Single-segment four-point supporting sliding construction method for steel structure of main bridge under continuous orbit

Abstract

This invention discloses a method for the four-point support sliding construction of a single-segment main bridge steel structure under a continuous track, comprising the following steps: Step 1, prefabricating each main bridge steel structure segment; Step 2, constructing a temporary support system on the construction site; Step 3, arranging lateral limiting devices on both sides of the sliding track; Step 4, completing the construction of a single-span main bridge steel structure using a single-segment assembly-four-support sliding scheme on the temporary support system. Therefore, this invention provides a new bridge construction solution that addresses the challenge of constructing main bridge steel structures where land-based scaffolding methods are not feasible while prioritizing economic efficiency, and ensures smooth sliding of each segment into position.

Description

Technical Field

[0001] This invention relates to bridge construction engineering, specifically to a method for four-point support sliding construction of a single segment of the main bridge steel structure under a continuous track. Background Technology

[0002] The construction of the steel structure of the north span of the main bridge on the Yinzhou side (east side) of Section IV of the Yinzhou Avenue Expressway (Airport Road - Yinheng Line) project is particularly challenging. This is partly due to the extremely demanding construction conditions: 1) It spans the Xiku River, with a total width of 50m, including two 15m wide channels and a 20m wide island; 2) The river makes a 90° turn near the bridge site. The river is parallel to the newly built bridge in the turning section. The distance between the river edge and the bridge edge is less than 3.0m. The total width of the river exceeds 30m. 3) A 110kV power line is located on the side of the newly built bridge adjacent to the parallel river channel, and part of the power line coincides with the projected plane of the new bridge structure; 4) The other side of the newly built bridge is the existing Yinzhou Bridge. The gap between the bridge structures is less than 4.0m, and a 10kV power duct (1.6m wide) and a DN800 water supply pipe are installed in between. 5) The main pier of the newly built bridge is less than 28m wide from the vertical river channel. It is equipped with a 110kV power duct, a flood control wall, a support pile, and a bank wall.

[0003] On the other hand, it is because the Yinzhou side (east side) span of the north main bridge has both vertical and horizontal curves: 1) Within 50m of the adjacent abutment, the plane curves, with a peak lateral curvature of 1.49m; 2) The steel structure of the side spans has a non-uniform cross section. The total beam height at the main pier is 10.0m, and the total beam height at the side pier is 6.0m. The range of 26.1m adjacent to the main pier is a variable height section.

[0004] Therefore, existing steel structure construction methods are either not feasible or too costly to implement. 1) The scaffolding method (land transport) is unsuitable. One side is an existing bridge with insufficient width and pipelines. The other side is adjacent to water and requires the construction of a long trestle system. However, it is limited by the 110kV power line (the net distance between the steel pipe piles and the pipeline is not less than 2.0m). The maximum distance between the center of the trestle and the center of the main bridge truss exceeds 20m, requiring a 300T crawler crane. The site (trestle) has limited load-bearing capacity and is difficult to match.

[0005] 2) The support method (water transport) is feasible, but it is costly. On the one hand, the water area is relatively small, so the specifications (operating radius) of the floating crane are used to offset the limited range of activities. Therefore, the specifications of the floating crane should not be less than 250T. On the other hand, land assembly sites need to be set up in the surrounding area.

[0006] 3) Both the dragging method (continuous jacking process) and the conventional jacking method (walking jacking process) rely on the structural bearing capacity and rigidity of the main bridge itself, and both require the installation of a guide beam system. They cannot be applied to the side span of the north main bridge on the Yinzhou side (east side) - ① The variable cross section is not suitable for the jacking or dragging method construction, so the jacking / dragging section is limited to the constant cross section, with a total length of about 80m; ② In order to balance the overall progress target requirements caused by the delay in pipeline relocation, the elevated section (precast small box girder system) of the north Yinzhou side connection section should be implemented simultaneously with the side span of the main bridge, so a guide beam cannot be installed.

[0007] Therefore, in order to complete the construction of the main bridge steel structure described above, a corresponding construction plan needs to be developed. Summary of the Invention

[0008] The purpose of this invention is to provide a four-point support sliding construction method for a single segment of the main bridge steel structure under a continuous track, so as to provide a new solution for bridge construction and solve the problem of main bridge steel structure construction that cannot be carried out by land transportation support method but is in pursuit of construction economy.

