A high-speed railway cable-stayed bridge prefabricated segment beam prestress assembly construction method

Abstract

The application discloses a high-speed railway cable-stayed bridge prefabricated segment beam prestress assembling construction method, relates to the high-speed railway cable-stayed bridge segment beam assembling field, and comprises the following steps: S1, when the concrete segment beam is prefabricated, metal bellows is used to form holes, and a plurality of embedded ducts are formed on the concrete segment beam; S2, hoisting the concrete segment beam to the beam support; S3, the joint of the adjacent concrete segment beam is assembled through the cementation method; the prestressed high-strength threaded steel bar is inserted into the embedded ducts corresponding to the adjacent two concrete segment beams and is tensioned; S4, after the plurality of concrete segment beams are assembled in place, the prestressed steel strand bundle is arranged and tensioned. The application has the effect of improving the structural strength between the adjacent concrete segment beams and the connection stability during stress.

Description

Technical Field

[0001] This invention relates to the field of segmental beam assembly for high-speed railway cable-stayed bridges, and in particular to a prestressed assembly construction method for precast segmental beams of high-speed railway cable-stayed bridges. Background Technology

[0002] In high-speed railway cable-stayed bridge projects, steel box girders or cast-in-place concrete box girders are usually used as segmental beams for bridge erection.

[0003] In bridge construction, the segmental beams are usually hoisted in sections first, then wet joints are constructed between adjacent segmental beams, and finally the steel strand bundles are threaded and the prestressed steel strand bundles are tensioned.

[0004] However, when constructing cable-stayed bridges for high-speed railways, it is difficult to meet the design strength requirements by using only the wet joint method to connect adjacent beam segments.

[0005] Therefore, this application provides a prestressed assembly construction method for precast segmental beams of high-speed railway cable-stayed bridges to improve the connection strength between adjacent segmental beams. Summary of the Invention

[0006] To improve the connection strength between adjacent beam segments, this application provides a prestressed assembly construction method for precast beam segments of high-speed railway cable-stayed bridges.

[0007] This application provides a prestressed assembly construction method for precast segmental beams of high-speed railway cable-stayed bridges, which adopts the following technical solution:

[0008] A prestressed assembly construction method for precast segmental beams of high-speed railway cable-stayed bridges includes the following steps:

[0009] S1. When prefabricating concrete segmental beams, corrugated metal pipes are used to form holes, creating several pre-embedded channels on the concrete segmental beams.

[0010] S2. Hoist the concrete segmental beam to the beam erection support;

[0011] S3. The joints of adjacent concrete segment beams are assembled using adhesive bonding.

[0012] Prestressed high-strength threaded steel bars are inserted into the corresponding pre-embedded ducts of two adjacent concrete segment beams and then tensioned and grouted.

[0013] S4. After several concrete segment beams are assembled and positioned, prestressed steel strand bundles are threaded through them and tensioned and grouted.

[0014] By adopting the above technical solution, a hybrid bundle technology combining prestressed high-strength threaded steel bars tensioned during internal assembly with external temporary splicing and post-tensioning of internal prestressed steel strands is applied. This fully leverages the advantages of prestressed high-strength threaded steel bars, such as quick and convenient construction and low shrinkage, and applies them to the segmental beam assembly process. Meanwhile, prestressed steel strand bundles with high tensile strength and adjustable prestressed cable shape are used for temporary prestressing, adapting to the stress requirements of cable-stayed bridge structures and segmental prefabrication assembly methods. This fully combines the respective advantages of prestressed high-strength threaded steel bars and prestressed steel strand bundles, improving the structural strength and connection stability between adjacent concrete segmental beams under stress.

[0015] Preferably, in step S1, a pre-embedded steel pipe is provided inside the metal corrugated pipe;

[0016] After the prestressed high-strength threaded steel bars are inserted in step S3 and before tensioning, the embedded steel pipe is pulled out.

[0017] By adopting the above technical solution, in the actual installation and construction process, the pre-embedded duct has an inclination and the wall thickness of the metal corrugated pipe is extremely thin. When inserting prestressed high-strength threaded steel bars, the metal corrugated pipe is easily crushed, damaged and blocked. By setting up pre-embedded steel pipes, the problem of large friction between prestressed high-strength threaded steel bars and metal corrugated pipes and difficulty in insertion is eliminated.

[0018] Preferably, the pre-embedded steel pipe in step S1 is exposed on the beam surface of the concrete segmental beam.

[0019] By adopting the above technical solution, the exposed connection of the pre-embedded steel pipe is achieved, which is conducive to the insertion of prestressed high-strength threaded steel bars.

