Lower cross beam structure of cable-stayed bridge cable bent tower

Abstract

The utility model discloses a lower cross beam structure of a cable-stayed bridge pylon, which comprises a plurality of lower cross beam sections arranged along the transverse bridge direction, a concrete layer is poured at the joint between two adjacent lower cross beam sections, each lower cross beam section is of a box-shaped section concrete structure, prestressed pipeline assemblies are arranged in the plurality of lower cross beam sections, and the prestressed pipeline assemblies are connected with the lower cross beam sections. The pre-stressed pipeline assembly comprises a first pre-stressed pipeline, a second pre-stressed pipeline and a third pre-stressed pipeline, the first permanent prestressing tendon is tensioned and anchored in the lower cross beam section in the midspan area of the lower cross beam through a first prestressing pipeline; the second prestressed pipeline is pre-buried at the top of the lower cross beam section outside the midspan area of the lower cross beam; the second permanent prestressing tendon is tensioned and anchored in the lower cross beam section outside the midspan area of the lower cross beam through the second prestressing pipeline, the single-time concrete pouring amount can be effectively reduced by pouring the lower cross beam section by section in the transverse bridge direction, and the pouring interruption risk is reduced.

Description

Technical Field

[0001] The present application relates to the field of bridge construction, and in particular to a lower crossbeam structure of a cable-stayed bridge tower. Background Art

[0002] The cable tower of a cable-stayed bridge is an important part of the cable-stayed bridge. It is a tower-shaped structure that bears the tension of the main cable in the cable-stayed bridge. It usually constitutes the main load-bearing system of the cable-stayed bridge together with the main beam and the cable. The height of the cable tower is usually related to the main span of the bridge. The accuracy of its design and construction is directly related to the safety and stability of the entire bridge. The cable tower plays the role of supporting the main beam and transmitting the force of the cable in the cable-stayed bridge. It is also part of the aesthetic expression of the cable-stayed bridge. Its design and shape often become the visual focus of the bridge.

[0003] However, in the process of implementing relevant technical solutions, at least the following technical problems were found: microcracks exist inside the concrete lower crossbeam during the construction process, and it is easy to crack under the huge dead load and live load transmitted by the support. Considering the shrinkage effect of concrete, the age of the pedestal is longer than that of the lower crossbeam. Before the construction of the lower crossbeam is completed, the shrinkage of the pedestal concrete has been basically completed. After the structural system is formed, the lower crossbeam with the shortest age will produce the most shrinkage effect, resulting in a great risk of shrinkage and cracking of the lower crossbeam, affecting the stability of the cable-stayed bridge tower. Utility Model Content

[0004] The present application solves the problem of a large risk of cracking in the lower crossbeam of a cable-stayed bridge tower in the prior art by providing a lower crossbeam structure of a cable-stayed bridge tower, thereby reducing the risk of initial microcracks in the lower crossbeam caused by deformation of the cast-in-place bracket of the lower crossbeam.

[0005] The present application provides a lower crossbeam structure of a cable-stayed bridge tower, comprising a plurality of lower crossbeam segments arranged along a transverse bridge direction, a concrete layer is cast at a joint between two adjacent lower crossbeam segments, each of the lower crossbeam segments is a box-section concrete structure, and a prestressed pipe assembly is arranged inside the plurality of lower crossbeam segments, wherein the prestressed pipe assembly comprises: a first prestressed pipe, pre-buried at the bottom of the lower crossbeam segment located in a mid-span area of ​​the lower crossbeam, and the first prestressed pipes in two adjacent lower crossbeam segments are connected along the transverse bridge direction; a first permanent prestressed bundle, tensioned and anchored in the lower crossbeam segment located in the mid-span area of ​​the lower crossbeam through the first prestressed pipe; a second prestressed pipe, pre-buried at the top of the lower crossbeam segment located outside the mid-span area of ​​the lower crossbeam, and the first prestressed pipes in two adjacent lower crossbeam segments are connected along the transverse bridge direction; and a second permanent prestressed bundle, tensioned and anchored in the lower crossbeam segment located outside the mid-span area of ​​the lower crossbeam through the second prestressed pipe.

[0006] Furthermore, multiple layers of full-length prestressed beam pipe layers arranged at intervals along the vertical direction are pre-buried in the plurality of the lower cross beam segments, each layer of the full-length prestressed beam pipe layer includes a plurality of full-length prestressed beam pipes arranged at intervals along the longitudinal direction for the full-length prestressed beams to pass through, and each of the full-length prestressed beams passes through all the lower cross beam segments along the transverse direction.

