Replaceable bent steel bar-shear plate combined metal damper and mounting method

Abstract

The invention relates to a replaceable bent steel bar-shear plate combined metal damper and a mounting method, and belongs to the technical field of bridge engineering. Comprising a left connecting steel plate, a right connecting steel plate, bolt fixing plates, high-strength bolts and energy dissipation assemblies. The left connecting steel plate and the right connecting steel plate are respectively connected with the concrete straining beam, bolt fixing plates are fixed on the left connecting steel plate and the right connecting steel plate, and the left connecting steel plate and the right connecting steel plate are connected with the energy dissipation assembly through high-strength bolts; the energy dissipation assembly is installed between the left connecting steel plate and the right connecting steel plate and comprises a bent steel bar and a shear plate. The shear plate is a combined body formed by an H-shaped steel plate and bent steel bars at the upper end and the lower end; the multiple groups of bent steel bars and the at least one shearing plate are arranged together side by side; the anti-seismic performance of the bridge can be improved, the construction speed can be greatly increased, and the good energy dissipation capacity and the replaceable performance after an earthquake are guaranteed.

Description

Technical Field

[0001] The invention relates to a replaceable bent steel bar-shear plate combined metal damper and an installation method thereof, belonging to the technical field of bridge engineering. Background Art

[0002] my country is located between the Pacific Rim and the Eurasian seismic belt, and high-intensity areas are widely distributed. Therefore, bridge structures in high-intensity areas are easily affected by earthquakes. For bridges that need to add concrete tie beams between piers to increase the stability and lateral stiffness of the piers, once subjected to earthquake loads, it is very easy to cause bending and shear failure at the connection between the concrete tie beam and the pier, which will lead to the destruction of the entire bridge.

[0003] When designing bridge piers, concrete tie beams are usually designed as ductile components. It is necessary to ensure that the concrete tie beams are damaged at the ends, consume the seismic load through their own plastic deformation, and protect other parts of the piers from damage. Therefore, under the action of an earthquake, plastic hinges are often formed first at the connection between the pier column and the concrete tie beam. Once the concrete tie beam is damaged and seriously loses its working ability, it will cause changes in the structural system, making the entire pier more susceptible to damage. Therefore, adding dampers to the concrete tie beams can improve the seismic performance of the piers and prevent the piers from being damaged prematurely.

[0004] Common bridge dampers include viscous dampers, friction dampers, metal dampers, etc. Among them, viscous dampers can provide a large damping force and effectively dissipate the energy of the input structure, thereby significantly reducing the vibration response of the structure. However, the performance of the damper is affected by the environment, temperature, etc., and the internal viscous fluid may leak due to poor sealing or aging, thereby affecting the performance of the damper, which is not conducive to complex environmental conditions such as high-intensity areas; the friction damper has a low cost and a simple mechanical model, and can effectively control the lateral displacement of the structure, but its friction force needs to be determined by adjusting the preload, and its performance is greatly affected by temperature, and it is not conducive to installation and maintenance in complex terrain conditions such as high-intensity areas; the metal damper is an energy-absorbing device that is formed into different shapes by processing metal materials and installed in locations such as bridge tie beams, and has broad application prospects. The research and development and application of metal dampers is equivalent to installing a "safety airbag" on the bridge. When an earthquake occurs, the damper absorbs and consumes the impact energy of the earthquake on the structure to the maximum extent, greatly alleviating the impact and damage caused by the earthquake to the structure. The use of metal dampers can not only achieve the advantages of light weight, easy construction, and replaceability, but also enhance the seismic performance of the structure.

