Lightweight flexible supporting device suitable for vibration reduction of ultra-long inhaul cable

Abstract

A lightweight flexible supporting device suitable for vibration reduction of a super-long inhaul cable belongs to the technical field of supporting devices and comprises an upper sleeve, a spiral spring, a guide rod and a bottom plate, the bottom plate is fixedly arranged, the guide rod is rotatably connected to the bottom plate, the lower end of the spiral spring is fixedly connected to the guide rod, the spiral spring wraps the outer side wall of the guide rod, and the upper sleeve is fixedly connected to the guide rod. The upper end of the spiral spring is connected with the lower end of the upper sleeve, a penetrating hole is axially formed in the upper sleeve, the upper end of the guide rod extends into the upper sleeve through the lower end of the penetrating hole, and the upper sleeve is connected with the inhaul cable; the spiral spring is used for introducing flexibility, the geometric dimension and the physical weight of the support are reduced, and the guide rod and other detail structures are used for ensuring that the whole body can reciprocate in the axial direction, so that damping vibration attenuation is achieved, out-of-plane instability is avoided, the large installation height is achieved, and the requirement of an ultra-long inhaul cable is met.

Description

Technical Field

[0001] The present invention belongs to the technical field of support devices, and specifically refers to a lightweight flexible support device suitable for vibration reduction of ultra-long stay cables. Background Art

[0002] The cable-stayed bridge has a beautiful configuration and reasonable force distribution, and is one of the main forms of long-span bridges. In a cable-stayed bridge, as the connection between the main girder and the bridge tower, the stay cable is an important load-bearing member. However, it has a large flexibility and a low internal damping level, and is extremely prone to large-amplitude and violent vibrations. Especially with the continuous increase in the span, the length of the stay cable continues to increase, resulting in a decrease in the fundamental frequency and the emergence of various multi-modal vibrations. Various vibrations will cause fatigue damage to the anchorage end, shorten the service life of the stay cable, and further affect the normal operation and structural safety, increase the maintenance cost, and even cause adverse social impacts, becoming a challenge and bottleneck restricting the high-quality development of bridges in China.

[0003] Installing a damper near the end of the main girder to improve the damping level of the stay cable is the most commonly used and relatively effective vibration reduction method at present. In recent years, the inertance damper has great potential in the vibration reduction of ultra-long stay cables due to its excellent mechanical properties. As a two-endpoint inertial force device, the inertance damper has two significant characteristics: one is to achieve a large "virtual mass" through a mechanical amplification mechanism with a small actual mass, and the actual mass can be effectively reduced while achieving the required control force, thereby realizing local "lightweight" of itself; the other is that the control force is proportional to the acceleration difference between the two ends, and it can completely track the frequency characteristics of the acceleration response, and is more suitable for the vibration control of high-order multi-modal. Scholars at home and abroad have carried out extensive research. The results show that compared with traditional dampers, the force-displacement hysteresis curve of the inertance damper shows a negative stiffness trend, which can generate high-frequency control force, thus improving the energy dissipation capacity and having a certain control effect on the vibration of stay cables, especially ultra-long stay cables.

[0004] In actual engineering applications, in order to install an inertance damper, a support is needed to connect it to the bridge deck main girder. The traditional mechanical concept believes that the greater the stiffness of the support, the better. Therefore, in the support design, a large cross-sectional shape is usually selected, so that the axial stiffness value is relatively large and is approximately rigid. However, as the length of the stay cable increases, the installation position needs to be raised accordingly. In addition to bearing the axial force of the damping device, the support also faces the risk of out-of-plane instability. Therefore, the geometric size required for the rigid support increases rapidly, and the structural weight also increases significantly, restricting the economy and feasibility of the rigid support. For example, the maximum installation height of the cable-end damper of the Third Bosphorus Bridge reaches 7.4m, and the maximum weight of the required support system reaches 5t, with relatively high economic costs and difficult installation and implementation.

[0005] Therefore, in view of the limitations of the rigidity of traditional supports, it is necessary to analyze the mechanism of the action of support stiffness, study its reasonable value, and conduct lightweight design to reduce the support stiffness and self-weight, improve the control effect, and meet the application requirements of ultra-long stay cables. Summary of the Invention

[0006] In order to overcome some of the problems mentioned in the above background, the present invention provides a lightweight flexible support device suitable for vibration reduction of ultra-long stay cables to at least partially solve the above technical problems.

