Mounting structure and construction method of steel box girder

Abstract

The invention provides a mounting structure and a construction method of a steel box girder, and the mounting structure comprises a first base plate which is movably arranged on a sliding rail; the sand box is arranged on the first base plate and is provided with an inner cavity and a first positioning piece, one end of the first positioning piece is movably arranged in the inner cavity, and the other end of the first positioning piece protrudes out of the inner cavity; the second base plate is arranged at the top end of the sand box and abuts against the protruding end of the first positioning piece; wherein the first base plate is provided with a second positioning piece, the second positioning piece and the first positioning piece are arranged independently, the second positioning piece is located on the moving path of the first positioning piece, and under the action of external force, when the protruding end of the first positioning piece moves in the direction close to the inner cavity, the second positioning piece abuts against the second base plate; the protruding end of the first positioning piece is separated from the second base plate. The technical problem that in the prior art, after a steel box girder is assembled, a mounting support is inconvenient to detach is solved.

Description

Technical Field

[0001] The invention relates to the technical field of bridge construction, and in particular to an installation structure and a construction method of a steel box girder. Background Art

[0002] Bridge construction in mountainous cities often faces the difficult conditions of being close to railways and having extremely limited three-dimensional space. There are the following difficulties in constructing steel structure bridges in this complex environment: 1. The access roads are difficult or there are no access roads. Methods such as setting up a channel across the railway line can be directly eliminated. If the mountain tunnel is opened before constructing the bridge in the "encirclement circle", the construction progress will not be guaranteed; 2. The local mountain slope is steep, which has great restrictions on the manufacture, transportation, and erection of large steel box girders, making it difficult to use mechanical equipment; 3. Railway-related protection is difficult. In order to ensure the safe operation of the railway and shorten the window period for cross-rail construction, the current bridge cantilever assembly method and jacking method are difficult to meet the requirements of railway-related protection. Bridge rotation construction has gradually become the only choice for railway-related protection. However, in mountainous areas close to railways, due to railway restrictions, the swivel bracket can only be erected in a direction parallel to the railway line, and there is no access road on site for mobile hoisting machinery to move in the direction of the bracket axis in mountainous environments. In addition, considering the matching of the capacity and economy of steel box girder hoisting equipment, large-tonnage hoisting equipment is generally not used to cover the entire swivel bracket. Therefore, it is usually necessary to set up an assembly platform on the bracket, and then transport the steel box girder in blocks to the hoisting position, and then hoist it to the assembly bracket position for splicing by hoisting equipment, and then slide it on the bracket after splicing is completed. In the process of building bridges across rivers, the piers are often on both sides of the river or in the shallow areas of the river. The steel box girder in the span can be directly transported to the lifting position by transport barges and then directly lifted by cranes. However, due to the insufficient water depth on both sides of the river and the insufficient draft of the barge, the steel box girder cannot be transported to the lifting position. At this time, more consideration is given to setting up brackets on the side spans, installing tracks on the brackets, lifting the steel box girder on the side spans to the brackets, and sliding the steel box girder to the designated position by dragging and traction. Whether the steel box girder is erected by rotation or sliding construction, a sliding trolley will be used. After all the steel box girders are spliced, the sliding trolley and the bracket need to be unloaded. Before the bracket is unloaded, the steel box girder is in a cantilever state. How to efficiently and conveniently unload it while ensuring that the steel box girder is evenly stressed and the bracket is safely stressed has become a major technical problem in the current bracket removal and unloading. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention provides an installation structure and a construction method for a steel box girder, which solves the technical problem in the prior art that the installation bracket is inconvenient to remove after the steel box girder is assembled.