[0009] To achieve the above-mentioned technical objectives, the present invention will adopt the following technical solution: A method for four-point support sliding construction of a single segment of the main bridge steel structure under a continuous track includes the following steps: Step 1: Prefabricate the steel structure segments of each main bridge: The steel structure of the single-span main bridge is divided into several main bridge steel structure segments, and then each main bridge steel structure segment is further divided into several segmental components, and the corresponding segmental components of each main bridge steel structure segment are prefabricated in the factory. Step 2: Construct a temporary support system at the construction site: At the construction site, a temporary support system was built between two adjacent main piers along the bridge direction. The two adjacent main piers are the first and second main piers. The temporary support system includes a steel pipe pile support system, a main support beam, and a sliding track; the main support beam is set above the steel pipe pile support system and supported by the steel pipe pile support system, and the sliding track is arranged along the longitudinal direction of the main support beam. Step 3: Install lateral limiting devices on both sides of the sliding track; Step 4: The construction of the single-span main bridge steel structure is completed using a single-segment assembly-four-support sliding scheme on the temporary support system. According to the single-segment assembly-four-support sliding scheme, after assembling the j-th assembly-sliding segment on the temporary support system near the first main pier, the j-th assembly-sliding segment is slid forward one step; then, the (j+1)-th assembly-sliding segment is assembled on the temporary support system of the first main pier, and the (j+1)-th assembly-sliding segment is assembled with the j-th assembly-sliding segment along the longitudinal direction of the bridge to form a segmental assembly body. After sliding the segmental assembly body forward one step, the j-th assembly-sliding segment is released. The j+1th assembled-sliding segment is connected to the jth assembled-sliding segment along the longitudinal direction of the bridge. Then, the jth assembled-sliding segment is slid to the pier position and placed on the beam using a four-support sliding system. This process is repeated until all assembled-sliding segments are assembled, slid in place, and placed on the beam. Then, the current assembled-sliding segment after placement is spliced ​​with the previous assembled-sliding segment along the longitudinal direction of the bridge to form a single unit. Where: j∈m, m is a positive integer and m represents the total number of assembled-sliding segments. In the single-segment assembly-four-support sliding scheme: the construction sequence of each assembly-sliding segment is the opposite of the arrangement sequence of each main bridge steel structure segment along the bridge direction. Each assembly-sliding segment is calculated and determined based on the prefabricated main bridge steel structure segments in step one, according to the distribution of each support point of the temporary support system built in step two and the economic efficiency of construction. The sliding of each assembled-sliding segment on the temporary support system is achieved through the cooperation of the track trolley assembly arranged between itself and the sliding track and the longitudinal sliding system arranged between the current assembled-sliding segment and the main pier; the track trolley assembly and the longitudinal sliding system together form the aforementioned four-support sliding system; The sliding length of each assembly-sliding segment on the temporary support system should be sufficient to ensure that after the current assembly-sliding segment slides forward one step on the first main support beam, there is enough area left on the first main support beam for the construction of the next assembly-sliding segment. The first main support beam is the part of the main support beam that is arranged close to the first main pier in the temporary support system.

[0010] Preferably, in step four, the bridge-direction sliding system includes a braking device, a traction device, a braking wire rope, and a traction wire rope; and the braking device is arranged on the first main pier on the high elevation side, while the traction device is arranged on the second main pier on the low elevation side. The top surface of the upper chord of both segments of any main bridge steel structure segment is provided with traction end lugs, while the lower bridge deck is provided with braking end lugs. The power output end of the braking device is connected to the brake end lug via a brake wire rope, while the power output end of the traction device is connected to the traction end lug via a traction wire rope.

[0011] Preferably, in step four, the assembly of the single-span main bridge steel structure specifically includes the following steps: Step 4.1: Arrange track trolley assembly A on the temporary support system near the first main pier and temporarily fix track trolley assembly A along the bridge direction; Step 4.2: Assemble the first assembly-sliding segment on the track trolley assembly A arranged in Step 4.1; Step 4.3: Construct a longitudinal sliding system on the first assembled-sliding segment completed in Step 4.2; Step 4.4: Activate the longitudinal sliding system and release the temporary longitudinal constraint of the track carriage assembly A arranged in Step 1, so that the first assembly-sliding segment can be moved forward one step by the track carriage assembly A below the first assembly-sliding segment, and the connection between the braking device in the longitudinal sliding system and the first assembly-sliding segment can be released; the sliding length of the first assembly-sliding segment moving forward one step is sufficient for the assembly of the next assembly-sliding segment; Step 4.5: Arrange the track trolley assembly B on the temporary support system vacated in Step 4.4, and temporarily fix the track trolley assembly B along the bridge direction; Step 4.6: Assemble the second assembly-sliding segment on the track vehicle assembly B arranged in step 4.5, and connect it with the first assembly-sliding segment in the longitudinal direction of the bridge to form a segment splice body; Step 4.7: Connect the braking device in the longitudinal sliding system to the second assembly-sliding segment; Step 4.8: Activate the longitudinal sliding system and release the longitudinal temporary constraint of the track carriage assembly B arranged in step 4.5, so that the segment splice formed by the splicing of the first and second assembly-sliding segments can be moved forward one step by the track carriage assembly below the first and second assembly-sliding segments, so as to make enough space on the temporary support system for the assembly of the next assembly-sliding segment; Step 4.9: Disconnect the braking device from the second assembly-slip segment in the longitudinal sliding system, and disconnect the first and second assembly-slip segments; Step 4.10: Connect the braking device in the longitudinal sliding system to the first assembled-sliding segment; Step 4.11: Activate the longitudinal sliding system to move the first assembly-sliding segment towards the side pier via the track trolley assembly A below the first assembly-sliding segment until it reaches the second main pier; Step 4.12: Slide the assembled-sliding section beam into place as described in Step 4.11; Repeat steps 4.1 to 4.12 until all assembled-sliding segments have slid into place along the temporary support system and the beam has been lowered. At the same time, assemble the next assembled-sliding segment with the previous assembled-sliding segment in the longitudinal direction of the bridge, thereby completing the construction of the single-span main bridge steel structure between the first and second main piers.

[0012] Preferably, the single-span main bridge steel structure comprises six main bridge steel structure segments, corresponding to the first main bridge steel structure segment, the second main bridge steel structure segment, ..., the sixth main bridge steel structure segment; in the assembly-sliding scheme, there are a total of four assembly-sliding segments, wherein: the first assembly-sliding segment is the sixth main bridge steel structure segment, the second assembly-sliding segment is the fifth main bridge steel structure segment, the third assembly-sliding segment is a segmental splice formed by splicing the fourth and third main bridge steel structure segments, and the fourth assembly-sliding segment is a segmental splice formed by splicing the second and first main bridge steel structure segments.

