Construction method for horizontal beam under tower of space four-limb a type cable-stayed bridge

Abstract

The application discloses a construction method for a lower cross beam of a space four-limb A type cable-stayed bridge tower, relates to the technical field of tower construction of a long-span cable-stayed bridge, and divides the lower cross beam into five pouring blocks, the lower cross beam is located at a set tower column segment height position, the five pouring blocks are divided into two layers, a first pouring area, a second pouring area and a third pouring area are located at a lower layer, the first pouring area is located at a middle part of the cross beam and a middle beam area, the second pouring area is located at one side of the middle part of the cross beam and a same side edge beam area, the third pouring area is located at the other side of the middle part of the cross beam and the same side edge beam area, a fourth pouring area and a fifth pouring area are located at an upper layer, the fifth pouring area is located above the second pouring area and partially extends into the first pouring area, the fourth pouring area is located above the remaining part of the first pouring area and above the third pouring area, and pouring construction is sequentially carried out, so that the waiting time existing between the pouring areas is reduced, and the construction efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of construction technology for long-span cable-stayed bridge towers, specifically to a construction method for the lower crossbeam of a spatial four-limb A-type cable-stayed bridge tower. Background Technology

[0002] The rapid development of road transportation has led to a continuous increase in the number of cable-stayed bridges for both highways and railways, among which long-span cable-stayed bridges for both highways and railways are widely used in bridge construction. As the span of long-span cable-stayed bridges for both highways and railways continues to increase, the construction height of the main towers is also increasing, which places higher demands on construction, especially the construction of the crossbeams under the main towers, which have complex spatial structures.

[0003] In existing technologies, the construction scheme for the lower crossbeam of the main tower, which has a large structural volume, generally adopts a segmented casting method. Since the existing method divides the lower crossbeam into two pre-cast sections, the construction of the internal blocks of the pre-cast sections may take a long time due to the construction sequence, which may prolong the project time and reduce construction efficiency. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a construction method for the lower crossbeam of a spatial four-limb A-type cable-stayed bridge tower. This method solves the problem that existing construction schemes for the lower crossbeam of a large main tower typically employ a sectional casting method. However, existing methods divide the lower crossbeam into two pre-cast sections, which may lead to prolonged waiting times during construction within the pre-cast sections due to construction sequence issues, thus extending the project time and reducing construction efficiency.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] This application provides a construction method for the lower crossbeam of a spatial four-limb A-type cable-stayed bridge tower, which includes the following steps:

[0007] The lower crossbeam is divided into five casting blocks. The lower crossbeam is located at a set tower column segment height. The five casting blocks are divided into two layers. The first casting area, the second casting area, and the third casting area are located in the lower layer. The first casting area is located in the middle of the crossbeam and the central tie beam area. The second casting area is located on one side of the middle of the crossbeam and the same side tie beam area. The third casting area is located on the other side of the middle of the crossbeam and the same side tie beam area. The fourth casting area and the fifth casting area are located in the upper layer. The fifth casting area is located above the second casting area and partially extends above the first casting area. The fourth casting area is located above the remaining part above the first casting area and above the third casting area.

[0008] During the construction of the segment below the set tower segment height, the reinforcement binding and concrete pouring of the first pouring area are carried out;

[0009] After the reinforcement binding of the tower column segment corresponding to the lower layer of the lower beam is completed, the reinforcement binding and pouring construction of the second and third pouring areas are carried out in stages.

[0010] When binding the reinforcing bars of the tower column segment corresponding to the upper layer of the lower crossbeam, the reinforcing bars of the fourth and fifth pouring areas are bound, and the pouring construction of the fourth and fifth pouring areas is completed in stages.

[0011] Based on the above technical solutions,

[0012] In some alternative solutions, after dividing the lower crossbeam into five pouring blocks, the design of the lower crossbeam construction support formwork system is also included, comprising the following steps:

[0013] A construction support calculation model for the lower crossbeam was established using finite element method software.

[0014] The calculation model of the construction support was modeled and analyzed to verify its stress safety.

[0015] Based on the safety calculation results, optimization and adjustments were made to obtain the construction support formwork system for the lower crossbeam.

[0016] In some alternative solutions, the verification of its stress safety includes:

[0017] When pouring the lower block, the weight borne by the construction support of the lower crossbeam is the actual weight of the concrete in the lower block.

