A three-level seismic design method for bridge pier bottoms that can achieve rapid post-earthquake repair

Abstract

The present invention relates to the field of bridge seismic design, and specifically proposes a three-level seismic design method for bridge pier bottoms that can achieve rapid post-earthquake repair. The method is applicable to various newly built railway bridges, highway bridges, and urban viaducts, and can improve the overall seismic performance of the structure under sudden earthquakes. It is characterized in that the method process is as follows: in order to achieve seismic reduction and isolation at the bottom of the bridge pier, the pier bottom is designed to be an inverted T-shaped structure; vertically, seismic reduction and isolation bearings are installed between the abutment and the inverted T-shaped pier bottom; circumferentially, the inverted T-shaped pier bottom is placed between the block system; to meet basic force stability and safety guarantees. The present invention is applicable to the multi-level seismic reduction and isolation design of commonly used continuous rigid frame bridges and high pier bridges that play a controlling role in the vibration characteristics of the pier body, which improves its seismic reduction and isolation effect, and has the characteristics of simple structure, low cost, simple installation and maintenance, and easy repair.

Description

Technical Field

[0001] The present invention relates to the field of bridge seismic design, and specifically proposes a three-level seismic design method for bridge pier bottoms that can achieve rapid post-earthquake repair. The method is applicable to various newly built railway bridges, highway bridges, and urban viaducts, and can improve the overall seismic performance of the structure under sudden earthquakes. Background Art

[0002] Compared with the traditional seismic design concept, the design concept of seismic isolation technology is to transfer the seismic energy from the important components of the structure to the seismic isolation device through the seismic isolation device to avoid the damage of the important components of the structure. When the seismic isolation device is damaged, it is relatively simple to replace, which is convenient for rapid repair after the earthquake. Based on this, the seismic isolation design method has become one of the main design methods for bridge seismic design. At present, bridge structures generally adopt upper seismic isolation technology, that is, seismic isolation devices are used to replace ordinary bearings to achieve the purpose of shock absorption and energy dissipation. However, for the commonly used continuous rigid frame bridges, due to the consolidation form of the upper part, the purpose of seismic isolation design cannot be achieved through seismic isolation bearings; in addition, for some common high pier bridge structures with high pier height and large pier body mass, the vibration characteristics of the piers themselves control their seismic design, and the shock absorption effect of the upper seismic isolation technology is not obvious. Summary of the invention

[0003] In response to the problems existing in the prior art, the present invention provides a three-level seismic design method for bridge pier bottoms that can achieve rapid post-earthquake repair, realize the pier bottom seismic reduction and isolation of commonly used continuous rigid frame bridges and high pier bridges that control the vibration characteristics of the pier body, transfer the upper seismic reduction and isolation technology applied to conventional bridge structures to the bridge pier bottoms, further expand the application scope of bridge seismic reduction and isolation technology, and realize the three-level (common earthquakes, rare earthquakes and unexpected earthquakes) seismic design of the structure.

[0004] The technical solution of the present invention is:

[0005] A three-level seismic design method for bridge pier bottoms that can achieve rapid post-earthquake repair, characterized in that the method process is as follows:

[0006] (i) To achieve seismic isolation at the bottom of the bridge pier, the bottom of the pier is designed to be an inverted T-shaped structure; vertically, a seismic isolation bearing 7 is installed between the cap 9 and the bottom of the inverted T-shaped pier; circumferentially, the bottom of the inverted T-shaped pier is placed between the block system; to meet basic force stability and safety assurance;

[0007] (ii) In normal operation and minor earthquakes, the temporary consolidation effect is maintained by restraining the bottom of the pier and the block system;

[0008] The horizontal displacement of the structure is limited by shear pins, and the rotational displacement of the structure is limited by horizontal stops, which together achieve a temporary consolidation effect on the bottom of the pier.

[0009] (3) Under the action of common earthquakes, the upper shear pins in the block system are sheared off, and the horizontal restraint of the shear pins fails. The bottom of the pier can move between the horizontal blocks on both sides, and the seismic isolation bearings play a role, changing the stiffness of the structure, extending the natural vibration period of the structure, and achieving a seismic isolation effect. The horizontal displacement and rotational displacement of the structure are limited by the upper horizontal blocks, ensuring the stability and safety of the structure.

[0010] (iv) Under the action of rare earthquakes, the horizontal blocks in the block system are sheared off, and the bottom of the pier can move between the blocks on both sides, and the horizontal and rotational displacements of the pier are limited by the lower trapezoidal blocks.

