An accurate jacking construction method for curved steel box girders across existing expressways

Abstract

The present application discloses a precise jacking construction method for curved steel box girders across existing expressways. First, temporary piers are constructed along the designed jacking line, and jacking devices are installed on the temporary piers; the curved steel box girder is hoisted onto the temporary piers; the leading girder is hoisted in front of the jacking direction of the curved steel box girder, and the leading girder is connected to the curved steel box girder; the trailing girder is hoisted behind the jacking direction of the curved steel box girder, and the trailing girder is connected to the curved steel box girder; the curved steel box girder is jacked forward through the jacking device until the front end of the curved steel box girder crosses the existing expressway to the preset position; a slideway is installed on the temporary pier, a traction device is installed on the offset side of the curved steel box girder, and the traction device is connected to the curved steel box girder; the traction device is started, and the curved steel box girder is pulled along the slideway to the designed position; the temporary piers, slideways, traction devices and jacking devices are removed. The present application has the effects of improving the construction efficiency and the landing accuracy of the curved steel box girder across the existing expressway.

Description

Technical Field

[0001] The present invention relates to the technical field of road construction, and in particular to a precise jacking construction method for a curved steel box girder spanning an existing expressway. Background Art

[0002] When constructing a bridge above an existing expressway, in order to reduce the impact on the traffic of the existing expressway, shorten the construction period, and reduce the risk and management difficulty, a steel box girder is usually used to span the existing expressway. In the related art, the jacking construction method is adopted for the steel box girder to span the existing expressway. This method is to first erect auxiliary supports such as assembly brackets and temporary piers, and then use a large truck crane to hoist the steel box girder splicing members and the guide beam members to the auxiliary supports for splicing. After the steel box girder is spliced, the walking jacking construction is carried out to jack the steel box girder forward to the designed position. However, when this jacking construction method is used for the jacking construction of a curved steel box girder, the curved steel box girder is prone to deviation, the jacking error is large, and it is necessary to continuously and precisely correct the angle of the curved steel box girder during the jacking process. The operation is troublesome, the construction efficiency is low, and the positioning accuracy of the curved steel box girder is poor. Summary of the Invention

[0003] In order to improve the construction efficiency and the positioning accuracy of the curved steel box girder spanning the existing expressway, the present application provides a precise jacking construction method for a curved steel box girder spanning an existing expressway.

[0004] The precise jacking construction method for a curved steel box girder spanning an existing expressway provided by the present application adopts the following technical solutions:

[0005] A precise jacking construction method for a curved steel box girder spanning an existing expressway includes the following steps:

[0006] Construct temporary piers along the designed jacking line, and install jacking devices on the temporary piers;

[0007] Hoist the curved steel box girder onto the temporary piers and place it above the jacking devices;

[0008] Hoist the front guide beam to the front of the jacking direction of the curved steel box girder, support the front guide beam on the temporary piers, and then connect the front guide beam to the curved steel box girder;

[0009] Hoist the tail beam to the rear of the jacking direction of the curved steel box girder, and connect the tail beam to the curved steel box girder;

[0010] Jack the curved steel box girder forward through the jacking devices until the front end of the curved steel box girder crosses the existing expressway to a preset position. At this time, both ends of the curved steel box girder are respectively supported on the temporary piers close to the existing expressway;

[0011] Install a slideway and a traction device on the temporary pier close to the existing expressway. The traction device is arranged on one side of the curved steel box girder, and the traction device is connected to the curved steel box girder.

[0012] Start the traction device and traction the curved steel box girder to slide along the slideway to the designed position.

[0013] Demolish the temporary pier, slideway, traction device and jacking device.

[0014] By adopting the above technical solution, after the jacking device jacks the curved steel box girder forward to cross the existing expressway, the curved steel box girder is moved through the slideway and the traction device, so that the curved steel box girder can be accurately positioned at the designed position. Therefore, the errors generated in the jacking construction of the curved steel box girder will be improved in the subsequent traction step, and finally the curved steel box girder will cross the existing expressway and be accurately positioned; during the jacking construction of the curved steel box girder, there is no need to accurately control the errors, which reduces the difficulty of jacking construction and improves the efficiency of jacking construction.

