A single-tower cable-stayed bridge longitudinal single-mode plastic damping system, design method and system

Abstract

The application relates to a longitudinal monotonic plasticity damping system, a design method and a system of a single-tower cable-stayed bridge, a monotonic plasticity constraint device is arranged at the tower-beam connection of the single-tower cable-stayed bridge, the monotonic plasticity constraint device comprises at least one pair of high-strength steel pull rods, one end of each high-strength steel pull rod is anchored to a cross beam of a main tower, the other end is anchored to a beam bottom of a main beam, one pair of high-strength steel pull rods are arranged on the front and back sides of the main tower to form symmetrical constraints in the positive and negative directions along the longitudinal direction of the bridge, the high-strength steel pull rod only enters plasticity in a tensile state, the main beam is suspended by a 0th cable or uses a longitudinal sliding support at the main tower, and the supports at auxiliary piers and transition piers are all longitudinal sliding supports, so as to form a tower-beam longitudinal monotonic plasticity damping system. Compared with the prior art, the damping system can meet the needs of the longitudinal constraint stiffness of the tower and the beam of the bridge structure in a normal operation state, can effectively cope with various seismic actions, and has a wide application range.

Description

Technical Field

[0001] This invention relates to the field of vibration reduction technology for bridge engineering structures, and in particular to a longitudinal monotonic plastic vibration reduction system, design method and system for a single-tower cable-stayed bridge. Background Technology

[0002] Currently, the focus of my country's transportation infrastructure construction is gradually shifting to the central and western regions, leading to a new peak in bridge construction. Because the central and western regions of my country are mostly mountainous and hilly, with numerous deeply eroded river valleys, there is a significant demand for large-span bridges with single spans of 200m to 400m. Furthermore, the central and western regions of my country face a high risk of earthquakes. Therefore, in this span range, single-tower cable-stayed bridges have become a highly competitive bridge type, offering advantages such as aesthetic appeal, ease of construction, and cost-effectiveness.

[0003] Cable-stayed bridges in high-intensity seismic zones generally employ fully floating or semi-floating systems. This involves releasing the longitudinal constraints between the towers and beams to avoid excessive inertial force response of the main beam under seismic loading. Simultaneously, to control the large seismic displacement response of the floating system, additional constraints or damping energy dissipation measures are often installed between the towers and beams. In the long-span cable-stayed bridges already built in my country, the most common tower-beam damping device is the viscous damper. For classic double-tower cable-stayed bridge structures, whether under static loads during daily operation or significant dynamic loads such as earthquakes, the floating system combined with viscous damping energy dissipation measures is an ideal load-bearing system. This is because, considering the effects of daily temperature changes, it is necessary to release the tower-beam constraints to accommodate their deformation. Simultaneously, under seismic loading, extending the structural period creates a seismic isolation effect. Furthermore, the viscous damper is a damping measure with theoretically zero constraint stiffness, meaning it does not affect the static load effect.

[0004] However, the situation is different for single-tower cable-stayed bridges. The tower-beam connection should ideally be considered the zero point for the overall structural temperature rise and fall effect, which helps reduce frictional losses at the supports. Simultaneously, the necessary constraint effect between the tower and beam helps control structural displacement under horizontal loads such as wind loads. This is especially important for mountain bridges where strong winds in local canyons must be considered; a floating system could lead to significant wind-induced displacement, which is detrimental to the supports and expansion joints. This indicates that a fixed tower-beam system is more suitable for single-tower cable-stayed bridges under static loads during daily operation. However, under seismic loads, a certain degree of release of the tower-beam constraint is needed to create a damping effect similar to a floating system. Therefore, the structural systems required for single-tower cable-stayed bridges under static loads during daily operation and under seismic loads are not the same.