[0011] Furthermore, the block system includes horizontal blocks and vertical blocks; the shear pins, horizontal blocks and connecting steel bars in the block system are all replaceable.

[0012] Specifically, the vertical block in the block system is designed as a trapezoidal block 3;

[0013] The trapezoidal stopper 3 is a vertical stopper in the stopper system and is arranged on the upper part of the support platform 9 to play a limiting role.

[0014] A gap is left between the bottom of the pier and the trapezoidal stopper 3 .

[0015] Specifically, reserved openings 4 are provided on the upper portions of the horizontal extensions of the inverted T-shaped structures on both sides of the pier bottom for installing the shear pins 1 .

[0016] Specifically, the horizontal stopper 2 is placed above the trapezoidal stopper 3 and is connected to the trapezoidal stopper 3 via the connecting steel bar 5 ; the other end of the horizontal stopper 2 is connected to the shear pin 1 .

[0017] A buffer rubber pad 6 is arranged around the inverted T-shaped structure of the pier 8 to buffer the collision between the bottom of the pier 8 and the trapezoidal stopper 3 .

[0018] Further, the shear pin design method is as follows:

[0019] By properly setting the shear strength and number of shear pins, temporary horizontal fixing effect under normal service load can be achieved. The setting parameters of the shear pins are as follows: Assuming that the shear force at the bottom of the pier is Q E1 , the shear strength of a single shear pin is V J , then the number of shear pins required on one side is n = 0.9Q E1 / V J .

[0020] Further, the anchor reinforcement design method is as follows:

[0021] By setting the number of connecting steel bars between the horizontal stopper and the lower trapezoidal stopper and the anchorage depth, the temporary rotation consolidation effect under normal service load and the limiting effect under rare earthquake can be achieved; the setting parameters of the anchorage steel bars are as follows: Assuming that under rare earthquake, the shear force at the bottom of the pier is Q E2 , then the area of ​​the required steel bar is A sv =0.9Q E2 / f sv cosα, where α is the twisting angle of the steel bar when it is bent and damaged, which can be measured by experiment; f sv is the ultimate tensile strength of the steel bar, A sv is the area of ​​the required steel bars; under rare earthquakes, the bending moment at the bottom of the pier is M E2 , then the axial tension of the single-side anchor steel bar is N = 0.9M E2 / L (L is the distance between the center points of the anchor steel bars on both sides). According to the concrete structure reinforcement design specification, the required steel bar diameter and anchor length l can be calculated. d ; Based on the above calculation results, the setting parameters required for anchoring steel bars can be obtained. By setting the above parameters, the purpose of setting horizontal blocks can be achieved;

[0022] Furthermore, considering the possible errors between earthquake calculation and actual situation, in order to ensure that the shear pins and horizontal connecting steel bars can achieve the setting purpose, a reliability coefficient of 10% is selected when calculating the corresponding parameters;

[0023] Beneficial effects of the present invention:

[0024] The present invention is applicable to the multi-level seismic isolation design of commonly used continuous rigid frame bridges and high pier bridges where the vibration characteristics of the pier body play a controlling role, thereby improving the seismic isolation effect thereof and having the characteristics of simple structure, low cost, easy installation and maintenance, and easy repair. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of the present invention.

[0026] Numbers in the figure: 1 shear pin, 2 horizontal block, 3 trapezoidal block, 4 reserved opening, 5 connecting steel bars, 6 buffer rubber pad, 7 seismic isolation bearing, 8 bridge pier, 9 abutment. DETAILED DESCRIPTION

[0027] The technical solution provided by the present application will be further described below in conjunction with specific embodiments and accompanying drawings. The advantages and features of the present application will become more apparent with the following description.

[0028] It should be noted that the embodiments of the present application have better practicability and are not any form of limitation to the present application. The technical features or combinations of technical features described in the embodiments of the present application should not be considered to be isolated, and they can be combined with each other to achieve better technical effects. The scope of the preferred implementation of the present application may also include other implementations, and this should be understood by those skilled in the art of the present application embodiment.

[0029] Techniques, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0030] The drawings of this application are in very simplified form and in non-precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of this application, and are not intended to limit the restrictive conditions under which this application can be implemented. Any structural modification, change in proportional relationship, or adjustment of size should fall within the scope of the technical content disclosed in this application without affecting the effects and purposes that can be achieved by this application. The same reference numerals appearing in the drawings of this application represent the same features or components, which can be applied in different embodiments.

