Auxiliary device for cantilever state construction of steel box girder

Abstract

The utility model relates to the technical field of bridge engineering construction, in particular to a construction method and an auxiliary device for dragging a small-section steel box girder. The cable saddle is fixedly connected to the top end of the stand column, the steel strand is installed on the cable saddle in a sliding mode, one end of the steel strand is connected to a first hollow jack, and the other end of the steel strand is connected to a second hollow jack; the two jacks are fixedly connected to the two ends of an upper cover plate of the steel box girder respectively. According to the device, the downwarping value of the steel box girder in the maximum cantilever state in the dragging process is reduced, the hidden danger that the front end of the steel box girder is prone to invading the safety distance of an existing railway return line in the dragging process is eliminated, the girder falling height is reduced, and the girder falling procedure is simplified.

Description

Technical Field

[0001] The utility model relates to the technical field of bridge engineering construction, in particular to a cantilever state construction auxiliary device for a steel box girder. Background Art

[0002] Steel box girder, also known as steel plate box girder, is a widely used structural form in bridge construction. Its basic structure includes upper cover, lower cover, longitudinal partition, transverse partition, web, side plate and other parts. With the rapid development of cities and the improvement of economic level, steel box girder bridges are more and more widely used in municipal road reconstruction or new construction projects. Due to its many advantages, they are often used to cross existing railways, highways, houses, dams and other buildings. There are many construction methods for the construction of steel box girders, including in-situ hoisting method, traction method, and top-pushing method. The in-situ hoisting method requires the erection of a bracket, and the use of lifting equipment to hoist the beam body in sections. It is suitable for construction environments with good construction site conditions, convenient bracket erection and convenient lifting equipment operation, but it cannot be used to cross existing lines and construction environments with many obstacles on the construction site. The traction method and top-pushing method have lower requirements for the construction site and are often used in the construction of crossing existing lines. During construction, the beam body is moved into place through the traction system or top-pushing system, and then the beam is dropped to the designed position. For example, Chinese patent 2022101827425 discloses the "Construction device for installing highway variable-section steel box girders with dragging and sliding brackets", with announcement number CN114541276B. By setting up a sliding load-bearing frame and a driving component, the sliding load-bearing frame is used to drive the steel box girder to move, thereby reducing the time for disassembly and installation and improving the problem of high construction cost of steel box girders. Another Chinese patent 2023201389416 discloses a "Steel Box Girder Towing and Traction Device" with the announcement number CN219621609U. The device uses a winch to pull the traction slide rail on the supporting slide rail to move and install it, and then the winch pulls the steel box girder to move on the traction slide rail to make the steel box girder reach the installation position, and the jack drives the supporting slide rail and the traction slide rail to fall back, so that the steel box girder falls on the bridge support and separates from the traction slide rail, and finally the traction slide rail is pulled out from the bottom of the steel box girder, thereby realizing the traction construction of the steel box girder without setting up Bailey frames on the railway and highway, so that the railway and highway can also operate normally during the construction of the steel box girder. However, the small-section steel box girder has a simple structure and poor rigidity. The conventional dragging or jacking process has many shortcomings in the construction of small-section steel box girders across railway operating lines. The deflection value of the front end of the steel box girder is large under the maximum cantilever condition during the dragging construction. The front end of the steel box girder is very easy to invade the safety distance of the railway return line during the dragging process, and it is difficult to control the height of the beam. Therefore, it is necessary to detect and control the deflection of the steel box girder in the cantilever state during the dragging process. Utility Model Content

[0003] In view of the above technical problems, the utility model provides a cantilever state construction auxiliary device for steel box girders, which reduces the downward deflection value of the steel box girder in the maximum cantilever state during the dragging process, eliminates the hidden danger that the front end of the steel box girder is easy to invade the safety distance of the existing railway return line during the dragging process, reduces the height of the beam drop, simplifies the beam drop process, and avoids the problems of increased cost, difficulty in beam drop, and extended cycle caused by the lifting system, thereby improving construction efficiency and reducing safety risks caused by construction across the railway operating line.

