CN-115772846-B - Vibration reduction system for long sling cable end of suspension bridge

CN115772846BCN 115772846 BCN115772846 BCN 115772846BCN-115772846-B

Abstract

The invention discloses a cable end vibration reduction system of a long sling of a suspension bridge, which comprises a vibration reduction bracket and cable end vibration reduction assemblies, wherein a main cable of the suspension bridge is connected with a bridge deck girder through a plurality of groups of long slings, each group of long slings comprises two slings which are arranged in parallel, the vibration reduction bracket comprises a main cable clamp, an annular tie rod and vertical support rods, the main cable clamp is tightly locked and erected on the outer side of the main cable, the annular tie rod is horizontally and coaxially sleeved on the periphery of one group of long slings right below the main cable, the annular tie rod is connected with the main cable clamp through the plurality of vertical support rods, the cable end vibration reduction assemblies are symmetrically arranged in an inner cavity of the annular tie rod, two ends of each group of cable end vibration reduction assemblies are respectively connected with the corresponding slings and the annular tie rod, and each group of cable end vibration reduction assemblies comprises two cable end dampers which are arranged in a V shape or an L shape. The wind vibration control device can effectively control wind vibration at the upper end of the long sling exceeding 200m, can prevent falling off, and saves manufacturing cost.

Inventors

TAO TIANYOU
GAO WEIJIE
WANG SHENG
WANG HAO

Assignees

东南大学

Dates

Publication Date: 20260505
Application Date: 20221208

Claims (6)

1. The vibration reduction system for the long sling cable end of the suspension bridge is characterized by comprising a vibration reduction bracket and two groups of cable end damping vibration reduction assemblies; The main cable of the suspension bridge is connected with the bridge deck main girder through a plurality of groups of long slings, and each group of long slings comprises two slings and more slings which are arranged in parallel; the vibration reduction bracket comprises a main cable clamp, an annular tie rod and a vertical supporting rod; The annular tie rod is horizontally and coaxially sleeved on the periphery of one group of long slings under the main cable, and is connected with the main cable clamp through a plurality of vertical support rods; The two groups of cable end damping vibration attenuation components are symmetrically arranged in the inner cavity of the annular tie rod, and two ends of each group of cable end damping vibration attenuation components are respectively connected with the corresponding sling and the annular tie rod; Each group of cable end damping vibration attenuation components comprises two cable end dampers which are arranged in a V shape or an L shape; The elevation angle gamma between the plane where two cable end dampers are positioned and the horizontal plane in each group of cable end damping vibration attenuation components is in a range of 0-6 degrees, and the specific calculation formula is as follows: ; wherein: the maximum static damping force of the single cable end damper is a design value, and G is the dead weight of the single cable end damper.
2. The long-sling cable end vibration-damping system of a suspension bridge as recited in claim 1, wherein the vibration-damping bracket further comprises an auxiliary connecting rod for connecting the middle parts of the plurality of vertical supporting rods into a whole.
3. The long-sling cable end vibration-damping system of suspension bridge as recited in claim 1, wherein the average value of the projection of all vertical supporting rods on the vertical surface is called the cable end damper mounting height Then The calculation formula of (2) is as follows: ; Wherein: ; ; In the formula, The damping ratio is designed for the minimum of the cable end damping system; Designing a damping ratio for the sling; designing a damping ratio for a beam-end damper; Is the inherent damping ratio of the sling; the height of the beam end damper from the ground; Is the sling length.
4. A long sling cable end vibration damping system of a suspension bridge as defined in claim 2, wherein the damping ratio is designed at the cable end vibration damping system By reducing the mass of the vibration-damping bracket on the premise of keeping unchanged Thereby reducing the manufacturing cost of the cable end vibration reduction system 。
5. A long-sling cable end vibration reduction system of a suspension bridge as defined in claim 4, wherein the cost is reduced by constructing the cable end vibration reduction system Regarding vibration damping support mass Obtaining optimized cable end vibration damping system design parameters, wherein the cable end vibration damping system design parameters comprise unit mass price of annular tie rod materials Density of material Cross-sectional area of annular tie bar Shape function of annular tie bar Price per unit mass of auxiliary connecting rod material Density of material Cross-sectional area of auxiliary link Shape function of auxiliary connecting rod Price per unit mass of vertical supporting rod material Density of material Cross-sectional area of vertical support bar And the total length of all vertical supporting rods Vibration-damping support mass Is the mass of the annular tie rod Auxiliary link mass And vertical support rod mass Manufacturing cost of cable end vibration reduction system Regarding vibration damping support mass The functional expression of (2) is: ; Wherein: ; ; ; Wherein ds represents the curve in the curve integration Or (b) In addition, the manufacturing cost of the cable end vibration reduction system In the solving process, the following 7 constraint conditions are required to be satisfied: ; In the formula, 、 And Stress in the annular tie bar, the auxiliary connecting rod and the vertical supporting rod respectively; 、 And The material allowable stress of the annular tie rod, the auxiliary connecting rod and the vertical supporting rod is respectively; 、 And Strain in the annular tie bar, the auxiliary connecting rod and the vertical supporting rod respectively; 、 And The materials of the annular tie rod, the auxiliary connecting rod and the vertical supporting rod are respectively subjected to strain; For the amount of deformation of the cable end vibration reduction system, The deformation limit value of the cable end vibration reduction system is a set value.
6. The long sling cable end vibration reduction system of a suspension bridge as recited in claim 1, further comprising an anti-drop device comprising an annular tie rod anti-drop flexible rope and cable end damper anti-drop flexible ropes, wherein each sling is connected with the annular tie rod through the symmetrically arranged annular tie rod anti-drop flexible rope, and each cable end damper is connected with the main cable clamp through one cable end damper anti-drop flexible rope.

