments of this application, the above-mentioned step S1 has been optimized. Specifically, the method based on the side span concrete beam 1 in the steel-concrete composite section of the tower column construction is as follows: when the side span concrete beam 1 is poured, a lifting ring 4 for swinging the steel box girder 2 is pre-embedded at the end of the side span concrete beam 1 facing the steel box girder 2.

[0028] The lifting ring 4 is the point of force used to pull 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 the construction personnel to swing the steel box girder 2 on the side span concrete beam 1 based on the lifting ring 4.

[0029] The arrangement structure of the lifting ring 4 is as follows Figures 2-3 As shown, in this embodiment, lifting rings 4 are respectively installed on both sides of the transverse bridge at the end of the side span concrete beam 1 near the steel box girder 2. That is, two sets of lifting rings 4 are installed at the end of the side span concrete beam 1. During the swinging operation of the steel box girder 2, the steel box girder 2 can be easily transferred to the sliding support 3 by the combined action of the two sets of lifting rings 4. The simultaneous action of the two sets of lifting rings 4 makes the structure more stable and avoids problems such as deflection or oscillation during the swinging process. Construction safety is ensured.

[0030] In a further embodiment of this application, the above step S2 has been optimized. Specifically, the method of building a sliding support 3 below the steel-concrete composite section is as follows: the steel-concrete composite section is close to the shore, so the sliding support 3 can be built based on the shore terrain or the tower column. The sliding support 3 can be a full-span support structure or other support structure forms, as long as it meets the function of supporting and adjusting the steel box girder 2. A sliding support 3 is erected below the steel-concrete composite section, and sliding beams 6 arranged along the longitudinal direction of the bridge are erected on the sliding support 3. In this embodiment, multiple sliding beams 6 are arranged on the upper end face of the sliding support 3, and the multiple sliding beams 6 are arranged at intervals along the transverse direction of the bridge. The sliding beams 6 themselves are arranged along the longitudinal direction of the bridge. Several sliders 7 that can slide along the sliding beams 6 are installed on the sliding beams 6. Adjacent sliders 7 on the same sliding beam 6 are connected as one unit by a rigid rod structure. A traction tensioning structure is arranged on the sliding support 3.

[0031] like Figure 5 As shown, in this embodiment, channel steel 12 is provided on both sides of the slide beam 6 in the transverse direction. The channel steel 12 includes a transverse side plate and a vertical side plate. The transverse side plate is fixed to the lower flange of the slider 7, and the vertical side plate is located on the transverse side of the slide beam 6. The channel steel 12 is a structure used to restrict 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 plate extending horizontally from the upper end of the channel steel 12 is fixed to the upper end face of the lower flange of the slider 7. The channel steel 12 on both sides can effectively restrict 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. This structure can effectively improve the stability of the sliding of the steel box girder 2 and avoid deviation.

[0032] Furthermore, a PTFE plate is installed on the lower end face of the slider 7. The PTFE plate can effectively reduce the frictional resistance between the slide beam 6 and the slider 7, making the sliding of the slider 7 on the slide beam 6 smoother and reducing the traction force required for the sliding of the steel box girder 2. In addition, a rubber pad is installed on the upper end face of the slider 7 in this embodiment. The rubber pad allows the steel box girder 2 to sit more stably on the slider 7, making the connection between the two tighter, reducing the likelihood of the steel box girder 2 overturning, and making the sliding process of the steel box girder 2 along the slide beam 6 safer.

[0033] In some other embodiments of this application, this embodiment optimizes the above-described method of arranging the traction tensioning structure on the sliding support 3. A tensioning jack 8 is installed at one end of the slide beam 6 near the side span concrete beam 1, and the tensioning jack 8 is connected to the slider 7 of the same slide beam 6 that is closest to the tensioning jack 8 by a steel wire rope 9.

[0034] like Figure 4As shown, the tensioning jack 8 is a traction structure installed on the sliding beam 6. A reaction seat is provided on the sliding beam 6, and the tensioning jack 8 is fixed to the reaction seat and connected to the slider 7 in the same group via a steel wire rope 9. When traction is required on the steel box girder 2, the tensioning jack 8 applies a force along the longitudinal direction of the bridge to the slider 7, moving it closer to the side span concrete beam 1. The steel box girder 2 follows the slider 7 along the sliding beam 6 until it reaches the position where it connects with the side span concrete beam 1. In practical applications, multiple tensioning jacks 8 work together to ensure that the steel box girder 2 can move stably and accurately to the connection position.