[0005] Currently, common metal dampers include shear-type metal dampers, bending-type metal dampers, and bending-shear metal dampers. Shear-type dampers can provide greater stiffness, but the shear plate is destroyed more quickly. Bending dampers can generate greater energy consumption and are destroyed more slowly, but their lateral stiffness is smaller than that of shear plates. Existing bending-shear dampers have greater stiffness and energy dissipation capacity, but their replaceability is relatively limited. New forms of exploration are still needed to seek damper structures that are more suitable for complex terrain conditions in high-intensity areas, so that bridge tie beams can be protected to a certain extent and are easy to replace after an earthquake. Summary of the invention

[0006] In view of the above defects in the prior art, the present invention proposes a replaceable bent steel bar-shear plate combined metal damper and an installation method. The replaceable bent steel bar-shear plate combined metal damper can not only improve the seismic performance of the bridge, but also greatly speed up the construction speed, ensure good energy dissipation capacity and post-earthquake replaceability.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] A replaceable bent steel bar-shear plate combined metal damper, comprising a left connecting steel plate, a right connecting steel plate, a bolt fixing plate, high-strength bolts and an energy dissipation component;

[0009] The left connecting steel plate and the right connecting steel plate are connected to the concrete tie beam respectively, and bolt fixing plates are fixed on the left connecting steel plate and the right connecting steel plate, and are connected to the energy dissipation component through high-strength bolts; wherein, four groups of bolt fixing plates are provided, which are respectively located at the upper and lower ends of the inner sides of the left connecting steel plate and the right connecting steel plate, and each group of bolt fixing plates includes upper and lower bolt fixing plates;

[0010] The energy dissipation component is installed between the left connecting steel plate and the right connecting steel plate, and includes a bent steel bar and a shear plate; when the relative deformation of the left and right connecting steel plates is small, the shear plate has a higher rigidity, so the deformation is preferentially concentrated in the middle of the shear plate. When the relative displacement is large, the middle part of the shear plate is sheared off, and the bent steel bar continues to play a bending deformation role to maintain its connection and energy dissipation function. The shear plate is a combination of an "H"-shaped steel plate and bent steel bars at the upper and lower ends; multiple groups of bent steel bars and at least one shear plate are arranged side by side; both ends of the bent steel bar are provided with bolt holes reserved for the bent steel bar, and the bolt fixing plate is also provided with bolt holes reserved for the bolt fixing plate. The two ends of the bent steel bar are fixed to each group of bolt fixing plates through the bolt holes reserved for the bent steel bar, the bolt holes reserved for the bolt fixing plate, and high-strength bolts.

[0011] Furthermore, the bent steel bars are divided into two groups, an upper group and a lower group, and both ends of the bent steel bars in the upper group and the lower group are clamped between two bolt fixing plates in each group through high-strength bolts.

[0012] Furthermore, the curved steel bar is arc-shaped, and the upper and lower groups of curved steel bar arc-shaped protruding parts are arranged opposite to each other. The bending strength calculation formula of the curved steel bar is: W = bh 2 / 6, where b is the flange width and h is the height; the torsional strength calculation formula is W t =2b 3 h / 3L, where L is the length of the curved steel bar. The curved steel bar is more beautiful than ordinary straight steel bars, and has good ductile deformation capacity when subjected to earthquake loads.

[0013] Furthermore, the shear plate is arranged in the middle of the multiple groups of bent steel bars, and the multiple groups of bent steel bars are symmetrically arranged on both sides of the shear plate.

[0014] Furthermore, the number of shear plates and bent steel bars is calculated based on the strength and stiffness of the tie beam in the corresponding bridge structure, and the stiffness and strength of the entire damper must be maintained at 0.8 times the corresponding indicators of the concrete tie beam to ensure that the damper structure is weaker than the tie beam structure so that the damage is concentrated at the damper position; the arrangement of the shear plates and bent steel bars should be adjusted based on the number of shear plates and bent steel bars, but it should be ensured that the shear plates and bent steel bars of the entire damper are symmetrically distributed to avoid out-of-plane damage caused by improper construction.

[0015] Furthermore, the bent steel bars are in groups of 2, 4, 6 or 8.

[0016] Furthermore, the "H"-shaped steel plate has a middle cross-section between its left and right limbs that is larger than its upper and lower end cross-sections.

[0017] Furthermore, the left connecting steel plate and the right connecting steel plate are welded together with the bolt fixing plate.

[0018] Furthermore, the "H"-shaped steel plate in the shear plate is integrally formed or welded with the bent steel bars at the upper and lower ends.