[0007] According to the technical solution of the present invention, there is provided a lightweight flexible support device suitable for vibration reduction of ultra-long stay cables, including an upper sleeve, a helical spring, a guide rod, and a bottom plate. The bottom plate is fixedly arranged, the guide rod is rotatably connected to the bottom plate, the lower end of the helical spring is fixedly connected to the guide rod, the helical spring is wrapped around the outer side wall of the guide rod, the upper end of the helical spring is connected to the lower end of the upper sleeve, the upper sleeve is axially provided with a through hole, and the upper end of the guide rod extends into the upper sleeve through the lower end of the through hole. The upper sleeve is connected to the stay cable.

[0008] Further, the upper sleeve includes an outer cylinder, a lower base, and a reserved hole. The outer cylinder is arranged on the lower base, and the reserved hole is arranged on the outer cylinder for connecting the stay cable.

[0009] Further, the outer cylinder and the lower base are coaxially arranged. The outer diameter of the outer cylinder is smaller than the outer diameter of the lower base, and the reserved hole is arranged at a position on the outer cylinder far from the lower base;

[0010] The lower end of the lower base is connected to the upper end of the helical spring. The outer diameter of the lower base is larger than the outer diameter of the helical spring, and the inner diameter of the lower base is smaller than the inner diameter of the helical spring.

[0011] Further, it further includes a connecting piece. The reserved hole is connected to the stay cable through the connecting piece, and the connecting piece and the reserved hole are connected by a pin;

[0012] The connecting piece includes shock absorption devices such as an inertial damper and a negative stiffness damper.

[0013] Further, a fixing block is provided on the bottom plate. The lower end of the guide rod and the fixing block are hingedly connected by a hinge pin, and the fixing block is fixedly connected to the middle of the upper end surface of the bottom plate.

[0014] Further, the bottom plate is provided with an installation hole vertically penetrating therethrough, and the bottom plate is fixedly connected to the bridge surface through bolts.

[0015] Further, the lower end of the helical spring is connected to the guide rod through a lower backing plate, and the lower backing plate is arranged at a position on the side of the guide rod close to the bottom plate.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] The present invention introduces flexibility by using a helical spring, reduces the geometric size and physical weight of the support, and through detailed structures such as guide rods, ensures that the whole can reciprocate axially to achieve damping and vibration reduction without out-of-plane instability, realizes a larger installation height, and meets the requirements of ultra-long stay cables. Brief Description of the Drawings

[0018] Figure 1 is a schematic structural diagram of an embodiment of the present invention;

[0019] Figure 2 is a schematic structural diagram of the upper sleeve in the embodiment of the present invention;

[0020] Figure 3 is an installation schematic diagram of the application to the vibration reduction of ultra-long stay cables in the embodiment of the present invention;

[0021] Figure 4 is the additional damping ratio achieved during vibration reduction in the embodiment of the present invention.

[0022] In the figure: 1 - upper sleeve, 2 - helical spring, 3 - lower backing plate, 4 - guide rod, 5 - fixing block, 6 - bottom plate, 7 - mounting hole, 8 - reserved hole, 9 - outer cylinder, 10 - lower base. Detailed Embodiment

[0023] Next, the technical solutions in the embodiments will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection.

[0024] As Figures 1-4 shown, the embodiment of the present invention provides a lightweight flexible support device applicable to the vibration reduction of ultra-long stay cables, including an upper sleeve 1, a helical spring 2, a guide rod 4, and a bottom plate 6. The bottom plate 6 is fixedly arranged, the guide rod 4 is rotatably connected to the bottom plate 6, the lower end of the helical spring 2 is fixedly connected to the guide rod 4, the helical spring 2 is wrapped around the outer side wall of the guide rod 4, the upper end of the helical spring 2 is connected to the lower end of the upper sleeve 1, the upper sleeve 1 is axially provided with a through hole, and the upper end of the guide rod 4 extends into the upper sleeve 1 through the lower end of the through hole. The upper sleeve 1 is connected to the stay cable.

[0025] In a further embodiment of this embodiment, the upper sleeve 1 includes an outer cylinder 9, a lower base 10, and a reserved hole 8. The outer cylinder 9 is arranged on the lower base 10, and the reserved hole 8 is arranged on the outer cylinder 9. The reserved hole 8 is used to connect the stay cable.