[0007] Furthermore, top plates are provided on the tops of the plurality of lower beam segments, bottom plates are provided on the bottoms of the plurality of lower beam segments, and partition assemblies are provided inside the plurality of lower beam segments, and the partition assemblies include: a first partition arranged inside the lower beam segment located in the mid-span area of ​​the lower beam; a first longitudinal web plate arranged inside the lower beam segment located in the mid-span area of ​​the lower beam, the first partition plate and the first longitudinal web plate intersect and are fixedly connected, and through holes for the first prestressed pipe to pass through are respectively provided on the top plate, the bottom plate and the first longitudinal web plate.

[0008] Furthermore, the partition assembly also includes: a second partition, which is arranged inside the lower beam segment outside the mid-span area of ​​the lower beam; a second longitudinal web, which is arranged inside the lower beam segment outside the mid-span area of ​​the lower beam, the second partition and the second longitudinal web intersect and are fixedly connected, and the top plate, the bottom plate and the second longitudinal web are respectively provided with through holes for the first prestressed pipe to pass through.

[0009] Furthermore, the first partition is a full-height partition, the second partition is a half-height partition, the top of the first partition and the second partition are connected to the bottom of the top plate, and the bottom of the first partition and the second partition are connected to the top of the bottom plate.

[0010] Furthermore, the wall surface of the joint is serrated.

[0011] The technical solution provided by this application has at least the following technical effects or advantages:

[0012] By casting the lower cross beam in sections along the transverse direction of the bridge, the volume of concrete poured in a single time can be effectively reduced, the risk of pouring interruption caused by insufficient concrete transportation capacity on the water can be solved, and the risk of initial micro cracks in the lower cross beam caused by deformation of the cast-in-place bracket of the lower cross beam is reduced. At the same time, it is convenient to configure prestress in sections, eliminates the construction of prestressed anchor teeth, and facilitates formwork processing. The lower cross beam segments have a certain storage period before the system is formed, and the concrete shrinkage is basically completed, reducing the risk of structural cracking after the bridge is completed. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of the combined structure of the lower cross beam and the tower column in one embodiment of the utility model;

[0014] Figure 2 It is a schematic diagram of the overall structure of an embodiment of the utility model;

[0015] Figure 3 It is a schematic diagram of the overall structure after the full-length prestressed bundle is tensioned in one embodiment of the utility model;

[0016] Figure 4 The force and bending moment diagram of the lower beam in one embodiment of the utility model;

[0017] Figure 5 It is a schematic plan view of a lower cross beam in one embodiment of the utility model;

[0018] Figure 6 It is one of the cross-sectional schematic diagrams of the lower cross beam in one embodiment of the utility model;

[0019] Figure 7 The second schematic cross-sectional view of the lower cross beam in one embodiment of the utility model;

[0020] Figure 8 The third schematic cross-sectional view of the lower cross beam in one embodiment of the utility model;

[0021] In the figure: 10, lower cross beam segment; 20, joint; 30, concrete layer; 40, top plate; 50, bottom plate; 60, prestressed pipe assembly; 70, partition assembly; 61, first prestressed pipe; 62, first permanent prestressed bundle; 63, second prestressed pipe; 64, second permanent prestressed bundle; 65, full-length prestressed bundle pipe layer; 651, full-length prestressed bundle pipe; 652, full-length prestressed bundle; 71, first partition; 72, first longitudinal web; 73, second partition; 74, second longitudinal web. DETAILED DESCRIPTION

[0022] An embodiment of the present application discloses a lower crossbeam structure of a cable-stayed bridge tower. By casting multiple lower crossbeam segments in 10 sections, the volume of single concrete pouring can be effectively reduced, the risk of pouring interruption caused by insufficient water concrete transportation capacity can be solved, and the risk of initial microcracks in the lower crossbeam caused by deformation of the cast-in-place bracket of the lower crossbeam is reduced.

