Overall incremental launching construction method of large-span steel box tied arch bridge over-crossing railway

Abstract

The invention discloses an integral incremental launching construction method of a large-span steel box tied arch bridge over-crossing railway. The method comprises three core processes: T1, a guide beam passing pier jacking process: enabling a guide beam to smoothly cross a front buttress by integrally jacking a main beam; t2, based on synchronous control and deviation correction of a walking type pushing system, cooperative action and linear control of full-bridge pushing equipment are achieved; and a T3 support post-installation and inverted jacking beam falling process is adopted, and accurate falling of the main beam is achieved through alternate replacement of the jacks and the cushion blocks. The invention further relates to a guide beam pier passing system and an inverted top beam falling system which are used for achieving the method. The guide beam pier passing system comprises a walking type pushing system and a central control system; the inverted jacking beam falling system comprises a beam falling jack and a plurality of sets of rigid cushion blocks. The method effectively solves the technical problems of guide beam downwarping, difficulty in synchronous control, high requirement on large-tonnage beam falling precision and the like in large-span arch bridge incremental launching construction, has the advantages of high safety, accurate control and high construction efficiency, and is particularly suitable for bridge construction in complex environments such as crossing railways and the like.

Description

Technical fields:

[0001] This invention belongs to the field of bridge engineering construction technology, specifically relating to a method for jacking construction of a long-span bridge structure spanning existing facilities. Background technology:

[0002] The incremental launching method is a common construction method for long-span bridges crossing obstacles. However, for long-span, wide-deck, steel box girder tied arch bridges with arch ribs, the incremental launching construction across railways faces a series of challenges, including difficulties in placing the guide beam on the pier, difficulties in long-distance synchronous control, and extremely high precision requirements for dropping large-tonnage beams. Conventional incremental launching technology is inadequate in the face of these challenges, resulting in significant safety risks, difficulties in precision control, and significant interference with railway operations. Summary of the Invention:

[0003] The purpose of this invention

[0004] The purpose of this invention is to provide a safe, precise, and efficient method for the overall jacking construction of a long-span steel box girder arch bridge spanning a railway, in order to solve the above-mentioned technical problems.

[0005] Technical solution of the present invention

[0006] This invention systematically solves the challenges of jacking construction in complex environments through a series of innovative methods, including the guide beam lifting process over the pier, synchronous control and correction based on the walking-type jacking system, and the post-installation of supports and the inverted jacking and lowering process.

[0007] Beneficial effects:

[0008] The guide beam crossing-pier technique ingeniously solves the interference problem caused by guide beam deflection, ensuring a controllable and safe process. An advanced synchronization and correction control system guarantees the stability and alignment of the bridge's long-distance jacking, handling loads of thousands of tons. The post-installation of supports and the inverted jacking and lowering of the beam achieve millimeter-level precision in the placement of large-tonnage bridge structures. This has resulted in a complete safety, quality, and technical control system, yielding significant socio-economic benefits. Attached image description:

[0009] Figure 1 Schematic diagram of the overall layout and pier numbering for the jacking construction.

[0010] Figure 2 Schematic diagram of the "guide beam crossing the pier" process.

[0011] Figure 3 Schematic diagram of walking-type jacking equipment

[0012] Figure 4 Schematic diagram of the process of rear-mounting the support and lowering the beam.

[0013] Figure 5 Block diagram of the jacking synchronous control system.

[0014] Figure 1 The overall layout of the jacking construction is shown, and the positional relationship of each support and the jacking direction are clearly defined; Figure 2 The four key processes for the guide beam to pass over the pier are explained in detail, and the technical problem of guide beam deflection is solved. Figure 3 The three-dimensional motion mechanism of the walking jacking device was revealed, demonstrating the device's innovation; Figure 4 The illustration shows the precise positioning process of the support after installation and the inverted beam lowering; Figure 5 This demonstrates a synchronous control system architecture based on modern control theory. Detailed implementation method:

[0015] The present invention will now be further described with reference to the accompanying drawings.

