High-precision integral assembly construction method for arch ribs of large-span steel box tied arch bridge

Abstract

The invention discloses a high-precision integral assembly construction method for arch ribs of a large-span steel box tied arch bridge, and belongs to the technical field of bridge engineering construction. The core of the method is as follows: a double-machine cooperative dynamic stowage turning-over technology is initiated, and the problem of stable control of air attitude conversion of large-size arch rib sections is solved; a bridge bearing type space stabilizing support system is provided, an assembling platform is constructed on a formed bridge floor, and the limitation of a complex environment under a bridge is avoided; according to the hinged type posture conversion lifting appliance, stepless posture adjustment and precise butt joint of arch rib sections from a lifting state to a mounting state are achieved; a temperature self-adaptive closure technology based on real-time monitoring is researched and developed, and unstressed closure of the arch ribs is achieved through data driving. The method systematically solves the problems of precision, safety and efficiency of arch rib installation of the large-span arch bridge in a complex environment.

Description

Technical fields:

[0001] This invention relates to the field of bridge engineering construction technology, and in particular to a high-precision integral assembly construction method for the arch ribs of a long-span steel box girder arch bridge. Background technology:

[0002] Long-span steel box girder arch bridges are lightweight and aesthetically pleasing, but the installation of their arch ribs has always been a major construction challenge. Traditional methods such as cable hoisting have significant impacts on site conditions and navigation, the full-span scaffolding method is unsuitable for cross-line construction, and the rotation method is costly and technically complex. Especially when crossing sensitive areas such as railways and highways, extreme demands are placed on construction precision, safety, and schedule. Therefore, there is an urgent need for a high-precision, safe, and suitable method for the integral assembly of arch ribs in complex environments. Summary of the Invention:

[0003] The purpose of this invention

[0004] To address the problems of high risk of arch rib segment overturning, difficult installation and positioning, insufficient support stability, and complex control of closure precision in existing technologies, this invention proposes a high-precision integral assembly construction method for arch ribs.

[0005] Technical solution of the present invention

[0006] This invention achieves safe, precise, and efficient assembly of the arch rib through key steps such as dual-machine coordinated turning of arch rib segments, erection of bridge deck support system, hoisting with special conversion lifting tools, control of lateral stability of support, and temperature-adaptive precise closure.

[0007] Beneficial effects:

[0008] The dual-machine collaborative turning process is safe and efficient, and solves the problem of posture conversion for large-sized components.

[0009] Erecting scaffolds on the bridge deck overcomes site limitations and is particularly suitable for cross-line construction.

[0010] Specialized conversion lifting tools ensure stability and precision during the lifting process.

[0011] The additional diagonal bracing significantly improves the lateral stability of the support structure, ensuring construction safety.

[0012] The closure process based on real-time monitoring effectively ensures that the bridge's alignment and internal force state meet design requirements. Attached image description:

[0013] Figure 1 Schematic diagram of the arch rib segment dual-machine coordinated turning process

[0014] Figure 2 Elevation layout of the arch rib assembly support structure

[0015] Figure 3 Cross-sectional layout diagram of arch rib assembly support structure

[0016] Figure 4 Schematic diagram of the special conversion lifting device

[0017] Figure 5 Schematic diagram of the lateral stabilization measures (diagonal bracing) for the support structure.

[0018] Figure 6 Schematic diagram of the installation and locking of the arch rib closure section. Detailed implementation method:

[0019] The present invention will now be further described with reference to the accompanying drawings.

[0020] like Figure 1 As shown, the arch rib segment (7) is flipped in the air in the assembly area by a 300t crawler crane (8) and a 200t truck crane (9). The crawler crane (8) serves as the main lifting point, and the truck crane (9) serves as the auxiliary lifting point. With the help of long and short ropes, the segment rotates smoothly 90° around the main lifting point, changing from a horizontal to a vertical position.

[0021] like Figure 2 and Figure 3 As shown, an arch rib assembly support (5) is erected on the bridge deck tie beam (6). The support is a spatial lattice system consisting of Φ820×10mm steel pipe columns (10), [16a channel steel horizontal bracing (11), and longitudinal diagonal bracing (12). The bottom of the columns is welded to the bridge deck embedded parts, and the top is equipped with HM400×300 steel distribution beams (13) and weathering steel support plates (14).

[0022] like Figure 4 As shown, a special conversion lifting tool is used for hoisting the arch rib segment. The lifting beam (1) is composed of double-layered [25a channel steel clamped with 16mm steel plate ribs. The upper lifting point (2) is a 25mm thick single-ear plate, which is connected to the hook through a 35t shackle. The lower lifting point (3) is a 16mm thick double-ear plate, which is connected to the arch rib lifting lug (15) through a pin shaft to achieve stable control of the segment's posture.