[0023] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0024] Please refer to Figure 1The present embodiment provides a lower cross beam structure of a cable-stayed bridge tower, comprising a plurality of lower cross beam segments 10 arranged along the transverse direction of the bridge, a concrete layer 30 is poured at the joint 20 between two adjacent lower cross beam segments 10, the wall surface of the joint 20 is serrated, a top plate 40 is arranged on the top of the plurality of lower cross beam segments 10, a bottom plate 50 is arranged on the bottom of the plurality of lower cross beam segments 10, each lower cross beam segment 10 is a box-shaped section concrete structure, and the use of segmented pouring of multiple lower cross beam segments 10 along the transverse direction of the bridge can effectively reduce the single concrete pouring volume, and can solve the problem of overwater concrete pouring. The risk of pouring interruption caused by insufficient soil transportation capacity is reduced, and the risk of initial micro cracks in the lower beam caused by deformation of the cast-in-place bracket of the lower beam is reduced. At the same time, it is convenient to configure prestressed in sections, eliminating the construction of prestressed anchor teeth and facilitating formwork processing. The lower beam segment 10 has a certain beam storage period before forming the system, and the concrete shrinkage is basically completed, reducing the risk of structural cracking after the bridge is completed. The joint 20 adopts an open seam or a serrated seam, which can increase the bite and bonding force between the precast concrete and the post-cast joint 20, improve the connection reliability of the joint 20, and further enhance the crack resistance of the lower beam.

[0025] Please refer to Figure 1-Figure 4 A prestressed pipe assembly 60 is arranged inside the plurality of lower beam segments 10, and the prestressed pipe assembly 60 includes a first prestressed pipe 61, a first permanent prestressed bundle 62, a second prestressed pipe 63, a second permanent prestressed bundle 64, and a through-length prestressed bundle pipe layer 65. The first prestressed pipe 61 is pre-buried at the bottom of the lower beam segment 10 located in the middle span area of ​​the lower beam, and the first prestressed pipes 61 in two adjacent lower beam segments 10 are connected along the transverse bridge direction. The first permanent prestressed bundle 62 is tensioned and anchored in the lower beam segment 10 located in the middle span area of ​​the lower beam through the first prestressed pipe 61. The second prestressed pipe 63 is pre-buried at the top of the lower beam segment 10 located outside the middle span area of ​​the lower beam, and the first prestressed pipes 61 in two adjacent lower beam segments 10 are connected along the transverse bridge direction. The second permanent prestressed bundle 64 is tensioned and anchored in the lower beam segment 10 located in the middle span area of ​​the lower beam through the second prestressed pipe 63. In the lower cross beam segment 10 located outside the mid-span area of ​​the lower cross beam, multiple lower cross beam segments 10 are located between the tower column spans, and the prestressed stress of the lower cross beam is affected by the horizontal force of the tower column and the reaction force of the lower cross beam support, that is, after balancing the horizontal force of the tower column, there is still a certain surplus to withstand the bending moment caused by the reaction force of the top support of the lower cross beam, ensuring that the upper and lower edge concrete of the lower cross beam under the normal use limit state is not subjected to tension, by pre-burying the corresponding first prestressed pipe 61 at the bottom of the lower cross beam segment 10 located in the mid-span area of ​​the lower cross beam (positive bending moment area) for the first permanent prestressed beam 62 to pass through, and pre-burying the corresponding second prestressed pipe 63 at the top of the lower cross beam segment 10 outside the mid-span area of ​​the lower cross beam (negative bending moment area) for the second permanent prestressed beam 64 to pass through, ultimately ensuring that the upper and lower edge concrete of the lower cross beam under the normal use limit state is not subjected to tension, thereby effectively reducing the risk of cracking of the lower cross beam.

[0026] Please refer to Figure 1-Figure 4 Multiple layers of through-length prestressed beam pipe layers 65 arranged at intervals along the vertical direction are pre-buried in multiple lower cross beam segments 10. Each layer of through-length prestressed beam pipe layer 65 includes multiple through-length prestressed beam pipes 651 arranged at intervals along the longitudinal direction for the through-length prestressed beams 652 to pass through. Each through-length prestressed beam 652 passes through all lower cross beam segments 10 along the transverse direction. The number of layers of the through-length prestressed beam pipe layer 65 can be set to multiple layers according to design requirements. During actual construction, the middle tower column steel mesh can be tied in sections and tower column prestressed beam pipes corresponding to the through-length prestressed beam pipes 651 can be pre-buried in the middle tower column steel mesh. Finally, the through-length prestressed beam 652 passes through the through-length prestressed beam pipe 651 and the tower column prestressed beam pipe, and the two ends of the through-length prestressed beam 652 are respectively anchored to the outside of the middle tower column. By arranging the through-length prestressed beam 652, the structural strength of the lower cross beam segment 10 can be improved and the risk of cracking of the lower cross beam can be reduced.

