Construction method for large-span bracket of middle cross beam of cable-stayed suspension bridge girder main tower

Abstract

The invention provides a cable-stayed suspension bridge main tower middle cross beam large-span bracket construction method which comprises the steps that cross braces are arranged in the main tower block construction process, and after at least two layers of cross braces are arranged, a support is erected; the support comprises a large-span bracket and a pouring formwork arranged on the large-span bracket. A first layer of concrete of the middle cross beam is poured based on the pouring formwork, and after the first layer of concrete is poured, the prestressed tendons of the poured part are tensioned; and a second layer of concrete of the middle cross beam is poured based on the pouring formwork, and after the second layer of concrete is poured, all prestressed tendons of the middle cross beam are tensioned. According to the construction method for the large-span bracket of the middle cross beam of the cable-stayed suspension bridge girder main body, the construction difficulty can be greatly lowered by using the light large-span bracket, meanwhile, the middle cross beam is poured twice, the construction method can be better suitable for construction of a cable-stayed-suspension cooperative system bridge, and the construction method is safer and more efficient.

Description

Technical Field

[0001] The invention belongs to the technical field of bridge construction, and in particular relates to a construction method for a large-span bracket of a cross beam in a main tower of a cable-stayed suspension bridge. Background Art

[0002] A cable-stayed bridge is a combined system bridge in which the tower is under compression, the cable is under tension, and the beam is under bending. This system can effectively reduce the height of the building structure, reduce weight, and save materials. Modern cable-stayed bridges occupy an important position in modern bridge structures with their good structural performance, large span capacity, reasonable economic indicators, and beautiful architectural shapes. Due to the progress of modern structural theory, high-strength materials, computer technology, and construction methods, cable-stayed bridges have developed rapidly.

[0003] In the construction of cable-stayed bridges, the construction of crossbeams is usually inseparable from the bearing capacity of brackets or supports. For cable-stayed-cable cooperative bridges, the main tower structure is usually more complex, so the construction difficulty of the main tower crossbeam is relatively large. In order to ensure the convenience and safety of construction, large-span brackets are often required. However, the existing large-span bracket design has problems with bearing capacity and structural quality balance, and is not conducive to on-site construction, which increases the difficulty of crossbeam construction and affects the construction efficiency of the crossbeam. Summary of the invention

[0004] In view of this, the present invention aims to propose a method for constructing a large-span bracket for a cross beam in a main tower of a cable-stayed suspension bridge, so as to solve the problems existing in the existing large-span bracket design and the problem of affecting the construction efficiency.

[0005] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0006] A method for constructing a large-span bracket for a cross beam in a main tower of a cable-stayed suspension bridge, comprising:

[0007] During the construction of the main tower in blocks, horizontal braces are arranged, and after at least two layers of horizontal braces are arranged, brackets are erected; wherein the brackets include large-span brackets and casting templates arranged on the large-span brackets;

[0008] Cast the first layer of concrete of the middle beam based on the casting formwork, and after the first layer of concrete casting is completed, tension the prestressed tendons of the cast part;

[0009] The second layer of concrete of the middle cross beam is poured based on the casting formwork, and after the second layer of concrete pouring is completed, all the prestressed tendons of the middle cross beam are tensioned.

[0010] Furthermore, the large-span bracket is arranged on the main tower block via a supporting assembly at the bottom, and is arranged on the main tower block via a connecting assembly at the top.

[0011] Furthermore, the large-span bracket includes a plurality of main trusses arranged at intervals along the length direction of the bridge, and the main trusses are connected by a connecting system; the supporting assembly includes corbels arranged on the main tower blocks corresponding to the main trusses, and the corbels are connected by a transverse bottom beam, and each main truss is connected to the transverse bottom beam.

[0012] Furthermore, the density of the main trusses at the edges of the middle cross beam is greater than the density of the main trusses in the middle of the middle cross beam.

[0013] Furthermore, the main truss includes a support beam and a support frame. The length direction of the support beam is the same as the length direction of the middle cross beam, and two support frames are correspondingly provided at both ends of the support beam.