[0026] In a further embodiment of the present embodiment, the outer cylinder 9 and the lower base 10 are coaxially arranged, the outer diameter of the outer cylinder 9 is smaller than the outer diameter of the lower base 10, and the reserved hole 8 is arranged at a position of the outer cylinder 9 far from the lower base 10;

[0027] The lower end of the lower base 10 is connected to the upper end of the helical spring 2. The outer diameter of the lower base 10 is larger than the outer diameter of the helical spring 2, and the inner diameter of the lower base 10 is smaller than the inner diameter of the helical spring 2.

[0028] In a further embodiment of the present embodiment, a connecting member is further included. The reserved hole 8 is connected to the cable through the connecting member, and the connecting member and the reserved hole 8 are connected by a pin;

[0029] The connecting member includes shock absorption devices such as an inertial damper and a negative stiffness damper.

[0030] In a further embodiment of the present embodiment, a fixing block 5 is provided on the bottom plate 6. The lower end of the guide rod 4 and the fixing block 5 are hinged through a hinge pin, and the fixing block 5 is fixedly connected to the middle of the upper end face of the bottom plate 6.

[0031] In a further embodiment of the present embodiment, an installation hole penetrating in the vertical direction is provided on the bottom plate 6, and the bottom plate 6 is fixedly connected to the bridge surface through bolts in the installation hole.

[0032] In a further embodiment of the present embodiment, the lower end of the helical spring 2 is connected to the guide rod 4 through a lower backing plate 3, and the lower backing plate 3 is arranged at a position on the side of the guide rod 4 close to the bottom plate 6.

[0033] Embodiment 1

[0034] A lightweight flexible support device adapted to the vibration reduction of ultra-long cables, the specific structure is as Figure 1 shown, where 1 is the upper sleeve, 2 is the helical spring, 3 is the lower backing plate, 4 is the guide rod, 5 is the fixing block, 6 is the bottom plate, and 7 is the installation hole.

[0035] A through hole is left in the middle of the upper sleeve 1, and it can reciprocate up and down along the axial direction of the guide rod 4. The lower end of the upper sleeve 1 is fixed to the upper end of the helical spring 2, and the lower end of the helical spring 2 is fixed to the lower backing plate 3. The inner diameter of the helical spring 2 is slightly larger than the outer diameter of the guide rod 4, ensuring that the helical spring 3 can move freely along the axial direction of the guide rod 4 when compressed or stretched, and is restricted by the guide rod 4 so as not to cause out-of-plane instability deviating from the axial direction of the guide rod 4.

[0036] The lower backing plate 3 is fixedly connected to the guide rod 4 and is located near the lower position. Therefore, the lower half of the guide rod 4 is sufficiently stable to achieve a greater supporting height, thus meeting the installation requirements for ultra-long stay cables. The lower end of the guide rod 4 is fixedly connected to the fixing block 5 through a bottom hinge connection, and the hinge connection is achieved through a pin. Installation holes 7 are reserved on the bottom plate 6 and connected to the bridge deck through bolts, thereby realizing the overall fixation of the support of the present invention.

[0037] The specific structure of the upper sleeve 1 is as Figure 2 shown. 8 is a reserved hole, which is connected to the stay cable damping device through a pin. 9 is an outer cylinder, the inner diameter of which is slightly larger than the outer diameter of the guide rod 4 to ensure reciprocating movement along the axial direction of the guide rod 4. 10 is a lower base, which is fixedly connected to the outer cylinder 9. The inner diameter of the lower base 10 is slightly larger than the outer diameter of the guide rod 4, and the outer diameter of the lower base 10 is larger than the outer diameter of the helical spring 2 and is fixedly connected to the helical spring.

[0038] In view of the deficiencies of traditional rigid supports, this embodiment constructs a new type of lightweight flexible support. The flexibility is introduced by using a helical spring to reduce the geometric size and physical weight of the support. Through detailed structures such as the guide rod, it is ensured that the whole can reciprocate along the axial direction to achieve damping and vibration reduction without out-of-plane instability, and a greater installation height is achieved to meet the requirements of ultra-long stay cables.

[0039] Embodiment 2

[0040] As Figure 3 shown, it is a schematic diagram of the installation of the lightweight flexible support device provided by the embodiment of the present invention applied to stay cable damping. Considering the inherent mechanical properties of the present invention, the lightweight flexible support is used in combination with damping devices such as an inertance or negative stiffness damper. The upper end of the damping device is fixedly connected to the stay cable, and the lower end of the damping device is connected to the reserved hole 8 in the present invention. A slot is reserved at the top of the guide rod 4 to ensure that the damping device can reciprocate along the slot to dissipate vibration energy. Near the bridge deck, installation holes 7 are reserved on the lower part of the lightweight flexible support of the present invention on the bottom plate 6, and the fixation with the bridge deck is achieved through anchor bolts.