[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0005] The utility model discloses a cantilever state construction auxiliary device for a steel box girder, comprising a column, a saddle fixedly connected to the top of the column, and a steel strand slidably mounted on the saddle, wherein one end of the steel strand is connected to a first hollow jack, which is fixedly mounted on a first anchor reaction seat, and the other end of the steel strand is connected to a second hollow jack, which is fixedly mounted on a second anchor reaction seat; the first anchor reaction seat comprises a reaction seat frame fixedly connected to an upper cover plate of the steel box girder, a steel strand channel arranged in the reaction seat frame, and a jack connecting plate fixedly connected to one end of the steel strand channel, wherein the steel strand channel is inclined, and the jack connecting plate is located at the lower end of the steel strand channel; the structure of the second anchor reaction seat is mirror-imaged to the first anchor reaction seat.

[0006] Through this scheme, the auxiliary device can be used during construction to effectively reduce the deflection value of the steel box girder in the maximum cantilever state during the dragging process, eliminate the hidden danger that the front end of the steel box girder is easy to invade the safety distance of the existing railway return line during the dragging process, reduce the height of the beam drop, simplify the beam drop process, avoid the problems of increased costs, difficulty in beam drop, and extended cycle caused by the lifting system, thereby improving construction efficiency and reducing safety risks caused by construction across the railway operating line.

[0007] Preferably, the column is a tubular structure with strip reinforcement ribs fixed together in a criss-cross pattern, and is welded together. Circular or rectangular column head plates are welded at both ends of the column, and a stiffening plate is welded between the column head plate and the column. The column head plate at the lower end of the column is fixedly connected to the upper cover plate of the steel box girder; the first anchor reaction seat and the second anchor reaction seat are fixedly connected to the upper cover plate of the steel box girder, and are respectively located at the front and rear ends of the column.

[0008] Through this solution, the column is light in weight and high in strength, and can withstand the large tensile force at both ends of the steel box girder.

[0009] Preferably, the center of the column is located at 1 / 2 of the length of the steel box girder, the centers of the first anchor reaction seat and the second anchor reaction seat are located at 1 / 4 and 3 / 4 of the length of the steel box girder respectively, and the height of the column is 1 / 4-1 / 2 of the length of the steel box girder.

[0010] Through this solution, the steel strands are subjected to reasonable force, making it convenient to retract and extend the steel strands.

[0011] Preferably, the saddle includes a bottom plate fixedly connected to the top of the column, a sleeve arranged above the bottom plate, and a plurality of support plates fixedly connected between the sleeve and the bottom plate and arranged parallel to each other.

[0012] Through this solution, the saddle structure is firm and the steel strand can be stably installed.

[0013] Preferably, a transverse partition is provided in the inner cavity of the steel box girder below the column and the first anchor reaction seat and the second anchor reaction seat, and the periphery of the transverse partition is fixedly connected to the inner cavity wall of the steel box girder.

[0014] Through this solution, the strength of the steel box girder at the force application point of the steel strand can be improved.

[0015] The utility model can effectively reduce the deflection value of the steel box girder in the maximum cantilever state during the dragging process of the steel box girder, eliminates the hidden danger that the front end of the steel box girder is easy to invade the safety distance of the existing railway return line during the dragging process, reduces the height of the beam drop, simplifies the beam drop process, and avoids the problems of increased cost, difficulty in beam drop, and extended cycle caused by the lifting system, thereby improving construction efficiency and reducing safety risks caused by construction across the railway operating line. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Other features, objects and advantages of the present invention will become more apparent by reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0017] Figure 1 It is a structural schematic diagram of an embodiment of the utility model;

[0018] Figure 2 It is a schematic diagram of the longitudinal cross-sectional structure of the cable saddle;

[0019] Figure 3 for Figure 2 AA cross-sectional structural diagram;

[0020] Figure 4 is a schematic diagram of a longitudinal cross-sectional structure of a first anchor reaction seat;

[0021] Figure 5 is a schematic diagram of the lateral structure of the first anchor reaction seat;

[0022] Figure 6 It is an enlarged structural diagram of the upper end of the column;

[0023] Figure 7 It is a schematic diagram of the structure from a top view of the upper end of the column. DETAILED DESCRIPTION

[0024] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below in conjunction with specific implementation methods.

