Swing type self-resetting bridge pier structure provided with belleville springs

Abstract

The utility model discloses a swing type self-resetting bridge pier structure provided with belleville springs, belongs to the field of bridge engineering, and solves the problems of how to improve the anti-seismic property of a bridge and ensure self-resetting and repairability of a bridge pier after an earthquake. A bridge pier base is arranged at the bottom of a bridge pier and arranged on a bearing platform, the bridge pier base and the bearing platform are connected through a swing type self-resetting device, the swing type self-resetting device comprises a steel bar and a belleville spring, the steel bar vertically penetrates through the bridge pier base and downwards extends into the bearing platform, and an anchoring end is arranged at the lower end of the steel bar. The anchoring end is located in the bearing platform, a fastening end is arranged at the upper end of the steel bar, and the belleville spring is arranged on the steel bar in a sleeving mode and located between the fastening end and the pier base. In a normal use state, the pier base after the fastening force is applied bears the bending moment of the bottom of the pier, and the pier base does not slide and does not deform at a corner; when the pier swings under the action of an earthquake, the belleville springs are stretched and compressed in a reciprocating manner, and self-resetting force is provided for the pier.

Description

Technical Field

[0001] The utility model belongs to the field of bridge engineering, and particularly relates to a rocking self - resetting pier structure configured with disc springs. Background Technique

[0002] Bridge structures play a crucial role in transportation. When an earthquake occurs, preventing the devastating damage of road bridges is a prerequisite for disaster relief and rescue. With the continuous deepening of people's understanding of earthquakes and their disaster - causing mechanisms, the theory and methods of bridge seismic fortification have been continuously developed, from the early strength - based seismic design to the current ductility - based seismic design concept and methods commonly adopted in domestic and foreign urban and highway bridge seismic design codes. The ductility - based seismic design method allows the main bridge structures such as piers to have plastic hinge damage and the bridge structure to have large deformations during strong earthquakes but not collapse. However, whether before, during, or after an earthquake, as the main vertical load - bearing component, once the pier is severely damaged, its load - bearing capacity will be seriously affected. The large residual deformation caused by plastic damage of the pier makes it difficult for the bridge to quickly recover its function after an earthquake, and even difficult to repair, seriously affecting post - earthquake emergency rescue and the restoration of post - disaster production and life. Especially for urban bridges, the inability to quickly restore the traffic function after an earthquake will seriously affect the rapid restoration of urban functions after the earthquake, causing serious social and economic impacts. Therefore, the ductility - based seismic design method for urban bridges with the goal of bridge anti - collapse can no longer meet the development requirements of resilient cities, and bridge seismic design should gradually shift towards the design of resilient bridges with easy repair and rapid recoverability. At the same time, coupling the vertical load - bearing function and horizontal seismic function of bridge piers in strong earthquake areas significantly increases the reinforcement of piers or uses seismic isolation bearings / devices, resulting in a significant increase in cost. Resilient bridges are the key nodes of the resilient urban transportation infrastructure. The goal is that under strong earthquake action, urban bridges should not only meet the basic performance goal of not collapsing, but also pay more attention to the recoverability and easy repairability of the bridge function after an earthquake, so as to avoid more serious adverse social and economic impacts caused by the loss of urban bridge functions. Developing resilient bridges with recoverable functions and repairability is a new concept and new structural system of high - performance bridge structures being developed at home and abroad, and is the key to realizing resilient bridges. Content of the Utility Model

[0003] The purpose of the utility model is to provide a rocking self - resetting pier structure configured with disc springs to solve the problems of how to improve the seismic performance of bridges and ensure the self - resetting and repairability of piers after an earthquake.