[0031] Example 1

[0032] Based on the design method of the present invention, the embodiment product is obtained, such as Figure 1 The structure of this embodiment is as follows:

[0033] It includes: a shear pin 1, a horizontal stopper 2, a trapezoidal stopper 3, a reserved opening 4, a connecting steel bar 5, a seismic isolation bearing 7, a buffer rubber pad 6, a bridge pier 8 and a cap 9;

[0034] The bottom of the pier 8 is an inverted T-shaped structure, and reserved openings 4 are provided at the horizontal extensions of the inverted T-shaped structure on both sides of the pier bottom; the reserved openings 4 are used to install the shear pins 1;

[0035] Two trapezoidal stoppers 3 are arranged on the upper part of the pedestal 9 to limit the position; the trapezoidal stoppers 3 and the pedestal 9 are integrally cast;

[0036] The horizontal stopper 2 is placed above the trapezoidal stopper 3 and connected to the trapezoidal stopper 3 via the connecting steel bar 5; the other end of the horizontal stopper 2 is connected to the shear pin 1;

[0037] A buffer rubber pad 6 is arranged around the inverted T-shaped structure of the bridge pier 8 to buffer the collision between the bottom of the bridge pier 8 and the trapezoidal stopper 3;

[0038] The seismic isolation bearing 7 is installed between the cap 9 and the pier 8 .

[0039] By properly setting the shear strength and number of shear pins, temporary horizontal fixing effect under normal service load can be achieved. The setting parameters of the shear pins are as follows: Assuming that the shear force at the bottom of the pier is Q E1 , the shear strength of a single shear pin is V J , then the number of shear pins required on one side is n = 0.9Q E1 / V J ;

[0040] By setting the number of connecting steel bars between the horizontal stopper and the lower trapezoidal stopper and the anchorage depth, the temporary rotation consolidation effect under normal service load and the limiting effect under rare earthquake can be achieved; the setting parameters of the anchorage steel bars are as follows: Assuming that under rare earthquake, the shear force at the bottom of the pier is Q E2 , then the area of ​​the required steel bar is A sv =0.9Q E2 / f sv cosα, where α is the twisting angle of the steel bar when it is bent and damaged, which can be measured by experiment; f sv is the ultimate tensile strength of the steel bar, A sv is the area of ​​the required steel bars; under rare earthquakes, the bending moment at the bottom of the pier is M E2 , then the axial tension of the single-sided anchor steel bar is N = 0.9M E2 / L (L is the distance between the center points of the anchor steel bars on both sides). According to the concrete structure reinforcement design specification, the required steel bar diameter and anchor length l can be calculated. d According to the above calculation results, the setting parameters required for anchoring steel bars can be obtained. By setting the above parameters, the purpose of setting horizontal blocks can be achieved.

[0041] The embodiment product is applied to the bottom of bridge piers, and can achieve three-level seismic resistance for rapid post-earthquake repair. The specific mechanism of action is: through the shear pins and horizontal blocks set above to anchor the steel bars, the horizontal displacement and rotational displacement of the structure are limited, and the temporary consolidation effect of the pier bottom under normal use load is jointly achieved; when the seismic load exceeds the shear strength of the shear pins set, the shear pins are sheared off, and the temporary horizontal fixing effect of the pier bottom fails, thereby realizing the activity function of the device, and then changing the stiffness of the structure, extending the natural vibration period of the structure, and achieving a seismic reduction and isolation effect; when the seismic load exceeds the tensile strength and anchoring length of the connecting steel bars between the upper horizontal block and the lower trapezoidal block, the connecting steel bars are damaged, and the horizontal limit and temporary rotational consolidation effect of the pier bottom fail, the activity function of the device is further increased, and the seismic reduction and isolation effect is further obvious; the lower trapezoidal block can be used to prevent the displacement effect under the action of unexpected earthquakes in the future, thereby improving the overall seismic safety of the structure.

[0042] The above-mentioned shear pins, horizontal stops and connecting steel bars can all be replaced.