[0025] like Figure 1 As shown, the utility model of the cantilever state construction auxiliary device of the steel box beam comprises a column 1 fixedly connected to the upper surface of the steel box beam 3. The column 1 is welded with a tubular structure with crisscrossed strip reinforcement ribs fixed together. It is light in weight and has a large load-bearing capacity. Figure 6 , Figure 7 As shown, circular or rectangular column head plates 11 are welded at both ends of the column 1, and a stiffening plate 12 is welded between the column head plate 11 and the column 1. The column head plate at the lower end of the column 1 is fixedly connected to the upper surface of the steel box girder 3, that is, the upper cover plate of the steel box girder 3, by bolts. Of course, the column head plate at the lower end of the column 1 can also be directly welded to the upper cover plate of the steel box girder 3. A saddle 2 is provided at the upper end of the column 1, and a steel strand 4 is installed on the saddle 2. One end of the steel strand 4 is fixedly connected to the upper surface of the steel box girder 3 in front of the column 1 through a first anchor reaction seat 5, and the other end is fixedly connected to the upper surface of the steel box girder 3 behind the column 1 through a second anchor reaction seat 6. Tightening the steel strand 4 can generate an upward pulling force on both ends of the steel box girder 3, offsetting the weight of the steel box girder 3 itself in the cantilever state, thereby achieving the purpose of reducing the deflection value generated in the cantilever state.

[0026] like Figure 2 , Figure 3 As shown, the cable saddle 2 comprises a bottom plate 21 fixedly connected to the top of the column 1, a sleeve 23 arranged above the bottom plate 21, and a plurality of support plates 22 fixedly connected between the sleeve 23 and the bottom plate 21 and arranged parallel to each other. The bottom plate 21 is welded to the column head plate 11 at the upper end of the column 1, and the column head plate 11 at the upper end of the column 1 can also be directly used as the bottom plate 21 of the cable saddle 2. The support plate 22 is vertically welded to the bottom plate 21 to support the sleeve 23. The upper end of the support plate 22 is provided with an arc-shaped notch for installing the sleeve 23. The arc-shaped sleeve 23 is clamped on the arc-shaped notch of the support plate 22. The connection between the arc-shaped notch and the sleeve 23 is welded. In addition, a cross-connecting plate 24 parallel to the bottom plate 21 is arranged between adjacent support plates 2. The two ends of the cross-connecting plate 24 are respectively welded to two adjacent support plates to form a stable and firm frame structure.

[0027] A hollow jack is installed on at least one of the first anchor reaction seat 5 and the second anchor reaction seat 6, and the steel strand 4 is connected through the hollow jack. In this embodiment, one end of the steel strand 4 is connected to the first hollow jack 71, the first hollow jack 71 is fixedly mounted on the first anchor reaction seat 5, and the other end of the steel strand 4 is connected to the second hollow jack 7.

[0028] Hollow jack is a double-acting jack that uses double hydraulic cylinders to tension prestressed tendons and top pressure anchors. It is suitable for tensioning steel bar bundles or steel strand bundles of anchors. After being equipped with support legs and tie rods, it can also be used as a tie rod jack to tension prestressed tendons with screw end rod anchors and head anchors. Figure 4 , Figure 5 As shown, when used to install the hollow jack, the first anchor reaction seat 5 includes a reaction seat frame 51 fixedly connected to the upper cover plate of the steel box girder 3, a steel strand channel 52 arranged in the reaction seat frame 51, and a jack connecting plate 53 fixedly connected to one end of the steel strand channel 52. The steel strand channel 52 is inclined, and the jack connecting plate 53 is located at the lower end of the steel strand channel 52. The end of the steel strand 4 is connected to the hollow jack, and the steel strand 4 can be tightened by operating the hollow jack. The tightened steel strand 4 acts on the front end of the steel box girder 3 through the first anchor reaction seat 5, and an upward component force is applied to the front end of the steel box girder 3. This upward component force can offset a part of the deadweight of the steel box girder 3, thereby reducing the deflection value generated in the cantilever state.

