Replaceable anti-falling beam device for improving transverse anti-seismic performance of bridge and design method of replaceable anti-falling beam device

Abstract

The invention belongs to the technical field of bridge engineering, and discloses a replaceable anti-beam-falling device for improving the transverse anti-seismic performance of a bridge and a design method thereof.The device comprises a first support and a second support which are arranged in a vertically spaced mode, the first support is connected with a cross beam, and the free end of the cross beam is fixedly connected with the bottom end of a bridge superstructure; the first support and the second support are connected through a plurality of steel plates, and each steel plate comprises a plurality of energy dissipation ribs. According to the scheme, key parameters such as the initial rigidity, the yield strength, the number of the steel plates and the number of the rib plates of the replaceable anti-beam-falling device are designed, so that the replaceable anti-beam-falling device can limit sliding of the rubber support through damage and deformation of the steel plates and preferentially dissipate earthquake energy under the action of medium and small earthquakes, and the replaceable anti-beam-falling device can effectively prevent the rubber support from falling off under the action of large earthquakes. Earthquake energy is jointly dissipated by means of yield deformation of the steel plate, sliding isolation of the support and limited plasticity of the pier, the purpose of expected graded energy dissipation is achieved, and the function of the bridge can be quickly recovered only by replacing the steel plate after an earthquake.

Description

Technical Field

[0001] This solution belongs to the field of bridge engineering technology, specifically involving a replaceable anti-falling beam device and its design method for improving the lateral seismic performance of bridges. Background Technology

[0002] Traditional ductile seismic design codes for bridges stipulate that bearing damage is not permitted, and seismic resistance is achieved through the energy dissipation mechanism of pier plastic hinges. However, the devastation caused by earthquakes such as the Wenchuan earthquake shows that the code's expected goals have not been achieved in actual earthquakes. The frictional slippage of plate rubber bearings creates a natural seismic isolation mechanism. The quasi-seismic isolation design concept, which utilizes the sliding isolation of bearings and the energy dissipation limiting effect of abutments to achieve limited plastic damage to piers and avoid severe damage to the bridge structure, is a current research hotspot. As a key component in achieving this goal, the rational design method of abutments is crucial.

[0003] Currently, due to the lack of design specifications for reinforced concrete abutments, their functional positioning in bridges is unclear, resulting in insufficient seismic resistance. Numerous actual earthquake damages demonstrate that reinforced concrete abutments, due to their high stiffness, low ductility, and lack of energy dissipation capacity, not only hinder the flexibility of plate rubber bearings under seismic loads, increasing the seismic response of the substructure, but also lose their ability to limit the displacement of the main beam and bearings due to brittle shear failure, leading to lateral collapse of the main beam and even severe beam collapse. These traditional reinforced concrete abutments cannot effectively utilize the flexible seismic isolation function of plate rubber bearings and lack sufficient deformation energy dissipation capacity. Although some elastoplastic energy-dissipating steel abutments have been proposed in existing research, they are typically simply applied to bridges for limiting and dissipating energy. However, their application scenarios are relatively limited to different seismic intensities, failing to fully utilize their function for varying random earthquake strengths. The lack of reasonable design methods leads to frequent replacements and low utilization efficiency.

[0004] Currently, the design calculations for quasi-isolation systems of highway bridges typically employ nonlinear seismic response analysis based on elastoplastic finite element models. The parameter values ​​of the steel retainers that meet the design objectives are generally obtained through extensive parameter analysis. This design calculation method has two main shortcomings: 1. Elastoplastic finite element modeling is relatively complex, and nonlinear seismic response analysis is prone to computational convergence problems; 2. The computational workload for determining the design parameters of the steel retainers through parameter analysis is large and time-consuming, making it unable to meet the design requirements of different types of bridges and hindering the application of this method by designers in actual engineering projects. These issues urgently need to be addressed in depth. Summary of the Invention

[0005] This invention provides a replaceable anti-falling beam device and its design method to improve the lateral seismic performance of bridges, thereby solving the above-mentioned problems.