[0004] According to an embodiment of the present invention, the present invention adopts the following technical solution:

[0005] An installation structure for a steel box girder, comprising a slide rail erected on the ground and an installation structure slidably arranged on the slide rail, and the installation structure includes:

[0006] A first backing plate, movably arranged on the slide rail;

[0007] A sand box, arranged on the first backing plate and having an inner cavity;

[0008] A first positioning member, one end of the first positioning member is movably arranged in the inner cavity, and the other end protrudes outside the inner cavity;

[0009] A second backing plate, arranged at the top of the sand box and abutted against the protruding end of the first positioning member;

[0010] Wherein, the first backing plate is provided with a second positioning member independently arranged from the first positioning member, the second positioning member is located on the moving path of the first positioning member, and under the action of an external force, when the protruding end of the first positioning member moves towards the direction close to the inner cavity, the second positioning member abuts against the second backing plate, and the protruding end of the first positioning member is separated from the second backing plate.

[0011] Preferably, the first positioning member includes:

[0012] An installation disc, slidably attached to the inner wall of the inner cavity;

[0013] A plurality of positioning rods, arranged at intervals on the installation disc.

[0014] Preferably, the installation disc is provided with a plurality of sand-permeating holes.

[0015] Preferably, the inner cavity is provided with a plurality of limiting grooves, the installation disc is provided with a plurality of limiting posts adapted to the limiting grooves, and the limiting posts are slidably arranged in the limiting grooves.

[0016] Preferably, the inner cavity is filled with a number of fine sands, and a plurality of sand discharge openings are arranged at one end of the inner cavity close to the first backing plate.

[0017] Preferably, the sand discharge openings are distributed at intervals along the radial direction of the inner cavity.

[0018] Preferably, the second positioning member is a prefabricated rod arranged on the first backing plate, and the length of the prefabricated rod is greater than the height of the sand box.

[0019] Preferably, the first backing plate and / or the second backing plate are provided with cushion blocks.

[0020] Preferably, the sand box is provided with lifting lugs.

[0021] The present invention also provides a construction method, including the installation structure of the steel box girder described above. The construction method includes:

[0022] S1. Install other structures except the longitudinal sliding track and the transverse sliding track to provide passage conditions for the hoisting machinery and equipment:

[0023] S2. Install the longitudinal sliding track and the transverse sliding track in reverse order by using hoisting machinery and equipment on the steel box girder installation platform;

[0024] S3. Complete the pile foundation of the swing pier by the method of manual dug pile. Materials such as steel bars, formworks, and concrete are transported by the steel box girder assembly platform and the steel box girder sliding platform built at the rear;

[0025] S4. Transport, assemble the steel box girder blocks and install the steel box girder segments;

[0026] S5. Remove the installation structure after the steel box girder is spliced.

[0027] Compared with the prior art, the present invention has the following beneficial effects: 1. In the composition of this installation structure, compared with the ordinary installation of sand barrels at the pile top for dropping, the same component does not cost more materials, and the number of sand barrels is reduced by more than 40% compared with the traditional required number;

[0028] 2. The load borne by this installation structure is only the self-weight of the steel box girder. Compared with the traditional pile top sand box, it reduces the weight of the support above the sand box and the weight of the protection. It is more compact, lighter in weight, more convenient to install and more convenient to drop.

[0029] 3. The dropping process does not affect the support structure, and the force on the support remains basically unchanged, which can ensure the overall force of the box girder and the support and ensure the safety of the support structure;

[0030] 4. After the dropping is completed, the structure is not damaged at all, and the sand box can be used as the dropping device for other supports and can be reused repeatedly. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a schematic diagram of the installation structure in an embodiment of the present invention;

[0032] Figure 2 is Figure 1 the cross-sectional view taken along A-A in

[0033] Figure 3 is a schematic diagram of the installation structure in another orientation in an embodiment of the present invention.

