A multi-tower asymmetric low tower cable-stayed bridge

Abstract

The present invention discloses a multi-tower asymmetric low-tower cable-stayed bridge. The multi-tower low-tower cable-stayed bridge is a long-span structure with a large structural temperature effect; the existing symmetrical structure causes waste of engineering investment. The present invention includes side spans, main spans, and bridge towers, and the steel trusses are fixedly connected to the bottom of the bridge towers; supports are set on the top surfaces of the main piers, auxiliary piers, and connecting piers, and the main pier at the center position is provided with longitudinal and transverse fixed supports on one side of the transverse bridge direction, and longitudinal fixed supports on the other side, and longitudinal movable supports and longitudinal and transverse movable supports are set at other piers; dampers are set on both sides of the supports along the bridge direction; the bridge towers are set at different heights, with high bridge towers configured for large-span spans and low bridge towers configured for small-span spans, and the number of inclined cables matches the height of the bridge towers. The bridge piers where the longitudinal fixed supports are set in the present invention bear longitudinal additional forces such as braking force, and the main beams at other piers can freely expand and contract longitudinally, solving the problem of large bending moments of bridge towers caused by temperature effects in long-span and long-span asymmetric structures.

Description

Technical Field

[0001] The present invention belongs to the technical field of bridge engineering, and in particular relates to a multi-tower asymmetric low-tower cable-stayed bridge. Background Art

[0002] The low-tower cable-stayed bridge, also known as the partial cable-stayed bridge, is a cable-stayed composite system bridge type between the continuous beam bridge and the cable-stayed bridge. It has the advantages of high main beam stiffness, strong spanning capacity, simple construction, good economy, and beautiful appearance. It is highly competitive in bridge schemes with a main span between 200 and 300 meters, a long-coupled structure, and limited tower height.

[0003] Multi-tower, low-tower cable-stayed bridges are long-span structures, which have difficulties such as large structural temperature effect, difficult structural foundation design, and prominent seismic resistance problems. In addition, the main spans of the multi-tower, low-tower cable-stayed bridges built so far are all symmetrical and equal-span arrangements. However, due to the influence of boundary conditions such as flood control and navigation, if a symmetrical and equal-span arrangement is adopted, the small main span must be consistent with the span of the most controlled largest main span, and the bridge tower height corresponding to the small main span must be consistent with the bridge tower height corresponding to the most controlled largest main span. This will uniformly increase the bridge span and bridge tower height, increase the main bridge length, and make the span arrangement inflexible and unfree, resulting in waste of project investment or mismatch between the bridge span and the bridge tower height, unreasonable structural force, and greatly reduced the economy and applicability of the bridge. Summary of the Invention

[0004] In order to make up for the shortcomings of the existing technology, the present invention provides a multi-tower asymmetric low-tower cable-stayed bridge to solve the problems of large temperature effect of long-span structure of multi-tower asymmetric low-tower cable-stayed bridge, difficult foundation design, difficult seismic fortification, negative reaction force on secondary piers, and difficulty in symmetrical and equal span arrangement of spans under complex boundary control conditions.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A multi-tower asymmetric low-tower cable-stayed bridge, characterized in that: it comprises side spans, a main span, and bridge towers, wherein steel trusses are fixedly connected to the bottoms of the bridge towers; one end of the inclined cable is fixedly connected to the bridge tower, and the other end is fixedly connected to the steel truss;

[0007] A main pier, an auxiliary pier and a connecting pier are provided at the lower part of the steel truss beam, a cap is provided below the main pier, the auxiliary pier and the connecting pier, and a foundation is provided below the cap;

[0008] The top surfaces of the main piers, auxiliary piers and connecting piers are provided with supports. A longitudinal and transverse fixed support is provided on one side of the main pier at the center, and a longitudinal fixed support is provided on the other side. Longitudinal movable supports and longitudinal and transverse movable supports are provided on other piers.

[0009] Dampers are arranged on both sides of the support along the bridge direction, the top of the damper is fixedly connected to the steel truss, and the bottom is fixedly connected to the top surface of the pier.