[0006] The first aspect of the present invention provides a replaceable anti-fall beam device for improving the lateral seismic performance of a bridge, including a first support and a second support arranged at intervals. The first support is connected to a crossbeam, and the free end of the crossbeam is fixedly connected to the bottom end of the bridge superstructure. The first support and the second support are connected by a plurality of steel plates, and each steel plate includes a plurality of energy-dissipating ribs.

[0007] In some embodiments, the bottom end of the upper structure is further provided with a rubber support; the opposing surfaces of the first support and the second support are symmetrically provided with a plurality of spaced slots, and the steel plate is disposed in the slots.

[0008] A second aspect of the present invention provides a design method for a replaceable anti-falling beam device to improve the lateral seismic performance of a bridge, comprising the following steps: Step S1: Calculate the mechanical parameters of the bridge system before the installation of the replaceable anti-falling beam device; including the mass of the bridge superstructure. m sup and substructure mass m sub Lateral effective yield strength of bridge piers F py The initial lateral stiffness K of the bridge pier py Lateral effective yield displacement of bridge pier D py Total friction of rubber bearing F LRy Total shear stiffness of rubber bearing K LR Total yield displacement of rubber bearing D LRy ; Step S2: Initially set the design parameters of the replaceable anti-fall beam device, including the initial stiffness K and yield strength Q of the replaceable anti-fall beam device and the rubber support, as well as the number of energy-dissipating ribs n and the number of steel plates N of a single steel plate; Step S3: Estimate the initial design displacement Δd of the superstructure; Step S4: Calculate the equivalent viscous damping ratio ξ in the transverse direction of the rubber bearings, replaceable anti-fall beam devices, and piers. i ; Step S5: Based on the equivalent viscous damping ratio ξ of the rubber bearing, replaceable anti-fall beam device, and pier transverse direction. i Calculate the equivalent viscous damping ratio ξ of the bridge system. sys ; Step S6: Calculate the equivalent mass of the bridge system M e equivalent stiffness k e Effective basic cycleT e ; Step S7: Calculate the damping reduction factor R ξ ; Step S8: Modify the 5% damping design displacement S d ; Step S9: Check the design displacement S d Lateral effective yield displacement of the bridge pier D py If the relative error does not exceed the preset threshold, the design parameters of the replaceable anti-falling beam device are output; if not, the process returns to step S2 to readjust the initial value of the design parameters of the replaceable anti-falling beam device, and steps S2 to S8 are repeated until the relative error meets the preset threshold requirement. Step S10: Determine the design parameters of the replaceable anti-fall beam device and verify them using a scaled-down shaking table model.

[0009] The present invention has the following advantages over the prior art: 1. By designing key parameters such as the initial stiffness, yield strength, number of steel plates, and number of ribs of the replaceable anti-fall beam device, the designed replaceable anti-fall beam device can limit the slippage of the rubber bearing through the damage deformation of the steel plates under small and medium earthquakes, thus preferentially dissipating seismic energy. Under large earthquakes, it relies on the yield deformation of the steel plates, the seismic isolation of bearing slippage, and the "limited" plasticity of the piers to dissipate seismic energy, achieving the expected graded energy dissipation purpose. After the earthquake, only the replaceable anti-fall beam device needs to be replaced to quickly restore the bridge function, prevent the main beam from falling and collapsing, and protect the safety of the bridge.

[0010] 2. By employing the method provided by this invention, and through the design of the aforementioned reasonable replaceable anti-falling beam device's mechanical performance parameters for earthquakes of different magnitudes, it can fully utilize the seismic isolation effect of the supports and the limiting energy dissipation capacity of the replaceable anti-falling beam device to delay and reduce seismic damage to the bridge piers, and effectively prevent beam collapse from occurring in the superstructure, thereby improving the seismic resistance of the beam bridge. Furthermore, the replaceable anti-falling beam device proposed in this invention will not damage the cap beam and abutment upon failure; the steel plates are easily disassembled and installed after an earthquake; the main beam displacement can be easily reset; and the bridge can be restored to its usability more quickly.