[0005] As viscous dampers are increasingly used in actual bridge engineering, some inherent problems have gradually become apparent. These include leakage and cavitation issues caused by the viscous fluid in the damper being affected by ambient temperature, and fatigue stress issues caused by vehicle loads. These issues prevent viscous dampers from achieving the ideal vibration reduction and energy dissipation effects seen in calculations. Furthermore, considering the tower-beam constraint requirements of a single-tower cable-stayed bridge under static loads during daily operation, viscous dampers cannot provide the expected tower-beam constraint effect. Therefore, while a floating system combined with viscous dampers is a reasonable vibration reduction system for double-tower cable-stayed bridges, it is not an ideal system for single-tower cable-stayed bridges. Early cable-stayed bridges in Japan often used a tower-beam elastic cable constraint system, such as the Meiko-Nishi Bridge. This elastic cable system forms a flexible constraint system between the tower and beam, providing a certain level of constraint stiffness under normal operating conditions while allowing for significant relative displacement of the tower and beam under seismic conditions, thus achieving seismic isolation. Elastic cables are simple in construction and reliable in performance, but they generally require a long length and are not convenient to install on bridges. In addition, since elastic cables themselves do not provide an energy dissipation mechanism, their structural damping effect is low.

[0006] In summary, it is necessary to design a vibration reduction system based on monotonic plasticity suitable for single-tower cable-stayed bridges. Summary of the Invention

[0007] The purpose of this invention is to overcome the defects of the prior art by providing a longitudinal monotonic plastic damping system, design method and system for single-tower cable-stayed bridges. This damping system can improve the structural constraint state and performance under normal operating conditions, can adapt to various seismic actions, and has excellent durability and reliability.

[0008] The objective of this invention can be achieved through the following technical solutions:

[0009] According to a first aspect of the present invention, a longitudinal monotonic plastic damping system for a single-tower cable-stayed bridge is provided. A monotonic plastic constraint device is provided at the tower-beam connection of the single-tower cable-stayed bridge. The monotonic plastic constraint device includes at least one pair of high-strength steel tie rods. One end of each high-strength steel tie rod is anchored to the crossbeam of the main tower, and the other end is anchored to the bottom of the main beam. The pair of high-strength steel tie rods are respectively arranged on the front and rear sides of the main tower to form symmetrical constraints in the positive and negative directions along the longitudinal direction of the bridge. The high-strength steel tie rods only enter the plastic state under tension, thereby forming the characteristic of monotonic plasticity.

[0010] Furthermore, the main beam is suspended by No. 0 cable or longitudinal sliding support at the main tower, and the supports at the auxiliary piers and transition piers are all set as longitudinal sliding supports, thereby forming a tower-beam longitudinal monotonic plastic damping system.

[0011] According to a second aspect of the present invention, a design method for a longitudinal monotonic plastic damping system for a single-tower cable-stayed bridge is provided, for designing the area A and effective length L of the high-strength steel tie rod in the longitudinal monotonic plastic damping system for a single-tower cable-stayed bridge as described in the first aspect of the present invention, wherein the design formula is:

[0012]

[0013] In the formula, λ is the design limit elongation of the high-strength steel tie rod, preferably λ = 0.05; S a η is the spectral acceleration value corresponding to the first-order longitudinal vibration mode period of the main girder of the single-tower cable-stayed bridge; M is the total mass of the main girder of the cable-stayed bridge, including the secondary dead load; ξ is the damping adjustment coefficient of the high-strength steel tie rod; k1 is the longitudinal constraint stiffness of the main tower and cable-stayed system on the main beam, preferably... Where T0 is the longitudinal vibration period of the main girder of the cable-stayed bridge without considering the high-strength steel tie rod; k2 is the constraint stiffness of the high-strength steel tie rod on the main girder under the design displacement, preferably k2 = AF. y / λL;F y α represents the equivalent yield strength of the high-strength steel tie rod; α is the strength verification enhancement factor for fatigue of the high-strength steel tie rod considering non-seismic load combinations such as wind and vehicle braking, preferably α = 2.5~3.0; F s To consider the maximum longitudinal shear force of the tower beam under non-seismic load combinations such as wind and vehicle braking.

[0014] Furthermore, S a The spectral acceleration value corresponding to the first-order longitudinal vibration mode period of the main girder of a single-tower cable-stayed bridge is calculated according to the design spectral function S. a (T1) takes a value, where T1 is calculated according to the following formula:

[0015]

[0016] In the formula, M is the total mass of the main girder of the cable-stayed bridge, including the secondary dead load; k1 is the longitudinal constraint stiffness of the main girder by the main tower and cable system; k2 is the constraint stiffness of the high-strength steel tie rod on the main girder under the design displacement.