[0019] The installation method of the replaceable bent steel bar-shear plate combined metal damper comprises the following steps:

[0020] S1. Piers and concrete tie beams are manufactured in the processing plant. Screws are embedded in the concrete tie beams to reserve installation positions for combined metal dampers.

[0021] S2. The left connecting steel plate, the right connecting steel plate and the bolt fixing plate are processed and manufactured in the processing plant, and reserved bolt holes for the bolt fixing plate are set on the bolt fixing plate. The left connecting steel plate and the right connecting steel plate are bolted together by screws embedded in the concrete tie beam, and a reserved position is ensured between the left connecting steel plate and the right connecting steel plate to facilitate the installation of energy-consuming components;

[0022] S3. The bent steel bars and shear plates are manufactured in the processing plant, and the bolt holes reserved for the bent steel bars are reserved at both ends of the bent steel bars. The bolt holes reserved for the bent steel bars on the bent steel bars and shear plates are aligned with the bolt holes reserved for the bolt fixing plates of the bolt fixing plates, and they are connected with high-strength bolts respectively; it is ensured that when the shear plates are subjected to loads and the pier column concrete tie beams undergo relative movement, the left and right limbs of the middle "H" steel can shift relative to each other, forming plastic deformation and dissipating energy;

[0023] S4. When the bent steel bars or shear plates are deformed and damaged under the action of an earthquake, they can be replaced by disassembling and reinstalling the high-strength bolts and replacing them with new bent steel bars or shear plates. This allows the replaceable bent steel bar-shear plate combined metal damper to achieve sustainable working capabilities, restore the temporary working capacity of the bridge piers, and facilitate the development of post-earthquake rescue work.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention proposes a combined metal damper of a curved steel bar and a shear plate, which is installed at the concrete tie beam and connected by high-strength bolts. The damper absorbs the energy dissipation of earthquake loads by the vertical shear deformation of the shear plate and the bending deformation of the curved steel bar, ensuring that the concrete tie beam is not seriously damaged and concentrating the damage at the damper position; and after damage occurs, the damper can be quickly removed and replaced with a new one, realizing the rapid installation and replaceability of the damper, so that the tie beam bridge pier can realize the ability to serve temporarily after an earthquake, facilitating the timely implementation of post-earthquake rescue work.

[0026] Under the action of earthquake load, the pier column and the concrete tie beam produce mutual movement, which can drive the energy dissipation component to deform and generate energy. The deformation of the entire energy dissipation component is divided into two stages. When the relative deformation of the left and right connecting steel plates is small, the shear plate has a higher stiffness, so the deformation is concentrated in the middle of the shear plate first. When the relative displacement is large, the middle part of the shear plate is cut off, and the bent steel bar continues to play a bending deformation role to maintain its connection and energy dissipation. When the actual earthquake load acts, the relative displacement between the pier column and the concrete tie beam is first borne by the shear plate, and then by the bent steel bar, so as to achieve the purpose of consuming earthquake energy. In this way, the root of the concrete tie beam is avoided from being damaged due to the large bending and shear load, and the damage is transferred to the bent steel bar-shear plate combined metal damper, which improves the seismic performance of the bridge pier; at the same time, the bent steel bar-shear plate combined metal damper is connected by bolts, which has the advantages of light weight, quick and convenient installation, and post-earthquake replacement compared with traditional concrete tie beams. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the structure of the present invention;

[0028] Figure 2 This is a schematic diagram of the structure of the left and right connecting steel plates of the present invention;

[0029] Figure 3 It is a schematic diagram of the structure of the energy-consuming component of the present invention;

[0030] Figure 4 It is a detailed schematic diagram of the bent steel bar and shear plate of the present invention;

[0031] Figure 5 This is an elevation view of a single bent steel bar;

[0032] Figure 6 It is a top view of a single bent steel bar;

[0033] Figure 7 The bending moment diagram of the right end of the bent steel bar under different actions;

[0034] Figure 8 This is a schematic diagram of the shear plate size;

[0035] Fig. 9 It is a schematic diagram of stiffness equivalence, where (a) is a cast-in-place tie beam and (b) is a replaceable tie beam;

[0036] Fig.10 is the Pareto optimization curve. DETAILED DESCRIPTION

[0037] The following is combined with Figure 1-10 The present invention is further described in detail with specific implementations to facilitate a clear understanding of the present invention, but they do not constitute a limitation on the present invention.