[0018] When pouring the upper block, the lower crossbeam construction support bears 45% of the concrete load of the upper block, depending on the hardening degree of the lower block that has already been poured.

[0019] The ultimate load that the construction support for the lower crossbeam needs to withstand during construction is determined.

[0020] In some alternative solutions, when verifying the stress safety of the formwork system, it is also necessary to verify the stress safety of the formwork system under the following working conditions:

[0021] Verify the stress safety of the construction support of the lower crossbeam under wind load during sectional pouring and full load;

[0022] The stress safety of the first pouring area after concrete pouring was verified when the Bailey beams on both sides of the construction support of the lower crossbeam were not installed and the construction support was under no load and no wind load.

[0023] In some alternative solutions, the process of binding the reinforcing bars and pouring concrete in the first pouring area during the construction of the segment below the set tower segment height includes:

[0024] During the construction of the second segment below the set tower segment height, the reinforcement binding of the first pouring area is carried out;

[0025] During the construction of the first segment below the height of the tower column segment set on the lower crossbeam, concrete is poured in the first pouring area.

[0026] In some alternative solutions, before the reinforcement binding of the first pouring area is carried out during the construction of the second segment below the tower column segment height position of the lower crossbeam, the installation of part of the support of the lower crossbeam is also included during the construction of the tower column foundation segment.

[0027] In some alternative solutions, before the reinforcement binding of the tower column segment corresponding to the lower beam's lower layer casting block is completed, and before the reinforcement binding and casting of the second and third casting areas are carried out in stages, the installation of the lower beam support bracket is also included to complete the installation of the remaining support.

[0028] In some alternative designs, if the thickness of the lower crossbeam is 8m, the lower layer is designed to be 5.5m and the upper layer to be 2.5m.

[0029] In some alternative solutions, the concrete pouring process follows the principle of bottom-up pouring, first the bottom slab, then the web, and finally the top slab, with layered pouring and symmetrical material distribution.

[0030] In some alternative solutions, during the construction of the lower crossbeam, the temperature of the concrete construction steps is intelligently monitored, and the temperature of the relevant cooling water is intelligently adjusted according to the temperature difference.

[0031] Compared with the prior art, the advantages of the present invention are as follows:

[0032] By dividing the lower crossbeam into five pouring blocks, located at a predetermined tower segment height, and dividing the five pouring blocks into two layers, the first, second, and third pouring areas are located on the lower layer. The first pouring area is located in the middle of the crossbeam and the central tie beam area; the second pouring area is located on one side of the middle of the crossbeam and the tie beam area on the same side; the third pouring area is located on the other side of the middle of the crossbeam and the tie beam area on the same side; and the fourth and fifth pouring areas are located on the upper layer. The fifth pouring area is located above the second pouring area and partially extends above the first pouring area; the fourth pouring area is located above the remaining part of the first pouring area and above the third pouring area. Pouring is carried out sequentially, reducing waiting time between pouring areas, improving construction efficiency, and solving the problem of existing construction schemes for large-scale main tower lower crossbeams, which generally use a sectional pouring method. Because the existing scheme divides the lower crossbeam into two pre-pouring sections, the construction of the blocks within the pre-pouring sections may involve long waiting times due to construction sequence, extending the project time and reducing construction efficiency. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the tower column segment in an embodiment of the construction method for the lower crossbeam of a spatial four-limb A-type cable-stayed bridge tower according to the present invention;

[0035] Figure 2 This is a schematic diagram of the lower crossbeam structure in an embodiment of a construction method for a spatial four-limb A-type cable-stayed bridge tower according to the present invention.

[0036] Figure 3 This is a schematic diagram of the vertical cross-sectional structure of the lower crossbeam in an embodiment of a construction method for a spatial four-limb A-type cable-stayed bridge tower according to the present invention.

[0037] Figure 4 This is a schematic diagram of the transverse cross-section structure of half of the lower crossbeam in an embodiment of the construction method for the lower crossbeam of a spatial four-limb A-type cable-stayed bridge tower according to the present invention;

[0038] Figure 5 This is a schematic diagram of the cooling water pipe distribution structure in the ninth segment of the tower column in an embodiment of a construction method for the lower crossbeam of a spatial four-limb A-type cable-stayed bridge tower according to the present invention;

[0039] Figure 6This is a schematic diagram of the cooling water pipe distribution structure in the tenth segment of the tower column in an embodiment of a construction method for the lower crossbeam of a spatial four-limb A-type cable-stayed bridge tower according to the present invention.