[0017] Furthermore, η ξ The damping adjustment coefficient for the high-strength steel tie rod is calculated using the following formula:

[0018]

[0019] Wherein, ξ is the equivalent damping ratio considering the energy consumption of the high-strength steel tie rod, β is the reduction coefficient considering the monotonic energy consumption of the high-strength steel tie rod, preferably β=0.5; E is the material elastic modulus of the high-strength steel tie rod, E=195GPa.

[0020] Furthermore, in the design formulas for the area A and effective length L of the high-strength steel tie rod, the value obtained when one of the inequalities satisfies the equality condition and the other inequality satisfies the greater than or equal to condition is the design scheme for the high-strength steel tie rod.

[0021] According to a third aspect of the present invention, a design system for a longitudinal monotonic plastic damping system for a single-tower cable-stayed bridge is provided, for designing the area A and effective length L of the high-strength steel tie rod in the longitudinal monotonic plastic damping system for a single-tower cable-stayed bridge as described in the first aspect of the present invention, comprising:

[0022] The data input module is used for inputting data;

[0023] The solver module is used to solve for the area A and effective length L of the high-strength steel tie rod. The design formulas for the area A and effective length L of the high-strength steel tie rod are as follows:

[0024]

[0025] In the formula, λ is the design limit elongation of the high-strength steel tie rod, preferably λ = 0.05; S a η is the spectral acceleration value corresponding to the first-order longitudinal vibration mode period of the main girder of the single-tower cable-stayed bridge; M is the total mass of the main girder of the cable-stayed bridge, including the secondary dead load; ξ is the damping adjustment coefficient of the high-strength steel tie rod; k1 is the longitudinal constraint stiffness of the main tower and cable-stayed system on the main beam, preferably... Where T0 is the longitudinal vibration period of the main girder of the cable-stayed bridge without considering the high-strength steel tie rod; k2 is the constraint stiffness of the high-strength steel tie rod on the main girder under the design displacement, preferably k2 = AF. y / λL;F y α represents the equivalent yield strength of the high-strength steel tie rod; α is the strength verification enhancement factor for fatigue of the high-strength steel tie rod considering non-seismic load combinations such as wind and vehicle braking, preferably α = 2.5~3.0; F s To consider the maximum longitudinal shear force of the tower beam under non-seismic load combinations such as wind and vehicle braking.

[0026] Furthermore, S a The spectral acceleration value corresponding to the first-order longitudinal vibration mode period of the main girder of a single-tower cable-stayed bridge is calculated according to the design spectral function S. a (T1) takes a value, where T1 is calculated according to the following formula:

[0027]

[0028] In the formula, M is the total mass of the main girder of the cable-stayed bridge, including the secondary dead load; k1 is the longitudinal constraint stiffness of the main girder by the main tower and cable system; k2 is the constraint stiffness of the high-strength steel tie rod on the main girder under the design displacement.

[0029] Furthermore, η ξ The damping adjustment coefficient for the high-strength steel tie rod is calculated using the following formula:

[0030]

[0031]

[0032] Wherein, ξ is the equivalent damping ratio considering the energy consumption of the high-strength steel tie rod, β is the reduction coefficient considering the monotonic energy consumption of the high-strength steel tie rod, preferably β=0.5; E is the material elastic modulus of the high-strength steel tie rod, E=195GPa.

[0033] Furthermore, in the design formulas for the area A and effective length L of the high-strength steel tie rod, the value obtained when one of the inequalities satisfies the equality condition and the other inequality satisfies the greater than or equal to condition is the design scheme for the high-strength steel tie rod.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] (1) By setting pairs of high-strength steel tie rods in the longitudinal direction of the tower-beam, the high-strength steel tie rods have greater constraint stiffness. The high-strength steel tie rods form a new bridge vibration reduction system in the longitudinal constraint of the tower-beam, so as to meet the constraint stiffness requirements under normal use and the vibration reduction requirements under seismic action. This can significantly improve the normal use performance of single-tower cable-stayed bridges. At the same time, different performance states are adopted to consider different seismic actions, which can adapt well to various seismic actions and have a wide range of applications.