[0035] In some embodiments of this application, step S4 described above has been optimized. Specifically, the method for the cable crane 5 to lift the steel box girder 2 from the lower barge to a set height is as follows: the trolley of the cable crane 5 moves along the bridge direction towards the tower column to the maximum distance position, which is actually the position closest to the tower column. This reduces the amplitude of the steel box girder 2's swing along the bridge direction. The cable crane 5 lifts the steel box girder 2 from the lower barge vertically until the lower end face of the steel box girder 2 exceeds the upper end face of the sliding support 3 by a set distance. In this embodiment, the set distance is 1000mm~2000mm, that is, the cable crane 5 lifts the steel box girder 2 until the lower end face of the steel box girder 2 exceeds the upper end face of the sliding support 3 by 1000mm~2000mm. This ensures that when the steel box girder 2 swings above the sliding support 3, the lower end face of the steel box girder 2 exceeds the upper end face of the sliding support 3 by more than 500mm. This avoids collisions or interference between the steel box girder 2 and other structures during the swinging process. This also allows the steel box girder 2 to finally and stably land on the slider 7.

[0036] In a further embodiment of this application, the above-mentioned step S5 is optimized. Specifically, the method of using a swing-shifting method to pull the steel box girder 2 to the sliding support 3 along the bridge direction is as follows: a hand-operated hoist 10 is installed at the lifting ring 4, one end of the sling 11 is connected to the hand-operated hoist 10 and the other end is connected to the steel box girder 2. The steel box girder 2 is shifted to the side of the side span concrete beam 1 by the tensioning of the sling 11 by the hand-operated hoist 10 until the steel box girder 2 is completely above the sliding support 3. The cable crane 5 slowly lowers the steel box girder 2 to the sliding support 3.

[0037] The two chain hoists 10 on the two lifting rings 4 work together to apply a pulling force along the longitudinal direction of the bridge towards the side of the concrete beam 1 of the side span of the steel box girder 2. At this time, the steel box girder 2 is suspended by the cable suspender 5, so the force to drive the steel box girder 2 to move along the longitudinal direction of the bridge does not need to be too large, and the conventional chain hoist 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 has completely swung above the sliding support 3, the cable crane 5 slowly lowers the steel box girder 2. At this time, the hand-operated hoist 10 is in a tensioned state until the steel box girder 2 slowly lands 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 disconnected.

[0039] In some other embodiments of this application, this embodiment optimizes the above step S6. Specifically, the method of driving the steel box girder 2 to move on the sliding support 3 until it is connected with the side span concrete beam 1 is as follows: the tension jack 8 is used to pull the steel box girder 2 along the sliding beam 6 to the position where it is connected with the side span concrete beam 1. After sliding into place, multiple three-way jacks are arranged between the steel box girder 2 and the sliding support 3. The elevation, lateral position and longitudinal position of the steel box girder 2 are precisely adjusted by using the three-way jacks.

[0040] Multiple three-way jacks are arranged between the steel box girder 2 and the sliding support 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 in the manner of first adjusting the elevation, then adjusting the longitudinal position of the bridge, and finally adjusting the transverse position of the bridge, until the docking accuracy requirements are met.

[0041] The three-way jack is used in conjunction with slider 7 for adjustment. When the three-way jack is retracted, it is lower than the upper surface of slider 7. After the three-way jack is adjusted once, the steel box girder 2 can be lowered back onto slider 7. This process is repeated multiple times until the steel box girder 2 is precisely aligned.