[0020] Preferably, in step S1, when the concrete segmental beam is prefabricated, the corrugated metal pipe and the positioning steel bars used for positioning it are installed together, and the positioning steel bars are used to limit the floating of the corrugated metal pipe during the concrete pouring process.

[0021] By adopting the above technical solution, the positioning reinforcement restricts the floating of the metal corrugated pipe during concrete pouring, ensuring the positioning accuracy of the metal corrugated pipe and preventing it from affecting the subsequent insertion of prestressed high-strength threaded steel bars.

[0022] Preferably, the positioning reinforcement includes a supporting reinforcement and a U-shaped ring positioned on the supporting reinforcement. The supporting reinforcement is connected to the reinforcement skeleton in the concrete segmental beam, and the U-shaped ring abuts against the outside of the metal corrugated pipe.

[0023] By adopting the above technical solution, the supporting steel bars connect the corrugated metal pipe to the steel reinforcement cage, and the U-shape restricts the upward movement of the corrugated metal pipe.

[0024] Preferably, in step S2, when the concrete segment beam is hoisted by the cantilever in the mid-span, a construction platform is fixed on the bridge deck crane for inserting and tensioning the prestressed high-strength threaded steel bars throughout the cross section of the concrete segment beam.

[0025] By adopting the above technical solution, the construction platform can move with the bridge deck crane as the concrete segmental beams are continuously erected, making it convenient for construction personnel to insert and tension prestressed high-strength threaded steel bars on the construction platform.

[0026] Preferably, in step S3, when assembling the concrete segmental beam, rollers are installed on the construction platform and aligned with the pre-embedded duct. The prestressed high-strength threaded steel bars are placed on the rollers and pushed into the pre-embedded duct by the rear end of the prestressed high-strength threaded steel bars.

[0027] By adopting the above technical solution, when inserting prestressed high-strength threaded steel bars, since the prestressed high-strength threaded steel bars are placed on rollers, construction personnel only need to push them from the rear end to easily send them into the pre-embedded ducts, overcoming the defect that the prestressed high-strength threaded steel bars are difficult to lift and insert due to their heavy weight.

[0028] Preferably, the roller is provided with a groove for placing prestressed high-strength threaded steel bars.

[0029] By adopting the above technical solution, the prestressed high-strength threaded steel bars are restricted, limiting their left and right movement and reducing the difficulty of insertion.

[0030] Preferably, in step S3, when assembling adjacent concrete segment beams by adhesive bonding, the adjacent concrete segment beams are interlocked by shear keys and the mating surfaces are bonded with adhesive.

[0031] By adopting the above technical solution, adhesive bonding between adjacent concrete segments was achieved.

[0032] In summary, this application includes at least one of the following beneficial technical effects:

[0033] 1. A hybrid bundle technology combining high-strength prestressed threaded steel bars tensioned during internal assembly with external temporary splicing and post-tensioning of internal prestressed steel strands was applied. This fully leverages the advantages of high-strength prestressed threaded steel bars, such as quick and convenient construction and low shrinkage, and applies them to the segmental beam assembly process. Meanwhile, prestressed steel strand bundles with high tensile strength and adjustable prestressing cable shape are used for temporary prestressing, adapting to the stress requirements of cable-stayed bridge structures and segmental prefabrication assembly methods.

[0034] 2. By fully combining and applying the respective advantages of prestressed high-strength threaded steel bars and prestressed steel strand bundles, the structural strength and connection stability between adjacent concrete segment beams are improved.

[0035] 3. In actual installation and construction, the pre-embedded ducts have an inclination, and the wall thickness of the metal corrugated pipe is extremely thin. When inserting prestressed high-strength threaded steel bars, the metal corrugated pipe is easily crushed, damaged, and blocked. By setting up pre-embedded steel pipes, the problem of large friction between prestressed high-strength threaded steel bars and metal corrugated pipes, making it difficult to insert them, is eliminated. Attached Figure Description

[0036] Figure 1 This is a structural schematic diagram of the concrete segmental beam and the embedded steel pipe in the embodiment shown.

[0037] Figure 2 This is a schematic diagram showing the relationship between the metal corrugated pipe and the prestressed high-strength threaded steel bar in the embodiment.

[0038] Figure 3 This is a schematic diagram showing the fit between the positioning steel bar and the prestressed high-strength threaded steel bar in the embodiment.

[0039] Figure 4 This is a schematic diagram showing the positional relationship of the construction platform in the embodiment.

[0040] Figure 5 This is a schematic diagram showing the relationship between the prestressed high-strength threaded steel bar and the positioning fixture in the embodiment.