[0034] In the above-mentioned drawings: 1. Slide rail; 2. First backing plate; 3. Sand box; 301. Sand discharge opening; 302. Lifting lug; 4. Inner cavity; 5. Limit groove; 6. Second backing plate; 7. Mounting plate; 701. Sand permeating hole; 702. Limit post; 8. Positioning rod; 9. Prefabricated rod; 10. Steel box girder. Detailed implementation manners

[0035] In order to make the objectives, technical solutions and beneficial effects of the present invention clearer and more understandable, the technical solutions in the present invention will be further described below in conjunction with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0036] Refer to Figures 1 to 3 , the present invention provides an installation structure for a steel box girder 10, including a slide rail 1 erected on the ground, and an installation structure slidably arranged on the slide rail 1. The installation structure includes:

[0037] The first backing plate 2 is movably arranged on the slide rail 1;

[0038] The sand box 3 is arranged on the first backing plate 2 and has an inner cavity 4.

[0039] The first positioning member, one end of the first positioning member is movably arranged in the inner cavity 4, and the other end protrudes outside the inner cavity 4;

[0040] The second backing plate 6 is arranged at the top of the sand box 3 and abuts against the protruding end of the first positioning member;

[0041] Wherein, the first backing plate 2 is provided with a second positioning member independently arranged from the first positioning member. The second positioning member is located on the moving path of the first positioning member. Under the action of an external force, when the protruding end of the first positioning member moves towards the inner cavity 4, the second positioning member abuts against the second backing plate 6, and the protruding end of the first positioning member is separated from the second backing plate 6.

[0042] In this embodiment, in order to construct a bridge in a mountainous terrain, two sliding rails 1 are first erected at this terrain. The two sliding rails 1 are respectively located on both sides of the bridge pier, providing basic support and guidance for the entire installation structure. The first backing plate 2 is movably arranged on the sliding rail 1, and the sand box 3 is placed on the first backing plate 2. The sand box 3 has an inner cavity 4. One end of the first positioning member is movably arranged in the inner cavity 4 of the sand box 3, and the other end protrudes outside the inner cavity 4 for installing the second backing plate 6. In order to stably install the steel box girder 10, during the welding and assembly process of each steel box girder 10, each section of the steel box girder 10 requires 4 sand boxes 3 (due to the shape of the steel box girder 10 itself, it cannot be directly lowered for splicing. Therefore, after being supported by the installation structure, segmented welding is carried out. After all the steel box girders are spliced, the construction temporary support of the steel box girder 10 needs to be removed. Before the support is removed, at this time, the steel box girder 10 is in a cantilever state. Therefore, a platform cannot be directly built to splice the steel box girder 10. This is the prior art, and those skilled in the art can clearly understand it through their learned knowledge). After the assembly of the steel box girder 10 segments is completed, a winch is used to tow the steel box girder 10 to slide forward on the sliding rail 1 to the designated position (the designated position is the lowering place of the steel box girder 10, that is, the bridge pier or the splicing place with other steel box girders 10). This step is repeated until all the steel box girders 10 are installed and assembled. After the steel box girder 10 has completed its sliding, preparations are made to remove the installation structure; specifically, the first positioning member is moved downward by an external force, so that the bottom of the steel box girder 10 moves downward synchronously until the second positioning member located on the moving path of the first positioning member abuts against the bottom end of the second backing plate 6, and the movement of the first positioning member is stopped (the moving height of the first positioning member is regarded as the lowering height of the steel box girder 10). At this time, the steel box girder 10 can be towed by a winch to slide on the second backing plate 6 to each bridge pier or splicing place. At the same time, each sand box 3 is gradually removed from between the first backing plate 2 and the second backing plate 6 by means of a winch (not shown); compared with the ordinary pile-top installation of sand barrels for removal, for the same component, no more materials are spent, and the number of sand barrels is reduced by more than 40% compared with the traditional required number; the detachable sand box 3 only bears the self-weight of the steel box girder 10 during the assembly of the steel box girder 10, reducing the weight of the support above the sand box 3 and the weight of the protection compared with the traditional pile-top sand box 3. It is more compact, lighter in weight, more convenient to install and more convenient to remove; in addition, the removal process of this structure does not affect the support structure, the force on the support remains basically unchanged, which can ensure the overall force of the box girder and the support, and ensure the safety of the support structure; after the removal is completed, the installation structure is not damaged at all, and can be used for the removal device of other supports. The place where a sliding trolley is still needed in the whole project can also be reassembled into an installation structure again, and it can be recycled and reused.Compared with the traditional method of directly using oxyacetylene to perform high-temperature gas cutting on the sliding trolley, this method directly damages the structure of the sliding trolley. Moreover, during the process of destroying and removing the sliding trolley, the force on the undemolished sliding structure blocks gradually increases, and the local forces on the steel box girder 10 and the supports gradually increase, which is unfavorable for the forces on the steel box girder 10 and the supports. Or use a jack to lift the entire steel box girder 10, use the support as a support point to lift the box girder upward as a whole, and then remove the sliding trolley. However, during the lifting process, the local forces on the steel box girder 10 and the supports are very large, and the local deformation of the steel box girder 10 and the safety of the supports cannot be guaranteed. Moreover, during the lifting process of multiple hydraulic jacks, the oil pressure control of the jacks is also a difficult problem. In addition, a sand box 3 is provided at the top of the steel pipe pile of the support. Using the sand box 3 for unloading is the most common unloading method. However, the sand box 3 needs to be set on each steel pipe pile, and the load borne by the sand box 3 is not only the weight of the upper steel box girder 10, but also the weight of all the support members above the sand box 3, protective measures, etc. This not only increases the number of sand boxes 3, but also increases the load borne by the sand box 3, making the use of the sand box 3 for unloading complicated and inefficient. Moreover, during the unloading process, the supports above the sand box 3 will be unloaded downward as a whole, with a relatively large safety risk of unloading. This installation structure has the advantages of quickly removing the steel box girder 10 installation structure compared with the existing technology under the premise of not damaging the original installation structure, and can be recycled and reused, with simple installation and convenient removal.