[0042] In a preferred embodiment of this application, step S7 above has been optimized. Specifically, the method for pouring the joint between the side span concrete beam 1 and the steel box girder 2 is as follows: Reinforcing bars and prestressed ducts are installed inside the steel box girder 2. The lower steel grating longitudinal reinforcing bars are installed sequentially from bottom to top, followed by the upper steel grating longitudinal reinforcing bars, then the joint section crossbeam reinforcing bars, and finally the box girder connecting reinforcing bars. Formwork is arranged at the joint between the steel box girder 2 and the side span concrete beam 1. A "bottom-wrapping" method is used between the bottom formwork of the inclined bottom slab and the bottom formwork itself. A layer of sponge strip is attached to the side of the bottom formwork to prevent grout leakage at the bottom opening. When installing the bottom formwork of the inclined bottom slab and the outer formwork, the support is firm to prevent displacement of the formwork during concrete pouring. Simultaneously, the overlap length between the bottom formwork of the inclined bottom slab and the outer formwork and the joint section wall panel along the bridge direction is not less than 10cm, and is sealed with sponge strips. To ensure the construction quality of the joint section, concrete is poured into the formwork. The concrete used is C55 micro-expansion concrete with good fluidity and self-compacting properties. After selecting the concrete material, cross-tests should be conducted to determine the optimal concrete mix ratio that meets the construction requirements. The pouring should be carried out in the following order: bottom plate of the reserved box girder, lower steel grating chamber, bottom of the crossbeam, joint section and reserved section (inner and outer) inclined bottom plate (height difference ≤30cm), middle of the crossbeam, web of the reserved section, top plate of the reserved box girder, upper steel grating chamber, top of the crossbeam. After the concrete is poured, it should be covered and kept warm immediately for a curing period of not less than 7 days. After the concrete at the joint is cured, longitudinal prestressing tensioning should be carried out on steel box girder 2 and side span concrete beam 1. The prestressing duct should be grouted and anchored as soon as possible using vacuum-assisted grouting technology within 24 hours after the steel strand tensioning is completed.

[0043] In practical applications, the following method can be used: Based on the side span concrete beam 1 in the steel-concrete composite section of the tower column construction, during the pouring of the side span concrete beam 1, a lifting ring 4 for swinging the steel box girder 2 is pre-embedded at one end of the side span concrete beam 1 facing the steel box girder 2; a sliding support 3 is built below the steel-concrete composite section, and a sliding beam 6 arranged along the longitudinal direction of the bridge is built on the sliding support 3. Several sliders 7 that can slide along the sliding beam 6 are installed on the sliding beam 6. Adjacent sliders 7 on the same sliding beam 6 The components are connected as one unit by a rigid rod-like structure; a tensioning jack 8 is installed at one end of the slide beam 6 near 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 trolley of the cable crane 5 moves along the bridge direction towards the tower column to the maximum distance position, and the cable crane 5 lifts the steel box girder 2 on the barge below vertically until the lower end face of the steel box girder 2 exceeds the upper end face of the sliding support 3 by a set distance; at the lifting ring 4 Install the hand-operated hoist 10, connect one end of the sling 11 to the hand-operated hoist 10 and the other end to the steel box girder 2. Tension the sling 11 using the hand-operated hoist 10 to shift the steel box girder 2 towards the side span concrete beam 1 until the steel box girder 2 is completely above the sliding support 3. The cable crane 5 slowly lowers the steel box girder 2 onto the sliding support 3. Using the tensioning jack 8, pull the steel box girder 2 along the sliding beam 6 to the position where it connects with the side span concrete beam 1. After sliding into place, the steel box girder 2 and the sliding support... Multiple three-way jacks are arranged between the three frames to precisely adjust the elevation, lateral position, and longitudinal position of the steel box girder 2. After alignment, reinforcing bars and prestressing ducts are installed inside the steel box girder 2. 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 at the junction has cured, longitudinal prestressing is performed on the steel box girder 2 and the side span concrete beam 1. After tensioning, the prestressing steel strands are grouted and anchored.

[0044] like Figure 2 As shown, the bridging direction of this application Figure 2 In the left and right directions, the transverse direction of this application refers to... Figure 2 The direction perpendicular to the paper in this application refers to the vertical direction. Figure 2 The up and down directions in the middle.

[0045] The foregoing has shown and described the basic principles, main features, and advantages of this application. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this application. Various changes and modifications can be made to this application without departing from the spirit and scope thereof, and all such changes and modifications fall within the scope of this application as claimed. The scope of protection of this application is defined by the appended claims and their equivalents.