[0010] Furthermore, the angle between the damper and the center of the support is 45°;

[0011] Furthermore, the steel truss includes an upper deck structure and a lower deck structure, two main trusses are arranged in the transverse direction of the bridge, and the upper deck structure, the lower deck structure and the main trusses are fixedly connected by transverse cross braces, transverse diagonal braces, diagonal braces and hangers;

[0012] Furthermore, the upper deck structure of the standard steel truss section is an orthotropic steel deck, and the upper deck structure of the weighted section is a steel truss concrete composite deck; the middle driving area of the lower deck structure is an orthotropic steel deck, and the decks on both sides of the driving area are hollow structures;

[0013] Furthermore, both the side span and the main span adopt an asymmetric span arrangement;

[0014] Furthermore, the bridge towers are arranged at different heights, with high bridge towers being configured for large spans and low bridge towers being configured for small spans;

[0015] Furthermore, the number of stay cables matches the height of the bridge towers, with taller towers having more stay cables and shorter towers having fewer stay cables.

[0016] Beneficial effects of the present invention:

[0017] 1) This invention adopts a structural system in which the tower and beam are consolidated and the tower and pier are separated. The piers where the longitudinal fixed supports are set bear longitudinal additional forces such as braking force, while the main beams at other piers can freely expand and contract longitudinally. This solves the technical problem of large bending moments in bridge towers caused by temperature effects in long-bridged and long-span asymmetric structures. At the same time, the horizontal force and longitudinal bending moment in the foundation are both small, thus significantly reducing the engineering workload of the lower foundation.

[0018] 2) Each pier of the asymmetric, low-tower, cable-stayed bridge of the present invention is equipped with a damper, arranged at a 45-degree angle to the main beam. Under earthquake action, the longitudinal and transverse fixed supports shear off, becoming movable supports. The dampers function to simultaneously reduce the seismic response of the long-span, multi-tower, low-tower cable-stayed bridge in both the longitudinal and transverse directions.

[0019] 3) The present invention uses a steel-truss concrete composite bridge deck for weighting within a certain length range of the long-distance side span, combining structural force with weighting, avoiding negative reaction forces on the secondary piers of asymmetric low-tower cable-stayed bridges and effectively improving the durability of the bridge structure.

[0020] 4) The asymmetric low-tower cable-stayed bridge of the present invention rationally arranges spans based on actual boundary conditions, breaking the traditional symmetrical span arrangement of multi-tower low-tower cable-stayed bridges. The span arrangement is flexible, making it easier to meet navigation and flood control requirements, avoiding the need to increase spans to achieve a symmetrical arrangement, and saving construction costs.

[0021] 5) The multi-tower asymmetric low-tower cable-stayed bridge of the present invention has the characteristics of "high towers for large spans, low towers for small spans, more cables for high towers, and fewer cables for low towers." It has a well-arranged structure and reasonable force distribution. It maximizes the material properties of the bridge towers and cables, saves engineering materials, and is economical.

[0022] 6) When the multi-tower asymmetric low-tower cable-stayed bridge of the present invention is built near an airport, low bridge towers are configured on the side close to the airport and high bridge towers are configured on the side away from the airport. The arrangement of high and low bridge towers makes good use of the aviation height limit on the sloped surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the facade layout of a multi-tower asymmetric low-tower cable-stayed bridge in an embodiment;

[0024] Figure 2 Schematic diagram of the vertical arrangement of supports and dampers in the embodiment;

[0025] Figure 3 Schematic diagram of the plane arrangement of the support and damper in the embodiment;

[0026] Figure 4 2. ...

[0027] Figure 5 2. It is a schematic cross-sectional view of a steel truss girder in a weight-bearing section in an embodiment;

[0028] In the figure, 1. side span; 2. main span; 3. bridge tower; 4. cable-stayed cable; 5. steel truss; 6. connecting pier; 7. auxiliary pier; 8. main pier; 9. abutment; 10. foundation; 11. main truss; 12. upper deck structure; 13. lower deck structure; 14. transverse cross brace; 15. transverse diagonal brace; 16. diagonal brace; 17. hanger; 18. orthotropic steel deck; 19. steel truss-concrete combined deck; 20 bearing; 21. damper; 22. longitudinal and transverse fixed bearings; 23. longitudinal fixed bearing; 24. longitudinal movable bearing; 25. longitudinal and transverse movable bearing. DETAILED DESCRIPTION

[0029] The present invention will be described in detail below with reference to specific embodiments.

