A method for assembling large sections of steel beams in a three-main-truss box-truss composite structure

Abstract

The present invention discloses a method for assembling large sections of steel beams of a three-main-truss box-truss composite structure. The method comprises the following steps: providing a cradle, a ground sample line and an observation tower component cradle system as an assembly basis; firstly, arranging the middle truss, then sequentially providing the lower bridge decks on both sides, and then sequentially assembling the side trusses and the upper bridge deck; during the assembly process, positioning is performed by a total station to ensure assembly accuracy, and the lower bridge deck blocks and trusses can be better supported in conjunction with steel wire ropes and tension and compression rods; the above method can be used to precisely fine-tune the positioning of the lower bridge deck blocks and the trusses through a gantry crane in conjunction with a three-way hydraulic jack, thereby facilitating rapid and accurate positioning; and the lower bridge deck blocks and trusses can be better supported in conjunction with steel wire ropes and tension and compression rods, thereby providing a solid foundation for subsequent splicing and improving safety; and precise positioning can be provided by a total station or a theodolite in conjunction with ground sample lines and an observation tower, thereby improving assembly accuracy.

Description

Technical Field

[0001] The invention relates to the field of large steel structure bridge manufacturing. Background Art

[0002] The integrated installation of large steel bridge sections significantly reduces overhead work at the bridge site and accelerates construction cycles, becoming a future trend in steel bridge construction. The completed Hutong Yangtze River Bridge and Wufengshan Yangtze River Bridge, as well as the Changtai Bridge currently under construction, all utilize this integrated installation process.

[0003] This technology features a steel beam structure consisting of three main trusses, a monolithic steel box deck structure for the lower railway deck, and an orthotropic steel plate deck structure with crossbeams for the upper highway deck. The three trusses and two upper and lower deck blocks are assembled into large sections in the factory. The large steel beam sections of this double-section, three-truss box-truss composite beam structure are heavy and have a large profile. The order in which the trusses and deck blocks are assembled during assembly directly affects the manufacturing accuracy of the large steel beam sections.

[0004] For example, patent application CN105735129A discloses a modular assembly method for fully welded truss segments, disclosing the assembly sequence of truss segment modules as follows: lower deck block on one side, middle truss, lower deck block on the other side, trusses on both sides, and upper deck block. While the assembly sequence is merely described, no detailed technical explanation is provided regarding how to position and assemble the large steel structure, or how to ensure the stability of the individual steel components during the assembly process. This makes it difficult to effectively assemble the large-scale steel bridge structure based solely on the assembly sequence. Summary of the Invention

[0005] In order to solve the deficiencies in the prior art, a method for assembling large steel beam segments with accurate positioning, safety, reliability, and reasonable assembly sequence is provided. The technical solution adopted by the present invention is:

[0006] A method for assembling a large segment of a three-main-truss box-truss composite structure steel beam comprises the following steps:

[0007] S1. Build a cradle system consisting of a set of support piers, ground sample lines, and measurement towers at the construction site;

[0008] S2. Arrange the intermediate truss. Using a gantry crane, wire ropes, and fall chains to assist in positioning, the truss is hoisted to the desired position in the cradle system. After fine-tuning its position, it is lowered onto the support piers. Wire ropes and tension and compression rods are installed on both sides of the truss as a lateral support system to secure it.

[0009] S3. Assemble one side of the lower deck block. Use a gantry crane to hoist the lower deck block to the pre-positioned position on the side of the truss located in step S2. Use the gantry crane to roughly position it. Then, use the three-way hydraulic jack at the bottom of the lower deck block to fine-tune the position of the lower deck block. Then, use the stacking plate to fix the connection between the lower deck block and the middle truss. Install cross wire ropes between the bottom of the beam of the lower deck block and the ground to reinforce it.

[0010] S4. Assemble the lower deck blocks on the other side, using the S3 method to secure the lower deck blocks on the other side of the middle truss.

[0011] S5. Assemble a side truss. Hoist the truss into position using a gantry crane. Using wire ropes and fall chains to assist in positioning, secure the truss to the lower deck block with stacking plates. Install wire ropes and tension and compression rods on the sides of the truss as a lateral support system to secure it securely.