[0027] Please refer to Figure 1-Figure 8, a plurality of lower beam segments 10 are provided with a partition assembly 70 inside, the partition assembly 70 includes a first partition 71, a first longitudinal web 72, a second partition 73, and a second longitudinal web 74, the first partition 71 is arranged inside the lower beam segment 10 located in the middle span area of ​​the lower beam, the first longitudinal web 72 is arranged inside the lower beam segment 10 located in the middle span area of ​​the lower beam, the first partition 71 and the first longitudinal web 72 intersect and are fixedly connected, the top plate 40, the bottom plate 50 and the first longitudinal web 72 are respectively provided with through holes for the first prestressed pipe 61 to pass through, the second partition 73 is arranged inside the lower beam segment 10 located outside the middle span area of ​​the lower beam, and the second longitudinal web 74 is arranged inside the lower beam segment 10 located outside the middle span area of ​​the lower beam The second partition 73 and the second longitudinal web 74 intersect and are fixedly connected, the top plate 40, the bottom plate 50 and the second longitudinal web 74 are respectively provided with through holes for the first prestressed pipe 61 to pass through, the first partition 71 is a full-height transverse partition, the second partition 73 is a half-height transverse partition, the top of the first partition 71 and the second partition 73 are connected to the bottom of the top plate 40, the bottom of the first partition 71 and the second partition 73 is connected to the top of the bottom plate 50, each lower beam segment 10 is a box-section concrete structure, a box-shaped concrete section structure in the form of longitudinal and transverse transverse partitions is provided in the lower beam segment 10, which can effectively distribute the vertical force to the webs and partitions in each lower beam segment 10 of the lower beam, so as to prevent the local stress deformation of the top plate 40 of the lower beam segment 10 from being too large and causing cracking. It is also worth noting that both the transverse full-height diaphragms and the transverse half-height diaphragms can meet the requirements of force transmission (they can transmit shear force to the web to make the web evenly stressed). At the same time, the transverse half-height diaphragms are simple in structure and save materials. By setting up transverse full-height diaphragms and transverse half-height diaphragms, the diaphragm steel bars do not need to be anchored in the bottom plate 50 of the lower cross beam segment 10 where steel bars and prestressed tendons are densely distributed. In particular, the transverse half-height diaphragms reduce the cross-embedded steel bars and make it easier to ensure construction quality. The vertical force transmission effect is equivalent to that of the transverse full-height diaphragms. In the preferred example, torsional force usually only requires one transverse full-height diaphragm, which avoids the possibility of later cracking of the transverse full-height diaphragm due to uneven force on the connected plates.

[0028] This application can explain its functional principle through the following operation methods:

[0029] When in use, the lower cross beam can be divided into an odd number (1, 3, 5, 7...) of segments in the longitudinal direction of the bridge according to the on-site construction conditions, and a post-cast joint 20 of a certain width is set between the segments. According to actual needs, multiple lower cross beam segments 10 are cast in segments along the transverse direction of the bridge, which can effectively reduce the single concrete pouring volume, solve the risk of pouring interruption caused by insufficient water concrete transportation capacity, and reduce the risk of initial micro cracks in the lower cross beam caused by deformation of the cast-in-place bracket of the lower cross beam. The corresponding first prestressed pipe 61 is pre-buried at the bottom of the lower cross beam segment 10 located in the positive bending moment area of ​​the mid-span area of ​​the lower cross beam for the first permanent prestressed beam 62 to pass through, and the corresponding second prestressed pipe 63 is pre-buried at the top of the lower cross beam segment 10 in the negative bending moment area outside the mid-span area of ​​the lower cross beam for the second permanent prestressed beam 64 to pass through, ultimately ensuring that the upper and lower edges of the lower cross beam are concreted in the limit state of normal use. The concrete is not subjected to tension, thereby effectively reducing the risk of cracking of the lower cross beam. During actual construction, the steel mesh of the middle tower column is tied in sections and tower column prestressed beam pipes corresponding to the full-length prestressed beam pipes 651 are pre-buried in the steel mesh of the middle tower column. Finally, the full-length prestressed beam 652 runs through the full-length prestressed beam pipe 651 and the tower column prestressed beam pipe, and the two ends of the full-length prestressed beam 652 are respectively anchored to the outside of the middle tower column. By arranging the full-length prestressed beam 652, the structural strength of the lower cross beam segment 10 can be improved, and the risk of cracking of the lower cross beam can be reduced. Each lower cross beam segment 10 is a box-section concrete structure, and a box-shaped concrete section structure in the form of longitudinal and transverse diaphragms is provided in the lower cross beam segment 10, which can effectively distribute the vertical force to the webs and diaphragms in each lower cross beam segment 10 of the lower cross beam, thereby preventing the local stress deformation of the top plate 40 of the lower cross beam segment 10 from being too large and causing cracking.