[0040] In the diagram: 1. First pouring area; 2. Second pouring area; 3. Third pouring area; 4. Fourth pouring area; 5. Fifth pouring area; 6. Lower crossbeam; 7. Seventh segment of tower column; 8. Eighth segment of tower column; 9. Ninth segment of tower column; 10. Tenth segment of tower column; 11. Foundation segment of tower column; 12. Cooling water pipe. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0042] The following describes in further detail an embodiment of the construction method for the lower crossbeam of a spatial four-limb A-type cable-stayed bridge tower according to the present invention, with reference to the accompanying drawings.

[0043] like Figures 1-6 As shown, this application provides a construction method for the lower crossbeam of a spatial four-limb A-type cable-stayed bridge tower, which includes the following steps:

[0044] S0: If the thickness of the lower crossbeam 6 is 8m, the lower layer will be designed to be 5.5m and the upper layer to be 2.5m.

[0045] In this embodiment, the lower layer is designed to be 5.5m high and the upper layer to be 2.5m high. Finite element analysis revealed that as the lower layer's pouring height increases, the stress on the construction support of the lower crossbeam 6 gradually increases, but all stress requirements are met. Meanwhile, the tensile stress of crossbeam A, the middle tie beam B, and the side tie beam C decreases with increasing lower layer pouring height, posing a risk of concrete cracking. Therefore, considering the prestressed arrangement, cross-sectional structure, and formwork arrangement of the lower crossbeam, this scheme is adopted. In this scheme, the concrete crossbeam itself has no tensile stress during construction, the maximum tensile stress of the tie beam is 0.6MPa, the stress meets the specifications, and the risk of cracking is relatively low.

[0046] S1: Divide the lower crossbeam 6 into five casting blocks. The lower crossbeam 6 is located at the set tower column segment height. The five casting blocks are divided into two layers. The first casting area 1, the second casting area 2, and the third casting area 3 are located in the lower layer. The first casting area 1 is located in the middle of the crossbeam and the middle tie beam area. The second casting area 2 is located on one side of the middle of the crossbeam and the same side tie beam area. The third casting area 3 is located on the other side of the middle of the crossbeam and the same side tie beam area. The fourth casting area 4 and the fifth casting area 5 are located in the upper layer. The fifth casting area 5 is located above the second casting area 2 and partially extends above the first casting area 1. The fourth casting area 4 is located above the remaining part of the first casting area 1 and above the third casting area 3.

[0047] In some optional embodiments, after dividing the lower crossbeam 6 into five casting blocks, the method further includes designing a construction support formwork system for the lower crossbeam 6, including the following steps:

[0048] S101: Use finite element analysis software to establish a construction support calculation model for the lower crossbeam 6.

[0049] S102: Model and analyze the construction support calculation model and verify its stress safety.

[0050] S103: Based on the safety calculation results, optimization and adjustment are carried out to obtain the construction support formwork system for the lower crossbeam 6.

[0051] The verification of its stress safety includes:

[0052] S102.1: When pouring the lower block, the weight borne by the construction support of the lower crossbeam 6 is the actual weight of the concrete in the lower block.

[0053] S102.2: When pouring the upper block, the lower crossbeam 6 construction support shall bear 45% of the self-weight of the upper block concrete, depending on the hardening degree of the lower block that has already been poured.

[0054] S102.3: Determine the ultimate load that the construction support for the lower crossbeam 6 needs to withstand during construction.

[0055] In verifying the stress safety of the formwork system, it is also necessary to verify the stress safety of the formwork system under the following working conditions:

[0056] Verify the stress safety of the construction support of the lower beam 6 under wind load during sectional pouring and full load;

[0057] Verify the stress safety of the first pouring area 1 after concrete pouring when the Bailey beams on both sides of the construction support of the lower beam 6 are not installed and the construction support is under no load and no wind load.

[0058] In this embodiment, after dividing the lower crossbeam 6 into five pouring blocks, the design of the construction support formwork system for the lower crossbeam 6 is also included. By modeling and analyzing the construction support formwork system, verifying the stress safety, and optimizing and adjusting it based on the safety verification results, the safety of the construction process can be improved, and excessive reinforcement can be prevented from wasting construction time and resources.