[0015] Preferably, before the curved steel box girder is jacked forward, a trial jacking test is carried out. The curved steel box girder is jacked forward 4-6 m through the jacking device, and the force conditions of each device and each support structure are detected to see if they meet the design requirements.

[0016] By adopting the above technical solution, through the trial jacking test, the stability of each device and each support structure can be detected before the jacking construction of the curved steel box girder officially starts, thus improving the safety of jacking construction.

[0017] Preferably, the temporary pier includes multiple columns, distribution beams, support columns and support beams. The multiple columns are connected to each other by steel pipes. The distribution beam is installed at the upper end of the columns and is connected to the multiple columns. The support column is installed on the distribution beam, and the support beam is installed at the upper end of the support column. The jacking device is installed on the distribution beam.

[0018] By adopting the above technical solution, the distribution beam can distribute the forces of the support column, support beam and jacking device to each column, thus improving the support stability.

[0019] Preferably, the jacking device includes a walking jack and a bearing beam. The walking jack is installed on the distribution beam, the bearing beam is installed on the walking jack, and the walking jack drives the bearing beam to move along a preset direction.

[0020] By adopting the above technical solution, the bearing beam supports the curved steel box girder from below, and then the walking jack drives the bearing beam to move, so as to jack the curved steel box girder forward.

[0021] Preferably, an assembly support is also constructed on one side of the design route of the bridge. The assembly support is arranged between the two rear temporary piers. The curved steel box girder is welded in sections relying on the assembly support. Before the curved steel box girder is jacked forward, the assembly support is operated to be separated from the curved steel box girder.

[0022] By adopting the above technical solution, the curved steel box girder is welded at the assembly support, and the curved steel box girder can be hoisted in sections, reducing the hoisting difficulty of the curved steel box girder.

[0023] Preferably, during the process of jacking the curved steel box girder forward by the jacking device, according to actual needs, steel plates are padded or extracted between the jacking fulcrum of the jacking device and the bottom of the curved steel box girder.

[0024] By adopting the above technical solution, the curved steel box girder is stably connected to the jacking device, so that the stress position at the bottom of the curved steel box girder is more reliable and the accuracy of jacking forward is higher.

[0025] Preferably, before the curved steel box girder is jacked, leveling structures are respectively installed at both ends of the curved steel box girder, and the leveling structures are arranged along the axial direction of the curved steel box girder.

[0026] By adopting the above technical solution, the leveling structure makes the sliding surface of the curved steel box girder in the same plane, keeps the curved steel box girder sliding smoothly, and improves the safety and accuracy of the sliding of the curved steel box girder.

[0027] Preferably, pulling ropes are respectively tied to both sides of the front end of the leading girder. During the process of jacking the curved steel box girder forward, the direction of jacking the curved steel box girder forward is adjusted by tightening the pulling ropes.

[0028] By adopting the above technical solution, when the direction of jacking the curved steel box girder forward deviates, by tightening the corresponding pulling rope, the direction of jacking the curved steel box girder forward can be gradually restored to the normal direction, thereby improving the jacking efficiency of the curved steel box girder.

[0029] In summary, the present application at least includes the following beneficial technical effects: After the jacking device jacks the curved steel box girder forward across the existing expressway, the curved steel box girder is moved through the slideway and the traction device, so that the curved steel box girder can be accurately positioned at the design position. Therefore, the errors generated during the jacking construction of the curved steel box girder will be improved in the subsequent traction step, and finally the curved steel box girder is spanned across the existing expressway and accurately positioned; moreover, during the jacking construction process of the curved steel box girder, it is not necessary to precisely control the errors, reducing the difficulty of jacking construction and improving the efficiency of jacking construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1It is a schematic diagram after the construction of the temporary pier and the assembly support in the embodiment of the present application.

[0031] Figure 2 It is a schematic diagram after the hoisting of the curved steel box girder, the leading girder and the trailing girder in the embodiment of the present application.

[0032] Figure 3 It is a schematic diagram after partial demolition of the assembly support in the embodiment of the present application.