[0013] Preferably, the main support beam is configured into several support beam segments along the longitudinal direction of the bridge. Each support beam segment is connected at the joint position by a butt joint + welded steel plate reinforcement mode. At the same time, the joint position between the support beam segments is as close as possible to the support point to avoid the joint being located in the middle 1 / 2 area of ​​the span.

[0014] Preferably, in step 4.12, a beam-sliding stage support system is used to achieve the assembly-sliding segment beam segmentation where each section slides into place; The support system for the beam lowering stage includes several replacement jacks; each replacement jack is arranged in two rows along the longitudinal direction of the temporary support system and two rows along the transverse direction of the temporary support system. The two replacement jacks arranged along the transverse direction are supported under the assembled-sliding segment after sliding into place by transverse support devices. The transverse support devices include two or more vertical jack supports arranged on the transverse distribution beam and jack beams supported by the vertical supports of each jack. The two replacement jacks arranged along the transverse direction are placed one-to-one between the jack beams and the assembled-sliding segment.

[0015] Preferably, the lower end of the jack is connected to the transverse support device via a leveling component, while the upper end is tightened against the lower chord of the assembly-sliding section via a wedge-shaped steel plate, in order to control the vertical state of the jack and prevent the risk of non-vertical operation.

[0016] Preferably, the assembly-sliding section beam operation, where each section slides into place, specifically includes the following steps: Step 6.1: Construct the support system for the beam lowering stage; A support system for the beam lowering stage is constructed below the assembled-sliding segment that has been slid into place; Step 6.2: Based on the relative position before replacement, keep the replacement jack in a holding state, and raise the replacement jack 1-2mm after the stroke is in place. Step 6.3: Remove the track trolley components below the assembled-sliding segment that has been slid into place; By following steps 6.1-6.3 above, the assembly and sliding section beam segmentation can be completed.

[0017] Based on the above technical solution, compared with the prior art, the present invention has the following advantages: 1. The present invention divides the steel structure of a single-span main bridge into several main bridge steel structure segments, and then divides each main bridge steel structure segment into several segmental components and prefabricates the corresponding segmental components of each main bridge steel structure segment in the factory, which facilitates the transportation of components and the on-site construction.

[0018] 2. This invention employs a single-segment, four-support sliding method on a continuous track for the construction of single-span main bridge steel structures. This effectively overcomes the technical limitations of existing jacking or dragging methods, which are unsuitable for variable cross-section sections, and also overcomes the limitations of site constraints that prevent the use of scaffolding methods for bridge construction. Furthermore, it effectively avoids the phenomenon of uneven stress distribution at too many support points, which can lead to poor sliding or even failure when sliding a single-span main bridge steel structure as a whole. Attached Figure Description

[0019] Figure 1 This is a flowchart of the four-point support sliding construction method for a single segment of the main bridge steel structure under a continuous track, as described in this invention. Figure 2 This is a structural schematic diagram of the temporary support system (in the transverse direction of the bridge). Figure 3 This is a flowchart illustrating the assembly process of the single-span main bridge steel structure described in this invention on a temporary support system adjacent to the first main pier. Figure 4 This is a structural diagram showing the longitudinal sliding system arranged on the sixth main bridge steel structure segment after it has been assembled. Figure 5 It is a layout diagram of the braking end lugs and traction end lugs on any main bridge steel structure segment; Figure 6 This is a schematic diagram of the layout of the correction device; Figure 7 This is a schematic diagram of the arrangement of the lateral limiting device; Figure 8 This is a schematic diagram of the arrangement of temporary constraints along the bridge direction; Figure 9 This is a schematic diagram of the support system layout during the beam lowering stage; Figure 10 yes Figure 9A partial schematic diagram of the support system during the mid-beam lowering stage; In the diagram: 11. First main pier; 12. Second main pier; 13. Main support beam; 131. Steel pipe pile; 132. Support beam pad; 133. Longitudinal distribution beam; 134. Transverse distribution beam; 135. Track support beam; A1, Main bridge steel structure segment 1; A2, Main bridge steel structure segment 2; A3, Main bridge steel structure segment 3; A4, Main bridge steel structure segment 4; A5, Main bridge steel structure segment 5; A6, Main bridge steel structure segment 6; 21-Tractor assembly; 210-Tank support beam; 211-Tank; 212-Tank guide wheel; 213-Tank support; 31. Braking device; 32. Brake wire rope; 33. First wire rope guide pulley; 34. Brake end lifting lug; 341. First brake end lifting lug; 342. Second brake end lifting lug; 35. Traction end lifting lug; 351. First traction end lifting lug; 352. Second traction end lifting lug; 36. Second wire rope guide pulley; 37. Traction wire rope; 38. Traction device; 39. Pulley bracket; 41. First corrective lug; 42. Second corrective lug; 43. Hand-operated hoist; 5. Sliding segment; 6. Lateral limiting component; 7. Temporary restraints along the bridge direction; 81. First replacement jack; 82. Jack beam; 83. Jack vertical support; 84. Second replacement jack; 9. Side span leveling assembly. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention. Unless otherwise specifically stated, the relative arrangement, expressions, and values ​​of components and steps set forth in these embodiments do not limit the scope of the present invention. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0021] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used here to describe the spatial positional relationship of a device or feature as shown in the figure with other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figure. For example, if the device in the figure is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations).