[0059] During the calculation of its stress safety, when pouring the lower block, the weight borne by the construction support of the lower beam 6 is the actual weight of the concrete in the lower block. When pouring the upper block, the hardening degree of the lower block changes, which will share the weight of the upper block concrete borne by the construction support. As a result, the load borne by the construction support of the lower beam 6 on the upper block concrete is 45% of the self-weight of the upper block concrete. The ultimate load that the construction support of the lower beam 6 needs to bear during construction can be obtained, which can prevent excessive reinforcement and waste of construction time and resources.

[0060] In verifying its stress safety, the stress safety of the construction support of the lower beam 6 under wind load and under full load was verified; the stress safety of the construction support of the lower beam 6 under no load and no wind load after the concrete is poured in the first pouring area 1 was verified when the Bailey beams on both sides of the construction support were not installed. The stress situation in the above two working conditions is complex and there is a high possibility of safety accidents. Verification under these two working conditions can improve the safety of construction.

[0061] In this example, the first pouring area 1 is located in the middle of the crossbeam A and the central tie beam B, the second pouring area 2 is located on the left side of the middle of the crossbeam A and the same side tie beam C, and the third pouring area 3 is located on the right side of the middle of the crossbeam A and the same side tie beam C. The first pouring area 1 is separated from the second pouring area 2 and the third pouring area 3 by a stepped dividing line a, and the fifth pouring area 5 and the fourth pouring area 4 are separated by a dividing line b.

[0062] S2: During the construction of the segment below the set tower segment height, the reinforcement binding and concrete pouring of the first pouring area 1 are carried out.

[0063] In some optional embodiments, step S2 specifically includes:

[0064] S20: During the construction of tower column foundation segment 11, the installation of part of the support for the lower crossbeam 6 is completed simultaneously.

[0065] S21: During the construction of the second segment below the set tower segment height, the reinforcement binding of the first pouring area 1 is carried out.

[0066] S22: During the construction of the first segment below the tower column segment height position set on the lower crossbeam 6, concrete pouring is carried out in the first pouring area 1.

[0067] In this embodiment, before the reinforcement binding of the first pouring area 1 is carried out during the construction of the second segment below the tower column segment height position of the lower crossbeam 6, the installation of part of the support of the lower crossbeam 6 is also completed simultaneously during the construction of the tower column foundation segment 11, which further improves the construction efficiency and reduces the construction time.

[0068] During the construction of the first and second segments below the tower column segment height position of the lower crossbeam 6, the reinforcement binding and concrete pouring of the first pouring area 1 are carried out to shorten the construction time and improve the construction efficiency.

[0069] In this example, the second segment below the height position of the tower column segment is designated as the seventh segment 7 of the tower column, the first segment below the height position of the tower column segment is designated as the eighth segment 8 of the tower column, and the segments below the height position of the tower column segment are designated as the seventh segment 7, the eighth segment 8 of the tower column, and the foundation segment 11 of the tower column.

[0070] S30: Install the lower crossbeam 6-bracket bracket to complete the installation of the remaining brackets.

[0071] S3: After the reinforcement binding of the tower column segment corresponding to the lower layer of the lower beam 6 is completed, the reinforcement binding and pouring construction of the second pouring area 2 and the third pouring area 3 are carried out in stages.

[0072] In this embodiment, after the reinforcement binding of the tower column segment corresponding to the lower layer of the lower beam 6 is completed, the reinforcement binding and pouring construction of the second pouring area 2 and the third pouring area 3 are carried out in stages. The bracket of the lower beam 6 is installed to complete the installation of the remaining bracket, which reduces the idle time and further shortens the construction time.