[0036] (2) High-strength steel tie rods have high material utilization, good economy, are easy to install, and have greater constraint stiffness to better meet the constraint stiffness requirements under normal use conditions. They also have a wider range of applicable parameters and can adapt well to various seismic actions.

[0037] (3) The present invention establishes relevant calculation expressions based on the concept of dynamics. The physical meaning is clear, simple and easy to operate. At the same time, the inequalities also give designers a greater degree of freedom of choice. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the connection between a high-strength steel tie rod tower beam.

[0039] Figure 2 This is a schematic diagram of a monotonic plastic damping system for a high-strength steel tie rod of a single-tower cable-stayed bridge.

[0040] Figure 3 This is a comparison chart of the effective design parameter ranges for high-strength steel tie rods and elastic cables.

[0041] Figure 4This is a comparison diagram of the displacement response of the high-strength steel tie rod and the elastic cable main beam.

[0042] Figure 5 This is a comparison diagram of the elastic stiffness of high-strength steel tie rods and elastic cables.

[0043] In the diagram: 1-High-strength steel tie rod, 2-Main tower, 3-Crossbeam, 4-Main beam, 5-Longitudinal sliding support, 6-Auxiliary pier, 7-Transition pier. Detailed Implementation

[0044] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are implemented based on the technical solutions of the present invention, providing detailed implementation methods and specific operating procedures. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them, and the scope of protection of the present invention is not limited to the following embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0045] In the accompanying drawings, components with the same structure are indicated by the same numerical designation, and components with similar structures or functions are indicated by similar numerical designations. The dimensions and thicknesses of each component shown in the drawings are arbitrary, and the present invention does not limit the dimensions and thicknesses of each component. To make the illustrations clearer and show the mating relationships between the components, some parts in the drawings have been appropriately scaled down, and the distances between the components have been increased or decreased.

[0046] In the description of the embodiments of this application, it should be understood that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly placed when the product of this application is used, or the orientation or positional relationship commonly understood by those skilled in the art. They are only for the convenience of describing this application and simplifying the description, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0047] As used herein, "an embodiment" or "embodiment" refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the invention. In the description of the invention, it should be understood that the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such processes, methods, products, or apparatus.

[0048] In the description of the embodiments of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set," "install," "connect," and "link" 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0049] A longitudinally monotonic plastic damping system for a single-tower cable-stayed bridge comprises high-strength steel tie rods arranged in pairs, placed on the front and rear sides of the main tower respectively, and connected to the main tower crossbeam and main beam respectively through anchor blocks. Specifically, such as... Figure 1 As shown, a monotonic plastic constraint device is first installed at the tower-beam connection of the single-tower cable-stayed bridge. This device includes at least one pair of high-strength steel tie rods 1. Each high-strength steel tie rod 1 is anchored at one end to the crossbeam 3 of the main tower 2 and at the other end to the bottom of the main beam 4. The pair of high-strength steel tie rods 1 are respectively installed on the front and rear sides of the main tower 2 to form symmetrical constraints along the longitudinal direction of the bridge. The high-strength steel tie rods 1 are anchored using a through-hole anchoring method, with only the outer tension anchor nuts installed. This allows the high-strength steel tie rod 1 to slide out through the hole when under compression, entering plasticity only under tension, thus forming the characteristic of monotonic plasticity. Of course, in specific applications, the structural design and installation can be tailored to the actual construction scenario so that the high-strength steel tie rods are not under compression and only enter plasticity under tension. Those skilled in the art can set this up themselves, and it will not be listed here. A typical single-tower cable-stayed bridge in an 8-degree seismic intensity zone uses a longitudinal monotonic plastic damping system, such as... Figure 2 As shown, the main beam 4 is suspended by cable No. 0 or longitudinal sliding support 5 at the main tower 2, and the supports at the auxiliary pier 6 and transition pier 7 are all set as longitudinal sliding supports 5, thus forming a tower-beam longitudinal monotonic plastic damping system.