[0011] 3. This invention has a simple structure and is easy to construct. Through a simple structural design, it reduces the maximum and residual displacement of the main beam, avoids beam collapse damage, reduces maintenance costs, and can prevent beam collapse. The structural system is similar to the rubber bearing support system, which is inexpensive, simple in construction, and easy to construct and maintain. Compared with typical isolation systems, it has a higher cost performance and a wider range of applications, showing significant advantages in a large number of highway bridges. Attached Figure Description

[0012] Figure 1 This is a schematic diagram illustrating the design process of the replaceable anti-falling beam device of the present invention. Figure 2 This is a structural schematic diagram of the replaceable anti-falling beam device and bridge of the present invention; Figure 3 This is a scaled-down model drawing of the vibration table of the present invention. Figure 4 This is a table of component values ​​for the design model, scaled-down model, and experimental model of this invention; Figure 5 This is a graph showing the acceleration envelope along the bridge height according to the present invention. Figure 6 This is a diagram showing the maximum relative displacement and residual relative displacement between the main beam and the pier of this invention; Figure 7 This is a diagram showing the strain envelope curve of the reinforcing steel along the height of the pier according to the present invention.

[0013] The reference numerals in the accompanying drawings include: superstructure 1, steel pad 11, rubber bearing 2, replaceable anti-falling beam device 3, first support 31, second support 32, crossbeam 33, steel plate 34, pad stone 4, cap beam 5, and pier 6. Detailed Implementation

[0014] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0015] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0016] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0017] The following describes in detail, with reference to the accompanying drawings, a replaceable anti-falling beam device for improving the lateral seismic performance of bridges according to an embodiment of the present invention.

[0018] Please see Figure 1 The initial design of the bridge structure was completed using the traditional ductility method, determining the basic components of the bridge structure. The main body of the bridge consists of, from top to bottom, the superstructure 1, the pad stone 4, the cap beam 5, and the pier 6. The bottom of the superstructure 1 (i.e., the end in contact with the pad stone 4) is composed of several spaced reinforced concrete T-beams, with the bottom of the T-beams shaped like horseshoes. A steel pad 11 is installed at the bottom of the T-beams, with the other end of the steel pad 11 contacting the rubber bearing 2. The other end of the rubber bearing 2 contacts the pad stone 4. The contact area between the pad stone 4 and the rubber bearing 2 must be larger than the area of ​​the rubber bearing 2, and the rubber bearing 2 is a common plate-type rubber bearing 2. The upper end of the cap beam 5 supports the superstructure 1 and the pad stone 4, and the lower end contacts the pier 6. The pier 6 consists of a double-column pier 6 made of reinforced concrete and supported on an extension pile foundation.

[0019] Please continue reading. Figure 1 A replaceable anti-falling beam device 3 is installed on the cap beam 5. In this embodiment, two sets are configured, located at the extreme positions on both sides of the superstructure 1 of the bridge. The device includes a first support 31 and a second support 32 arranged vertically. The first support 31 is located directly above the second support 32, and a crossbeam 33 is connected to the side of the first support 31 closest to the superstructure 1. The free end of the crossbeam 33 is provided with a retaining ring structure (not shown) adapted to the bottom end of the T-beam. This is existing technology. The retaining ring connects the free end of the crossbeam 33 to the T-beam, and the retaining ring is fixed to the T-beam by bolts. The opposing surfaces of the first support 31 and the second support 32 are symmetrically provided with several spaced slots (not shown). Steel plates 34 are provided within the slots. The steel plates 34 are multiple pieces of slotted steel plates 34 with strong deformation and energy dissipation capabilities. Several energy dissipation ribs (not shown) are provided on the steel plates 34 spaced along their length and width.