[0022] like Figure 1 As shown, the four-point support sliding construction method for a single segment of the main bridge steel structure under a continuous track, as described in this invention, includes the following steps: Step 1: Prefabricate the steel structure segments of each main bridge: According to the engineering construction requirements, the steel structure of each span of the main bridge is divided into several main bridge steel structure segments. These segments, arranged sequentially along the bridge direction, are designated as segment 1, segment 2, ..., segment i, ..., segment n, where i ∈ n and n is a positive integer. In this invention, n = 6. That is, this invention divides each span of the main bridge steel structure into 6 main bridge steel structure segments, corresponding to segment 1, segment 2, ..., segment 6.

[0023] Each main bridge steel structure segment can be assembled from several individual segments. All individual segments of the main bridge steel structure can be prefabricated in the factory, which facilitates transportation and on-site hoisting.

[0024] Each segment of the main bridge steel structure is divided according to its own structural characteristics, typically including a segmental lower chord, segmental upper chord, upper bridge deck, lower bridge deck, and cantilever deck. Specifically: there are two segmental lower chords; there are usually two segmental upper chords, which not only connect with the lower chord below them at the web member position, but also connect with the preceding and following main bridge steel structure segments at the chord member position. For ease of connection, adjusting web members may be provided between the segmental lower and upper chords; the lower bridge deck is composed of multiple pieces along the transverse direction, generally two pieces, spliced ​​between two segmental lower chords and flush with the upper surface of the segmental lower chords; the upper bridge deck is also composed of multiple pieces along the transverse direction, generally two pieces, spliced ​​between two segmental upper chords and flush with the upper surface of the segmental upper chords; there are two cantilever decks, correspondingly located on both sides of the upper bridge deck.

[0025] Step 2: Construct a temporary support system at the construction site: A temporary support system is constructed between two adjacent main piers along the longitudinal direction of the bridge. The two adjacent main piers are designated as the first and second main piers according to their longitudinal direction (matching the construction direction). The temporary support system includes a steel pipe pile support system, a main support beam, and sliding tracks. The main support beam is positioned above and supported by the steel pipe pile support system, and the sliding tracks are arranged along the longitudinal direction of the main support beam. Specifically, two continuous sliding tracks are laid on the upper surface of the main support beam at predetermined positions. Both sliding tracks extend along the longitudinal direction of the main bridge steel structure, and the position of each sliding track corresponds to the position of the lower chord of the main bridge steel structure.

[0026] The main support beam is configured into several support beam segments along the longitudinal direction of the bridge. Each support beam segment is connected at the joint using a "butt joint + reinforced steel plate" method. Simultaneously, the joint positions between the support beam segments are as close as possible to the support point (i.e., close to the steel pipe pile), avoiding joints located in the mid-span region, to reduce potential hazards (insufficient load-bearing capacity or weak stiffness) caused by inadequate flange splicing welds.

[0027] The main support beam is divided into two parts along the longitudinal direction between two adjacent main piers, corresponding to the first and second main support beams. The first main support beam is merely a sliding track beam, located adjacent to the first main pier, and is matched with the working platform (the cantilever assembly platform for the main bridge steel structure segments) to serve as a support system for the side span steel structure assembly. It will be dismantled after the sliding operation is completed. The second main support beam serves as both a sliding track beam and a temporary support beam. Therefore, the joint between the first and second main support beams must not exceed 1.0m from the center of the adjacent steel pipe piles to avoid conflict between subsequent scaffold-assembled segments and the main support beam.

[0028] The span of the main support beam should not be too large: firstly, there is the issue of lateral stability of the main support beam; secondly, excessive deflection can easily lead to the risk of uneven settlement at the sliding support point. Therefore, the maximum span is controlled at around 20m. That is, the maximum distance between adjacent steel pipe piles is 20 meters.

[0029] Lateral constraints are installed on the main support beam at 1 / 3 and 2 / 3 of the maximum span from the support point. Lateral constraints are only installed in the support area for the remaining spans, and not in the mid-span area. On the one hand, the center-to-center distance of the main support beam is 7.2m, and the beam height is 1.5m, making the cost of setting up a lateral support system quite high. On the other hand, due to the restrictions on the location of the temporary steel pipe piles, the maximum span of the support beam is 20.4m, the weak axis gyration radius is 131.7mm, the lateral slenderness ratio is 155, and the lateral stability coefficient is only 0.383 (based on Q345). The overall stability of the main beam is insufficient, so diamond-shaped supports are installed at 1 / 3 and 2 / 3 of the distance from the support point.

[0030] The use of a double steel pipe pile system distributes the concentrated reaction force, which improves the longitudinal stiffness of the bridge and reduces the driving depth of the steel pipe piles, while also effectively avoiding complex power lines. If the position of the steel pipes deviates due to the influence of power lines, the bearing capacity and deflection of the longitudinal and transverse distribution beams should be checked promptly.

[0031] The main support beam includes a longitudinal distribution beam, a transverse distribution beam, and a track support beam. The longitudinal distribution beam is arranged along the longitudinal direction of the bridge and is supported on the steel pipe piles by the support beam pad. The transverse distribution beam is arranged along the transverse direction of the bridge and is placed on the longitudinal distribution beam. The track support beam is set on the transverse distribution beam, and the sliding track is arranged through the track support beam.

[0032] Step 3: Install lateral limiting devices on both sides of the sliding track: Each lateral restraint device includes a lateral restraint component welded and fixed to the main support beam, comprising several channel steels intermittently arranged along the transverse direction of the temporary support system to provide lateral restraint for the subsequent sliding phase.

