A negative stiffness seismic device for long-span bridge structures

Abstract

The present invention provides a negative stiffness anti-seismic device for a large-span bridge structure, comprising a base, two fixed rods, and a movable hinge; the base comprises a bottom plate and two side plates; the two fixed rods are fixed to the side plates; each fixed rod is provided with a sliding sleeve; the movable hinge is fixedly connected to the two sliding sleeves at the same time through a pressure rod; and each fixed rod is sleeved with an elastic member. The beneficial effects of the present invention are as follows: the device reduces the overall stiffness of the device through the elastic member, and when the bridge body is subjected to vibration excitation, the spring provides negative stiffness for the device, extending the natural vibration period of the structure and improving the seismic resistance of the structure. Moreover, when the bridge body is subjected to large vibration excitation, the device will be in a state of maximum negative stiffness, and the two baffles can ensure that the sliding bearing will not slide out when subjected to large vibration, thereby ensuring the safety of the bridge body. At the same time, when the device is in normal use, it is fixed by a safety pin and has good structural stability. When the structure is subjected to vibration excitation, the safety pin falls off, and the spring expands and contracts to provide negative stiffness for the structure.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge engineering, and in particular to a negative stiffness anti-seismic device for a long-span bridge structure. Background Art

[0002] In earthquake-prone areas, earthquakes pose a significant threat to bridge structures, severely endangering human life and property and significantly impacting the economy. Traditional structural seismic mitigation methods focus on increasing the overall stiffness and bearing capacity of structures to counteract seismic forces. This approach primarily focuses on earthquake resistance, but structures often become unusable under small earthquakes. Subsequently, a new seismic mitigation method emerged: structural vibration control technology, which can be categorized as passive, active, semi-active, and hybrid. Passive control involves no external energy application and primarily includes base isolation, energy-dissipating vibration reduction, and energy-absorbing vibration reduction. Active control involves the application of external energy and primarily includes active mass dampers. Semi-active control involves the application of partial external energy and primarily includes variable damping devices and variable stiffness damping devices. Hybrid control combines passive and active control, or employs multiple passive control devices. Seismic isolation technology is the most mature. It employs an isolation layer to prevent the upward transmission of earthquake forces, thereby reducing the seismic response of the structure. To achieve seismic isolation, the stiffness of the support system must be modified or the mass of the structure must be increased to reduce the natural frequency of the structure. However, increasing the mass of the superstructure will inevitably increase the stiffness. Reducing the stiffness of the isolation layer will cause the structure to move under the influence of excitations such as wind loads and conventional loads, which is not allowed by the design. Summary of the Invention

[0003] In view of this, and to solve the above problems, the present invention provides a negative stiffness seismic device for long-span bridge structures. The high-strength coil springs used in the device effectively reduce the stiffness of the structure and increase the natural vibration period of the structure, thereby achieving a seismic effect. The present invention provides a negative stiffness seismic device for long-span bridge structures, comprising a base, two fixed rods, and a movable hinge;

[0004] The base includes two fixedly connected side panels;

[0005] The ends of the two fixing rods are respectively fixedly connected to the inner sides of the two side plates; and the ends of the fixing rods not connected to the side plates are close to each other, and the two fixing rods are coaxially arranged;

[0006] Each fixed rod is provided with a sliding sleeve; the movable hinge is fixedly connected to the two sliding sleeves at the same time through multiple pressure rods;

[0007] An elastic member is sleeved on each fixing rod, one end of the elastic member abuts against the side plate, and the other end abuts against a sliding sleeve;

[0008] The base is fixed on the bridge pier, and the movable hinge is connected to the main beam.

[0009] Furthermore, the base also includes a bottom plate, and both ends of the bottom plate are respectively connected to the two side plates to form a U-shaped structure.

[0010] Furthermore, the base also includes a safety pin, the upper end of which is connected to the movable hinge, and the lower end of which is connected to the base plate.

[0011] Furthermore, a plurality of diagonal support rods are provided on the base, one end of the diagonal support rod is connected to the bottom plate, and the other end is connected to the side plate.

[0012] Furthermore, each of the fixing rods is provided with a baffle at the end portion not connected to the side plate, and the baffle prevents the sliding sleeve from sliding off.

[0013] Furthermore, the movable hinge is a sphere.

[0014] Furthermore, both are coil springs, which are compressed between the side plate and the sliding sleeve.

[0015] The beneficial effects of the negative stiffness anti-seismic device for a long-span bridge structure of the present invention are as follows:

[0016] The device reduces the overall stiffness of the device through coil springs. When the bridge body is subjected to vibration excitation, the springs provide negative stiffness for the device, extending the natural vibration period of the structure and improving the seismic resistance of the structure.

[0017] When the bridge body is subjected to large vibration excitation, the device will be in the state of maximum negative stiffness. The two baffles can ensure that the sliding bearing will not slide out when subjected to large vibration, thereby ensuring the safety of the bridge body.

[0018] The device is fixed by a safety pin when in normal use and has good structural stability. When the structure is subjected to vibration excitation, the safety pin falls off and the spring expands and contracts to provide negative stiffness for the structure.

[0019] The device can adapt to different heights between main beams and pier caps by matching the height of the support with the bridge structure, thereby improving the applicability of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a three-dimensional structural diagram of a negative stiffness anti-seismic device for a long-span bridge structure according to an embodiment of the present invention.

[0021] Figure 2 It is a front view of a negative stiffness anti-seismic device for a long-span bridge structure according to an embodiment of the present invention.