[0020] Under random earthquakes of varying intensities, the superstructure 1 can undergo lateral displacement or sliding on the rubber bearings 2. Depending on the sliding displacement of the superstructure 1, the rubber bearings 2, the replaceable anti-fall beam device 3, and the piers 6 can function sequentially to achieve the anti-fall beam function. In this embodiment, a three-level seismic design requirement for the bridge is proposed, forming a three-tiered seismic fortification mechanism. Specifically, during a minor earthquake (Level 1), the performance objective of the bridge system is immediate post-earthquake use (Level 1), where the piers 6 are expected to remain resilient after the earthquake and require no maintenance. During a moderate earthquake (Level 2), the system's performance objective is rapid recovery (Level SR), at which point the rubber bearings 2 slide to isolate the seismic energy, and the replaceable anti-fall beam device 3 acts as a fuse to dissipate seismic energy. During the most credible earthquake (Level 3), the system's performance objective is to avoid severe damage and collapse (Level CP), through which the rubber bearings 2 slide to form seismic isolation, and the replaceable anti-fall beam device 3 dissipates seismic energy.

[0021] Please see the appendix Figure 2 This paper describes a design method for a replaceable anti-falling beam device to improve the lateral seismic performance of bridges, based on an embodiment of the present invention.

[0022] First, this embodiment selects a typical prototype bridge with the following initial information: Each span of the bridge consists of five reinforced concrete T-beams, with a total weight of 389 tons (including the dead load of non-structural components such as bridge deck pavement and guardrails). The substructure consists of reinforced concrete double-column piers 6, supported on extended pile foundations. The characteristic period (Tg) of the bridge site is 0.4s. All piers 6 have the same dimensions, with a clear height of 10.0m and a diameter of 1.4m. The bridge pier columns are reinforced with 28 longitudinal steel bars of 25mm in diameter, with a reinforcement ratio of 1.1%. The yield strength of the steel bars in the columns is 400MPa. The peak strength of the concrete used to construct the piers is 30MPa. Each T-beam is supported by two rubber bearings 2, each located at both ends in the longitudinal direction, therefore each pier has ten rubber bearings 2. The rubber bearing 2 is a planar rectangular structure with dimensions of 450×300mm and a height of 85mm. Since the bridge is supported on rock strata, the influence of soil-structure interaction can be ignored. The following section selects a typical T-beam bridge as a prototype to complete the design of the replaceable anti-falling beam device 3. The detailed design process is described below: Step S1: Perform pushover analysis and calculate the performance of the double-column pier 6 of the bridge, as shown in the table below. Key mechanical parameters code name Specific value Equivalent structural mass of the system (tons) <![CDATA[ M e ]]> 428.4 Dead load mass of superstructure (tons) <![CDATA[ m sup ]]> 389 Substructure mass (tons) <![CDATA[ m sub ]]> 118.2 Lateral effective yield strength of bridge pier (kN) <![CDATA[ F py ]]> 2443 Initial lateral stiffness of bridge piers (kN / mm) <![CDATA[K py ]]> 46.1 Lateral effective yield displacement of bridge pier (mm) <![CDATA[ D py ]]> 53 Total frictional force of rubber bearing (kN) <![CDATA[ F LRy ]]> 1143.7 Total shear stiffness of rubber bearing (kN / mm) <![CDATA[ K LR ]]> 28.2 Total yield displacement of rubber bearing (mm) <![CDATA[ D LRy ]]> 0.041