[0033] Figure 4 It is a schematic diagram after the curved steel box girder is jacked forward and crosses the existing expressway in the embodiment of the present application.

[0034] Figure 5 It is a schematic diagram after the leveling structure is installed in the embodiment of the present application.

[0035] Figure 6 It is a cross-sectional schematic diagram after the leveling structure is installed on the curved steel box girder in the embodiment of the present application.

[0036] Figure 7 It is a schematic diagram before the curved steel box girder rotates and slides in the embodiment of the present application.

[0037] Figure 8 It is a schematic diagram after the curved steel box girder rotates and slides in the embodiment of the present application.

[0038] Figure 9 It is a schematic diagram after the in-situ elongation construction of the curved steel box girder in the embodiment of the present application.

[0039] Figure 10 It is a structural schematic diagram of the temporary pier in the embodiment of the present application.

[0040] Description of reference numerals:

[0041] 1. Temporary pier; 11. First pier; 12. Second pier; 13. Third pier; 14. Fourth pier; 15. Fifth pier; 2. Assembly support; 21. First support; 22. Second support; 3. Jacking device; 31. Walking jack; 32. Cushion beam; 4. Concrete beam segment; 5. Curved steel box girder; 51. Intermediate segment; 52. Front segment; 53. Rear segment; 6. Leading girder; 7. Trailing girder; 8. Leveling structure; 9. Slideway; 10. Traction device; 111. Column; 112. Distribution beam; 113. Support column; 114. Support beam. Detailed implementation manners

[0042] The following further Figure 1-10 describes the present application in detail with reference to the attached

[0043] The embodiment of the present application discloses a precise jacking construction method for a curved steel box girder crossing an existing expressway.

[0044] A precise jacking construction method for a curved steel box girder across an existing expressway includes the following steps:

[0045] S1. Refer to Figure 1 , construct five groups of temporary piers 1 and two groups of assembly brackets 2 along the designed jacking route, and install jacking devices 3 on the temporary piers 1. Two jacking devices 3 are installed on each temporary pier 1. The five groups of temporary piers 1 are distributed along the jacking direction and are numbered as the first pier 11, the second pier 12, the third pier 13, the fourth pier 14, and the fifth pier 15 from the back to the front. Among them, the existing expressway passes through the fifth pier 15 between the fourth piers 14. The first pier 11 is connected to the already cast concrete beam segment 4 and transfers part of the load to the already cast concrete beam segment 4. The two groups of assembly brackets 2 are distributed along the jacking direction and are numbered as the first bracket 21 and the second bracket 22. The first bracket 21 is arranged between the first pier 11 and the second pier 12, and the second bracket 22 is arranged between the second pier 12 and the third pier 13.

[0046] S2. Refer to Figure 2 , use a crane to hoist the curved steel box girder 5 above the temporary pier 1 and support it on the upper end of the temporary pier 1. At this time, the jacking device 3 is located below the curved steel box girder 5. In this embodiment, the curved steel box girder 5 is fabricated in segments in the factory and is divided into three segments in total. The three beam segments are the front segment 52 with a length of 18.5 meters, the middle segment 51 with a length of 19 meters, and the rear segment 53 with a length of 18.5 meters. The front segment 52, the middle segment 51, and the rear segment 53 are transported to the site respectively and then hoisted and spliced in sequence to form a curved steel box girder 5 with a total length of 56m. During hoisting, first hoist the middle segment 51. The rear end of the middle segment 51 is supported on the first bracket 21, and the front end of the middle segment 51 is supported on the second pier 12. Then hoist the front segment 52. The rear end of the front segment 52 is supported on the second pier 12 and is butt-jointed with the front end of the middle segment 51. The front end of the front segment 52 is supported on the second bracket 22, and then the rear end of the front segment 52 and the front end of the middle segment 51 are welded and fixed to each other. Finally, hoist the rear segment 53. The front end of the rear segment 53 is supported on the first bracket 21, and the rear end of the rear segment 53 is supported on the first pier 11. Then the front end of the rear segment 53 and the rear end of the middle segment 51 are welded and fixed to each other to complete the hoisting and splicing of the curved steel box girder 5.