[0004] The technical solution of the utility model is: a swing-type self-resetting pier structure equipped with a disc spring, a pier base is provided at the bottom of the pier, the pier base is arranged on a cap, the pier base and the cap are connected by a swing-type self-resetting device, the swing-type self-resetting device comprises a steel rod and a disc spring, the steel rod passes through the pier base up and down and extends downward to the inside of the cap, an anchoring end is provided at the lower end of the steel rod, the anchoring end is located inside the cap, a fastening end is provided at the upper end of the steel rod, the disc spring is sleeved on the steel rod and is located between the fastening end and the pier base.

[0005] As a further improvement of the utility model, the fastening end is composed of a fastening nut and a pad, and the pad is against the upper end of the disc spring.

[0006] As a further improvement of the utility model, a plurality of sets of swing-type self-resetting devices are provided.

[0007] As a further improvement of the utility model, a plurality of reserved notches are provided on the pier base, and the disc springs are arranged in the reserved notches in a one-to-one correspondence.

[0008] As a further improvement of the utility model, a pre-embedded steel plate is provided on the bottom surface of the reserved notch, and the pre-embedded steel plate abuts against the lower end of the disc spring.

[0009] As a further improvement of the utility model, stainless steel pipes are provided at the holes in the pier base and the cap where the steel rods are located, and the steel rods are located in the stainless steel pipes.

[0010] As a further improvement of the utility model, a tenon is provided on the top of the pedestal, the tenon is in a hemispherical shape, and a mortise groove matching the tenon is provided at the bottom of the pier base, and the tenon is located in the mortise groove.

[0011] The beneficial effects of the utility model are:

[0012] Under normal use, the pier base bears the bending moment at the bottom of the pier after the tightening force is applied, and the tenon bears the shear force at the bottom of the pier, and the pier base does not slide or rotate. Under the action of an earthquake, the inertial force of the main beam and other upper structures is transmitted to the pier through the support. When the bending moment at the bottom of the pier caused by the inertial force is greater than the bending capacity at the pier base, the pier begins to swing with the tenon as the rotation center, extending the natural vibration period of the bridge system, avoiding the frequency section where the energy in the earthquake motion is more concentrated, and effectively protecting the safety of the main structure of the bridge. During the swinging process, the butterfly spring will undergo reciprocating stretching and compression deformation, providing the pier with a self-resetting force. The butterfly spring will generate vertical force after compression and stretching, which is beneficial to the reset of the pier. After an apparent inspection and repair after the earthquake, the normal operation state can be restored.

[0013] The rocking self - resetting pier configured with disc springs provided by the present utility model is applicable to various regular and irregular piers. Its working principle is clear, practical and reliable, with low construction cost and maintenance cost, and has certain popularization and application value. Description of the Drawings

[0014] Figure 1 is a schematic structural diagram of the structure of a rocking self - resetting pier configured with disc springs of the present utility model;

[0015] Figure 2 is a schematic diagram of the connection relationship between the bearing platform and the pier base of the present utility model;

[0016] Figure 3 is a plan view of the pier base of the present utility model.

[0017] In the figure: 1 - main beam; 2 - capping beam; 3 - pier; 4 - bearing platform; 5 - pile foundation; 6 - pier base; 7 - anchoring end; 8 - fastening end; 801 - fastening nut; 802 - backing plate; 9 - steel bar; 901 - stainless steel pipe; 10 - disc spring; 11 - tenon; 12 - embedded steel plate; 13 - reserved notch; 14 - mortise groove. Detailed Embodiment

[0018] The present utility model will be further described in detail below in conjunction with the drawings and specific embodiments.

[0019] As Figures 1-3 shown, for a structure of a rocking self - resetting pier configured with disc springs, a pier base 6 is provided at the bottom of the pier 3. The pier 3 and the pier base 6 are integrally cast. The pier base 6 is arranged on the bearing platform 4, and the bottom of the pier base 6 is in contact with the top of the bearing platform 4. The pier base 6 and the bearing platform 4 are only connected by a rocking self - resetting device. The rocking self - resetting device includes a steel bar 9 and a disc spring 10. The steel bar 9 penetrates through the pier base 6 vertically and extends downward into the bearing platform 4. An anchoring end 7 is provided at the lower end of the steel bar 9, and the anchoring end 7 is located inside the bearing platform 4. A fastening end 8 is provided at the upper end of the steel bar 9. The disc spring 10 is sleeved on the steel bar 9 and is located between the fastening end 8 and the pier base 6.