[0012] S6. Assemble the upper deck block on one side and hoist the upper deck block by the gantry crane to the side between the trusses and the middle trusses assembled in step S5 and to the connection between the code plate code;

[0013] S7. Assemble the other truss and secure it to the lower deck block using the same method as S5.

[0014] S8. Assemble the bridge deck blocks on the other side and stack and fix them in the same way as S6; complete the assembly.

[0015] Furthermore, when constructing the tire frame system, ground sample lines and a group of observation towers are arranged at the same time. The position of each observation tower corresponds to the center line position of each truss, and the position of each ground sample line corresponds to the center line position of each bridge deck block. During splicing, the position of each bridge deck block and each truss is measured and positioned using a total station or theodolite in combination with the ground sample line or the observation tower.

[0016] Furthermore, after the above assembly is completed, the welding of the connecting welds between the truss and the bridge deck blocks is completed after each inspection point is qualified, and finally flaw detection and trimming are carried out.

[0017] Furthermore, the support piers for the lower part of the side trusses in the tire frame system are support piers in the form of a combination of a field-shaped support pier and a cylinder hydraulic jack, and are arranged at the truss node position.

[0018] The above method can be used to precisely fine-tune the positioning of the lower bridge deck blocks and each truss through the gantry crane in conjunction with the three-way hydraulic jack, which is convenient for fast and accurate positioning. In conjunction with the steel wire rope and tension and compression rods, it can provide better support for the lower bridge deck blocks and trusses, provide a solid foundation for subsequent splicing, and improve safety; through the total station or theodolite combined with the ground sample line and the observation tower, precise positioning can be provided to improve assembly accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of the three-main-truss-box-truss composite structure steel beam after large-scale assembly;

[0020] Figure 2 Schematic diagram of the layout of the tire frame, ground sample line and observation tower

[0021] Figure 3 Schematic diagram of step S2;

[0022] Figure 4 This is a schematic diagram of step S3;

[0023] Figure 5 This is a schematic diagram of step S4;

[0024] Figure 6 This is a schematic diagram of step S5;

[0025] Figure 7 This is a schematic diagram of step S6;

[0026] Figure 8 This is a schematic diagram of step S7;

[0027] Figure 9 This is a schematic diagram of step S8;

[0028] Figure 10 This is a schematic diagram of the field-shaped support pier structure.

[0029] In the figure, the lower left bridge deck block 1; the lower right bridge deck block 2; the left truss 3; the right truss 4; the middle truss 5; the upper left bridge deck block 6; the upper right bridge deck block 7; the wire rope 8; the tension and compression rod 9; the support pier 10; the field-shaped support pier 10a; the ground sample line 11; the observation tower 12; and the node 13. DETAILED DESCRIPTION

[0030] In order to more clearly understand the assembling method of the present invention, the method of the present invention is further described in detail below with reference to the accompanying drawings.

[0031] like Figure 1The diagram shows the large-scale structure of the steel beam assembled using this method, consisting of two lower deck blocks, three truss sections, and two upper deck blocks. For ease of description, the two lower deck blocks are defined as the left lower deck block and the right lower deck block, respectively. The three trusses are defined as the left truss, the middle truss, and the right truss. The two upper deck blocks are defined as the left upper deck block and the right upper deck block.

[0032] The specific assembly method is:

[0033] S1. Build the cradle system. Arrange a set of supporting piers at the construction site to form the cradle system. Use this set of supporting piers to support the large steel structure segments to be built, and support each stress point so that it is suspended in the air. On the one hand, it provides operating space for hoisting and assembly, and on the other hand, it facilitates subsequent transfer and transportation. When building the cradle system, arrange the ground sample line and observation tower at the same time. Arrange the ground sample line in both the horizontal and vertical directions. The vertical ground sample line corresponds to the center line position of each truss and the lower bridge deck block. Considering the high height of the truss, arrange the observation tower on the ground sample line corresponding to the center line position of each truss. Figure 2 The five longitudinal ground sample lines shown correspond from left to right to the centerline position of the left truss, the centerline position of the lower left bridge deck block and the upper left bridge deck block, the centerline position of the lower right bridge deck block, the centerline position of the middle truss, the centerline position of the lower right bridge deck block and the upper right bridge deck block, and the centerline position of the right truss. The transverse ground sample lines correspond to the transverse centerline positions of each truss and bridge deck block, and the positioning positions of each truss and bridge deck block during splicing are determined by the above-mentioned ground sample line positions. In order to facilitate observation, observation towers can be set up at each ground sample line. Of course, since there are fewer obstructions at the centerline position of each bridge deck block, measurement and positioning can be directly performed by referring to the ground sample line. Therefore, in this embodiment, observation towers are only arranged at the ground sample lines corresponding to each truss.