[0033] Step 4: The construction of the single-span main bridge steel structure is completed using a single-segment assembly-four-support sliding scheme on the temporary support system. According to the single-segment assembly-four-support sliding scheme, after assembling the j-th assembly-sliding segment on the temporary support system near the first main pier, the j-th assembly-sliding segment is slid forward one step; then, the (j+1)-th assembly-sliding segment is assembled on the temporary support system of the first main pier, and the (j+1)-th assembly-sliding segment is assembled with the j-th assembly-sliding segment along the longitudinal direction of the bridge to form a segmental assembly body. After sliding the segmental assembly body forward one step, the j-th assembly-sliding segment is released. The j+1th assembled-sliding segment is connected to the jth assembled-sliding segment along the longitudinal direction of the bridge. Then, the jth assembled-sliding segment is slid to the side pier position and placed into the beam using a four-support sliding system. This process is repeated until all assembled-sliding segments are assembled, slid into place, and placed into the beam. Then, the current assembled-sliding segment after placement into the beam is spliced ​​with the previous assembled-sliding segment along the longitudinal direction of the bridge. Where: j∈m, m is a positive integer and m represents the total number of assembled-sliding segments.

[0034] The weight of each assembled-sliding segment should be as close as possible to the weight threshold of the sliding segment calculated based on the distribution of support points in the temporary support system. Therefore, each assembled-sliding segment may be a single main bridge steel structure segment prefabricated in Step 1, or it may be a segmental splice formed by splicing two or more consecutive main bridge steel structure segments prefabricated in Step 1. Using segmental splices will save sliding time and also facilitate the hoisting of individual segment components.

[0035] In the single-segment assembly-four-support sliding scheme: the construction sequence of each assembly-sliding segment is the reverse of the longitudinal arrangement sequence of the main bridge steel structure segments of the single-span main bridge steel structure. Furthermore, each assembly-sliding segment is determined based on the prefabricated main bridge steel structure segments from step one, according to the distribution of support points in the temporary support system established in step two and the economic viability of the construction. The sliding of each assembly-sliding segment on the temporary support system is achieved through the track trolley assembly arranged between itself and the sliding track, and the track trolley assembly arranged in the current assembly... - This is achieved through the coordination of the longitudinal sliding system between the sliding segment and the main pier; the track vehicle assembly and the longitudinal sliding system together form the aforementioned four-support sliding system; the sliding length of each assembled-sliding segment on the temporary support system should ensure that after the current assembled-sliding segment slides forward one step on the first main support beam, sufficient area can be left on the first main support beam for the construction of the next assembled-sliding segment. The first main support beam is the part of the main support beam that is arranged in the temporary support system close to the first main pier.

[0036] In this invention, four-point support sliding means that each sliding segment has four support points on the sliding track, that is, each sliding segment forms four support points through four tanks and two sliding tracks.

[0037] In this invention, the rail trolley assembly includes a tank vehicle and a tank vehicle support beam; two tank vehicles are mounted below the tank vehicle support beam, and the two tank vehicles are arranged one-to-one with the two sliding rails and are directly embedded in the corresponding sliding rails. At the same time, the tank vehicles and the lateral limiting members are slidably connected by lateral pulleys.

[0038] In this invention, the longitudinal sliding system includes a braking device, a traction device, a braking wire rope, and a traction wire rope; the braking device is arranged on the first main pier on the high elevation side, and the traction device is arranged on the second main pier on the low elevation side; the top surface of the upper chord of both segments of any main bridge steel structure segment is provided with a traction end lug, while the lower bridge deck is provided with a braking end lug; the power output end of the braking device is connected to the braking end lug through the braking wire rope, and the power output end of the traction device is connected to the traction end lug through the traction wire rope.

[0039] The braking and traction of the longitudinal sliding system both adopt a dual-point system, that is, the traction end is equipped with a lifting lug in the upper chord area of ​​the side span steel structure, and the braking end is equipped with a lifting lug in the lower bridge deck area of ​​the side span steel structure. In addition, each assembled segment is equipped with one set of traction lifting lugs (2 lugs) and one set of braking lifting lugs (2 lugs).

[0040] The center of the brake lug is aligned with the center of the brake hoist, the center of the traction lug is aligned with the center of the winch, and the relative position with the upper chord of the side span steel structure is not fixed.

[0041] If a large deviation occurs during the sliding process, construction should be stopped immediately. A lateral correction device is used to apply lateral force to correct the deviation. The first correction lug is welded to the crossbeam of the tank support, and the second correction lug is welded to the lateral distribution beam adjacent to the sliding segment. The first and second correction lugs are corrected by a 10T hand-operated hoist to ensure that the sliding segment moves forward on the centerline of the temporary support system.

[0042] The assembly of the steel structure of a single-span main bridge includes the following steps: Step 4.1: Arrange the track vehicle assembly A on the temporary support system near the first main pier and temporarily fix the track vehicle assembly A in the longitudinal direction of the bridge by arranging temporary constraints in the longitudinal direction of the bridge; In this invention, at the middle position of the two lateral limiting devices (lateral constraints) on both sides of the tank, weld a 300mm long [10 channel steel] on the top surface of the main support beam as a temporary constraint for the tank in the longitudinal direction of the bridge.