[0023] like Figure 5 As shown, to enhance the lateral stability of the support, a Φ500×10mm steel pipe is installed inside the support (5) as an additional diagonal brace (4). The upper end of the diagonal brace is welded to the top of the support, and the lower end is welded to the bridge deck tie beam (6), with an angle of approximately 55° with the bridge deck.

[0024] like Figure 6 As shown, before the installation of the arch closure section (16), the closure joint was continuously monitored for 48 hours. The closure section was precisely cut according to the monitoring data. During the period of stable temperature, the closure section (16) was hoisted into place, and steel clamps (17) were quickly used to weld and lock the top plate, bottom plate and web plate, and then the circumferential weld was completed.

[0025] After all the arch ribs are assembled, during the installation of the slings, the assembly supports are symmetrically dismantled from the mid-span to the arch foot according to the monitoring instructions, thus completing the system conversion.

Claims

1. A high-precision integral assembly construction method for the arch ribs of a long-span steel box girder arch bridge, characterized in that, Includes the following steps: S1: Arch rib segment dual-machine coordinated turning: A large-tonnage crawler crane is used as the main lifting point and a large-tonnage truck crane is used as the auxiliary lifting point. Through the cooperation of long and short ropes, the arch rib segment can be turned in the air from the horizontal assembly posture to the installation posture. S2: Bridge deck support system erection: an arch rib assembly support is erected on the installed bridge deck tie beam. The support is a spatial steel structure with transverse double-limb columns and longitudinal diagonal braces. S3: Segmental hoisting of arch rib sections: Using the crawler crane and truck crane, the arch rib sections are lifted to the top of the assembly support using a special conversion lifting tool for positioning and temporary fixation; S4: Lateral stability control of the support: An additional diagonal brace is set on the inner side of the arch rib assembly support. The upper end of the additional diagonal brace is connected to the top of the support, and the lower end is connected to the bridge deck tie beam. S5: Arch Closure: Before closure, the closure joint is continuously monitored, the closure section is matched and cut according to the monitoring data, and instantaneous closure and locking are carried out during the period of stable temperature. S6: System Conversion: After the arch rib is assembled as a whole, during the installation of the slings, the arch rib assembly support is symmetrically dismantled in the order instructed.

2. The method according to claim 1, characterized in that, In step S1, the main lifting point and the auxiliary lifting point coordinate the lifting, stabilizing and rotating actions of the control boom to enable the arch rib segment to rotate 90° in the air around the main lifting point.

3. The method according to claim 1, characterized in that, In step S2, the columns of the arch rib assembly support are made of Φ820×10mm steel pipes. The bottom is fixed to the bridge deck tie beam by pre-embedded parts, and the top is equipped with HM400×300 steel distribution beams and adjustable support devices.

4. The method according to claim 1, characterized in that, In step S3, the special conversion lifting tool includes a rigid lifting beam. The upper part of the lifting beam is provided with an upper lifting point connected to the lifting equipment, and the lower part is provided with a lower lifting point connected to the upper lifting lug of the arch rib segment through a pin.

5. The method according to claim 1, characterized in that, In step S4, the additional diagonal brace is a Φ500×10mm steel pipe, and the angle between it and the bridge deck tie beam is 50°~60°.

6. The method according to claim 1, characterized in that, In step S5, the continuous monitoring time is no less than 24 hours, and the monitoring parameters include ambient temperature, steel structure temperature and closure geometry.

7. A hoisting and conversion tool for arch rib segments used in the method of any one of claims 1 to 6, characterized in that, include: A lifting beam (1) is composed of double-channel steel and stiffening plates; the upper lifting point (2) is located at the center of the upper part of the lifting beam (1) and is a single-ear plate structure; the lower lifting point (3) is symmetrically located at both ends of the lower part of the lifting beam (1) and is a double-ear plate structure; wherein, the upper lifting point (2) is connected to the lifting equipment through a shackle, and the lower lifting point (3) is connected to the lifting lug of the arch rib segment through a pin.

8. A lateral stabilizing structure for an arch rib assembly support used in any one of the methods described in claims 1 to 6, characterized in that: It includes multiple diagonal braces (4), which are inclinedly arranged on the inner side of the arch rib assembly bracket (5), and their upper and lower ends are rigidly connected to the top of the assembly bracket (5) and the bridge deck tie beam (6) respectively.

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