[0034] S2. Arrange the intermediate trusses and use the gantry crane to lift the intermediate trusses to the predetermined position of the cradle system. Use a total station or theodolite to measure and locate the intermediate trusses with reference to the observation tower. Use wire ropes or fall chains to assist in adjustment and positioning. After positioning, the intermediate trusses are supported by support piers. To ensure safety and stability and prevent overturning, wire ropes and tension and compression rods are installed on both sides of the intermediate trusses as a lateral support system to secure them. After that, the gantry crane can be unhooked.

[0035] S3. Assemble the left lower bridge deck block. Use the gantry crane to move the left lower bridge deck block to the pre-positioned position on the left side of the middle truss. Use the gantry crane to achieve rough positioning of the left lower bridge deck block. Then keep the left lower bridge deck block in a suspended state. Use the three-way hydraulic jack arranged on the supporting pier to fine-tune the left lower bridge deck block. During the fine-tuning process, use a total station or theodolite to detect the position of the left lower bridge deck block to complete the docking with the middle truss. Then, stack the left lower bridge deck block and the middle truss, and use the supporting pier to support the left lower bridge deck block. Then, a cross steel wire rope is set between the bottom of the left lower bridge deck block and the ground to reinforce the left lower bridge deck block; since the webs of each truss need to be inserted into the bottom of the lower bridge deck block when assembling the trusses with the lower bridge deck block, the joint between the lower bridge deck block and the truss needs to maintain a certain distance from the supporting pier during assembly to avoid the truss web being blocked by the supporting pier and unable to be inserted into the bottom of the lower bridge deck block. In step S2, the position of the middle truss is positioned in advance, and then the left lower bridge deck block can be directly hoisted into place during assembly, and there is no need to adjust the supporting pier to make room for assembly.

[0036] S4. Assemble the lower right bridge deck block. Use the method of step S3 to weld and fix the lower right bridge deck block to the right side of the middle truss.

[0037] S5. Assemble the left truss. Use the gantry crane to lift the left truss to the left side of the lower left bridge deck block. Use a total station or theodolite to measure and locate it with reference to the observation tower. Use wire ropes or fall chains to assist in adjustment and positioning. After positioning, connect it to the lower left bridge deck block with stacking plates and secure it. Set wire ropes and tension and compression rods on both sides of the left truss as a lateral support system to secure it firmly. Since the web of the left truss needs to be inserted into the bottom of the lower left bridge deck block, the support pier on the side of the assembled left truss needs to maintain a certain distance from the lower left bridge deck block to make way for assembly. After the left truss is secured with stacking plates, adjust the support pier to support the left truss and the lower left bridge deck block.

[0038] S6. Assemble the upper left bridge deck block. Use the gantry crane to lift the upper left bridge deck block between the left truss and the top of the middle truss, and connect the upper left bridge deck block with the left truss and the top of the middle truss for stacking and fixing. During assembly, still use the total station or theodolite to refer to the ground sample line for positioning.

[0039] S7, assemble the right truss, using the same method as S5 to fix the right truss mounting plate to the right side of the right lower bridge deck block;

[0040] S8. Assemble the upper right bridge deck block. Use the method in S6 to fix the upper right bridge deck block between the right truss and the middle upper frame.

[0041] Of course, the installation order of the left and right trusses can be interchanged. After assembling the trusses on one side, the bridge deck blocks on that side can be assembled immediately.