[0016] like Figure 1 As shown, the jacking route crosses the railway station yard (5). The assembly yard is located on the high mileage side, and the jacking direction is as shown by the arrow. The supports include permanent supports (3#, 4#, 5#, 6#) and temporary supports (B, C, D, E), of which supports C and D are located in the railway track area.

[0017] like Figure 2 As shown, the guide beam crossing process includes four steps: a) the guide beam (6) deflects downwards and approaches the front support pier (7); b) all stepping jacks (8) simultaneously lift the main beam (2) to a height H (e.g., 160mm); c) all stepping jacks (8) simultaneously push the main beam forward a distance S (e.g., 1m); d) all stepping jacks (8) simultaneously descend, and the guide beam (6) lands on the support pier (7).

[0018] like Figure 3 As shown, the walking-type jacking device (8) includes an upper sliding seat (9), a jacking support cylinder (10), a longitudinal jacking cylinder (11), a transverse adjustment cylinder (12), and a base (13), and has three-way movement capability.

[0019] like Figure 4 As shown, the inverted beam lowering system includes a beam lowering jack (1), a first pad block group (3a), a permanent support (4), and a second pad block group (3b). By lifting with the jack (1), the first pad block group (3a) is removed or lowered, and the load of the main beam (2) is transferred to the second pad block group (3b). This cycle continues until the main beam is lowered onto the support (4).

[0020] like Figure 5 As shown, the jacking synchronization control system is based on the PLC main control (14), which communicates with each sub-control box (15) through the network. The sub-control box controls the hydraulic pump station (16) to drive the walking jack (8). The displacement and pressure sensors (17) form a feedback closed loop to achieve synchronization and correction.

Claims

1. A method for integral incremental launching construction of a long-span steel box tied-arch bridge over a railway, characterized in that, The method comprises the following steps: T1: pier passing girder lifting process: when the front end of the girder cannot directly pass the pier due to the cantilever deflection, the whole girder is lifted by a predetermined height by the vertical jack of the pushing system, so that the girder bottom exceeds the top surface of the pier, and after one stroke of pushing, the girder covers the pier, and then the whole girder is lowered, so that the girder is seated on the pier; T2: synchronous control and deviation correction based on the walking pushing system: the computer centralized control system is used to control the lifting, advancing, lowering and retreating of the whole bridge walking pushing, and the transverse adjustment mechanism of the walking pushing is used for real-time deviation correction; T3: pier rear loading and reverse lifting girder process: the permanent pier is not installed before pushing; after pushing, the girder is lifted by the girder lowering jack arranged on the pier top, the permanent pier is installed after the pushing equipment is removed, and then the girder is lowered to the design elevation by the alternate replacement of the girder lowering jack and the pier top cushion block.

2. The method of claim 1, wherein, In step T1, the predetermined height is to ensure that the lowest point of the girder bottom exceeds the top surface of the front pier by more than 10 mm.

3. The method of claim 1, wherein, In step T2, the synchronous control is mainly based on displacement sensor feedback and supplemented by pressure sensor feedback; and the deviation correction is realized by starting the transverse adjustment cylinder of the specific support point walking pushing.

4. The method of claim 1, wherein, In step T3, the single girder lowering step of the alternate replacement is not greater than 5 cm.

5. A process system for implementing the method of any one of claims 1 to 4, characterized in that, It comprises: a set of walking pushing system distributed in each support point, having vertical lifting, longitudinal pushing and transverse deviation correction functions; a central control system in communication connection with all walking pushing systems, used to control the synchronous lifting, pushing and lowering action sequence of all walking pushing to complete the girder passing the pier.

6. A counterforted beam system for implementing the method of any one of claims 1 to 4, characterized in that, It comprises: a plurality of large-tonnage girder lowering jacks (1) arranged at the design position of the pier top below the girder (2); a plurality of rigid cushion blocks (3), including a first cushion block group (3a) arranged at the piston top of the girder lowering jack (1) and a second cushion block group (3b) arranged at the top of the permanent pier (4); wherein the first cushion block group (3a) and the second cushion block group (3b) are alternately replaced by the reciprocating lifting and lowering of the girder lowering jack (1), so as to realize the step-by-step lowering of the girder (2).

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