[0073] In this example, the construction of the lower crossbeam 6 involves a support system including a bottom formwork system, distribution beams, Bailey beams, corbels, and steel pipe columns. The bottom formwork of the crossbeam adopts a ground-mounted steel pipe support system, which includes bamboo plywood, square timber, and distribution beams. The construction load of the lower crossbeam 6 is transferred to the corbels and steel pipe columns by the Bailey beams. Steel formwork is used for the side formwork, wooden formwork is used for the end formwork, and disc-lock scaffolding and wooden formwork are used for the inner cavity formwork. Before the foundation is poured, the embedded parts are laid out according to the design position, and the steel pipe columns are supported on the top surface of the foundation. Climbing cones are embedded at the design position of the eighth segment 8 of the tower column. The support columns are installed in sections, and the sections are connected by flanges. The columns are hoisted in the order from the middle to the larger and smaller mileage sides. After the two adjacent steel pipe columns are installed, they are connected by three rows of connecting systems. The corbel stiffening plates are made of thick steel plates and arranged in three layers. The sand cylinder plugs are made of steel pipes, and the sand cylinders at the columns and corbels are pre-stressed. The distribution beams are placed on top of the sand cylinders, and the distribution beams at the bottom of the crossbeams, corbels, and tie beams are made of steel sections. The support for the crossbeam area is a Bailey beam. The Bailey beams are installed after a certain distance is reserved on the upstream and downstream sides near the main tower. After the concrete of the eighth segment 8 of the tower column is poured and the climbing formwork on the inner side of the cross bridge is removed, the reserved sections of Bailey beams on the upstream and downstream sides are installed. The construction was carried out in two pre-stressing phases. The first pre-stressing was conducted after most of the Bailey beam supports were installed and before the bottom formwork system was constructed, to eliminate inelastic deformation of the supports. The second pre-stressing was carried out after the reserved sections of the Bailey beams on the upstream and downstream sides were installed. The pre-camber of the formwork was determined by calculation and the on-site pre-stressing results.

[0074] In this example, the climbing formwork for the middle tower column construction interferes with the formwork for the lower crossbeam construction, necessitating planning for the installation and dismantling of the climbing formwork. After the eighth segment of the tower column is completed and the concrete strength reaches over 20MPa, the inner climbing formwork of the main tower column is dismantled. Crossbeams are laid out according to the spacing of the frame beams, with one crossbeam positioned transversely near the inner side of the platform bottom, and one on each of the large and small mileage sides, serving as the base after the climbing formwork is dismantled. The dismantled climbing formwork is placed on top of the foundation. The dismantling process for the inner hydraulic climbing formwork is as follows: dismantling the fixed truss, formwork removal, moving the tripod and guide rails, dismantling the hydraulic device and power distribution device, hydraulic control pump station, hydraulic device, dismantling the wall-mounted device and climbing cone, main beam tripod and suspended platform, the top-level wall-mounted device and climbing cone, and repairing the climbing cone holes.

[0075] In this example, the lower layer of the lower beam 6 corresponds to the tower column segment 9, which is the ninth segment of the tower column.

[0076] S4: When binding the reinforcing bars of the tower column segment corresponding to the upper layer of the lower crossbeam 6, the reinforcing bars of the fourth pouring area 4 and the fifth pouring area 5 are bound in stages, and the pouring construction of the fourth pouring area 4 and the fifth pouring area 5 is completed in stages.

[0077] In the concrete pouring process, the pouring principle is to pour from bottom to top, first the bottom slab, then the web slab, and then the top slab, in layers, with symmetrical material distribution.

[0078] During the construction of the lower crossbeam 6, the temperature of the concrete construction steps is intelligently monitored, and the temperature of the relevant cooling water is intelligently adjusted according to the temperature difference.

[0079] In this embodiment, the lower crossbeam 6 is poured using a concrete pump truck, while the tower column is poured using a concrete delivery pump and a distribution trough. During the pouring of the first pouring area 1, two concrete pump trucks are used. During the pouring of the second pouring area 2, the third pouring area 3, the fourth pouring area 4, and the fifth pouring area 5, two concrete pump trucks are responsible for pouring the non-tower column portions, while the tower column portions are poured using a concrete delivery pump and a distribution trough. A material-receiving hole and a tremie pipe are installed at the concrete discharge point to ensure that the free fall height of the concrete upon entering the formwork is less than 2m. A crack-resistant steel mesh is installed at the bottom of the lower crossbeam 6 to prevent shrinkage cracks in the concrete.