[0041] Embodiment 3

[0042] The lightweight flexible support device provided by the present invention is used for ultra-long stay cable damping, and the superiority of the present invention is reflected by comparison using numerical calculation methods. An actual ultra-long stay cable of a cable-stayed bridge is selected. The length of the stay cable is 505.7 m, the mass per unit length is 85.4 kg / m, the cable force is 5708.3 kN, and the damping ratio of the stay cable itself is 0.3%. The design goal of vibration control is to make the additional damping ratio of the first-order mode of the stay cable reach 2%. Two design schemes are compared. One is a traditional rigid support and an inertance damper, and the other is the lightweight flexible support of the present invention. Through numerical simulation, it is found that both design schemes can achieve the same additional damping ratio, as Figure 4As shown, an additional damping ratio of 2% can be achieved in all cases.

[0043] To highlight the lightweight and superiority, the inertance, damping parameters, and the stiffness of the support itself required for the traditional rigid support and the lightweight flexible support of the present invention are further compared, as shown in Table 1.

[0044] Table 1

[0045] Required parameters Traditional rigid support device Support device of the present invention Relative descent rate <![CDATA[Inertia coefficient (10 3 kg)]]> 109.4 42.1 61.5％ Damping coefficient (kN s / m) 175.7 13.5 92.3％ Support stiffness (kN / m) Infinity 141.1 ＞99％

[0046] As can be seen from Table 1 above, compared with the traditional rigid support, when using the lightweight flexible support of the present invention, the required inertia coefficient is reduced by 61.5%, the required damping coefficient is reduced by 92.3%, and the required support stiffness drops by more than 99%.

[0047] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A lightweight flexible support device suitable for vibration reduction of ultra-long stay cables, characterized in that, It includes an upper sleeve, a helical spring, a guide rod and a bottom plate. The bottom plate is fixedly arranged. The guide rod is rotatably connected to the bottom plate. The lower end of the helical spring is fixedly connected to the guide rod. The helical spring is wrapped around the outer side wall of the guide rod. The upper end of the helical spring is connected to the lower end of the upper sleeve. The upper sleeve is axially provided with a through hole. The upper end of the guide rod extends into the upper sleeve through the lower end of the through hole. The upper sleeve is connected to a cable.

2. The lightweight flexible support device applicable to vibration reduction of ultra-long stay cables according to claim 1, wherein The upper sleeve includes an outer cylinder, a lower base and a reserved hole. The outer cylinder is arranged on the lower base. The reserved hole is arranged on the outer cylinder. The reserved hole is used for connecting the cable.

3. The lightweight flexible support device applicable to vibration reduction of ultra-long stay cables according to claim 2, characterized in that, The outer cylinder and the lower base are coaxially arranged. The outer diameter of the outer cylinder is smaller than the outer diameter of the lower base. The reserved hole is arranged at a position on the outer cylinder far from the lower base. The lower end of the lower base is connected to the upper end of the helical spring. The outer diameter of the lower base is larger than the outer diameter of the helical spring. The inner diameter of the lower base is smaller than the inner diameter of the helical spring.

4. The lightweight flexible support device applicable to vibration reduction of ultra-long stay cables according to claim 3, characterized in that, It further includes a connecting piece. The reserved hole is connected to the cable through the connecting piece. The connecting piece and the reserved hole are connected by a pin. The connecting piece includes shock-absorbing devices such as an inertial damper and a negative stiffness damper.

5. The lightweight flexible support device applicable to vibration reduction of ultra-long stay cables according to claim 1, wherein A fixing block is provided on the bottom plate. The lower end of the guide rod and the fixing block are hingedly connected by a hinge pin. The fixing block is fixedly connected to the middle of the upper end surface of the bottom plate.

6. The lightweight flexible support device applicable to vibration reduction of ultra-long stay cables according to claim 1, characterized in that, An installation hole vertically penetrating is provided on the bottom plate. The bottom plate is fixedly connected to the bridge surface through bolts in the installation hole.

7. The lightweight flexible support device applicable to vibration reduction of ultra-long cables according to claim 1, characterized in that, The lower end of the helical spring is connected to the guide rod through a lower backing plate. The lower backing plate is arranged at a position on the side of the guide rod close to the bottom plate.

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