[0043] The inner cavity 4 is provided with a plurality of limiting grooves 5, and the first positioning member is slidably arranged in the limiting grooves 5. Further, the inner cavity 4 is filled with a number of fine sands, and one end of the inner cavity 4 close to the first backing plate 2 is provided with a plurality of sand discharge openings 301. Further, the sand discharge openings 301 are distributed at intervals along the radial direction of the inner cavity 4.

[0044] In this embodiment, a plurality of limiting grooves 5 are arranged in the inner cavity 4 of the sand box 3, and the first positioning member is slidably arranged in the limiting grooves 5, which provides guidance and limitation for the movement of the first positioning member, ensures that its movement path is accurate and error-free, and increases stability; fine sand is selected to fill the inner cavity 4 in the sand box 3, and one end of the inner cavity 4 close to the first backing plate 2 is provided with a plurality of sand discharge openings 301. By opening the sand discharge openings 301, the fine sand is removed from the inner cavity 4, so that the first positioning member moves downward along the limiting grooves 5; at the same time, the sand discharge openings 301 are distributed at intervals along the radial direction of the inner cavity 4, ensuring that the fine sand can be evenly removed in any direction, which is beneficial to more accurately controlling the amount of fine sand in the sand box 3, further enabling the first positioning member to move stably and the steel box girder 10 to sink steadily.

[0045] The first positioning member includes: a mounting disc 7, which is slidably attached to the inner wall of the inner cavity 4, and the mounting disc 7 is provided with a plurality of limiting posts 702 adapted to the limiting grooves 5; a plurality of positioning rods 8, which are arranged on the mounting disc 7 at intervals. Further, the mounting disc 7 is provided with a plurality of sand-permeable holes 701.

[0046] In this embodiment, the mounting plate 7 slides and fits against the inner wall of the inner chamber 4 of the sand box 3. When the mounting plate 4 moves downward in the inner chamber 4, the fit with the inner wall of the inner chamber 4 ensures the stability and directionality during the movement. A plurality of positioning rods 8 are arranged at intervals on the mounting plate 7 to increase the contact area between the first positioning member and the second backing plate 6 and provide more stable support points, making the steel box girder 10 more stable when being lowered; a plurality of sand-permeating holes 701 are provided on the mounting plate 7. The purpose of the design of the sand-permeating holes 701 is to allow fine sand to pass through the sand-permeating holes 701 when the mounting plate 7 moves downward, thereby reducing the influence of the resistance of the fine sand on the movement of the mounting plate 7, helping to ensure that the mounting plate 7 can move downward more stably in the inner chamber 4, and at the same time being beneficial to adjusting the pressure distribution in the sand box 3, and further affecting the stability of the entire structure.