[0020] The steel bar 9 is made of precision rolled threaded steel. The fastening end 8 is composed of a fastening nut 801 and a backing plate 802. The backing plate 802 abuts against the upper end of the disc spring 10. By screwing the fastening nut 801, the disc spring 10 obtains a proper compressive deformation, so as to achieve the purpose of storing pre - applied force.

[0021] Multiple groups of rocking self - resetting devices are provided.

[0022] A plurality of reserved notches 13 are provided on the pier base 6, and the disc springs 10 are correspondingly arranged in the reserved notches 13.

[0023] The bottom surface of the reserved notch 13 is provided with a pre-embedded steel plate 12, and the pre-embedded steel plate 12 abuts against the lower end of the disc spring 10.

[0024] At the ducts in the pier base 6 and the bearing platform 4 where the steel bars 9 are located, thin-walled stainless steel pipes 901 are provided. The ducts are not grouted, and the stainless steel pipes 901 are connected in a non-bonded manner; the steel bars 9 are located inside the stainless steel pipes 901.

[0025] A tenon 11 is provided at the top of the bearing platform 4. The tenon 11 is integrally cast with the bearing platform 4 and is in a hemispherical shape. A mortise groove 14 matching the tenon 11 is provided at the bottom of the pier base 6, and the tenon 11 is located inside the mortise groove 14.

[0026] The contact surface between the bottom of the pier base 6 and the top of the bearing platform 4 is made of steel with good wear resistance and corrosion resistance.

[0027] A construction method for a rocking self-resetting pier configured with disc springs includes the following steps:

[0028] A. After completing the construction of the pile foundation 5, bind the steel bars of the bearing platform 4, accurately position and install the anchoring end 7, connect the steel bars 9 with the anchoring end 7, install the stainless steel pipes 901 at the same time, and pour the concrete of the bearing platform 4 and the tenon 11;

[0029] B. Apply a release agent on the surfaces of the bearing platform 4 and the tenon 11, bind the steel bars of the pier base 6, pay attention to avoiding and protecting the ducts of the thin-walled stainless steel pipes, and weld and fix the pre-embedded steel plate 12 to the steel bars of the pier base 6 at the same time. During the process of pouring the concrete of the pier base 6, ensure that the size and position of the reserved notch 13 are accurate;

[0030] C. Install the disc springs 10 on the steel bars 9, install the backing plates 802, and install the fastening nuts 801;

[0031] D. Determine the pre-tightening force that should be applied to the fastening nuts 801 according to the calculation. The principle is that: the bending resistance of the pier base 6 after applying the fastening force is greater than the maximum value of the bending moment at the bottom of the pier 3 under the normal service state and less than the target bending moment value at the bottom of the pier 3 under the seismic action; symmetrically and gradually tighten the fastening nuts 801 to the designed position to make the disc springs 10 obtain an appropriate compressive deformation, so as to achieve the purpose of storing the pre-applied force;

[0032] E. Pour the pier 3 and the capping beam 2; erect the main beam 1.

[0033] Example 1

[0034] A ramp bridge in a 7-degree seismic zone, where the main beam 1 is a precast small box girder and the pier 3 is a column pier. The cross-sectional dimension of the pier 3 is a diameter of 150 cm, and the dimension of the pier foundation 6 is 240 cm × 240 cm, with each side exceeding the outline of the pier 3 by 45 cm. Rocking self-centering devices are arranged around the pier foundation 6. The steel bar specification is high-strength cold-rolled ribbed steel with a diameter of 40 mm, and the outer diameter of the disc spring is 93 mm and the inner diameter is 46 mm. According to the calculation, the fastening force of a single rocking self-centering device is 1200 kN, that is, the pre-tightening force that should be applied to the fastening nut is 1200 kN.