[0043] Step 4.2: Assemble the first assembly-sliding segment on the track trolley assembly A arranged in Step 4.1; Step 4.3: Construct a longitudinal sliding system on the first assembled-sliding segment completed in Step 4.2; Step 4.4: Activate the longitudinal sliding system and release the temporary longitudinal constraint of the track carriage assembly A arranged in Step 1, so that the first assembly-sliding segment can be moved forward one step by the track carriage assembly A below the first assembly-sliding segment, and the connection between the braking device in the longitudinal sliding system and the first assembly-sliding segment can be released; the sliding length of the first assembly-sliding segment moving forward one step is sufficient for the assembly of the next assembly-sliding segment; Step 4.5: Arrange the track trolley assembly B on the temporary support system vacated in Step 4.4, and temporarily fix the track trolley assembly B along the bridge direction; Step 4.6: Assemble the second assembly-sliding segment on the track vehicle assembly B arranged in step 4.5, and connect it with the first assembly-sliding segment in the longitudinal direction of the bridge to form a segment splice body; Step 4.7: Connect the braking device in the longitudinal sliding system to the second assembly-sliding segment; Step 4.8: Activate the longitudinal sliding system and release the longitudinal temporary constraint of the track carriage assembly B arranged in step 4.5, so that the segment splice formed by the splicing of the first and second assembly-sliding segments can be moved forward one step by the track carriage assembly below the first and second assembly-sliding segments, so as to make enough space on the temporary support system for the assembly of the next assembly-sliding segment; Step 4.9: Disconnect the braking device from the second assembly-slip segment in the longitudinal sliding system, and disconnect the first and second assembly-slip segments; Step 4.10: Connect the braking device in the longitudinal sliding system to the first assembled-sliding segment; Step 4.11: Activate the longitudinal sliding system to move the first assembly-sliding segment towards the side pier via the track trolley assembly A below the first assembly-sliding segment until it reaches the second main pier; Step 4.12: Slide the assembled-sliding section beam into place as described in Step 4.11; In this step, a beam-dropping stage support system is used to achieve the sliding of each assembly-sliding segment into place. The beam-dropping stage support system includes several replacement jacks. Each replacement jack is arranged in two rows along the longitudinal direction of the temporary support system and two rows along the transverse direction of the temporary support system. The two replacement jacks arranged along the transverse direction are supported under the slid-in assembly-sliding segment by transverse support devices. The transverse support devices include two or more vertical jack supports arranged on the transverse distribution beam and jack beams supported by the vertical supports of each jack. The two replacement jacks arranged along the transverse direction are placed one-to-one between the jack beams and the assembly-sliding segment.

[0044] The lower end of the jack is connected to the transverse support device via a leveling component, while the upper end is tightened against the lower chord of the assembly-sliding section via a wedge-shaped steel plate to control the verticality of the jack and prevent the risk of non-vertical operation.

[0045] The assembly and sliding section beam operation, where each section is slid into place, includes the following steps: Step 4.12.1: Construct the support system for the beam lowering stage; A support system for the beam lowering stage is constructed below the assembled-sliding segment that has been slid into place; Step 4.12.2: Based on the relative position before replacement, keep the replacement jack in a holding state, and after the replacement jack has reached the end of its stroke, raise it by 1-2mm. Step 4.12.3: Remove the various track trolley components below the slid-in assembled-sliding segment; By following steps 4.12.1-4.12.3 above, the assembly and sliding section beam segmentation can be completed.

[0046] Repeat steps 4.1 to 4.12 until all assembled-sliding segments have slid into place along the temporary support system and the beam has been lowered. At the same time, assemble the next assembled-sliding segment with the previous assembled-sliding segment in the longitudinal direction of the bridge, thereby completing the construction of the single-span main bridge steel structure between the first and second main piers.

[0047] Example 1 The technical solution of the present invention will be described in detail below with reference to a specific embodiment.

[0048] like Figure 1-10 As shown, the single-span main bridge steel structure in this embodiment is divided into several segments along the longitudinal direction of the bridge according to construction requirements, corresponding to the 1st to 6th main bridge steel structure segments.

[0049] After calculation, the single-segment assembly-four-support sliding scheme described in this embodiment includes a total of four assembly-sliding segments, corresponding to the 1st to the 4th assembly-sliding segments. Specifically: the 1st assembly-sliding segment is the 6th main bridge steel structure segment; the 2nd assembly-sliding segment is the segmental splice formed by splicing the 4th and 5th main bridge steel structure segments; the 3rd assembly-sliding segment is the 3rd main bridge steel structure segment; and the 4th assembly-sliding segment is the segmental splice formed by splicing the 2nd and 1st main bridge steel structure segments.