[0030] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

[0031] What has been described above is only a preferred specific implementation manner of the embodiments of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can make equivalent substitutions or changes according to the technical scheme and concept of the present application within the technical scope disclosed in the present application, which should be covered by the protection scope of the present application.

Claims

1. A lower crossbeam structure of a cable-stayed bridge tower, characterized in that: The invention comprises a plurality of lower cross beam segments (10) arranged in a transverse direction of the bridge, a concrete layer (30) is poured at a joint (20) between two adjacent lower cross beam segments (10), each of the lower cross beam segments (10) is a box-section concrete structure, and a prestressed pipe assembly (60) is arranged inside the plurality of lower cross beam segments (10), and the prestressed pipe assembly (60) comprises: A first prestressed pipe (61) is pre-buried in the bottom of the lower beam segment (10) located in the mid-span area of ​​the lower beam, and the first prestressed pipes (61) in two adjacent lower beam segments (10) are connected in the transverse direction of the bridge; A first permanent prestressed strand (62) is tensioned and anchored in the lower beam segment (10) located in the mid-span region of the lower beam through the first prestressed pipe (61); A second prestressed pipe (63) is pre-buried at the top of the lower beam segment (10) outside the mid-span area of ​​the lower beam, and the first prestressed pipes (61) in two adjacent lower beam segments (10) are connected in the transverse direction of the bridge; The second permanent prestressed tendon (64) is tensioned and anchored in the lower beam segment (10) outside the mid-span area of ​​the lower beam through the second prestressed pipe (63).

2. The lower cross beam structure of a cable-stayed bridge tower according to claim 1, characterized in that: Multiple layers of through-length prestressed bundle pipe layers (65) arranged at intervals along the vertical direction are pre-buried in the plurality of lower cross beam segments (10); each layer of the through-length prestressed bundle pipe layer (65) comprises a plurality of through-length prestressed bundle pipes (651) arranged at intervals along the longitudinal direction for allowing through-length prestressed bundles (652) to pass through; each of the through-length prestressed bundles (652) passes through all the lower cross beam segments (10) along the transverse direction.

3. The lower cross beam structure of a cable-stayed bridge tower according to claim 2, characterized in that: A top plate (40) is arranged on the top of the plurality of lower beam segments (10), a bottom plate (50) is arranged on the bottom of the plurality of lower beam segments (10), and a partition assembly (70) is arranged inside the plurality of lower beam segments (10), wherein the partition assembly (70) comprises: A first partition plate (71) is arranged inside the lower beam segment (10) located in the mid-span area of ​​the lower beam; A first longitudinal web (72) is arranged inside the lower cross beam segment (10) located in the mid-span area of ​​the lower cross beam, and the first partition (71) and the first longitudinal web (72) intersect and are fixedly connected. The top plate (40), the bottom plate (50) and the first longitudinal web (72) are respectively provided with through holes for the first prestressed pipe (61) to pass through.

4. The lower cross beam structure of a cable-stayed bridge tower according to claim 3, characterized in that: The partition assembly (70) further includes: A second partition plate (73) is arranged inside the lower beam segment (10) outside the mid-span area of ​​the lower beam; The second longitudinal web (74) is arranged inside the lower cross beam segment (10) outside the mid-span area of ​​the lower cross beam, and the second partition (73) and the second longitudinal web (74) intersect and are fixedly connected. The top plate (40), the bottom plate (50) and the second longitudinal web (74) are respectively provided with through holes for the first prestressed pipe (61) to pass through.

5. The lower cross beam structure of a cable-stayed bridge tower according to claim 4, characterized in that: The first partition (71) is a full-height partition, and the second partition (73) is a half-height partition. The tops of the first partition (71) and the second partition (73) are connected to the bottom of the top plate (40), and the bottoms of the first partition (71) and the second partition (73) are connected to the top of the bottom plate (50).

6. The lower cross beam structure of a cable-stayed bridge tower according to claim 1, characterized in that: The wall surface of the joint (20) is in a sawtooth shape.

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