[0050] The conventional longitudinal systems of cable-stayed bridges mainly include longitudinal floating systems and longitudinal fixed systems. In a longitudinal floating system, the main girder can move freely under external forces, thus providing excellent seismic isolation. However, under normal operating conditions, it will displace under wind loads and vehicle braking forces, affecting normal use. The longitudinal fixed system is the opposite; under normal operating conditions, it avoids displacement caused by wind loads and vehicle braking forces, but under seismic loads, it will generate very large seismic shear forces. This design scheme takes into account both situations. The elastic stiffness of the high-strength steel tie rods can effectively restrain displacement caused by wind and braking forces, while under seismic loads, the tie rods yield, limiting the magnitude of seismic shear forces while hysteretly dissipating energy, thus effectively playing a seismic isolation role. This system can meet the longitudinal restraint stiffness requirements of the tower and girder structure under normal operating conditions and can effectively cope with various seismic loads, making it widely applicable.

[0051] The design parameters for high-strength steel tie rods include two components: the area A of the tie rod and the effective length L of the tie rod. These are determined using the following formula:

[0052]

[0053] In the formula, λ is the design limit elongation of the tie rod, preferably λ = 0.05; S a The spectral acceleration value corresponding to the first-order longitudinal vibration mode period of the main girder of a single-tower cable-stayed bridge is calculated according to the design spectral function S. a (T1) takes a value, where T1 is calculated according to the following formula:

[0054]

[0055] In equations (1) and (2), M is the total mass of the main girder of the cable-stayed bridge, including the secondary dead load; k1 is the longitudinal constraint stiffness of the main tower and cable-stayed system on the main girder, preferably k1 = 4π 2 M / T0 2 Where T0 is the longitudinal vibration period of the main girder of the cable-stayed bridge without considering the high-strength steel tie rod; k2 is the constraint stiffness of the high-strength steel tie rod on the main girder under the design displacement, preferably k2 = AF. y / λL, where F y η represents the equivalent yield strength of the high-strength steel tie rod. ξ The damping adjustment coefficient for the high-strength steel tie rod is calculated using the following formula:

[0056]

[0057] In equation (3), ξ is the equivalent damping ratio considering the energy dissipation of the high-strength steel tie rod, calculated by the following formula:

[0058]

[0059] In equation (4), β is the reduction factor considering the monotonic energy dissipation of the high-strength steel tie rod, preferably β = 0.5; E is the material elastic modulus of the high-strength steel tie rod, E = 195 GPa. In equation (1), α is the strength verification improvement factor for fatigue of the high-strength steel tie rod considering the combination of non-seismic loads such as wind and vehicle braking, preferably α = 2.5~3.0; F s This represents the maximum longitudinal shear force of the tower beam under a combination of non-seismic loads such as wind and vehicle braking.

[0060] According to the two inequalities in equation (1), the applicable design parameters A and L for high-strength steel tie rods are obviously not unique, which gives designers more freedom of choice. Generally, the most economical design scheme for high-strength steel tie rods is to satisfy one of the inequalities as equal to the other and the other as greater than or equal to the other.

[0061] Under normal operating conditions, the tower-beam longitudinal high-strength steel tie rods maintain an elastic working state, effectively controlling the relative displacement between each tower / pier and the main beam to improve the normal operational performance of the bridge structure. When the seismic force at the bridge site is relatively small, the tower-beam longitudinal high-strength steel tie rods can still maintain an elastic working state or only enter a slight plastic state, allowing the bridge structure to fully self-reset after an earthquake and possess full toughness. When the seismic force at the bridge site is large, especially when facing extreme seismic forces such as near-field earthquakes, the tower-beam longitudinal high-strength steel tie rods can fully enter a plastic state and utilize the monotonic high energy dissipation characteristics of the high-strength steel tie rods to overcome extreme seismic forces such as strong pulses. Although the tie rods that loosen due to plastic deformation after an earthquake cannot achieve complete self-resetting of the main beam, they can assist in achieving rapid post-earthquake resetting of the main beam.