[0038] Example 1

[0039] As attached Figure 1-4 As shown, a replaceable bent steel bar-shear plate combined metal damper of this embodiment includes a left connecting steel plate 1, a right connecting steel plate 2, a bolt fixing plate 3, high-strength bolts 4 and an energy dissipation component.

[0040] The left connecting steel plate 1 and the right connecting steel plate 2 are connected to the concrete tie beam respectively, and bolt fixing plates 3 are fixed on the left connecting steel plate 1 and the right connecting steel plate 2, and are connected to the energy dissipation component through high-strength bolts 4. Among them, four groups of bolt fixing plates 3 are provided, which are respectively located at the upper and lower ends of the inner sides of the left connecting steel plate 1 and the right connecting steel plate 2, and each group of bolt fixing plates 3 includes upper and lower bolt fixing plates 3. In this embodiment, the left connecting steel plate 1 and the right connecting steel plate 2 are welded to the bolt fixing plates 3.

[0041] The energy dissipation component is installed between the left connecting steel plate 1 and the right connecting steel plate 2, and includes a bent steel bar 5 and a shear plate 6. The shear plate 6 is a combination of an "H"-shaped steel plate and the bent steel bars 5 at the upper and lower ends. The "H"-shaped steel plate is welded with the bent steel bars 5 at the upper and lower ends. Figure 3-4 As shown, the middle section of the left and right limbs of the "H"-shaped steel plate is larger than the section of the upper and lower ends. Multiple groups of bent steel bars 5 and at least one shear plate 6 are arranged side by side. Both ends of the bent steel bar 5 are provided with bolt holes 8 reserved for bent steel bars, and the bolt fixing plate 3 is also provided with bolt holes 7 reserved for bolt fixing plates. The two ends of the bent steel bar 5 are fixed to each group of bolt fixing plates 3 through the bolt holes 8 reserved for bent steel bars, the bolt holes 7 reserved for bolt fixing plates, and the high-strength bolts 4.

[0042] The bent steel bars 5 are divided into two groups, upper and lower, and both ends of the upper and lower groups of bent steel bars 5 are clamped between the upper and lower bolt fixing plates 3 of each group by high-strength bolts 4. In this embodiment, the bent steel bars 5 are arc-shaped, and the arc-shaped protruding parts of the upper and lower groups of bent steel bars 5 are arranged opposite to each other.

[0043] like Figure 3As shown, the shear plate 6 is arranged in the middle position of the multiple groups of bent steel bars 5, and the multiple groups of bent steel bars 5 are symmetrically arranged on both sides of the shear plate 6. Among them, the number of shear plates 6 and bent steel bars 5 is calculated according to the strength and stiffness of the tie beam in the corresponding bridge structure, and the stiffness and strength of the entire damper must be maintained at 0.8 times the corresponding index of the concrete tie beam to ensure that the damper structure is weaker than the tie beam structure, so that the damage is concentrated at the damper position. The arrangement of the shear plates 6 and the bent steel bars 5 should be adjusted in combination with the number of shear plates 6 and the bent steel bars 5, but it should be ensured that the shear plates 6 and the bent steel bars 5 of the entire damper are symmetrically distributed to avoid out-of-plane damage caused by improper construction. In this embodiment, the bent steel bars 5 are specifically 4 groups.

[0044] Example 2

[0045] like Figure 5-9 As shown, the specific design method is:

[0046] According to the design principle, the seismic resistance of strong columns and weak beams is guaranteed, and the damage is expected to be concentrated in the high-energy-consuming structural position. The general principle is to meet the order that the damper yields before the tie beam, and the tie beam yields before the pier column, which can ensure that the damage occurs first at the damper position, followed by the tie beam, and finally the pier column. At the same time, many scholars realize the process of damper priority yielding by increasing the bending bearing capacity and shear force of the non-damper segment beam, and appropriately reduce the bending bearing capacity of the damper segment to achieve a reasonable yielding order, in which the damper reduction coefficient is designed to be 0.8.