[0041] Explanation of reference numerals in the attached figures:

[0042] 1. Concrete segmental beam; 11. Shear key; 2. Corrugated metal pipe; 21. Embedded duct; 3. Embedded steel pipe; 4. Prestressed high-strength threaded steel bar; 5. Connector; 6. Positioning fixture; 61. Fixing frame; 62. Roller; 621. Groove; 71. Tensioning end nut; 72. Tensioning end pad; 8. Positioning steel bar; 81. Supporting steel bar; 82. U-shaped ring; 9. Bridge deck crane; 91. Guide rail; 92. Traction equipment; 10. Construction platform. Detailed Implementation

[0043] The following is in conjunction with the appendix Figure 1-5 This application will be described in further detail.

[0044] This application discloses a method for prestressed assembly of precast segmental beams for high-speed railway cable-stayed bridges, including the following steps:

[0045] S1. Precast concrete segmental beams:

[0046] Combination Figure 1 and Figure 2The short-line method is used to prefabricate the concrete segmental beam 1 at the designated site. When prefabricating the concrete segmental beam 1, the positioning steel bar 8 and the metal corrugated pipe 2 are installed together. By setting up a number of metal corrugated pipes 2, a number of pre-embedded channels 21 are formed after the segmental beam is prefabricated.

[0047] Reference Figure 3 The positioning reinforcement 8 includes a supporting reinforcement 81 connected to the steel reinforcement skeleton in the concrete segmental beam 1 and a U-shaped ring 82 positioned on the supporting reinforcement 81. The U-shaped ring 82 is inverted and abuts against the outside of the metal corrugated pipe 2 to restrict the upward floating of the metal corrugated pipe 2 during the concrete pouring process, so as to ensure the positioning accuracy of the metal corrugated pipe 2.

[0048] Among them, the inner side of the metal corrugated pipe 2 is provided with a pre-embedded steel pipe 3, and one end of the pre-embedded steel pipe 3 is exposed on the beam surface of the concrete segment beam 1 to achieve the exposed connection of the pre-embedded steel pipe 3.

[0049] S2. Lifting of concrete segmental beams:

[0050] In this embodiment, the side span concrete segmental beam 1 is installed using ground-mounted steel pipe piles in conjunction with Bailey beam steel supports. The support foundation uses Φ630x10mm steel pipe piles with a maximum span of 6m. Three piles are arranged on each side of a row, and every two rows of steel pipe piles are connected by a steel pipe connecting system to ensure the strength of the steel pipe piles and the overall stability of the support. A continuous longitudinal double-jointed structure 56a (with 20mm steel plates fully laid on the upper and lower flanges) and Bailey beams are set at the top of the piles. The inner double-jointed structure 56a serves as the track for the tank-wheel beam transport vehicle and as the storage and transportation channel for the concrete segmental beam 1. The outer Bailey beam is used for storing the concrete segmental beam 1. During the assembly of the concrete segmental beam 1, a construction platform 10 is erected on the tank-wheel beam transport vehicle. This construction platform 10 is used to insert and tension the prestressed high-strength threaded steel bars 4 throughout the cross-section of the concrete segmental beam 1.

[0051] Reference Figure 4 The bridge deck crane 9, used for the cantilever erection of the concrete segmental beam 1 in the mid-span, is a tower crane. The construction platform 10, used for inserting and tensioning the prestressed high-strength threaded steel bars 4 that occupy the entire cross-section of the concrete segmental beam 1, is fixed to the tower crane. A traveling guide rail 91 is welded to the main beam of the bridge deck crane 9, and four traveling traction devices 92 are installed on the left and right sides. The construction platform 10 is suspended on the traveling guide rail 91, enabling forward and backward movement. During the prestressing tensioning process, anchor bolts are used to fix the construction platform 10 to the already erected concrete segmental beam 1.

[0052] The concrete segment beam 1 is lifted by a winch and a beam lifting device and then placed into the corresponding position on the beam erection support.

[0053] S3. Assembly of concrete segmental beams:

[0054] S31. Adhesive bonding of adjacent concrete segment beams:

[0055] Adjacent concrete segment beams 1 are assembled by adhesive bonding, with shear keys 11 interlocking between adjacent concrete segment beams 1 and adhesive bonding between mating surfaces.

[0056] S32. Construction of prestressed high-strength threaded steel bars:

[0057] A connector 5 is provided at one end of the pre-embedded duct 21 near the tensioning end of the concrete segmental beam 1. The connector 5 is used to connect two adjacent prestressed high-strength threaded steel bars 4.

[0058] A positioning fixture 6 is installed on the construction platform 10 used for assembling the concrete segmental beam 1. The positioning fixture 6 is used to assist in the insertion of prestressed high-strength threaded steel bars 4.