[0047] S3. Refer to Figure 2, before the launching, use a crane to hoist the front guide beam 6 to the front in the jacking direction of the curved steel box girder 5, support the front guide beam 6 on the jacking device 3, and then connect the front guide beam 6 to the curved steel box girder 5. The front guide beam 6 is 35 meters long and is spliced into multiple sections. After the front guide beam 6 is spliced on the ground, it is hoisted as a whole. During hoisting, the rear end of the front guide beam 6 is supported by the second support 22, the front end of the front guide beam 6 is supported by the fourth pier 14, the middle part of the front guide beam 6 is supported by the third pier 13, and then the rear end of the front guide beam 6 and the front end of the curved steel box girder 5 are welded and fixed to each other.

[0048] S4. Refer to Figure 2 , after the hoisting of the front guide beam 6 is completed, hoist the tail beam 7. The tail beam 7 is 10 meters long. Use a crane to hoist the tail beam 7 to the rear of the curved steel box girder 5, and fix and weld the front end of the tail beam 7 to the rear end of the curved steel box girder 5.

[0049] S5. Refer to Figure 3 , completely or partially remove the assembly support 2 so that the assembly support 2 is separated from the curved steel box girder 5. It is preferred to remove the part of the assembly support in contact with the curved steel box girder 5 while retaining other parts.

[0050] S6. Install and debug the jacking operation system, conduct a trial jacking test, and control the jacking device 3 through the jacking operation system to jack the curved steel box girder 5 forward by 4 - 6 m, preferably 5 m, and detect whether the force conditions of each jacking device 3 and each temporary pier 1 meet the design requirements. If the force of the jacking device 3 does not meet the design requirements, replace the corresponding jacking device 3; if the force of the temporary pier 1 does not meet the design requirements, strengthen the temporary pier 1.

[0051] S7. Refer to Figure 4 , control the jacking device 3 through the jacking operation system to jack the curved steel box girder 5 forward until the front end of the curved steel box girder 5 crosses the existing highway to the preset position. At this time, the rear end of the curved steel box girder 5 is supported on the fourth pier 14, and the front end of the curved steel box girder 5 is supported on the fifth pier 15. Remove part of the front guide beam 6, retain the last section of the front guide beam 6, and retain the tail beam 7.

[0052] S8. Refer to Figure 5 and Figure 6 , install leveling structures 8 at the bottom of both ends of the curved steel box girder 5 respectively. The leveling structures 8 are made of stiffened HM488×300 steel and are arranged along the axial direction of the curved steel box girder 5. Since the bottom surface of the curved steel box girder 5 is an arc surface, it is easy to cause the curved steel box girder 5 to shake and be unstable during the subsequent sliding process. After installing the leveling structures 8, the bottom surfaces of the leveling structures 8 are horizontal planes, which can improve the stability of the subsequent sliding of the curved steel box girder 5. Refer to Figure 7, then install two slideways 9 and a set of traction devices 10 on the fourth pier 14 and the fifth pier 15 respectively. The slideway 9 is made of Φ30 round steel. The slideway 9 extends to the designed position of the curved steel box girder 5, and limit blocks are installed at both ends of the slideway 9. Then install the traction device 10 on the offset side of the curved steel box girder 5 and connect the traction device 10 to the curved steel box girder 5.

[0053] S9. Refer to Figure 7 and Figure 8 , start the traction device 10 and traction the curved steel box girder 5 to rotate and slide along the slideway 9 to the designed position.

[0054] S10. Refer to Figure 9 , remove the temporary piers 1, slideways 9, traction devices 10, jacking devices 3 and the remaining assembly brackets 2. Fine-tune the elevation of the curved steel box girder 5 through the jacking jacks, and after reaching the designed elevation, enter the construction process of in-situ elongation of the curved steel box girder 5.