[0050] The following will be combined with the appendix Figure 3 The detailed construction steps for the single-span main bridge steel structure in this implementation are as follows: Step A: Assemble the 6th main bridge steel structure segment (i.e., the 1st assembly-sliding segment); Step B: After sliding the 6th main bridge steel structure segment forward by one sliding length, assemble the 5th main bridge steel structure segment, and make the 5th main bridge steel structure segment be spliced ​​with the 6th main bridge steel structure segment in the longitudinal direction of the bridge to form a whole. Step C: After sliding the 5th and 6th main bridge steel structure segments, which are spliced ​​together, forward by one sliding length, release the connection between the 5th and 6th main bridge steel structure segments. Step D: Assemble the fourth main bridge steel structure segment and connect it with the fifth assembly-sliding segment in the longitudinal direction of the bridge; at the same time, slide the sixth main bridge steel structure segment toward the second main pier until the sixth main bridge steel structure segment is in place, then adjust the alignment and elevation of the sixth main bridge steel structure segment before lowering the beam; Step E: Slide the 4th and 5th main bridge steel structure segments, which are spliced ​​together, forward by one sliding length as a whole; Step F: Splice the third main bridge steel structure segment and ensure that the segment splice formed by splicing the third main bridge steel structure segment with the fourth and fifth main bridge steel structure segments is connected in the longitudinal direction of the bridge. Step G: After sliding the main bridge steel structure segments 3-5 forward by one sliding length, disconnect the connection between the main bridge steel structure segment 3 and the main bridge steel structure segment 4. Step H: Assemble the second main bridge steel structure segment, ensuring that the second main bridge steel structure segment is spliced ​​together with the third main bridge steel structure segment in the longitudinal direction of the bridge; at the same time, slide the spliced ​​fourth and fifth main bridge steel structure segments as a whole towards the second main pier until the spliced ​​fourth and fifth main bridge steel structure segments are in place, then adjust the overall alignment and elevation of the spliced ​​fourth and fifth main bridge steel structure segments before lowering the beam; Step 1: After sliding the spliced ​​2nd and 3rd main bridge steel structure segments forward by one sliding length, disconnect the connection between the 2nd and 3rd main bridge steel structure segments. Step J: Splice the first main bridge steel structure segment, ensuring that the first main bridge steel structure segment is spliced ​​into one piece with the second main bridge steel structure segment in the longitudinal direction of the bridge; at the same time, slide the third main bridge steel structure segment toward the second main pier until the third main bridge steel structure segment is slid into place, then adjust the linearity and elevation of the third main bridge steel structure segment before lowering the beam; Step K: Slide the first and second main bridge steel structure segments, which are spliced ​​together, toward the second main pier until they are in place. Then, adjust the alignment and elevation of the first and second main bridge steel structure segments and lower them into place.

[0051] By following the steps AK above, the sliding construction of the single-span main bridge steel structure located between the first and second main piers can be completed.

Claims

1. A method for four-point support sliding construction of a single segment of the main bridge steel structure under a continuous track, characterized in that, Includes the following steps: Step 1: Prefabricate the steel structure segments of each main bridge: The steel structure of the single-span main bridge is divided into several main bridge steel structure segments, and then each main bridge steel structure segment is further divided into several segmental components, and the corresponding segmental components of each main bridge steel structure segment are prefabricated in the factory. Step 2: Construct a temporary support system at the construction site: At the construction site, a temporary support system was built between two adjacent main piers along the bridge direction. The two adjacent main piers are the first and second main piers. The temporary support system includes a steel pipe pile support system, a main support beam, and a sliding track; the main support beam is set above the steel pipe pile support system and supported by the steel pipe pile support system, and the sliding track is arranged along the longitudinal direction of the main support beam. Step 3: Install lateral limiting devices on both sides of the sliding track; Step 4: The construction of the single-span main bridge steel structure is completed using a single-segment assembly-four-support sliding scheme on the temporary support system. According to the single-segment assembly-four-support sliding scheme, after assembling the j-th assembly-sliding segment on the temporary support system near the first main pier, the j-th assembly-sliding segment is slid forward one step, and the weight of each assembly-sliding segment is close to the sliding segment weight threshold calculated based on the distribution of each support point of the temporary support system; then, the (j+1)-th assembly-sliding segment is assembled on the temporary support system of the first main pier, and the (j+1)-th assembly-sliding segment is assembled with the j-th assembly-sliding segment in the longitudinal direction of the bridge to form a section. The assembly is performed by first assembling a segment and then sliding it forward one step. Then, the connection between the (j+1)th assembly-sliding segment and the jth assembly-sliding segment in the longitudinal direction is released. The jth assembly-sliding segment is then slid to the pier position via a four-support sliding system and lowered into place. This process is repeated until all assembly-sliding segments are assembled, slid into place, and lowered into place. Finally, the current assembly-sliding segment after lowering into place is joined to the previous assembly-sliding segment in the longitudinal direction. Where: j∈m, m is a positive integer and m represents the total number of assembly-sliding segments. In the single-segment assembly-four-support sliding scheme, four supports refer to the fact that each assembly-sliding segment has four support points on the sliding track. In the single-segment assembly-four-support sliding scheme: the construction sequence of each assembly-sliding segment is the opposite of the arrangement sequence of each main bridge steel structure segment along the bridge direction. Each assembly-sliding segment is calculated and determined based on the prefabricated main bridge steel structure segments in step one, according to the distribution of each support point of the temporary support system built in step two and the economic efficiency of construction. The sliding of each assembled-sliding segment on the temporary support system is achieved through the cooperation of the track trolley assembly arranged between itself and the sliding track and the longitudinal sliding system arranged between the current assembled-sliding segment and the main pier; the track trolley assembly and the longitudinal sliding system together form the aforementioned four-support sliding system; The sliding length of each assembly-sliding segment on the temporary support system should be sufficient to ensure that after the current assembly-sliding segment slides forward one step on the first main support beam, there is enough area left on the first main support beam for the construction of the next assembly-sliding segment. The first main support beam is the part of the main support beam that is arranged close to the first main pier in the temporary support system.

2. The method for integral sliding construction of main bridge steel structure segments under a continuous track as described in claim 1, characterized in that, In step four, the bridge-sliding system includes braking equipment, traction equipment, braking wire rope, and traction wire rope; the braking equipment is arranged on the first main pier on the high elevation side, and the traction equipment is arranged on the second main pier on the low elevation side. The top surface of the upper chord of both segments of any main bridge steel structure segment is provided with traction end lugs, while the lower bridge deck is provided with braking end lugs. The power output end of the braking device is connected to the brake end lug via a brake wire rope, while the power output end of the traction device is connected to the traction end lug via a traction wire rope.