[0023] Step S2: Use the equation to assume the initial value of the design force of the replaceable anti-falling beam device 3 on one side of the main beam. F dy : kN kN, kN / mm Determine the number of steel plates 34 included in the replaceable anti-fall beam device 3: Determine the total initial elastic stiffness of the replaceable anti-fall beam device 3: kN / mm Step S3: Estimate the design displacement of superstructure 1. Assume the initial design displacement of superstructure 1 is estimated as (Δd = 0.15m). This is calculated by subtracting the effective lateral yield displacement of pier 6. D py =0.053m), the design displacement of rubber bearing 2 is calculated to be 0.097m. If we define the ductility of rubber bearing 2 as the ratio of design displacement to critical sliding displacement (0.041m), then the ductility design value of rubber bearing 2 is 2.39. If the yield displacement of replaceable anti-falling beam device 3 is 0.002m, then the ductility value of replaceable anti-falling beam device 3 is calculated to be 49.4. The coefficient of friction between rubber bearing 2 and the main beam. The value is 0.3, representing the acceleration due to gravity. Using a value of 9.8 m / s², calculate the maximum load on the replaceable anti-fall beam device 3 and rubber bearing 2 at maximum displacement: = =0.3×389×9.8=1143.7kN kN Step S4: Assume the pier is in a non-yielding state. Calculate the equivalent viscous damping ratio ξ of the rubber bearing 2, the replaceable anti-falling beam device 3, and the pier. i : Step 5: Calculate the equivalent viscous damping ratio ξ of the rubber bearing 2, the replaceable anti-falling beam device 3, and the bridge system. sys : Step S6: Calculate Me, Ke, and Te as follows: ton kN / m s Step S7: Calculate the damping reduction factor Rξ : Step S8: Calculate and modify the design displacement S d The attenuation exponent γ of the acceleration design spectrum can be calculated. The corresponding displacement for the effective period (Te = 1.1s) can be determined as S. d =0.062m, equal to the initial design value D py =0.053m, error is |S d - D py | / D py =16.8%. This indicates that the results have converged.

[0024] m Step S9: Specify 0.1m as the new design displacement value and iterate the design process from steps S3 to S8 until convergence is obtained. After the first iteration, the final design displacement is updated to 0.052m, which matches the specified value of 0.55m well, with a slight difference of 3.2%. This indicates that the result has converged.

[0025] Step S10: Design the dimensions of the steel plate 34 according to the parameters of the replaceable anti-falling beam device 3 on one side of the main beam, including the number of steel plates 34 N and the total initial elastic stiffness K. BSP and yield strength K BSPy As shown below: , kN, kN / mm To verify the seismic performance of the bridge design, a scaled-down design and scaled-down shaking table test were conducted. A 1:8 scale test model of the original bridge was used. Then, the designed bridge superstructure (1), piers (6), rubber bearings (2), and replaceable anti-falling beam device (3) were scaled down proportionally. The model design drawings and parameters are as follows: Figure 3 and Figure 4 As shown. Figure 5 The maximum acceleration envelopes of the two systems along the bridge height are shown. From Figure 5It can be clearly seen that the acceleration varies significantly with the bridge height. When the PGA is less than 0.3g, the acceleration decreases with increasing bridge height. When it exceeds 0.3g, the acceleration of the main girder is generally less than that of the cap girder, mainly due to the lateral slippage of the rubber bearings. For example, under the RSN1044 motion with a PGA of 0.8g, the maximum acceleration of the B2 system is 0.95g and 1.26g. Therefore, the slippage of the rubber bearing 2 can significantly reduce the peak acceleration response of the bridge superstructure 1, but this reduction is less significant when the load-bearing capacity of the replaceable anti-falling beam device 3 increases.

[0026] Figure 6 The curves showing the maximum and residual displacements (relative displacements) between the main girder and pier 6 of the bridge system under different seismic intensities are displayed. It is clear that when the PGA reaches 0.3g, both the maximum and residual displacements increase synchronously. Beyond this point, the maximum displacement continues to rise, while the residual displacement does not increase significantly, indicating that the slippage of the rubber bearing 2 occurs when the PGA is 0.3g. Overall, the bridge system exhibits significant displacement limiting capability, with the residual displacement of the main girder and pier 6 accounting for approximately 77% to 93% of the maximum displacement reduction. Therefore, when a suitable replaceable anti-falling beam device 3 is designed, the maximum and residual displacements between the beam and pier 6 can be effectively controlled.