[0047] The second positioning member is a prefabricated rod 9 provided on the first backing plate 2, and the length of the prefabricated rod 9 is greater than the height of the sand box 3.

[0048] In this embodiment, the second positioning member is specifically a prefabricated rod 9 welded to the first backing plate 2. The length of the prefabricated rod 9 is designed to be longer than the height of the sand box 3, ensuring that when the first positioning member descends as the fine sand in the sand box 3 gradually decreases and descends in the inner chamber 4, the second positioning member can effectively abut against the second backing plate 6. By setting the prefabricated rod 9 with a length greater than the height of the sand box 3 as the second positioning member, the first positioning member is separated from the second backing plate 6, and the second positioning member bears the supporting role. At this time, the sand discharging of the sand box 3 can be stopped, and each sand box 3 can be sequentially removed from the first backing plate 2 by using a winch.

[0049] The first backing plate 2 and the second backing plate 6 are provided with cushion blocks.

[0050] In this embodiment, cushion blocks (not shown) made of polytetrafluoroethylene are provided on both the first backing plate 2 and the second backing plate 6 to reduce the friction between the steel box girder 10 and the second backing plate 6 and between the first backing plate 2 and the slide rail 1, so that the steel box girder 10 can slide smoothly.

[0051] The sand box 3 is provided with a lifting lug 302.

[0052] In this embodiment, a lifting lug 302 is provided on the sand box 3, which is convenient for the winch to drag when removing the sand box 3 and subsequent hoisting.

[0053] The present invention also provides a construction method, including the installation structure of the steel box girder 10 described above. The construction method includes: in step 1, installing other structures except the longitudinal sliding track and the transverse sliding track to provide passage conditions for the hoisting machinery and equipment: installing the steel box girder 10 installation platform span by span from the end of the mountain winding road on the mountain to the river side. First, construct the steel box girder 10 assembly platform, then construct the steel box girder 10 turning platform, and then construct the steel box girder 10 sliding platforms on both sides of the upstream and downstream of the steel box girder 10 turning platform and the turning piers that separate the steel box girder 10 sliding platforms, and install other structures except the longitudinal sliding track and the transverse sliding track to provide passage conditions for the hoisting machinery and equipment; in step 2, install the longitudinal sliding track and the transverse sliding track on the steel box girder 10 installation platform in reverse order by using the hoisting machinery and equipment. The longitudinal sliding track is disconnected at the intersection with the transverse sliding track, and the transverse sliding track is simply connected after being disconnected on both sides of the upstream and downstream of the turning pier; in step 3, construct the main body structure of the turning pier, including pile foundation, cap and pier column. When the steel box girder 10 installation platform is erected close to the turning pier, complete the pile foundation of the turning pier by the method of manual excavation; materials such as steel bars, formwork and concrete are transported by the steel box girder 10 assembly platform and the steel box girder 10 sliding platform built at the back; the crane is located on the erected steel box girder 10 installation platform, and the casting construction of the turning pier cap and pier column is completed by the fishing method; while constructing the main body structure of the turning pier, install the temporary consolidation pier on the upper turntable; the elevation of the top of the temporary consolidation pier is the same as the elevation of the top of the steel pipe column of the steel box girder 10 installation platform in the early stage, and the transverse sliding track between the two temporary consolidation piers is disconnected from the transverse sliding tracks on both sides of its upstream and downstream; after the construction of the temporary consolidation pier is completed, construct the sliding structure at the top of the turning pier: install the distribution beam and the transverse sliding track at the top of the turning pier to simply connect the transverse sliding track between the two temporary consolidation piers with the transverse sliding tracks disconnected on both sides of its upstream and downstream; in step 4, transport and assemble the steel box girder 10 segments one by one, and slide the steel box girder 10 segments assembled by multiple steel box girder 10 segments to the installation position, connect the steel box girder 10 segments one by one, and install each steel box girder 10 segment. The overall installation steps are: first install the steel box girder 10 segments on the side of the steel box girder 10 turning platform without the turning pier; then install the steel box girder 10 segments on the side including the turning pier; finally install the closing segment of the steel box girder 10 at the turning platform;