[0014] Furthermore, the support frame includes a long support rod, a short support rod, a long diagonal support rod and a short diagonal support rod; the lower end of the long support rod is connected to the horizontal bottom beam, and the upper end is connected to the end of the support beam; the oblique downward end of the long diagonal support rod is connected to the lower end of the long support rod, and the other end is connected to the middle of the support beam; the oblique downward end of the short diagonal support rod is connected to the middle of the long diagonal support rod, and the other end is connected to the end of the support beam; the short support rod is vertically arranged, the lower end of the short support rod is connected to the middle of the long diagonal support rod, and the upper end is connected to the support beam.

[0015] Furthermore, the connection system is arranged on the long support rod and the long diagonal support rod.

[0016] Furthermore, the casting formwork includes an inner membrane support and a frame, a plurality of Bailey plates are arranged at intervals along the length direction of the bridge below the frame, and two outer membrane supports that can cooperate with the inner membrane support are correspondingly arranged on the left and right sides of the frame. The Bailey plates are connected to the large-span bracket through a unloading block at one end and connected to the frame at the other end.

[0017] Furthermore, the unloading blocks are provided in plurality corresponding to the connection between the long support rod and the support beam, the connection between the short support rod and the support beam, the connection between the long diagonal support rod and the support beam, and the connection between the short diagonal support rod and the support beam.

[0018] Compared with the prior art, the method for constructing a large-span bracket for a cross beam in a main tower of a cable-stayed suspension bridge according to the present invention has the following advantages:

[0019] (1) The present invention discloses a method for constructing a large-span bracket for the middle cross beam of a main tower of a cable-stayed suspension bridge. The method can greatly reduce the difficulty of construction by using a light large-span bracket. At the same time, the casting of the middle cross beam is divided into two steps. After the casting of the lower cross beam is completed, the prestressed tendons of the cast part of the cross beam are tensioned to bear most of the load when the upper concrete is poured. A light large-span bracket is arranged under the middle cross beam as a support for the pouring of the lower concrete of the middle cross beam and to bear a small part of the load when the upper concrete is poured. The method can be better suitable for the construction of a cable-stayed-suspension cooperative system bridge, and is a safer and more efficient bracket construction method.

[0020] (2) The method for constructing a large-span bracket for the middle cross beam of a main tower of a cable-stayed suspension bridge described in the present invention has good load-bearing capacity and wind resistance by using a lightweight large-span bracket as the supporting structure of the middle cross beam of the main tower, and can enhance the overall stability of the main tower, thereby ensuring the safety of the cable-stayed-suspension cooperative system bridge when bearing large-span loads. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0022] Figure 1 A schematic diagram of a process for constructing a large-span bracket of a main tower of a cable-stayed suspension bridge according to an embodiment of the present invention;

[0023] Figure 2 It is a structural schematic diagram of the main tower of the bridge in a method for constructing a large-span bracket of a cross beam in a main tower of a cable-stayed suspension bridge according to an embodiment of the present invention;

[0024] Figure 3 It is a structural schematic diagram of the middle cross beam in the method for constructing a large-span bracket of the middle cross beam of the main tower of a cable-stayed suspension bridge according to an embodiment of the present invention;

[0025] Figure 4 It is a structural schematic diagram of the connection between the support frame and the support beam in a method for constructing a large-span bracket for a cross beam in a main tower of a cable-stayed suspension bridge described in an embodiment of the present invention.

[0026] Description of reference numerals:

[0027] 1. Large span bracket; 2. Unloading block; 3. Inner membrane support; 4. Horizontal bottom beam; 5. Corbel; 6. Frame; 7. Connection system; 8. Main truss; 9. Bailey plate; 10. Main tower block; 11. Middle cross beam; 12. Outer membrane support; 13. Long support rod; 14. Short support rod; 15. Long diagonal support rod; 16. Short diagonal support rod; 17. Connection assembly; 18. Support beam. DETAILED DESCRIPTION

[0028] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0029] A method for constructing a large-span bracket for a cross beam in a main tower of a cable-stayed suspension bridge, such as Figures 1 to 4 As shown, this method specifically includes the following steps:

[0030] Step 101: Arrange cross braces during the construction of the main tower block 10, and after arranging at least two layers of cross braces, erect the support; wherein the support comprises a large-span bracket 1 and a casting template arranged on the large-span bracket 1. The cross braces are arranged below the bracket (not shown in the figure), and both ends of the cross braces can be connected to the main tower block 10 through embedded reinforcement.