[0030] like Figure 1 As shown, this embodiment provides a multi-tower asymmetric low-tower cable-stayed bridge, including a side span 1, a main span 2, a bridge tower 3, and a stay cable 4. A steel truss 5 is fixedly connected to the bottom of the bridge tower 3. A main pier 8, an auxiliary pier 7, and a connecting pier 6 are arranged at the lower part of the steel truss 5. The connecting pier 6 is located at the starting and ending positions of the multi-tower asymmetric low-tower cable-stayed bridge. The main pier 8 is the pier at the position of the bridge tower 3, and the auxiliary pier 7 is the pier between the connecting pier 6 and the main pier 8. A pier 9 is located below the pier. A foundation 10 is located below the pier 9; as shown in FIG. Figure 2 and Figure 3 As shown, this embodiment also includes supports 20 and dampers 21. Supports 20 are installed on the top surfaces of connecting piers 6, auxiliary piers 7, and main piers 8. A longitudinal and transverse fixed support 22 is installed on one side of the main pier 8 at the center, and a longitudinal fixed support 23 is installed on the other side in the transverse direction of the bridge. The other piers are provided with longitudinal movable supports 24 and longitudinal and transverse movable supports 25. A structural system is adopted in which the bridge tower 3 is fixed to the steel truss 5 and separated from the piers. The piers at the longitudinal and transverse fixed supports 22 are subjected to longitudinal additional forces such as braking force, while the steel truss 5 at the other piers can freely expand and contract in the longitudinal direction of the bridge. This solves the technical problem of large bending moments in bridge towers caused by temperature effects in long-span, long-span asymmetric structures. The horizontal force and longitudinal bending moment of the foundation 10 are both small, thus significantly reducing the engineering workload of the lower foundation 10.

[0031] The dampers 21 are located on both sides of the supports 20 along the bridge direction, with their tops connected to the steel trusses 5 and their bottoms connected to the top surfaces of the piers. The function of the dampers 21 is to reduce the transverse and longitudinal displacements of the cable-stayed bridge under loads such as earthquakes, and to absorb and consume energy to reduce the stress on the piers. The dampers 21 are arranged at a 45° angle, which can simultaneously reduce the seismic response of the cable-stayed bridge in both the transverse and longitudinal directions.

[0032] like Figure 4 and Figure 5 As shown, in this embodiment, the steel truss 5 adopts the same width scheme of the upper bridge deck structure 12 and the lower bridge deck structure 13, and two main trusses 11 are used in the transverse direction of the bridge; the main trusses 11, the upper bridge deck structure 12 and the lower bridge deck structure 13 are connected by transverse cross braces 14, transverse diagonal braces 15, diagonal braces 16 and hangers 17; the upper bridge deck structure 12 is a six-lane first-class highway, and the lower bridge deck structure 13 is a ballasted double-track railway; in order to prevent the multi-tower asymmetric low-tower cable-stayed bridge from bearing under normal use Negative reaction forces 20 occur, effectively improving the durability of the bridge structure. A steel-truss-concrete composite deck 19 is used for weighting within a certain length of the long-distance side span 1, integrating structural force and weighting. The standard-section steel truss girder upper deck structure 12 utilizes an orthotropic steel deck 18, while the weighted-section steel truss girder upper deck structure 12 utilizes a steel-truss-concrete composite deck 19. The lower deck structure 13 utilizes an orthotropic steel deck 18 in the middle traffic area, with the deck panels on both sides of the traffic area hollowed out. This cross-sectional main truss 11 features a simple structure, direct force transmission, and easy installation. It also meets the width requirements of both highway and railway sections, achieving high cross-sectional efficiency and achieving the integration of highway and railway at the bridge site.

[0033] According to the requirements of flood control and navigation, this embodiment breaks the tradition of symmetric span arrangement for multi-tower low-tower cable-stayed bridges. Both the side span 1 and the main span 2 adopt asymmetric span arrangements. The side span 1 on the small mileage side has a span of L1 + L2, and the side span 1 on the large mileage side has a span of L2’ + L1’, where L1 ≠ L1’, L2 ≠ L2’. The main span 2 adopts a span arrangement of L3 + L4 + L3’, where L3 ≠ L3’. The asymmetric span arrangements of both the side span 1 and the main span 2 not only meet the requirements of complex boundary control conditions but also reduce the bridge construction cost.