[0080] Temperature sensors are installed inside and outside the concrete of the lower crossbeam 6 to monitor the temperature difference between the inner and outer surfaces of the large-volume concrete in real time during curing. The curing spray temperature is adjusted by an intelligent temperature-controlled water tank. Simultaneously, cooling water pipes 12 are arranged according to the temperature control design requirements and the thickness of each concrete layer. The cooling water pipes 12 are ordinary Q235 steel pipes with a 42mm outer diameter and 2.5mm wall thickness, exhibiting good thermal conductivity and sufficient strength. The pipes are connected by bends. The cooling water temperature is also intelligently controlled and adjusted based on the temperature difference between the inner and outer surfaces to ensure the quality of concrete curing. Six layers of cooling water pipes 12 are installed on the ninth segment 9 of the tower column, and four layers on the tenth segment 10. The vertical spacing of the cooling water pipes 12 is 1.0m, and the horizontal spacing is 1.0m.

[0081] In this example, the main reinforcement of the lower crossbeam 6 uses mechanical joints, while the stirrups of the lower crossbeam 6 can use welded joints. At the same time, the lower crossbeam 6 is cast in sections, and the main reinforcement between sections is connected using standard rolled straight thread sleeves. In the steel reinforcement workshop, the main reinforcement is cut according to the section height and then threaded. The reinforcement is tied in a figure-eight pattern at intervals, and the reinforcement cage should be tied firmly and have sufficient rigidity. All tie wire overlaps should be turned inward and should not intrude into the reinforcement protective layer.

[0082] In this example, during the construction of the lower crossbeam 6, the prestressing tensioning is carried out in two stages. After the concrete pouring of the lower section of the lower crossbeam 6 is completed, when the concrete strength and elastic modulus reach 75% or more of the design strength, the prestressing tendons of the bottom part are temporarily tensioned. The control stress under the tensioning anchor of the temporary prestressing tendons is 50% of the design value. The prestressing tendons are tensioned in a symmetrical manner along the center line of the crossbeam, starting from the middle and then moving to both sides, and are tensioned synchronously pair by pair. After the concrete pouring of the upper section is completed, the tensioning of all prestressing tendons is completed, and the duct friction test is completed before the prestressing construction.

[0083] In this example, the upper layer of the lower crossbeam 6 corresponds to the tower column segment 10, which is the tenth segment of the tower column.

[0084] In summary, by dividing the lower crossbeam 6 into five casting blocks, where the lower crossbeam 6 is located at the set tower column segment height, the five casting blocks are divided into two layers. The first casting area 1, the second casting area 2, and the third casting area 3 are located in the lower layer. The first casting area 1 is located in the middle of the crossbeam and the central tie beam area. The second casting area 2 is located on one side of the middle of the crossbeam and the same side tie beam area. The third casting area 3 is located on the other side of the middle of the crossbeam and the same side tie beam area. The fourth casting area 4 and the fifth casting area 5 are located in the upper layer. The fifth casting area 5 is located above the second casting area 2. The fourth pouring area 4 is located above the remaining part of the first pouring area 1 and above the third pouring area 3. The pouring is carried out in sequence, which reduces the waiting time between the pouring areas, improves the construction efficiency, and solves the problem of the existing technology for the construction scheme of the lower crossbeam of the main tower with a large structural volume. Generally, the method of sectional pouring is adopted. Since the existing method divides the lower crossbeam into two pre-poured sections, the construction of the blocks in the pre-poured sections may take a long time due to the construction sequence, which may prolong the project time and reduce the construction efficiency.

[0085] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0086] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0087] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A construction method for the crossbeam under the tower of a spatial four-limb A-type cable-stayed bridge, characterized in that, Includes the following steps: The lower crossbeam (6) is divided into five casting blocks. The lower crossbeam (6) is located at the height of the set tower column segment. The five casting blocks are divided into two layers. The first casting area (1), the second casting area (2) and the third casting area (3) are located in the lower layer. The first casting area (1) is located in the middle of the crossbeam and the middle tie beam area. The second casting area (2) is located in one side of the middle of the crossbeam and the same side tie beam area. The third casting area (3) is located in the other side of the middle of the crossbeam and the same side tie beam area. The fourth casting area (4) and the fifth casting area (5) are located in the upper layer. The fifth casting area (5) is located above the second casting area (2) and partially extends above the first casting area (1). The fourth casting area (4) is located above the remaining part above the first casting area (1) and above the third casting area (3). During the construction of the segment below the set tower segment height position, the reinforcement binding and concrete pouring of the first pouring area (1) are carried out; After the reinforcement binding of the tower column segment corresponding to the lower layer of the lower beam (6) is completed, the reinforcement binding and pouring construction of the second pouring area (2) and the third pouring area (3) are carried out in stages. When binding the reinforcing bars of the tower column segment corresponding to the upper layer of the lower crossbeam (6), the reinforcing bars of the fourth pouring area (4) and the fifth pouring area (5) are bound in stages, and the pouring construction of the fourth pouring area (4) and the fifth pouring area (5) is completed in stages.