[0031] Step 102: Cast the first layer of concrete of the middle beam 11 based on the casting template, and after the first layer of concrete casting is completed, tension the prestressed tendons of the cast part.

[0032] Step 103 , pouring a second layer of concrete for the middle cross beam 11 based on the pouring formwork, and after the pouring of the second layer of concrete is completed, tensioning all prestressed tendons of the middle cross beam 11 .

[0033] For the middle cross beam 11 of the main tower of the cable-stayed-cable cooperative system bridge, the construction is relatively difficult due to the complex structure of the main tower. The method described in this embodiment can greatly reduce the construction difficulty by using a light large-span bracket 1. At the same time, by casting the middle cross beam 11 in two times, after the casting of the lower cross beam is completed, the prestressed tendons of the cast part of the cross beam are tensioned to bear 75% of the load when pouring the upper concrete. By arranging a light large-span bracket 1 under the middle cross beam 11 as a support for the pouring of the lower concrete of the middle cross beam 11 and bearing 25% of the load when pouring the upper concrete, it can be better suitable for the construction of the cable-stayed-cable cooperative system bridge, which is a safer and more efficient support construction method.

[0034] In actual application, technicians in this field can arrange cross braces during the construction of the main tower block 10. After two layers of cross braces are arranged, the erection of the bracket can be started. Specifically, technicians in this field can adjust the diagonal braces and support rods on the bracket according to actual needs, and the installation of each rod needs to maintain the correct angle and length to provide sufficient support and stability. Then install the transverse support beam 18 to increase the overall stiffness and stability of the bracket. After the erection of the bracket is completed, start pouring the first layer of concrete for the middle beam 11. After the first layer of beams is poured, tension the prestressed tendons of the poured part of the beam. Finally, pour the second layer of concrete for the middle beam 11, and tension the prestressed tendons of all beams.

[0035] Preferably, the long-span bracket 1 is arranged on the main tower block 10 through a supporting assembly at the bottom, and is arranged on the main tower block 10 through a connecting assembly 17 at the top. Exemplarily, the connecting assembly 17 may adopt embedded reinforcement, and the long-span bracket 1 may be connected to the main tower block 10 through the embedded reinforcement to achieve a stable connection between the long-span bracket 1 and the main tower block 10. Those skilled in the art may also select other suitable connecting assemblies 17 to achieve connection and fixation according to actual needs, which will not be described in detail here. In addition, the connection method between the long-span bracket 1 and other components and the internal components thereof may also adopt the existing commonly used connection method, which will not be described in detail here.

[0036] In actual application, the long-span bracket 1 includes a plurality of main trusses 8 arranged at intervals along the length direction of the bridge, and each main truss 8 is connected by a connection system 7; the support assembly includes a corbel 5 arranged on the main tower block 10 corresponding to the main trusses 8, and each corbel 5 is connected by a transverse bottom beam 4, and each main truss 8 is connected to the transverse bottom beam 4. By arranging a plurality of main trusses 8 and corbels 5 at intervals, it is beneficial to disperse the force. At the same time, by connecting a plurality of corbels 5 through the transverse bottom beam 4, the structural strength and stability of the support assembly can also be ensured, and it can be ensured that the support assembly can continuously and stably support and fix the main trusses 8.

[0037] In addition, the density of the main trusses 8 at the edge of the middle cross beam 11 is greater than the density of the main trusses 8 in the middle of the middle cross beam 11. By adopting the above design, the mass of the long-span bracket 1 can be reduced while ensuring the overall structural strength of the long-span bracket 1, thereby achieving a lightweight design.