[0034] This embodiment is relatively close to the airport runway and is located within the aircraft takeoff climb surface. The airport control elevation gradually increases from the small mileage side to the large mileage side. To meet the aviation height limit requirements, the four bridge towers 3 are designed with unequal heights. The bridge towers 3 are arranged with unequal heights, with high bridge towers configured for large-span crossings and low bridge towers configured for small-span crossings. Low bridge towers 3 are configured near the airport side, and high bridge towers 3 are configured far from the airport side. The heights of the four bridge towers 3 are H1, H2, H3, and H4 respectively, where H1 < H2 < H3 < H4. At the same time, the number of pairs of stay cables 4 matches the tower height. The four bridge towers 3 respectively adopt seven pairs, eight pairs, eight pairs, and nine pairs of stay cables 4. Therefore, the characteristics of "large-span with high towers, small-span with low towers, high towers with more stay cables, and low towers with fewer stay cables" are formed. The structural force is reasonable, and the number of stay cables 4 is reduced to a certain extent, reducing the project cost.

[0035] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "small mileage side", "large mileage side", "up", "down", "transverse bridge direction", "longitudinal bridge direction", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0036] In the description of the present invention, unless otherwise clearly specified and limited, the terms "set", "install", "connect", "connect", "fix" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal connection of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0037] The content of the present invention is not limited to the examples listed. Any equivalent transformation of the technical solution of the present invention by those of ordinary skill in the art through reading the specification of the present invention is covered by the claims of the present invention.

Claims

1. A multi-tower asymmetric low-tower cable-stayed bridge, characterized by: It includes a side span (1), a main span (2), and a bridge tower (3), wherein a steel truss (5) is fixedly connected to the bottom of the bridge tower (3); one end of the inclined cable (4) is fixedly connected to the bridge tower (3), and the other end is fixedly connected to the steel truss (5); A main pier (8), an auxiliary pier (7) and a connecting pier (6) are provided at the lower portion of the steel truss (5); a cap (9) is provided below the main pier (8), the auxiliary pier (7) and the connecting pier (6); and a foundation (10) is provided below the cap (9); The main pier (8), auxiliary pier (7) and connecting pier (6) are provided with supports (20) on their top surfaces; a longitudinal and transverse fixed support (22) is provided on one side of the main pier (8) at the center position, and a longitudinal fixed support (23) is provided on the other side; longitudinal movable supports (24) and longitudinal and transverse movable supports (25) are provided on the other piers; Dampers (21) are provided on both sides of the support (20) along the bridge direction. The top of the damper (21) is fixedly connected to the steel truss (5), and the bottom is fixedly connected to the top surface of the pier.

2. The multi-tower asymmetric low-tower cable-stayed bridge according to claim 1, characterized in that: The center angle between the damper (21) and the support (20) is 45°.

3. The multi-tower asymmetric low-tower cable-stayed bridge according to claim 2, characterized in that: The steel truss (5) comprises an upper deck structure (12) and a lower deck structure (13), two main trusses (11) are arranged in the transverse direction of the bridge, and the upper deck structure (12), the lower deck structure (13) and the main trusses (11) are fixedly connected by transverse cross braces (14), transverse diagonal braces (15), diagonal braces (16) and hangers (17).

4. The multi-tower asymmetric low-tower cable-stayed bridge according to claim 3, characterized in that: The upper deck structure (12) of the standard section of the steel truss girder (5) is an orthotropic steel deck (18), and the upper deck structure (12) of the weighted section is a steel truss concrete composite deck (19); the middle driving area of the lower deck structure (13) is an orthotropic steel deck (18), and the deck plates on both sides of the driving area are hollow structures.

5. The multi-tower asymmetric low-tower cable-stayed bridge according to claim 4, characterized in that: Both the side span (1) and the main span (2) adopt an asymmetric span arrangement.

6. The multi-tower asymmetric low-tower cable-stayed bridge according to claim 5, characterized in that: The bridge towers (3) are arranged at different heights, with high bridge towers (3) being configured for large spans and low bridge towers (3) being configured for small spans.

7. The multi-tower asymmetric low-tower cable-stayed bridge according to claim 6, characterized in that: The number of the inclined cables (4) matches the height of the bridge tower (3), with a high bridge tower (3) being equipped with more inclined cables (4) and a low bridge tower (3) being equipped with fewer inclined cables (4).

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