[0035] Under the normal service condition, the pier foundation 6 after applying the fastening force bears the bending moment at the bottom of the pier 3, and the tenon 11 bears the shear force at the bottom of the pier 3. The pier foundation 6 does not undergo sliding and rotational deformation.

[0036] Under the action of an earthquake, the inertial force of the superstructure such as the main beam 1 is transmitted to the pier 3 through the bearing. When the bending moment at the bottom of the pier caused by the inertial force is greater than the flexural capacity at the pier foundation 6, the pier 3 starts to rock with the tenon 11 as the rotation center, extending the natural vibration period of the bridge system and avoiding the frequency section with relatively concentrated energy in the ground motion, effectively protecting the safety of the main structure of the bridge. During the rocking process, the disc spring 10 will undergo reciprocating tensile and compressive deformations, providing a self-centering force for the pier 3. After the visual inspection and repair after the earthquake, the normal operation state can be restored.

[0037] The utility model solves the basic performance goal of the bridge not collapsing under strong earthquake action, the recoverability and easy reparability of the bridge function after the earthquake, thus avoiding more serious adverse social and economic impacts caused by the loss of the bridge function. It is applicable to various regular and irregular piers, with a clear working principle, practical and reliable, low cost of construction and maintenance, and has certain popularization and application value.

Claims

1. A swing-type self-resetting bridge pier structure equipped with a disc spring, characterized in that: A pier base (6) is provided at the bottom of the pier (3). The pier base (6) is arranged on the pedestal (4). The pier base (6) and the pedestal (4) are connected via a swing-type self-resetting device. The swing-type self-resetting device comprises a steel rod (9) and a disc spring (10). The steel rod (9) passes through the pier base (6) from top to bottom and extends downward to the inside of the pedestal (4). An anchor end (7) is provided at the lower end of the steel rod (9). The anchor end (7) is located inside the pedestal (4). A fastening end (8) is provided at the upper end of the steel rod (9). The disc spring (10) is sleeved on the steel rod (9) and is located between the fastening end (8) and the pier base (6).

2. The swing-type self-resetting bridge pier structure equipped with a disc spring according to claim 1, characterized in that: The fastening end (8) is composed of a fastening nut (801) and a backing plate (802), and the backing plate (802) is against the upper end of the disc spring (10).

3. The swing-type self-resetting bridge pier structure equipped with a disc spring according to claim 2, characterized in that: The swing type self-resetting device is provided with multiple groups.

4. The swing-type self-resetting bridge pier structure equipped with a disc spring according to claim 3 is characterized in that: The pier base (6) is provided with a plurality of reserved notches (13), and the disc springs (10) are arranged in the reserved notches (13) in a one-to-one correspondence.

5. The swing-type self-resetting bridge pier structure equipped with a disc spring according to claim 4, characterized in that: The bottom surface of the reserved notch (13) is provided with an embedded steel plate (12), and the embedded steel plate (12) abuts against the lower end of the disc spring (10).

6. The swing-type self-resetting bridge pier structure equipped with a disc spring according to claim 5, characterized in that: A stainless steel pipe (901) is provided at the hole in the pier base (6) and the cap (4) where the steel rod (9) is located, and the steel rod (9) is located in the stainless steel pipe (901).

7. A swing-type self-resetting bridge pier structure equipped with a disc spring according to any one of claims 1 to 6, characterized in that: A tenon (11) is provided at the top of the cap (4), and the tenon (11) is in a hemispherical shape. A tenon groove (14) matching the tenon (11) is provided at the bottom of the pier base (6), and the tenon (11) is located in the tenon groove (14).

Images