[0062] Figure 3 , 4 Figures 5 and 6 show a comparison of the effective design parameter ranges, main beam displacement response, and elastic stiffness of the tower-beam longitudinal high-strength steel tie rods and elastic cables, respectively. It can be seen that the high-strength steel tie rods have a wider range of applicable parameters than the elastic cables, and therefore can better adapt to different seismic loads. With a main beam displacement of 0.3m as the design control target, the design parameters of the high-strength steel tie rods and elastic cables are compared in Table 1.

[0063] Table 3 Comparison of design parameters for high-strength steel tie rods and elastic cables corresponding to the 0.3m main beam displacement target

[0064]

[0065] It can be seen that the length of the high-strength steel tie rod is only about 32% of that of the elastic cable, and its area is only 40% of that of the elastic cable. The amount of main cable material used in the elasto-plastic cable is only 13% of that of the elastic cable. However, the elastic stiffness of the high-strength steel tie rod is 22% higher than that of the elastic cable, thus it has better normal operating performance; its maximum yield force under earthquake is only 40% of that of the elastic cable, thus it has greater shock absorption effect.

[0066] This invention uses high-strength steel tie rods, which has the following advantages:

[0067] 1) High-strength steel tie rods make full use of the plastic deformation capacity of high-strength steel. Compared with ordinary elastic cables, they can shorten the length by more than 3 times, significantly saving materials, reducing costs, and facilitating installation.

[0068] 2) The high-strength steel tie rod adopts a monotonic plastic mechanism that is only subjected to tension, which can avoid the problem of low cycle fatigue life under high strain, and at the same time significantly improve its ultimate plastic deformation capacity.

[0069] 3) Compared with elastic cables, high-strength steel tie rods can significantly improve the elastic stiffness of the cable, thus better improving its performance under normal use conditions.

[0070] 4) High-strength steel tie rods can be selected to maintain different performance states such as elasticity, slight plasticity and full plasticity according to the magnitude of the seismic action, so as to adapt to the requirements of different seismic actions.

[0071] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A longitudinally monotonic plastic damping system for a single-tower cable-stayed bridge, characterized in that, A monotonic plastic constraint device is installed at the tower-beam connection of the single-tower cable-stayed bridge. The monotonic plastic constraint device includes at least one pair of high-strength steel tie rods (1). One end of each high-strength steel tie rod is anchored to the crossbeam (3) of the main tower (2), and the other end is anchored to the bottom of the main beam (4). The pair of high-strength steel tie rods are respectively set on the front and rear sides of the main tower (2) to form symmetrical constraints in the positive and negative directions along the longitudinal direction of the bridge. When the high-strength steel tie rod is anchored (1), a through-type anchoring is adopted, and only the outer tension anchoring nut is set, so that the high-strength steel tie rod (1) can slide out through the core when compressed, and only enters the plastic state under tension.

2. The longitudinal monotonic plastic damping system for a single-tower cable-stayed bridge according to claim 1, characterized in that, The main beam (4) is suspended by cable No. 0 or by longitudinal sliding support (5) at the main tower (2), and the supports at the auxiliary pier (6) and transition pier (7) are all set as longitudinal sliding supports (5).

3. A design method for a longitudinal monotonic plastic damping system for a single-tower cable-stayed bridge, characterized in that, The area of ​​the high-strength steel tie rod used in designing the longitudinal monotonic plastic damping system of a single-tower cable-stayed bridge as described in claim 1 or 2. and the effective length of high-strength steel tie rods The design formula is: In the formula, This represents the design limit elongation of the high-strength steel tie rod. The spectral acceleration value corresponding to the first-order longitudinal vibration mode period of the main girder of a single-tower cable-stayed bridge; This refers to the total mass of the main girder of the cable-stayed bridge, including the secondary dead load. This is the damping adjustment coefficient for the high-strength steel tie rod; The longitudinal constraint stiffness of the main tower and cable-stayed system on the main beam; To design the constraint stiffness of the high-strength steel tie rod on the main beam under displacement; This represents the equivalent yield strength of the high-strength steel tie rod. The strength enhancement factor for fatigue verification of high-strength steel tie rods under non-seismic load conditions; This represents the maximum longitudinal shear force of the tower beam under non-seismic load conditions.