[0038] Preferably, the main truss 8 includes a support beam 18 and a support frame, wherein the length direction of the support beam 18 is the same as the length direction of the middle cross beam 11, and two support frames are correspondingly provided at both ends of the support beam 18. Exemplarily, both the support beam 18 and the support frame can be made of lightweight materials such as steel sections to further reduce the mass and cost of the long-span bracket 1. By providing two support frames correspondingly at both ends of the support beam 18, the two support frames and the support beam 18 can form a stable arch support structure, which improves the structural strength and stability of the single main truss 8 while ensuring a lightweight design.

[0039] In actual application, the support frame includes a long support rod 13, a short support rod 14, a long diagonal support rod 15, and a short diagonal support rod 16. The lower end of the long support rod 13 is connected to the horizontal bottom beam 4, and the upper end is connected to the end of the support beam 18; the long diagonal support rod 15 is connected to the lower end of the long support rod 13 at one end, and the other end is connected to the middle of the support beam 18; the short diagonal support rod 16 is connected to the middle of the long diagonal support rod 15 at one end, and the other end is connected to the end of the support beam 18; the short support rod 14 is vertically arranged, and the lower end of the short support rod 14 is connected to the middle of the long diagonal support rod 15, and the upper end is connected to the support beam 18. By adopting the support frame designed as above, the structural strength and stability are greatly improved without significantly increasing the weight of the structure.

[0040] Preferably, the connection system 7 is arranged on the long support rods 13 and the long diagonal support rods 15. Exemplarily, the connection system 7 can adopt a truss or Bailey plate 9, and by connecting the long support rods 13 and the long diagonal support rods 15 of each main truss 8 by the connection system 7, it is beneficial to further improve the overall structural strength of the long-span bracket 1.

[0041] In actual application, each long support rod 13 can be connected by a connection system 7, and each long diagonal support rod 15 can be connected by two connection systems 7 arranged at intervals, wherein the two connection systems 7 are arranged corresponding to the short diagonal support rods 16 or the two sides of the short support rods 14. By using the three connection systems 7 arranged as above to connect each main truss 8, a multi-point connection can be formed between each main truss 8, and the main truss 8 can not only maintain stability under the connection of the transverse bottom beam 4, but also maintain a high structural strength under the connection of the connection system 7, thereby realizing a lightweight design of a large-span bracket 1.

[0042] Preferably, the casting template includes an inner membrane support 3 and a bent frame 6, a plurality of Bailey plates 9 are arranged at intervals along the length direction of the bridge below the bent frame 6, two outer membrane supports 12 that can cooperate with the inner membrane support 3 are correspondingly arranged on the left and right sides of the bent frame 6, and one end of each Bailey plate 9 is connected to the large-span bracket 1 through a discharge block 2, and the other end is connected to the bent frame 6. Exemplarily, the inner membrane support 3, the outer membrane support 12 and the bent frame 6 can cooperate to form a casting template for casting the middle cross beam 11.

[0043] In actual application, by arranging a plurality of Bailey plates 9 at intervals below the bent frame 6, it is helpful to improve the structural strength and stability of the bent frame 6. By using the unloading block 2 to connect the Bailey plates 9 and the support beam 18 on the main truss 8, it is helpful to reduce the construction difficulty and improve the construction efficiency.

[0044] Preferably, a plurality of unloading blocks 2 are provided corresponding to the connection between the long support rod 13 and the support beam 18, the connection between the short support rod 14 and the support beam 18, the connection between the long diagonal support rod 15 and the support beam 18, and the connection between the short diagonal support rod 16 and the support beam 18. Since the structural strength of the above-mentioned connection is higher, by providing the unloading blocks 2 corresponding to the above-mentioned positions, it is helpful to ensure the supporting effect of the long-span bracket 1 on the casting formwork.

[0045] In actual application, the large-span bracket 1 described in this embodiment can optimize the force distribution in the bridge structure by adopting a more reasonably designed shape and size, so that the load is more evenly transferred to the main tower block 10 and the foundation, reducing local stress and deformation. At the same time, this lightweight large-span bracket 1 has the characteristics of light weight and small mass, and can also be made of lightweight materials, which is beneficial to reducing the load on the main tower and bridge structure and improving the overall stability and safety. In addition, this lightweight large-span bracket 1 adopts a modular design, which is easy to install and disassemble, and can quickly complete the erection of the bracket. Moreover, its lightweight characteristics also reduce the demand for manpower and mechanical equipment during the construction process, which is beneficial to improving construction efficiency.