[0055] Refer to Figure 10 , the temporary pier 1 includes multiple columns 111, multiple distribution beams 112, multiple support columns 113 and two support beams 114. The multiple columns 111 are divided into two groups that are aligned front and back with each other. Each group includes multiple columns 111, and the multiple columns 111 are fixedly connected to each other through steel pipes. The multiple distribution beams 112 are all installed between the front and back groups of columns 111. The two ends of the distribution beam 112 are respectively fixedly connected to the upper ends of two columns 111 that are aligned front and back. The multiple support columns 113 are respectively installed on the multiple distribution beams 112. Two support columns 113 are installed on each distribution beam 112. The multiple support columns 113 are arranged in two rows that are aligned front and back. The two support beams 114 are respectively installed on the upper ends of the front and back rows of support columns 113. The slideway 9 is fixedly installed on the upper surface of the support beam 114. One slideway 9 is installed on each support beam 114, and the slideway 9 is parallel to the support beam 114. The distribution beam 112 is made of stiffened HM488×300 steel, the support column 113 is made of Φ426×16 steel pipe, and the support beam 114 is made of stiffened HM488×300 steel.

[0056] Refer to Figure 10 , the jacking device 3 is installed on the distribution beam 112. The jacking device 3 includes a walking jack 31 and a bearing beam 32. The walking jack 31 is installed on the distribution beam 112, the bearing beam 32 is installed on the walking jack 31, and the walking jack 31 drives the bearing beam 32 to move along the preset direction. The stroke of the walking jack 31 is 600 mm, and the full-load jacking weight is 650 t. The bearing beam 32 is made of double HM488×300 steel. Pulling ropes (not shown in the figure) are respectively tied to both sides of the front end of the front guide beam 6. During the jacking forward process of the curved steel box girder 5, the direction of the jacking forward of the curved steel box girder 5 is adjusted by tightening the pulling ropes.

[0057] The traction device 10 can use a towing jack or a winch. Before installing the traction device 10, a towing cross beam is installed on the offset side of the curved steel box girder 5. Two support beams 114 are fixedly connected to both ends of the towing cross beam respectively, and the traction device 10 is fixedly installed on the towing cross beam.

[0058] During the jacking forward process of the curved steel box girder 5, if there is a gap between the cushion beam 32 and the curved steel box girder 5, steel plates are padded between the jacking fulcrum of the jacking device 3 and the bottom of the curved steel box girder 5; if the curved steel box girder 5 sways in the width direction, steel plates are extracted between the jacking fulcrum of the jacking device 3 and the bottom of the curved steel box girder 5. This makes the curved steel box girder 5 move forward smoothly, the supporting position at the bottom of the curved steel box girder 5 is more reliable in force, and the accuracy of jacking forward is higher. When towing the curved steel box girder 5 to rotate and slide along the slideway 9 to the designed position, if the positions of the front end and the rear end of the curved steel box girder 5 are not at the designed positions, first tow the rear end of the curved steel box girder 5 to make the rear end of the curved steel box girder 5 slide to the designed position, and then tow the front end of the curved steel box girder 5 to make the front end of the curved steel box girder 5 rotate and slide to the designed position. Repeat the process of towing the two ends of the curved steel box girder 5 until both ends of the curved steel box girder 5 rotate and slide to the designed positions.

[0059] The implementation principle of the precise jacking construction method for the curved steel box girder across the existing expressway in the embodiment of the present application is as follows: After the jacking device 3 pushes the curved steel box girder 5 across the existing expressway, the curved steel box girder 5 is moved through the slideway 9 and the traction device 10, so that the curved steel box girder 5 can be accurately positioned at the designed position. Therefore, the errors generated during the jacking construction of the curved steel box girder 5 will be improved in the subsequent traction steps, and finally the curved steel box girder 5 is crossed across the existing expressway and accurately positioned. Moreover, during the jacking construction process of the curved steel box girder 5, there is no need to precisely control the errors, which reduces the difficulty of jacking construction and improves the efficiency of jacking construction.

[0060] The above are all the preferred embodiments of the present application. The protection scope of the present application is not limited thereby. Therefore, all equivalent changes made according to the structure, shape, and principle of the present application should be covered within the protection scope of the present application.