4. The design method for a longitudinal monotonic plastic damping system for a single-tower cable-stayed bridge according to claim 3, characterized in that, The spectral acceleration value corresponding to the first-order longitudinal vibration mode period of the main girder of a single-tower cable-stayed bridge is calculated according to the design spectral function. Take values, where Calculate using the following formula: In the formula, This refers to the total mass of the main girder of the cable-stayed bridge, including the secondary dead load. The longitudinal constraint stiffness of the main tower and cable-stayed system on the main beam; To determine the constraint stiffness of the high-strength steel tie rod on the main beam under design displacement.

5. The design method for a longitudinal monotonic plastic damping system for a single-tower cable-stayed bridge according to claim 3, characterized in that, The damping adjustment coefficient for the high-strength steel tie rod is calculated using the following formula: in, To account for the equivalent damping ratio of energy dissipation in high-strength steel tie rods, To account for the reduction factor of monotonic energy consumption of high-strength steel tie rods; This refers to the elastic modulus of the high-strength steel tie rod.

6. The design method for a longitudinal monotonic plastic damping system for a single-tower cable-stayed bridge according to claim 3, characterized in that, Area of ​​high-strength steel tie rod and the effective length of high-strength steel tie rods In the design formula, the value obtained when one of the inequalities satisfies the equality condition and the other inequality satisfies the greater than or equal to condition is the design scheme for high-strength steel tie rods.

7. A design system for a longitudinally monotonic plastic damping system for a single-tower cable-stayed bridge, characterized in that, The area of ​​the high-strength steel tie rod used in designing the longitudinal monotonic plastic damping system of a single-tower cable-stayed bridge as described in claim 1 or 2. and the effective length of high-strength steel tie rods ,include: The data input module is used for inputting data; The solver module is used to calculate the area of ​​high-strength steel tie rods. and the effective length of high-strength steel tie rods The area of ​​the high-strength steel tie rod and the effective length of high-strength steel tie rods The design formula is: In the formula, This represents the design limit elongation of the high-strength steel tie rod. The spectral acceleration value corresponding to the first-order longitudinal vibration mode period of the main girder of a single-tower cable-stayed bridge; This refers to the total mass of the main girder of the cable-stayed bridge, including the secondary dead load. This is the damping adjustment coefficient for the high-strength steel tie rod; The longitudinal constraint stiffness of the main tower and cable-stayed system on the main beam; To design the constraint stiffness of the high-strength steel tie rod on the main beam under displacement; This represents the equivalent yield strength of the high-strength steel tie rod. The strength enhancement factor for fatigue verification of high-strength steel tie rods under non-seismic load conditions; This represents the maximum longitudinal shear force of the tower beam under non-seismic load conditions.

8. The design system for a longitudinal monotonic plastic damping system for a single-tower cable-stayed bridge according to claim 7, characterized in that, The spectral acceleration value corresponding to the first-order longitudinal vibration mode period of the main girder of a single-tower cable-stayed bridge is calculated according to the design spectral function. Take values, where Calculate using the following formula: In the formula, This refers to the total mass of the main girder of the cable-stayed bridge, including the secondary dead load. The longitudinal constraint stiffness of the main tower and cable-stayed system on the main beam; To determine the constraint stiffness of the high-strength steel tie rod on the main beam under design displacement.

9. The design system for a longitudinal monotonic plastic damping system for a single-tower cable-stayed bridge according to claim 7, characterized in that, The damping adjustment coefficient for the high-strength steel tie rod is calculated using the following formula: in, To account for the equivalent damping ratio of energy dissipation in high-strength steel tie rods, To account for the reduction factor of monotonic energy consumption of high-strength steel tie rods; This refers to the elastic modulus of the high-strength steel tie rod.

10. The design system for a longitudinal monotonic plastic damping system for a single-tower cable-stayed bridge according to claim 7, characterized in that, Area of ​​high-strength steel tie rod and the effective length of high-strength steel tie rods In the design formula, the value obtained when one of the inequalities satisfies the equality condition and the other inequality satisfies the greater than or equal to condition is the design scheme for high-strength steel tie rods.

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