[0027] Figure 7 The strain distribution envelope of the bridge system along the height of pier 6 is shown. For the considered transversely excited double-column pier 6, the column top and bottom are critical and vulnerable areas. The results show that the steel reinforcement strain varies greatly along the height of pier 6, with the maximum strain occurring at the top and bottom of pier 6. As the PGA increases, the strain at critical locations continues to rise, while the strain in the middle and upper parts of pier 6 remains almost constant. In the system, the steel reinforcement strain is below the yield strain (2545). Therefore, when the replaceable anti-fall beam device 3 designed according to the displacement method is used, pier 6 does not show significant damage. Therefore, a well-designed replaceable anti-fall beam device 3 can effectively protect pier 6 from severe damage during earthquakes.

[0028] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0029] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A replaceable anti-falling beam device for improving the lateral seismic performance of a bridge, comprising a first support (31) and a second support (32) arranged in an upper and lower interval, the first support (31) is connected with a cross beam (33), the free end of the cross beam (33) is fixedly connected with the bottom end of the bridge superstructure (1), characterized in that: The first support (31) and the second support (32) are connected through a plurality of steel plates (34), and each steel plate (34) comprises a plurality of energy dissipation ribs.

2. The replaceable anti-collapse device for improving the transverse seismic performance of a bridge according to claim 1, wherein the bottom end of the superstructure (1) is further provided with rubber bearings (2); the opposite faces of the first support (31) and the second support (32) are symmetrically provided with a plurality of spaced-apart clamping grooves, and the steel plates (34) are arranged in the clamping grooves.

3. A design method of the replaceable anti-collapse device for improving the lateral seismic performance of a bridge, comprising the replaceable anti-collapse device for improving the lateral seismic performance of a bridge according to claim 1 or 2, characterized in that, comprising the steps of: Step S1: calculating the bridge system mechanics parameters before installing the replaceable anti-falling beam device; including the superstructure mass of the bridge m sup and the substructure mass m sub , the lateral effective yield force of the pier F py , the lateral initial stiffness K of the pier py , the lateral effective yield displacement of the pier D py , the total friction of the rubber bearing F LRy , the total shear stiffness of the rubber bearing K LR , the total yield displacement of the rubber bearing D LRy ; Step S2: preliminary setting of the design parameters of the replaceable anti-collapse beam device, including the initial stiffness K and yield strength of the replaceable anti-collapse beam device and the rubber support , and the number of energy dissipation ribs n of the single steel plate and the number of steel plate pieces N; Step S3: estimating the initial design displacement Δd of the superstructure; Step S4: calculating the equivalent viscous damping ratio ξ of the rubber bearing, the replaceable anti-collapse beam device and the pier transverse direction i ; Step S5: calculating the equivalent viscous damping ratio ξ of the bridge system according to the rubber support, the replaceable anti-girder device and the transverse of the bridge pier i . sys ; Step S6: Calculate the equivalent mass of the bridge system M e , equivalent stiffness k e , effective fundamental period T e ; Step S7: Calculate the damping reduction factor R ξ ; Step S8: Modify 5% Damped Design Displacement S d ; Step S9: checking the design displacement S d whether the relative error of the lateral effective yield displacement of the bridge pier D py does not exceed a preset threshold value; If yes, the design parameters of the replaceable anti-collapse device are output; if no, the initial values of the design parameters of the replaceable anti-collapse device are re-adjusted, and steps S2 to S8 are repeated until the relative error meets the preset threshold requirement; Step S10: determining the design parameters of the replaceable anti-collapse device, and verifying by using a scaled shaking table model.

