A new composite beam cable-stayed bridge structural system

Abstract

The present invention relates to the field of bridge engineering technology, and specifically to a novel composite beam cable-stayed bridge structural system. The system of the present invention is a structural constraint system of "vertical full floating + single tower static longitudinal constraint". No vertical constraints are set between the two bridge towers and the main beam, but longitudinal dampers are set. A longitudinal constraint is set between one of the bridge towers and the main beam. When the earthquake exceeds the limiting force of the longitudinal constraint, the longitudinal constraint is sheared, and the entire bridge becomes a fully floating structural system. The effect of the present invention is that compared with the fully floating and semi-floating structural systems, it can significantly improve the stiffness of the structure and reduce the size of the expansion joint; compared with the tower-beam consolidation system and the semi-floating system, it can greatly reduce the bending moment of the tower root main beam and improve the force-bearing performance of the composite beam; under the action of small and medium earthquakes, the structural resistance can be used to resist the earthquake; under the action of a large earthquake, the longitudinal constraint is sheared, and the damper plays a shock-absorbing role, thereby achieving the purpose of protecting the safety of the structure.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge engineering, in particular to a novel composite beam cable-stayed bridge structural system. Background Art

[0002] Cable-stayed bridges, due to their excellent mechanical properties, large span capacity, and economical construction, have seen rapid expansion over the past half century, becoming the most widely used long-span bridge type. Composite-beam cable-stayed bridges fully utilize the mechanical properties of steel and concrete, while overcoming the shortcomings of steel deck systems, such as poor durability and high construction costs. Over the past two decades, they have gradually become a competitive alternative to domestic long-span cable-stayed bridges. Large-span composite-beam cable-stayed bridges generally utilize a tower-to-beam consolidation system, a semi-floating system, or a fully floating system. Both the tower-to-beam consolidation system and the semi-floating system result in large negative bending moments in the main beam near the tower base. This is particularly true for composite-beam cable-stayed bridges, which can cause tension in the bridge deck at the tower base. To control cracks, the deck requires extensive reinforcement and even longitudinal prestressing, increasing construction complexity. Semi-floating and fully floating systems also result in weak structural stiffness and large expansion joints at the beam ends. Therefore, research is needed on a new cable-stayed bridge structural system that can both improve structural stiffness and significantly reduce the main beam bending moments at the tower base and the size of the expansion joints at the beam ends. Summary of the Invention

[0003] Compared with the full-floating and semi-floating structural systems, in order to improve the stiffness of the composite beam cable-stayed bridge, reduce the size of the expansion joints at the beam ends, improve driving comfort, and optimize the stress performance of the composite beam, this application proposes a new composite beam cable-stayed bridge structure. The longitudinal constraint of the single tower of the structure limits the overall longitudinal displacement of the structure and reduces the size of the expansion joints at the beam ends; due to the reduction in the longitudinal displacement of the main beam, the longitudinal displacement of the main tower is reduced, and thus the vertical displacement of the main beam is also reduced accordingly, so the longitudinal and vertical stiffness of the entire structure are improved. Under the action of small and medium earthquakes, the structural resistance can be used to resist the earthquake; under the action of a large earthquake, the longitudinal constraint is sheared, and the damper is used to play a shock-absorbing role to achieve the purpose of protecting the safety of the structure.

[0004] The present invention mainly adopts the following technical solutions:

[0005] A novel composite beam cable-stayed bridge structure system comprises side piers, auxiliary piers, several bridge towers and a main beam erected on the side piers and the auxiliary piers. The side piers are constructed at the ends of the cable-stayed bridge, several auxiliary piers are constructed between the side piers and the bridge towers, several inclined cables are fixed between the bridge towers and the main beam, no vertical support members are arranged between the bridge towers and the main beam, dampers are arranged between the bridge towers and the main beam, and a longitudinal restraint device is arranged between the single-side bridge tower and the main beam.

[0006] In some embodiments disclosed in the present invention, the longitudinal restraint device includes a longitudinal restraint base and a shear pin arranged on the longitudinal restraint base.

[0007] In some embodiments disclosed in the present solution, there are two side piers and two bridge towers, and no auxiliary piers are constructed under the main beam between adjacent bridge towers.

[0008] In some embodiments disclosed in the present scheme, the side of the bridge tower is a fixed corbel structure, the side of the main beam is extended with a steel beam corbel structure, a damper is provided on the side of the main beam, the damper is connected to the fixed corbel, and the steel beam corbel is suitable for connecting the fixed corbel.

[0009] In some embodiments disclosed in the present solution, a longitudinal restraint device is provided between the bridge tower and the main beam, the longitudinal restraint base is welded to the side of the steel beam corbel, and the longitudinal restraint base is connected through the shear pin and the welded steel plate.

[0010] In some embodiments disclosed in the present solution, no longitudinal restraint device is provided between the bridge tower and the main beam.

[0011] The present invention has the following beneficial effects:

[0012] The novel composite-beam cable-stayed bridge structure of this invention utilizes a "full vertical floating" combined with static longitudinal restraints on a single pylon. The full vertical floating restraint effectively reduces negative bending moments at the pylon base, improving the structural load-bearing performance. Under static and small to moderate earthquakes, the longitudinal restraints activate, effectively increasing structural rigidity and enabling smaller expansion joints at the beam ends. Under large earthquakes, the longitudinal restraints shear, allowing the dampers to activate, effectively reducing the seismic response and safeguarding the structure. This structural system reduces vertical supports, steel beam thickness near the pylon base, and bridge deck reinforcement, lowering project costs and offering significant social and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a structural schematic diagram of a novel composite beam cable-stayed bridge in a specific embodiment of the present invention;

[0014] Figure 2 This is a cross-sectional view of a novel composite beam cable-stayed bridge structure in a specific embodiment of the present invention;

[0015] Figure 3 Schematic diagram of the arrangement of the longitudinal restraint device and damper of a single-side bridge tower in a specific embodiment of the present invention;

[0016] Figure 4 This is a schematic diagram of a bridge tower without a longitudinal restraint device in a specific embodiment of the present invention.