Claims

1. A three-level seismic design method for bridge pier bottoms that can achieve rapid post-earthquake repair, characterized in that: The method process is as follows: (i) To achieve seismic isolation at the bottom of the bridge pier, the bottom of the pier is designed to be an inverted T-shaped structure; in the vertical direction, a seismic isolation bearing 7 is installed between the cap 9 and the bottom of the inverted T-shaped pier; in the circumferential direction, the bottom of the inverted T-shaped pier is placed between the block system; in order to meet the basic force stability and safety guarantee; (ii) In normal operation and minor earthquakes, the temporary consolidation effect is maintained by restraining the bottom of the pier and the block system; The horizontal displacement of the structure is limited by shear pins, and the rotational displacement of the structure is limited by horizontal stops, which together achieve a temporary consolidation effect on the bottom of the pier. (iii) Under the action of common earthquakes, the shear pins in the upper part of the block system are sheared off, and the horizontal restraining effect of the shear pins fails. The bottom of the pier can move between the horizontal blocks on both sides, and the seismic isolation bearings play a role, changing the stiffness of the structure, extending the natural vibration period of the structure, and achieving a seismic isolation effect. The horizontal displacement and rotational displacement of the structure are limited by the upper horizontal blocks, ensuring the stability and safety of the structure. (iv) Under the action of a rare earthquake, the horizontal blocks in the block system are sheared off, and the bottom of the pier can move between the lower vertical blocks on both sides, and the horizontal and rotational displacements of the pier are limited by the lower vertical blocks; In the block system, the upper shear pin design method is as follows: By reasonably setting the shear strength and number of shear pins, the temporary horizontal fixing effect under normal service load can be achieved; the setting parameters of the shear pins are as follows: Assuming that under the action of a common earthquake, the shear force at the bottom of the pier is , the shear strength of a single shear pin is , then the number of shear pins required on one side is ; The design method of anchor reinforcement in the block system is as follows: By setting the number of connecting steel bars between the horizontal stopper and the lower trapezoidal stopper and the anchorage depth, the temporary rotation consolidation effect under normal service load and the limiting effect under rare earthquake can be achieved; the setting parameters of the anchorage steel bars are as follows: Assuming that under rare earthquake, the shear force at the bottom of the pier is , then the area of ​​the required steel bar is ,in It is the twisting angle of the steel bar when it is bent and damaged, which can be measured by test; is the ultimate tensile strength of the steel bar, is the area of ​​the required steel bars; under rare earthquakes, the bending moment at the bottom of the pier is , then the axial tension of the single-sided anchor steel bar is , where L is the distance between the center points of the anchor steel bars on both sides. According to the concrete structure reinforcement design specification, the required steel bar diameter and anchor length can be calculated. ; Based on the above calculation results, the setting parameters required for anchoring steel bars are obtained; By setting the above parameters, the purpose of setting horizontal blocks can be achieved.

2. A three-level seismic design method for bridge pier bottoms that can achieve rapid post-earthquake repair as claimed in claim 1, characterized in that: The block system includes shear pins, connecting steel bars, horizontal blocks and vertical blocks; wherein the shear pins, horizontal blocks and connecting steel bars are all replaceable.

3. A three-level seismic design method for bridge pier bottoms that can achieve rapid post-earthquake repair as claimed in claim 2, characterized in that: Specifically, the vertical block in the block system is designed as a trapezoidal block (3); The trapezoidal stopper (3) serves as a vertical stopper in the stopper system and is arranged on the upper part of the support platform (9) to play a limiting role.

4. A three-level seismic design method for bridge pier bottoms that can achieve rapid post-earthquake repair as claimed in claim 2, characterized in that: Specifically, reserved openings (4) are provided at the upper parts of the horizontal extensions of the inverted T-shaped structures on both sides of the pier bottom for installing the shear pins (1).

5. A three-level seismic design method for bridge pier bottoms that can achieve rapid post-earthquake repair as claimed in claim 3, wherein a gap is left between the pier bottom and the trapezoidal stopper (3).

6. A three-level seismic design method for bridge pier bottoms that can achieve rapid post-earthquake repair as described in claim 1, specifically, the horizontal block (2) is placed above the trapezoidal block (3) and is connected to the trapezoidal block (3) through a connecting steel bar (5); the other end of the horizontal block (2) is connected to the shear pin (1).

7. A three-level seismic design method for bridge pier bottoms that can achieve rapid post-earthquake repair as described in claim 1, wherein a buffer rubber pad (6) is arranged around the inverted T-shaped structure of the pier (8) to buffer the collision between the pier bottom (8) and the trapezoidal stopper (3).

8. A three-level seismic design method for bridge pier bottoms capable of achieving rapid post-earthquake repair as claimed in claim 1, characterized in that: Taking into account the possible errors between earthquake calculations and actual conditions, and to ensure that the shear pins and horizontal connecting steel bars achieve their setting purposes, a reliability coefficient of 10% is selected when calculating the corresponding parameters.

Images