4. The replaceable anti-collapse device design method for improving the transverse seismic performance of a bridge according to claim 3, characterized in that: The initial rigidity of the replaceable anti-beam-falling device in step S2 and yield strength Calculation formula: wherein is the number of energy dissipation ribs per steel sheet; is the number of steel sheets; is the Young's modulus; is the rib plate thickness of the energy dissipation rib; is the rib plate width of the energy dissipation rib; is the width of the single steel sheet; is the ratio of the plate rib width; is the ultimate stress of the steel sheet; is the height of the steel sheet; The stiffness of the anti-falling beam device after yielding needs to meet = 0.03 ; Assume the friction coefficient of the frictional slip between the rubber bearing and the bridge superstructure and the supporting reaction force The initial stiffness of the rubber bearing, which remains unchanged during the sliding process and the frictional slip strength Calculation formula: In the formula, G is the shear modulus of the rubber bearing; A is the force area of the rubber bearing; h is the thickness of the rubber bearing; The yield force of the replaceable anti-falling beam device in the step S2 F BSPy Calculation formula: wherein F LRy is the total friction of the rubber bearing; F py is the lateral yield force of the pier.

5. The replaceable fall prevention device design method for improving the transverse seismic performance of a bridge according to claim 4, characterized in that: In step S3, assuming the design value of the displacement of the bridge system Δd, the design displacement of the replaceable anti-collapse device and the rubber bearing is calculated by subtracting the lateral effective yield displacement of the pier D py Then the displacement ductility of the replaceable anti-collapse device and the rubber bearing is obtained D i The calculation formula is: ​ wherein is the displacement of the replaceable anti-collapse device or rubber bearing; is the yield displacement of the replaceable anti-collapse device or rubber bearing.

6. The replaceable anti-collapse device design method for improving the transverse seismic performance of a bridge according to claim 5, characterized in that: In the step S4, the equivalent viscous damping ratio ξ of the rubber support and the replaceable buckling restraining device i Calculation formula: In the formula, F im Design force of the replaceable anti-collapse beam device or rubber bearing; F iy Yield force of the replaceable anti-collapse beam device or rubber bearing; Assuming that the ductility coefficient of the pier is μ P The equivalent viscous damping ratio of the pier is ξ p The calculation formula is as follows: 。 7. The replaceable fall prevention device design method for improving the transverse seismic performance of a bridge according to claim 6, characterized in that: The equivalent viscous damping ratio of the bridge system is calculated in the step S5 ξ sys The damping ratio of the pier-beam constraint system formed by the single-pier support and the replaceable anti-falling beam device ξ PGC The force ratio and the displacement ratio are combined according to the force ratio; the damping ratio of the pier-beam constraint system ξ PGC and the damping ratio of the pier ξ P The displacement ratio method is used for combination; the pier-beam constraint system is calculated ξ PGC and the equivalent damping ratio of the bridge system ξ sys The force and displacement ratio method calculation formula of the equivalent damping ratio of the bridge system wherein ξ BSP Equivalent damping ratio of the replaceable buckling restraining device; ξ LR Equivalent damping ratio of the rubber bearing; F BSPy Yield force of the replaceable buckling restraining device; Design displacement of the rubber bearing.

8. The replaceable anti-collapse device design method for improving the transverse seismic performance of a bridge according to claim 7, characterized in that: In said step S6, the bridge effective fundamental period T e , the equivalent stiffness K e and the equivalent mass M e calculation formula: wherein is the maximum load of the rubber bearing at the maximum displacement; is the friction coefficient of the rubber bearing to the girder; is the acceleration of gravity.

9. The replaceable fall prevention device design method for improving the transverse seismic performance of a bridge according to claim 8, characterized in that: In the step S7, the damping reduction coefficient R ξ is calculated by the following formula: 。 10. The replaceable fall prevention device design method for improving the transverse seismic performance of a bridge according to claim 9, characterized in that: In the step S8, a design spectrum based on the spectral acceleration is calculated, which modifies the design displacement S d The calculation formula is: wherein T denotes the vibration period of the superstructure; R ξ denotes the damping reduction factor; α max denotes the maximum value of the horizontal seismic effect coefficient; T g denotes the characteristic period of the site; γ denotes the attenuation exponent of the acceleration design spectrum.

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