Description

Vibration reduction system for long sling cable end of suspension bridge Technical Field The invention relates to the field of bridge engineering, in particular to a vibration reduction system for a long sling cable end of a suspension bridge. Background Suspension bridges are one of the most advantageous competing bridge types for large-span bridges, in which the bridge structure is formed by cables suspended by cable towers and anchored to both sides as the main load-bearing members of the superstructure. Currently, some of the oversized span suspension bridges have spans exceeding 2000m. The main span of 1915 QIAGARY bridge which is put through in 2022 is 2023m, and the main span of bridge under Zhang Jinggao reaches 2300m. For suspension bridges, slings are an important component of their force transmission paths, and safe and reliable slings are an important guarantee that suspension bridges can be used normally. Due to the inherent characteristics of low damping, small mass and low frequency of the sling, the sling is extremely easy to generate large-amplitude vibration under the action of wind load, and even the phenomenon of collision rope occurs. The advent of oversized span suspension bridges has placed increasing demands on wind vibration control of long slings. At present, the main means for controlling the vibration of the sling are three methods of installing a rigid vibration reduction frame between ropes, installing a high-energy-consumption rubber damper between ropes and installing a damper at the bottom of the sling. The rigid vibration damper is one of the simplest control modes, and has limited control capacity due to the undamped energy consumption capacity. Although the high-energy-consumption rubber damper arranged between the ropes can provide enough additional damping, the material has poor durability and is easy to damage. Meanwhile, the two control modes have the risk that the control device falls down. In addition, for long slings exceeding 200m, the control effect on the upper end of the slings was to be examined. In view of the foregoing, there is a need for a new vibration damping control system that can effectively control wind vibration of a long sling of a suspension bridge while reducing the risk of device falling. Disclosure of Invention The technical problem to be solved by the invention is to provide a vibration reduction system for the long sling cable end of a suspension bridge, which can effectively control wind vibration at the upper end of a long sling exceeding 200m. In order to solve the technical problems, the invention adopts the following technical scheme: a vibration damping system for a long sling cable end of a suspension bridge comprises a vibration damping bracket and two groups of cable end damping vibration damping assemblies. The main cable of suspension bridge is connected with bridge deck girder steel through a plurality of long slings of group, and every long sling of group all includes two parallel arrangement's hoist cable. The vibration damping support comprises a main cable clamp, an annular tie rod and a vertical support rod. The main cable clamp is locked on the outer side of the main cable, the annular tie rod is horizontally and coaxially sleeved on the periphery of one group of long slings under the main cable, and the annular tie rod is connected with the main cable clamp through a plurality of vertical supporting rods. The two groups of cable end damping vibration attenuation components are symmetrically arranged in the inner cavity of the annular tie rod, and two ends of each group of cable end damping vibration attenuation components are respectively connected with the corresponding sling and the annular tie rod. Each group of cable end damping vibration attenuation components comprises two cable end dampers which are arranged in a V shape or an L shape. The vibration reduction support further comprises an auxiliary connecting rod, and the auxiliary connecting rod is used for connecting the middle parts of the plurality of vertical supporting rods into a whole. The average value of the projection of all the vertical support rods on the vertical plane is called a cable end damper mounting height a h, and then the calculation formula of a h is as follows: ah＝2lζh Wherein: ζh＝ζd-ζl-ζs Wherein ζ h is the minimum design damping ratio of the cable end damping system, ζ d is the suspension cable design damping ratio, ζ l is the beam end damper design damping ratio, ζ s is the suspension cable inherent damping ratio, a l is the height of the beam end damper from the ground, and l is the suspension cable length. On the premise that the design damping ratio ζ h of the cable end damping system is kept unchanged, the manufacturing cost F of the cable end damping system is reduced by reducing the mass M of the damping bracket. The cable end vibration reduction system design parameters are obtained by constructing a function of the cable end vibrati