[0046] The construction method described in this embodiment, by using a light large-span bracket as the supporting structure of the cross beam in the main tower, has good load-bearing capacity and wind resistance, can enhance the overall stability of the main tower, thereby ensuring the safety of the cable-stayed-suspension cooperative system bridge when bearing large-span loads.

[0047] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A method for constructing a large-span bracket for a cross beam in a main tower of a cable-stayed suspension bridge, characterized in that: include: During the construction of the main tower block (10), horizontal braces are arranged, and after at least two layers of horizontal braces are arranged, brackets are erected; wherein the brackets include (1) and a casting template arranged on the large-span bracket (1); Casting the first layer of concrete of the middle cross beam (11) based on the casting template, and after the first layer of concrete casting is completed, tensioning the prestressed tendons of the cast part; The second layer of concrete of the middle cross beam (11) is poured based on the pouring formwork, and after the second layer of concrete pouring is completed, all the prestressed tendons of the middle cross beam (11) are tensioned.

2. The method according to claim 1, characterized in that: The large-span bracket (1) is arranged on the main tower block (10) at the bottom through a supporting assembly, and is arranged on the main tower block (10) at the top through a connecting assembly (17).

3. The method according to claim 2, characterized in that: The large-span bracket (1) comprises a plurality of main trusses (8) arranged at intervals along the length direction of the bridge, and the main trusses (8) are connected to each other via a connection system (7); the support assembly comprises a bracket (5) arranged on the main tower block (10) corresponding to the main trusses (8), and the brackets (5) are connected to each other via a transverse bottom beam (4), and each main truss (8) is connected to the transverse bottom beam (4).

4. The method according to claim 3, characterized in that: The density of the main trusses (8) at the edges of the middle cross beam (11) is greater than the density of the main trusses (8) in the middle of the middle cross beam (11).

5. The method according to claim 3 or 4, characterized in that: The main truss (8) comprises a support beam (18) and a support frame, the length direction of the support beam (18) is the same as the length direction of the middle cross beam (11), and two support frames are correspondingly provided at both ends of the support beam (18).

6. The method according to claim 5, characterized in that: The support frame comprises a long support rod (13), a short support rod (14), a long oblique support rod (15) and a short oblique support rod (16); the lower end of the long support rod (13) is connected to the horizontal bottom beam (4), and the upper end is connected to the end of the support beam (18); the oblique downward end of the long oblique support rod (15) is connected to the lower end of the long support rod (13), and the other end is connected to the middle of the support beam (18); the oblique downward end of the short oblique support rod (16) is connected to the middle of the long oblique support rod (15), and the other end is connected to the end of the support beam (18); the short support rod (14) is vertically arranged, the lower end of the short support rod (14) is connected to the middle of the long oblique support rod (15), and the upper end is connected to the support beam (18).

7. The method according to claim 6, characterized in that: The connection system (7) is arranged on the long support rod (13) and the long diagonal support rod (15).

8. The method according to claim 6 or 7, characterized in that: The casting formwork comprises an inner membrane support (3) and a bent frame (6), a plurality of Bailey plates (9) are arranged at intervals along the length direction of the bridge below the bent frame (6), two outer membrane supports (12) that can cooperate with the inner membrane support (3) are correspondingly arranged on the left and right sides of the bent frame (6), and one end of each Bailey plate (9) is connected to the large-span bracket (1) through a discharge block (2), and the other end is connected to the bent frame (6).

9. The method according to claim 8, characterized in that: The unloading blocks (2) are provided in plurality corresponding to the connection between the long support rod (13) and the support beam (18), the connection between the short support rod (14) and the support beam (18), the connection between the long diagonal support rod (15) and the support beam (18), and the connection between the short diagonal support rod (16) and the support beam (18).

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