Claims

1. A precise jacking construction method for curved steel box girders across existing expressways, characterized in that, It includes the following steps: Construct temporary piers (1) along the designed jacking route, and install jacking devices (3) on the temporary piers (1); Lift and install the curved steel box girder (5) onto the temporary piers (1) and place it above the jacking devices (3); Lift and install the leading girder (6) in front of the jacking direction of the curved steel box girder (5), support the leading girder (6) on the temporary piers (1), and then connect the leading girder (6) to the curved steel box girder (5); Lift and install the trailing girder (7) behind the jacking direction of the curved steel box girder (5), and connect the trailing girder (7) to the curved steel box girder (5); Push the curved steel box girder (5) forward through the jacking devices (3) until the front end of the curved steel box girder (5) crosses the existing highway to the preset position. At this time, both ends of the curved steel box girder (5) are respectively supported on the temporary piers (1) close to the existing highway; Install slides (9) and traction devices (10) on the temporary piers (1) close to the existing highway. The traction devices (10) are arranged on one side of the curved steel box girder (5), and the traction devices (10) are connected to the curved steel box girder (5); Start the traction devices (10) to traction the curved steel box girder (5) to rotate and slide along the slides (9) to the designed position. When traction the curved steel box girder (5) to rotate and slide along the slides (9) to the designed position, if the positions of the front end and the rear end of the curved steel box girder (5) are not at the designed positions, first traction the rear end of the curved steel box girder (5) to make the rear end of the curved steel box girder (5) rotate and slide to the designed position, and then traction the front end of the curved steel box girder (5) to make the front end of the curved steel box girder (5) rotate and slide to the designed position. Repeat the traction of both ends of the curved steel box girder (5) in a cycle until both ends of the curved steel box girder (5) rotate and slide to the designed positions; Remove the temporary piers (1), slides (9), traction devices (10) and jacking devices (3).

2. The precise jacking construction method of the curved steel box girder across the existing expressway according to claim 1, characterized in that: Before the curved steel box girder (5) is pushed forward, conduct a trial jacking test. Push the curved steel box girder (5) forward 4 - 6 m through the jacking devices (3) to detect whether the force conditions of each device and each support structure meet the design requirements.

3. The precise jacking construction method of the curved steel box girder across the existing expressway according to claim 1, characterized in that: The temporary piers (1) include multiple columns (111), distribution beams (112), support columns (113) and support beams (114). Multiple columns (111) are interconnected by steel pipes. The distribution beams (112) are installed at the upper ends of the columns (111) and connect multiple columns (111). The support columns (113) are installed on the distribution beams (112). The support beams (114) are installed at the upper ends of the support columns (113). The jacking devices (3) are installed on the distribution beams (112).

4. A precise jacking construction method for curved steel box girders crossing existing expressways according to claim 3, characterized in that: The pushing device (3) includes a walking jack (31) and a cushion beam (32). The walking jack (31) is installed on the distribution beam (112), the cushion beam (32) is installed on the walking jack (31), and the walking jack (31) drives the cushion beam (32) to move in a preset direction.

5. A precise jacking construction method for curved steel box girders crossing existing expressways according to claim 1, characterized in that: On one side of the designed route of the bridge, an erection support (2) is also constructed. The erection support (2) is arranged between two of the rear temporary piers (1). The curved steel box girder (5) is welded in sections relying on the erection support (2). Before the curved steel box girder (5) is pushed forward, the erection support (2) is operated to be separated from the curved steel box girder (5).

6. The precise jacking construction method of a curved steel box girder crossing an existing expressway according to claim 1, characterized in that: During the process of pushing the curved steel box girder (5) forward by the pushing device (3), according to actual needs, steel plates are padded or extracted between the pushing fulcrum of the pushing device (3) and the bottom of the curved steel box girder (5).

7. A precise jacking construction method for curved steel box girders crossing existing expressways according to claim 1, characterized in that: Before the curved steel box girder (5) is pushed, leveling structures (8) are respectively installed at both ends of the curved steel box girder (5). The leveling structures (8) are arranged along the axial direction of the curved steel box girder (5).

8. A precise jacking construction method for curved steel box girders crossing existing expressways according to claim 1, characterized in that: Cable stays are respectively tied to both sides of the front end of the leading girder (6). During the process of pushing the curved steel box girder (5) forward, the direction of the forward pushing of the curved steel box girder (5) is adjusted by tightening the cable stays.

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