[0042] When fine-tuning with three hydraulic jacks, a set of three-way hydraulic jacks is arranged on each set of support piers, and it can be ensured that this set of three-way hydraulic jacks can achieve balanced support for the lower deck blocks. When adjusting other support piers to support the lower deck blocks and trusses, the gaps can be filled with pads, or adjustable height support piers can be used to adjust the height of the support piers to achieve contact with each lower deck block and truss to play a supporting role. When assembling the bridge deck blocks, the steel wire ropes and tension and compression rods on the trusses that affect the assembly of the bridge deck blocks should be appropriately removed. When arranging cross wire ropes at the bottom of the lower deck blocks, the ends of the steel wire ropes are fixed by setting fixed pull rings on the ground.

[0043] For easy transportation, the support piers at the bottom of the left and right side trusses in the tire frame system are as follows: Figure 10 The shown support pier is a combination of a T-shaped support pier and a cylinder hydraulic jack, and the T-shaped support pier is arranged at the left and right truss nodes. After the above assembly is completed and welding and fixing are performed, two sets of beam transport flat cars respectively enter the space below the T-shaped support piers under the left and right trusses, and drop the T-shaped support piers and the entire steel beam large section onto the beam transport flat cars for transportation. Since the support part provides effective support for the left and right truss nodes, and the truss nodes have good rigidity, the entire section can maintain better stability during transportation, avoiding damage to the section due to road conditions and other reasons during transportation.

[0044] After the overall assembly is completed through the above steps, each inspection point is checked for qualification. If qualified, the bridge deck blocks and truss connecting welds are welded. After welding is completed, flaw detection is required and unqualified parts are repaired.

Claims

1. A method for assembling a large segment of a three-main-truss box-truss composite structure steel beam, comprising the following steps: S1. Build a cradle system consisting of a set of support piers, ground sample lines, and measurement towers at the construction site; S2. Arrange the intermediate truss. Using a gantry crane, wire ropes, and fall chains to assist in positioning, the truss is hoisted to the desired position in the cradle system. After fine-tuning its position, it is lowered onto the support piers. Wire ropes and tension and compression rods are installed on both sides of the truss as a lateral support system to secure it. S3. Assemble one side of the lower deck block. Use a gantry crane to hoist the lower deck block to the pre-positioned position on the truss side located in step S2. Use the gantry crane to roughly position it. Then, use the three-way hydraulic jack at the bottom of the lower deck block to fine-tune the position of the lower deck block. Then, use the stacking plate to fix the connection between the lower deck block and the middle truss. Install cross wire ropes between the bottom of the beam of the lower deck block and the ground to reinforce it. S4. Assemble the lower deck blocks on the other side, using the S3 method to secure the lower deck blocks on the other side of the middle truss. S5. Assemble a side truss. Hoist the truss into position using a gantry crane. Using wire ropes and fall chains to assist in positioning, secure the truss to the lower deck block with stacking plates. Install wire ropes and tension and compression rods on the sides of the truss as a lateral support system to secure it securely. S6. Assemble the upper deck block on one side and hoist the upper deck block by the gantry crane to the side between the trusses and the middle trusses assembled in step S5 and to the connection between the code plate code; S7. Assemble the other truss and secure it to the lower deck block using the same method as S5. S8. Assemble the bridge deck blocks on the other side and stack and fix them in the same way as S6; complete the assembly.

2. The method for assembling large sections of steel beams of a three-main-truss box-truss composite structure according to claim 1, characterized in that: The position of each observation tower corresponds to the centerline position of each truss, and the position of each local sample line corresponds to the centerline position of each bridge deck block. During splicing, the position of each bridge deck block and each truss is measured and positioned using a total station or theodolite in combination with the local sample line or observation tower.

3. The method for assembling large sections of steel beams of a three-main-truss box-truss composite structure according to claim 1, characterized in that: After completing the above assembly, the welding of the connecting welds between the truss and the bridge deck blocks is completed after each inspection point is qualified, and finally flaw detection and trimming are carried out.

4. The method for assembling large sections of steel beams of a three-main-truss box-truss composite structure according to claim 1, characterized in that: The support piers for the trusses on both sides of the tire frame system are field-shaped support piers. Cylinder hydraulic jacks are arranged on the lower side of the field-shaped support piers, and the field-shaped support piers are all arranged at the node positions of the trusses.

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