[0022] In the above figure: 1-base, 11-side plate, 12-bottom plate, 23-diagonal support rod, 2-fixed rod, 21-baffle, 3-coil spring, 4-sliding sleeve, 5-pressure rod, 6-movable hinge, 7-safety pin, 8-main beam. DETAILED DESCRIPTION

[0023] To make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0024] Please refer to Figure 1 and Figure 2 The present invention provides a negative stiffness anti-seismic device for a long-span bridge structure, comprising a base 1, two fixed rods 2 and a movable hinge 6.

[0025] The base 1 includes two side panels 11 and a bottom plate 12. The two side panels 11 are vertical and spaced apart. The two sides of the bottom plate 12 are vertically connected to the two side panels 11, respectively, thereby forming a U-shaped plate structure base 1. The bottom plate 11 and the side panels 12 are connected by a strip triangular plate transition connection. The strip triangular plate transition connection can enhance the structural strength of the base 1.

[0026] The two fixed rods 2 are arranged horizontally, with one end of each fixed rod 2 fixedly connected to the inner side of a side plate 11. The ends of the two fixed rods 2 not connected to the side plate are close to each other, and the two fixed rods 2 are arranged coaxially. Each fixed rod 2 is provided with a sliding sleeve 4, which can optionally be a sliding sleeve bearing. The two sliding sleeves 4 are slidably mounted on the fixed rods 2. The movable hinge 6 is located between the two fixed rods 2 and is simultaneously fixedly connected to the two sliding sleeves 4 via multiple pressure rods 5. In this embodiment, the movable hinge 6 is a sphere. Each fixed rod 2 is provided with an elastic member, one end of which abuts the side plate 11 and the other end abuts a sliding sleeve 4. In this embodiment, both elastic members are coil springs 3, which are compressed between the side plate 11 and the sliding sleeve 4. The elastic force of the coil springs 3 restrains the movable hinge 6 between the two fixed rods 2. The base 1 is fixed to the bridge pier, and the movable hinge 6 is connected to the main beam 8 of the bridge.

[0027] Furthermore, a safety pin 7 is provided on the base 1. The safety pin 7 is a thin rod. The upper end of the safety pin 7 is connected to the movable hinge 6, and the lower end of the safety pin 7 is connected to the bottom plate 12 of the base 1. The safety pin 7 is used to fix the movable hinge 6 and can break when the bridge body vibrates greatly, thereby releasing the fixation of the movable hinge 6.

[0028] Furthermore, a plurality of diagonal bracing rods 13 are provided on the base 1 , one end of the diagonal bracing rod 13 is connected to the bottom plate 1 , and the other end of the diagonal bracing rod 13 is connected to the side plate 11 , and the diagonal bracing rod 13 is used to further strengthen the strength of the base 1 .

[0029] Furthermore, a baffle 21 is provided at the end of each fixing rod 2 that is not connected to the side plate 11 . The baffle 21 is fixed to the end of the fixing rod 2 by welding. The baffle 21 prevents the sliding sleeve 4 from sliding off.

[0030] The working process of a negative stiffness anti-seismic device for a large-span bridge structure of the present invention is as follows: when the negative stiffness anti-seismic device is in use, its base 1 is fixed on the bridge pier, and the movable hinge 6 is connected to the main beam 8 of the bridge body; when the bridge body vibrates, the upper or lower end of the safety pin 7 breaks under the action of the vibration, thereby releasing the restriction on the movable hinge 6; the movable hinge 6 swings left and right, and the pressure rod 5 can move left and right with the expansion and contraction of the coil spring 3. The coil spring 3 provides negative stiffness for the device, thereby extending the natural vibration period of the bridge structure and reducing the displacement and vibration speed of the main beam 8.

[0031] In this document, directional terms such as front, back, top, and bottom are defined based on the positions of components in the accompanying drawings and relative to each other, and are intended only for clarity and convenience in describing the technical solution. It should be understood that the use of these directional terms should not limit the scope of protection claimed in this application.

[0032] In the absence of conflict, the above embodiments and features in the embodiments may be combined with each other.

[0033] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A negative stiffness seismic device for a long-span bridge structure, characterized by: It includes a base, two fixing rods and a movable hinge; The base includes two fixedly connected side panels; The ends of the two fixing rods are respectively fixedly connected to the inner sides of the two side plates; and the ends of the fixing rods not connected to the side plates are close to each other, and the two fixing rods are coaxially arranged; Each of the fixed rods is provided with a sliding sleeve; the movable hinge is fixedly connected to the two sliding sleeves at the same time through a plurality of pressure rods; An elastic member is sleeved on each of the fixing rods, one end of the elastic member abuts against the side plate, and the other end abuts against a sliding sleeve; The base is fixed on the pier, and the movable hinge is connected to the main beam; The base also includes a bottom plate, and both ends of the bottom plate are connected to the two side plates to form a U-shaped structure; The base further includes a safety pin, the upper end of which is connected to the movable hinge, and the lower end of which is connected to the bottom plate; The end of each fixing rod not connected to the side plate is further provided with a baffle, which prevents the sliding sleeve from sliding off.

2. The negative stiffness anti-seismic device for a long-span bridge structure according to claim 1, characterized in that: A plurality of diagonal support rods are provided on the base, one end of the diagonal support rod is connected to the bottom plate, and the other end is connected to the side plate.

3. The negative stiffness anti-seismic device for a long-span bridge structure according to claim 1, characterized in that: The movable joint is a sphere.

4. The negative stiffness anti-seismic device for a long-span bridge structure according to claim 1, characterized in that: The two elastic members are both coil springs, which are compressed between the side plate and the sliding sleeve.

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