[0054] In step 5, after all the steel box girder 10 segments are installed and connected, remove the transverse sliding track and the bearing beam between the two temporary consolidation piers; extend the temporary consolidation piers to the design height, and temporarily consolidate the pier and the beam; after the temporary consolidation of the pier and the beam, gradually lower the steel box girder 10 from the cantilever end of the steel box girder 10 towards the turning pier, that is, remove the installation structure of the steel box girder 10.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A steel box girder installation structure, comprising a slide rail mounted on the ground, and an installation structure slidably mounted on the slide rail, characterized in that: The mounting structure comprises: A first pad, movably disposed on the slide rail; A sand box, disposed on the first pad and having an inner chamber; a first positioning member, one end of which is movably disposed in the inner chamber and the other end of which protrudes outside the inner chamber; A second pad is provided at the top of the sand box and abuts against the protruding end of the first positioning member; Among them, the first pad is provided with a second positioning member independently arranged from the first positioning member, and the second positioning member is located on the moving path of the first positioning member. Under the action of external force, when the protruding end of the first positioning member moves toward the direction close to the inner chamber, the second positioning member abuts against the second pad, and the protruding end of the first positioning member is separated from the second pad.

2. The installation structure of a steel box girder according to claim 1, characterized in that: The inner chamber is provided with a plurality of limiting grooves, and the first positioning member is slidably arranged in the limiting grooves.

3. The installation structure of a steel box girder according to claim 1, characterized in that: The inner chamber is filled with a plurality of fine sands, and one end of the inner chamber close to the first pad is provided with a plurality of sand discharge ports.

4. The installation structure of a steel box girder according to claim 3, characterized in that: The sand discharge ports are distributed at intervals along the radial direction of the inner chamber.

5. The installation structure of a steel box girder according to any one of claims 1 to 4, characterized in that: The first positioning member comprises: A mounting plate, slidably fitted to the inner wall of the inner chamber, the mounting plate being provided with a plurality of limiting columns adapted to the limiting grooves; A plurality of positioning rods are arranged at intervals on the mounting plate.

6. The installation structure of a steel box girder according to claim 5, characterized in that: The installation plate is provided with a plurality of sand-penetrating holes.

7. The installation structure of a steel box girder according to claim 1, characterized in that: The second positioning member is a prefabricated rod disposed on the first pad, and the length of the prefabricated rod is greater than the height of the sand box.

8. The installation structure of a steel box girder according to claim 1, characterized in that: The first pad and / or the second pad is provided with a pad.

9. The installation structure of a steel box girder according to claim 1, characterized in that: The sand box is provided with lifting lugs.

10. A construction method, comprising the installation structure of the steel box girder according to any one of claims 1 to 9, characterized in that: The construction method comprises: S1. Install other structures besides the longitudinal sliding track and the transverse sliding track to provide passage conditions for the lifting machinery and equipment: S2. Use lifting machinery to install the longitudinal sliding track and the transverse sliding track in reverse order on the steel box girder installation platform; S3. The pile foundation of the rotating pier is completed by manual digging. The steel bars, formwork, concrete and other materials are transported by the steel box girder assembly platform and steel box girder sliding platform built at the rear; S4. Transportation and assembly of steel box girder blocks and installation of steel box girder segments; S5. Dismantle the installation structure after the steel box girder is spliced.

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