[0029] In addition, in order to improve the strength of the steel box girder 3 at the position where the steel strand 4 applies force, a transverse partition 8 is provided in the inner cavity of the steel box girder 3 below the column 1 and the first anchor reaction seat 5 and the second anchor reaction seat 6, and the periphery of the transverse partition 8 is fixedly connected to the inner cavity wall of the steel box girder 3. In order to further improve the strength of the steel box girder 3, a plurality of mutually parallel transverse partitions 8 can be provided at the same position, and a longitudinal partition is provided between two adjacent transverse partitions 8, and the transverse partitions 8 and the longitudinal partitions are welded together to form a more stable frame structure supported in the inner cavity of the steel box girder 3.

[0030] The utility model discloses a method for dragging and constructing a small-section steel box beam, comprising the following steps:

[0031] Step 1: hoist the steel box girder 3 to the dragging operation station and make preparations before the dragging operation;

[0032] Step 2: According to the design requirements, the column installation position, the first anchor position, and the second anchor position are defined on the upper cover plate of the steel box girder 3. The column installation position is located in the middle of the length direction of the upper cover plate of the steel box girder, the first anchor position is located at the front end of the column installation position, and the second anchor position is located at the rear end of the column installation position. Under normal circumstances, as a better force application point, the center of the column installation position is located at 1 / 2 of the length direction of the steel box girder 3, or slightly behind 1-2 meters. The centers of the first anchor position and the second anchor position are located at 1 / 4 and 3 / 4 of the length direction of the steel box girder 3, respectively, and the height of the column 1 is 1 / 4-1 / 2 of the length of the steel box girder 3. Of course, the above three force application points are all located on the central axis of the steel box girder 3.

[0033] Step 3: add a transverse diaphragm 8 to the inner cavity of the steel box girder 3 below the column installation position, the first anchor position, and the second anchor position to improve the connection strength between the upper cover plate, the lower cover plate, and the web plate of the steel box girder 3; to further improve the strength of the steel box girder 3, multiple transverse diaphragms 8 parallel to each other can be set at the same position, and a longitudinal diaphragm can be set between two adjacent transverse diaphragms 8, and the transverse diaphragms 8 and the longitudinal diaphragms are welded together to form a more stable frame structure supported in the inner cavity of the steel box girder 3. In this way, the stress points on the reinforced steel box girder 3 are more solid.

[0034] Step 4: fix the column 1 on the column installation position, fix the first anchoring reaction seat 5 and the second anchoring reaction seat 6 on the first anchoring position and the second anchoring position respectively, set the saddle 2 on the upper end of the column 1, fix one end of the steel strand 4 on the first anchoring reaction seat 5, and the other end is fixedly connected to the second anchoring reaction seat 6 by passing the saddle 2, and tighten the steel strand 4 to reach the set tension by the tightening device on the first anchoring reaction seat 5 or the second anchoring reaction seat 6. The tightening device is a hollow jack installed on the first anchoring reaction seat 5 or the second anchoring reaction seat 6. Figure 1 In the embodiment, hollow jacks are installed on the first anchor reaction seat 5 and the second anchor reaction seat 6. The hollow jacks can be used to tighten the steel strands 4, thereby applying an upward force to the front and rear ends of the steel box girder 3 through the first anchor reaction seat 5 and the second anchor reaction seat 6, thereby reducing the gravity of the steel box girder 3 itself, thereby reducing the downward deflection value in the cantilever state.

[0035] Step 5: Connect the traction rope of the towing operation to the front end of the steel box girder, start the winch and other traction machinery to drag the steel box girder 3 into place and drop the beam. After the beam is dropped, loosen the steel strand 4, remove the first anchor reaction seat 5 and the second anchor reaction seat 6, and remove the column 1 and the saddle 2. During the process of towing the steel box girder 3, check the deflection of the steel box girder 3 at any time, and tighten the steel strand 4 to make the deflection of the steel box girder 3 meet the design requirements.