[0017] The numbers in the figure are: 1-side pier, 2-auxiliary pier, 3-bridge tower, 31-fixed corbel, 32-longitudinal restraint base, 33-shear pin, 4-main beam, 5-stayed cable, 6-longitudinal damper. DETAILED DESCRIPTION

[0018] The following describes the embodiments of the present invention by means of specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0019] Among them, the accompanying drawings are only for illustrative purposes and represent only schematic diagrams rather than actual pictures, and should not be understood as limiting the present invention. In order to better illustrate the embodiments of the present invention, some parts of the accompanying drawings may be omitted, enlarged or reduced, and do not represent the dimensions of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions may be omitted in the accompanying drawings.

[0020] See also Figure 1 and 2 , Figure 1 and 2 This is a schematic diagram of a new composite beam cable-stayed bridge structure. It primarily comprises two side piers 1, two towers 3, several auxiliary piers 2 constructed between the side piers 1 and towers 3, and a main beam 4 mounted on the side piers 1 and auxiliary piers 2. The side piers 1 are located at the ends of the cable-stayed bridge. The main beam 4 penetrates the towers 3 and is mounted on them. Fixed brackets 31 extend from the sides of the towers 3 and are secured to the main beam 4. There is no vertical support between the steel beam 4 and the towers 3. Several cable stays 5 are fixed between the towers 3 and the main beam 4, symmetrically arranged about the towers 3. No auxiliary piers are constructed beneath the main beam between adjacent towers.

[0021] See also Figure 3 , Figure 3This diagram illustrates a longitudinal restraint system installed in a single-sided tower. A fixed corbel 31 extends from the side of the tower 3. The fixed corbels 31 are two symmetrical structures. Steel corbels 41 extend from the sides of the main beam 4. The fixed corbels 31 of the tower 3 are connected to the steel corbels 41 of the main beam 4. Two longitudinal dampers 6 are also installed on the sides of the main beam 4 in this section, each connected to the fixed corbel 31 to effectively reduce the structural response to seismic effects. In this embodiment, only one tower 3 is equipped with a longitudinal restraint system. The longitudinal restraint system includes a longitudinal restraint base 32 and shear pins 33 mounted on the base 32. The longitudinal restraint base 32 is welded to the steel corbel 41 and is located on both sides of the steel corbel 41. The longitudinal restraint base 32 is secured to the fixed corbel 31 via a steel plate and shear pins 33.

[0022] See also Figure 4 , Figure 4 This is a schematic diagram of a longitudinal restraint device installed in another bridge tower. In this embodiment, the arrangement of the bridge tower 3 on one side is as described above. Figure 3 Similarly, two fixed brackets 31 extend from the sides of the pylon 3, and a steel beam bracket 41 extends from the side of the main beam 4. The fixed brackets 31 of the pylon 3 are connected to the steel beam bracket 41 of the main beam 4, and the steel beam bracket 41 is located between the two fixed brackets 31. Longitudinal dampers 6 are also installed on the sides of the main beam 4, and the two longitudinal dampers 6 are connected to the two fixed brackets 3 respectively. However, unlike the other pylon 3, this pylon 3 does not have longitudinal restraints between the pylon 3 and the main beam 4. Therefore, for the entire composite beam cable-stayed bridge structure, under static and small to medium earthquake conditions, the shear pins 33 can withstand the horizontal shear force between the pylon 3 and the main beam 4, the longitudinal restraint device is activated, and the longitudinal dampers 6 are inactive. Under large earthquake conditions, the shear pins 33 will be sheared, and the longitudinal restraint device will no longer withstand the horizontal force between the pylon 3 and the main beam 4. The longitudinal dampers 6 will be activated, reducing the seismic response and achieving the purpose of protecting the safety of the structure.

Claims

1. A novel composite beam cable-stayed bridge structure system, comprising side piers (1), auxiliary piers (2), a plurality of bridge towers (3) and a main beam erected on the side piers (1) and the auxiliary piers (2), characterized in that: The side pier (1) is constructed at the end of the cable-stayed bridge, a plurality of auxiliary piers (2) are constructed between the side pier (1) and the bridge tower (3), a plurality of inclined cables (5) are fixed between the bridge tower (3) and the main beam (4), no vertical support members are provided between the bridge tower (3) and the main beam (4), longitudinal dampers (6) are provided between the bridge tower (3) and the main beam (4), and a longitudinal restraint device is provided between the single-side bridge tower (3) and the main beam (4); The longitudinal restraint device comprises a longitudinal restraint base (32) and a shear pin (33) arranged on the longitudinal restraint base (32); The side of the bridge tower (3) is a fixed bracket (31) structure, the side of the main beam (4) extends a steel beam bracket (41) structure, the side of the main beam (4) is provided with a longitudinal damper (6), the longitudinal damper (6) is connected to the fixed bracket (31), and the steel beam bracket (41) is suitable for connecting to the fixed bracket (31); A longitudinal restraint device is provided between the bridge tower (3) and the main beam (4), the longitudinal restraint base (32) is welded to the side of the steel beam bracket (41), and the longitudinal restraint base (32) is connected via the shear pin (33) and the welded steel plate; no vertical restraint device is provided between the bridge tower (3) and the main beam (4).

2. The novel composite beam cable-stayed bridge structure system according to claim 1 is characterized in that: There are two side piers (1) and two bridge towers (3), and no auxiliary piers (2) are constructed below the main beams (4) between adjacent bridge towers (3).

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