Claims

1. A construction method for a steel-concrete composite section of a separated single-column cable-stayed bridge, characterized in that: Includes the following steps: Based on the side span concrete beam in the steel-concrete composite section of the tower column construction (1). A sliding support was built below the steel-concrete composite section (3); The barge transports the steel box girder (2) in the steel-concrete composite section to below the cable crane (5); The cable crane (5) lifts the steel box girder (2) from the barge below to the set height; The steel box girder (2) is pulled along the bridge direction to the sliding support (3) by a swing-slip method; Drive the steel box girder (2) to move on the sliding support (3) until it docks with the side span concrete beam (1); The joint between the side span concrete beam (1) and the steel box girder (2) was poured to complete the construction of the steel-concrete joint section; The method for constructing the side span concrete beam (1) in the steel-concrete composite section based on the tower column includes: pre-embedding a lifting ring (4) for swinging the steel box girder (2) at one end of the side span concrete beam (1) facing the steel box girder (2) during the pouring of the side span concrete beam (1). The method of using a swing-shifting method to pull the steel box girder (2) along the bridge direction to the sliding support (3) includes: installing a hand-operated hoist (10) at the lifting ring (4), connecting one end of the sling (11) to the hand-operated hoist (10) and the other end to the steel box girder (2), and using the hand-operated hoist (10) to tension the sling (11) to shift the steel box girder (2) to the side of the side span concrete beam (1) until the steel box girder (2) is completely above the sliding support (3), and the cable crane (5) slowly lowers the steel box girder (2) to the sliding support (3).

2. The construction method for a steel-concrete composite section of a separated single-column cable-stayed bridge as described in claim 1, characterized in that: The method of constructing a sliding support (3) below the steel-concrete composite section includes: constructing a sliding support (3) below the steel-concrete composite section; constructing a sliding beam (6) arranged along the bridge direction on the sliding support (3); installing several sliding blocks (7) that can slide along the sliding beam (6) on the sliding beam (6); connecting adjacent sliding blocks (7) on the same sliding beam (6) into one unit through a rigid rod structure; and arranging a traction tensioning structure on the sliding support (3).

3. The construction method for a steel-concrete composite section of a separated single-column cable-stayed bridge as described in claim 2, characterized in that: The method of arranging the traction tensioning structure on the sliding support (3) includes: installing a tensioning jack (8) at one end of the slide beam (6) near the side span concrete beam (1), and connecting the tensioning jack (8) to the slider of the same slide beam (6) closest to the tensioning jack (8) with a steel wire rope (9).

4. The construction method for a steel-concrete composite section of a separated single-column cable-stayed bridge as described in claim 1, characterized in that: The method for the cable crane (5) to lift the steel box girder (2) on the barge below to a set height includes: the trolley 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 vertically until the lower end face of the steel box girder (2) exceeds the upper end face of the sliding support (3) by a set distance.

5. The construction method for a steel-concrete composite section of a separated single-column cable-stayed bridge as described in claim 3, characterized in that: The method of driving the steel box girder (2) to move on the sliding support (3) until it is connected with the side span concrete beam (1) includes: using tension jacks (8) to pull the steel box girder (2) along the slide beam (6) to the position where it is connected 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 support (3), and using the three-way jacks to precisely adjust the elevation, lateral position and longitudinal position of the steel box girder (2).

6. The construction method for a steel-concrete composite section of a separated single-column cable-stayed bridge as described in claim 1, characterized in that: The method for constructing the joint between the side span concrete beam (1) and the steel box beam (2) includes: installing reinforcing bars and prestressing ducts inside the steel box beam (2); arranging formwork at the joint between the steel box beam (2) and the side span concrete beam (1); pouring concrete into the formwork; after the concrete at the joint has cured, longitudinally prestressing tensioning is performed on the steel box beam (2) and the side span concrete beam (1); after tensioning, grouting and anchoring of the prestressing steel strands is performed.

7. The construction method for a steel-concrete composite section of a separated single-column cable-stayed bridge as described in claim 2, characterized in that: Channel steel (12) is provided on both sides of the slide beam (6) in the transverse direction; the lower vertical part of the channel steel (12) is located on the transverse side of the slide beam (6), and the upper horizontal part is fixed to the lower flange of the slider (7) to limit the transverse and vertical displacement of the slider (7).

8. The construction method for a steel-concrete composite section of a separated single-column cable-stayed bridge as described in claim 7, characterized in that: The lower end face of the slider (7) is fitted with a PTFE plate, and the upper end face of the slider is fitted with a rubber pad.

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