[0036] like Figure 1As shown, as a comparative experimental example of the utility model, the application in the dragging construction of the newly added anti-collision independent structure steel box girder of a certain city overpass shows that a 5m high φ630×8mm steel pipe column is set 1m behind the center of the two-span steel box girder, and the column head plate is added within 50cm above and below the column for reinforcement. The bottom of the column is welded to the top surface of the steel box girder. Three transverse partitions and three longitudinal partitions are set inside the steel box girder for local reinforcement. The thickness of the steel plate is 16mm. A cable saddle is set on the top of the column. The cable saddle is made of Q235 steel with a steel plate thickness of 20mm. The top steel pipe uses a steel pipe with a diameter of Φ100mm as a sleeve for installing steel strands. The cable saddle is 720mm long and 300mm wide, and is welded and fixed on the top of the column. An anchor reaction seat is set 17.5m before and after the steel pipe column, and a hollow jack is installed on the anchor reaction seat. The material of the anchor reaction seat is Q235 steel. Except for the anchor cover plate of 30mm, the rest is 20mm thick and is welded and fixed on the top of the steel box girder. The steel strand with an area of ​​15×140mm² passes through the sleeve of the saddle at the top of the column, and the two ends are anchored on the hollow jacks at 17.5m of the steel box girder. Before dragging, the hollow jacks at both ends are used to simultaneously tension and anchor. After the dragging is completed, the steel strand is removed by a single-end tensioning method. After the steel box girder is dropped, the column and the anchor reaction seats at both ends are removed. After the utility model is adopted, the deflection value generated in the maximum cantilever state during the dragging process of the steel box girder is reduced from 39cm in the traditional dragging construction to 15cm, eliminating the hidden danger that the front end of the steel box girder is easy to invade the safety distance of the existing railway return line during the dragging process, reducing the height of the dropped beam, simplifying the dropped beam process, avoiding the problems of increased cost, difficult dropped beams, and extended cycle caused by the lifting system, greatly improving the construction efficiency, and reducing the safety risks caused by the construction of the overpass railway operating line.

[0037] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A cantilever construction auxiliary device for a steel box beam, comprising a column (1), a saddle (2) fixedly connected to the top of the column (1), and a steel strand (4) slidably mounted on the saddle (2). It is characterized by: One end of the steel strand (4) is connected to a first hollow jack (71), which is fixedly mounted on a first anchor reaction seat (5); the other end of the steel strand (4) is connected to a second hollow jack (7), which is fixedly mounted on a second anchor reaction seat (6); the first anchor reaction seat (5) comprises a reaction seat frame (51) fixedly connected to an upper cover plate of a steel box girder (3), a steel strand channel (52) arranged in the reaction seat frame (51), and a jack connecting plate (53) fixedly connected to one end of the steel strand channel (52); the steel strand channel (52) is inclined, and the jack connecting plate (53) is located at the lower end of the steel strand channel (52); the structure of the second anchor reaction seat (6) is mirror-imaged to the first anchor reaction seat (5).

2. According to claim 1, a cantilever state construction auxiliary device for a steel box girder, Features The column (1) is a tubular structure with strip reinforcement ribs fixed together in a crisscross pattern. A circular or rectangular column head plate (11) is welded at both ends of the column (1). A stiffening plate (12) is welded between the column head plate (11) and the column (1). The column head plate at the lower end of the column (1) is fixedly connected to the upper cover plate of the steel box girder (3). The first anchor reaction seat (5) and the second anchor reaction seat (6) are fixedly connected to the upper cover plate of the steel box girder (3) and are respectively located at the front and rear ends of the column (1).

3. According to claim 2, a cantilever state construction auxiliary device for a steel box girder, Features The center of the column (1) is located at 1 / 2 of the length of the steel box girder, the centers of the first anchor reaction seat (5) and the second anchor reaction seat (6) are located at 1 / 4 and 3 / 4 of the length of the steel box girder respectively, and the height of the column is 1 / 4 to 1 / 2 of the length of the steel box girder.

4. A cantilever state construction auxiliary device for a steel box girder according to claim 1, 2 or 3, Features The cable saddle (2) comprises a bottom plate (21) fixedly connected to the top end of the column (1), a sleeve (23) arranged above the bottom plate (21), and a plurality of support plates (22) fixedly connected between the sleeve (23) and the bottom plate (21) and arranged parallel to each other.

5. A cantilever state construction auxiliary device for a steel box girder according to claim 1, 2 or 3, Features: A transverse partition (8) is provided in the inner cavity of the steel box girder (3) below the column (1) and the first anchor reaction seat (5) and the second anchor reaction seat (6), and the periphery of the transverse partition (8) is fixedly connected to the inner cavity wall of the steel box girder (3).

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