[0059] The positioning fixture 6 includes a fixed frame 61 fixed on the construction platform 10 and multiple rollers 62 provided on the fixed frame. The multiple rollers 62 are arranged at intervals along the insertion direction of the prestressed high-strength threaded steel bars 4. The outer circumferential surface of the rollers 62 is provided with grooves for placing the prestressed high-strength threaded steel bars 4, and the grooves are aligned with the pre-embedded holes 21 in the concrete segmental beam 1.

[0060] When constructing the prestressed high-strength threaded steel bar 4, the prestressed high-strength threaded steel bar 4 is suspended and placed in the groove on the roller 62. The construction personnel push the prestressed high-strength threaded steel bar 4 from the rear end and gently send it into the pre-embedded duct 21. After the prestressed high-strength threaded steel bar 4 is connected to the previous prestressed high-strength threaded steel bar 4 through the connector 5, the pre-embedded steel pipe 3 is pulled out. The tensioning end nut and tensioning end pad are installed at the tensioning end of the prestressed high-strength threaded steel bar 4, and the prestressed high-strength threaded steel bar 4 is tensioned by the tensioning equipment. Finally, grouting is performed.

[0061] S4. Tensioning and grouting of prestressed steel strand bundles:

[0062] After several beam segments are assembled and positioned, prestressed steel strand bundles are threaded through them and tensioned and grouted.

[0063] The prestressed assembly construction method for precast segmental beams of high-speed railway cable-stayed bridges disclosed in this application embodiment applies a hybrid bundle technology that combines the tensioning of prestressed high-strength threaded steel bars 4 during the internal assembly process with temporary splicing of external prestressed steel strands and post-tensioning of internal prestressed steel strands. This fully leverages the advantages of prestressed high-strength threaded steel bars 4, such as quick and convenient construction and low shrinkage, and applies them to the segmental beam assembly construction process. Meanwhile, prestressed steel strand bundles with high tensile strength and adjustable prestressed cable shape are used for temporary prestressing, adapting to the stress requirements of cable-stayed bridge structures and segmental precast assembly methods. This method fully combines and applies the respective advantages of prestressed high-strength threaded steel bars 4 and prestressed steel strand bundles, improving the structural strength and connection stability between adjacent concrete segmental beams 1 under stress.

[0064] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A high-speed railway cable-stayed bridge precast segmental beam prestress assembly construction method, characterized in that, It comprises the following steps: S1, when the concrete segmental beam (1) is prefabricated, a metal bellows (2) is used to form holes, and a plurality of embedded channels are formed on the concrete segmental beam (1); a pre-embedded steel pipe (3) is arranged inside the metal bellows (2); the pre-embedded steel pipe (3) is exposed on the beam surface of the concrete segmental beam (1); the metal bellows (2) and the positioning steel bars (8) used for positioning the same are installed together, and the positioning steel bars (8) are used to limit the floating of the metal bellows (2) during the concrete pouring process; S2, hoist the concrete segmental beam (1) to the beam supporting frame; S3, the joints of adjacent concrete segmental beams (1) are assembled by the glueing method; the shear keys (11) are used to engage between the adjacent concrete segmental beams (1), and the matching surfaces are bonded by the adhesive; The pre-stressed high-strength threaded steel bars (4) are inserted into the corresponding embedded channels of the adjacent two concrete segmental beams (1) and are tensioned and grouted; When the concrete segmental beam (1) is assembled, the rollers (62) are installed on the construction platform (10) and are aligned with the embedded channels, the pre-stressed high-strength threaded steel bars (4) are placed on the rollers (62), and the pre-stressed high-strength threaded steel bars (4) are pushed to be sent into the embedded channels at the rear ends of the same; the rollers (62) are provided with grooves (621) for placing the pre-stressed high-strength threaded steel bars (4); after the insertion of the pre-stressed high-strength threaded steel bars (4) is completed, the pre-embedded steel pipes (3) are pulled out before tensioning; S4, after a plurality of concrete segmental beams (1) are assembled and positioned, the pre-stressed steel strand bundles are arranged and tensioned and grouted.

2. The precast segmental beam prestress assembly construction method of a high-speed railway cable-stayed bridge according to claim 1, characterized in that: The positioning steel bars (8) comprise supporting steel bars (81) and U-shaped rings (82) positioned on the supporting steel bars (81), the supporting steel bars (81) are connected with the steel reinforcement framework in the concrete segmental beam (1), and the U-shaped rings (82) abut against the metal bellows (2) outside.

3. The precast segmental beam prestress assembly construction method of a high-speed railway cable-stayed bridge according to claim 1, characterized in that: In step S2, when the concrete segmental beam is hoisted by the mid-span cantilever, the construction platform (10) for inserting and tensioning the pre-stressed high-strength threaded steel bars (4) of the entire cross section of the concrete segmental beam (1) is fixed on the bridge crane.

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