3. The method for integral sliding construction of main bridge steel structure segments under a continuous track according to claim 2, characterized in that, Step four, the assembly of the single-span main bridge steel structure specifically includes the following steps: Step 4.1: Arrange track trolley assembly A on the temporary support system near the first main pier and temporarily fix track trolley assembly A along the bridge direction; Step 4.2: Assemble the first assembly-sliding segment on the track trolley assembly A arranged in Step 4.1; Step 4.3: Construct a longitudinal sliding system on the first assembled-sliding segment completed in Step 4.2; Step 4.4: Activate the longitudinal sliding system and release the temporary longitudinal constraint of the track carriage assembly A arranged in Step 1, so that the first assembly-sliding segment can be moved forward one step by the track carriage assembly A below the first assembly-sliding segment, and the connection between the braking device in the longitudinal sliding system and the first assembly-sliding segment can be released; the sliding length of the first assembly-sliding segment moving forward one step is sufficient for the assembly of the next assembly-sliding segment; Step 4.5: Arrange the track trolley assembly B on the temporary support system vacated in Step 4.4, and temporarily fix the track trolley assembly B along the bridge direction; Step 4.6: Assemble the second assembly-sliding segment on the track vehicle assembly B arranged in step 4.5, and connect it with the first assembly-sliding segment in the longitudinal direction of the bridge to form a segment splice body; Step 4.7: Connect the braking device in the longitudinal sliding system to the second assembly-sliding segment; Step 4.8: Activate the longitudinal sliding system and release the longitudinal temporary constraint of the track carriage assembly B arranged in step 4.5, so that the segment splice formed by the splicing of the first and second assembly-sliding segments can be moved forward one step by the track carriage assembly below the first and second assembly-sliding segments, so as to make enough space on the temporary support system for the assembly of the next assembly-sliding segment; Step 4.9: Disconnect the braking device from the second assembly-slip segment in the longitudinal sliding system, and disconnect the first and second assembly-slip segments; Step 4.10: Connect the braking device in the longitudinal sliding system to the first assembled-sliding segment; Step 4.11: Activate the longitudinal sliding system to move the first assembly-sliding segment towards the side pier via the track trolley assembly A below the first assembly-sliding segment until it reaches the second main pier; Step 4.12: Slide the assembled-sliding section beam into place as described in Step 4.11; Repeat steps 4.1 to 4.12 until all assembled-sliding segments have slid into place along the temporary support system and the beam has been lowered. At the same time, assemble the next assembled-sliding segment with the previous assembled-sliding segment in the longitudinal direction of the bridge, thereby completing the construction of the single-span main bridge steel structure between the first and second main piers.

4. The method for integral sliding construction of main bridge steel structure segments under a continuous track according to claim 3, characterized in that, The single-span main bridge steel structure comprises six main bridge steel structure segments, corresponding to the first, second, ..., sixth main bridge steel structure segments. In the assembly-sliding scheme, there are four assembly-sliding segments: the first assembly-sliding segment is the sixth main bridge steel structure segment; the second assembly-sliding segment is the fifth main bridge steel structure segment; the third assembly-sliding segment is a segmental assembly formed by splicing the fourth and third main bridge steel structure segments; and the fourth assembly-sliding segment is a segmental assembly formed by splicing the second and first main bridge steel structure segments.

5. The method for integral sliding construction of main bridge steel structure segments under a continuous track according to claim 4, characterized in that, The main support beam is set into several support beam segments along the longitudinal direction of the bridge. Each support beam segment is connected at the joint by a butt joint and reinforced with a welded steel plate. At the same time, the joints between the support beam segments are as close as possible to the support point to avoid the joints being located in the middle half of the span.

6. The method for integral sliding construction of main bridge steel structure segments under a continuous track according to claim 5, characterized in that, In step 4.12, a beam-sliding stage support system is used to achieve the assembly-sliding segment beam segmentation by sliding each section into place; The support system for the beam lowering stage includes several replacement jacks; each replacement jack is arranged in two rows along the longitudinal direction of the temporary support system and two rows along the transverse direction of the temporary support system. The two replacement jacks arranged along the transverse direction are supported under the assembled-sliding segment after sliding into place by transverse support devices. The transverse support devices include two or more vertical jack supports arranged on the transverse distribution beam and jack beams supported by the vertical supports of each jack. The two replacement jacks arranged along the transverse direction are placed one-to-one between the jack beams and the assembled-sliding segment.

7. The method for integral sliding construction of main bridge steel structure segments under a continuous track according to claim 6, characterized in that, The lower end of the jack is connected to the transverse support device via a leveling component, while the upper end is tightened against the lower chord of the assembly-sliding section via a wedge-shaped steel plate to control the verticality of the jack and prevent the risk of non-vertical operation.

8. The method for integral sliding construction of main bridge steel structure segments under a continuous track according to claim 7, characterized in that, The assembly and sliding section beam operation, where each section is slid into place, includes the following steps: Step 6.1: Construct the support system for the beam lowering stage; A support system for the beam lowering stage is constructed below the assembled-sliding segment that has been slid into place; Step 6.2: Based on the relative position before replacement, keep the replacement jack in a holding state, and raise the replacement jack 1-2mm after the stroke is in place. Step 6.3: Remove the track trolley components below the assembled-sliding segment that has been slid into place; By following steps 6.1-6.3 above, the assembly and sliding section beam segmentation can be completed.

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