2. The construction method for the crossbeam under the tower of a spatial four-limb A-type cable-stayed bridge as described in claim 1, characterized in that, After dividing the lower crossbeam (6) into five pouring blocks, the design of the construction support formwork system for the lower crossbeam (6) is also included, comprising the following steps: A construction support calculation model of the lower crossbeam (6) was established using finite element calculation software; The calculation model of the construction support was modeled and analyzed to verify its stress safety. Based on the safety calculation results, the construction support formwork system of the lower crossbeam (6) was optimized and adjusted to obtain the formwork system.

3. The construction method for the crossbeam under the tower of a spatial four-limb A-type cable-stayed bridge as described in claim 2, characterized in that, The aforementioned verification of its stress safety includes: When pouring the lower block, the weight borne by the construction support of the lower crossbeam (6) is the actual weight of the concrete in the lower block; When pouring the upper block, the lower crossbeam (6) construction support bears a load of 45% of the self-weight of the upper block concrete, depending on the hardening degree of the poured lower block; The ultimate load that the construction support of the lower crossbeam (6) needs to withstand during construction is obtained.

4. The construction method for the crossbeam under the tower of a spatial four-limb A-type cable-stayed bridge as described in claim 2, characterized in that, When verifying the stress safety of the formwork system, it is also necessary to verify the stress safety of the formwork system under the following working conditions: Verify the stress safety of the construction support of the lower crossbeam (6) under wind load during sectional pouring and full load; When the Bailey beams on both sides of the construction support of the lower crossbeam (6) are not installed, the stress safety of the first pouring area (1) after concrete pouring is verified under no-load and no wind load conditions.

5. The construction method for the crossbeam under the tower of a spatial four-limb A-type cable-stayed bridge as described in claim 1, characterized in that, The aforementioned process of reinforcing bar binding and concrete pouring in the first pouring area (1) during the construction of the segment below the set tower column segment height includes: During the construction of the second segment below the set tower segment height position, the reinforcement binding of the first pouring area (1) is carried out; During the construction of the first segment below the tower column segment height position set by the lower crossbeam (6), the concrete pouring of the first pouring area (1) is carried out.

6. The construction method for the crossbeam under the tower of a spatial four-limb A-type cable-stayed bridge as described in claim 5, characterized in that, Before the reinforcement binding of the first pouring area (1) is carried out during the construction of the second segment below the tower column segment height position of the lower crossbeam (6), the installation of part of the support of the lower crossbeam (6) is also carried out simultaneously during the construction of the tower column foundation segment (11).

7. The construction method for the crossbeam under the tower of a spatial four-limb A-type cable-stayed bridge as described in claim 6, characterized in that, After the reinforcement binding of the tower column segment corresponding to the lower layer of the lower beam (6) is completed, before the reinforcement binding and pouring construction of the second pouring area (2) and the third pouring area (3) are carried out in stages, the bracket of the lower beam (6) is installed to complete the installation of the remaining bracket.

8. The construction method for the crossbeam under the tower of a spatial four-limb A-type cable-stayed bridge as described in claim 1, characterized in that, If the thickness of the lower crossbeam (6) is 8m, the lower layer is designed to be 5.5m and the upper layer is designed to be 2.5m.

9. A construction method for the crossbeam under the tower of a spatial four-limb A-type cable-stayed bridge as described in claim 1, characterized in that, During the concrete pouring process, the pouring principle is to pour from bottom to top, first the bottom slab, then the web slab, and then the top slab, in layers, with symmetrical material distribution.

10. A construction method for the crossbeam under the tower of a spatial four-limb A-type cable-stayed bridge as described in claim 1, characterized in that, During the construction of the lower crossbeam (6), the temperature of the concrete construction steps is intelligently monitored, and the temperature of the relevant cooling water is intelligently adjusted according to the temperature difference.

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