[0047] 1. Determine the reasonable internal force requirement M of the combined energy-consuming structure T

[0048] M T =0.8×M (1)

[0049] Where M T is the required bending moment of the damper, and M is the maximum bending moment that the tie beam can withstand at the damper position.

[0050] 2. Assume that the five dimensional parameters of the bent steel bar are l, r, t, h, and b, which correspond to the length, radius, half thickness, sagitta, and width of the bent steel bar (5). List the force equations of the bent steel bar.

[0051] like Figure 5-6 As shown, the curve equation of the bent steel bar is

[0052] x 2 +(rhy) 2 =r 2 (2)

[0053] Among them, x is the horizontal coordinate corresponding to the point on the curve of the bent steel bar, and y is the horizontal coordinate corresponding to the point on the curve of the bent steel bar.

[0054] When unit displacement and unit rotation occur at the end of the bent steel bar, the force method is used to solve the problem according to its boundary conditions: The typical equation of the force method is:

[0055]

[0056] In the formula, δ 11 , δ 22 , δ 33 is the main coefficient, δ ii (i=1,2,3) is the unit excess unknown force The displacement caused by a single action along its own direction; δ 12 , δ 13 , δ 21 , δ 23 , δ 31 , δ 32 is the secondary coefficient, δ ij (i=1,2,3;j=1,2,3) is the unit redundant unknown force When acting alone, the i Displacement in the (i≠j) direction; Δ 1c , Δ 2c , Δ 3c is the free term, Δ ic (i=1,2,3) is the load along X caused by the external load acting alone i Displacement in the X direction 1 is the rotation angle applied to the right end of the bent steel bar, X 2 is the horizontal displacement applied to the right end of the bent steel bar, X 3 is the vertical displacement applied to the right end of the bent steel bar; θ is the rotation angle of the right end of the bent steel bar, Z is the horizontal displacement of the right end of the bent steel bar, and Δ is the vertical displacement of the right end of the bent steel bar.

[0057] The basic structure is selected for calculation. Since there is no external load on the basic structure and the redundant constraints have been removed, Δ 1c =0, Δ 2c =0, Δ 3c =0, then make M 1 、M 2 、M 3 Perform the calculation:

[0058] Among them, M 1 The right end of the bent steel bar has a turning angle X 1 When the left end bending moment value is 2 The horizontal displacement X of the right end of the bent steel bar 2 When the left end bending moment value is3 The vertical displacement X of the right end of the bent steel bar 3 When , the bending moment value at the left end. Figure 7 shown.

[0059] According to the calculation formula, the coefficients can be obtained:

[0060]

[0061] The bending strength of the bent steel bar is calculated, and finally the bending strength calculation expression of a single bent steel bar 5 is obtained according to the following formula:

[0062] Assuming that the number of bent steel bars 5 is n, the bending moment borne by a single bent steel bar 5 is

[0063] According to the cross-sectional size, M c It can be expressed by the following formula:

[0064]

[0065] In the formula, σ y is the yield stress of the steel used for bending the steel bar, b is the width of the bent steel bar, and h is the sagittal height of the bent steel bar.

[0066] The results of the binding force method equation can be used to c calculate:

[0067] M 1 X 1 +M 2 X 2 +M 3 X 3 =M c (5)

[0068] 3. The results of the objective functions of maximum bending moment and minimum volume are obtained by using Matlab multi-objective optimization, in which genetic algorithm is used for analysis, and many groups of results of bending steel bars l, r, t, h, and b are obtained according to the Pareto optimization results. 5 parameter results.

[0069]

[0070] Where V 0 is the total volume of the bent steel bar.

[0071] 4. Determine the shear plate parameters

[0072] After solving the multi-objective function, the five key parameters of the curved steel bar are initially determined. Then, the internal force that the shear plate can provide needs to be determined based on the total internal force demand, and then the shear plate parameters are solved. Finally, the damper stiffness needs to be checked according to the stiffness of the cast-in-place pier, and the damper parameter values ​​are finally determined.

[0073] M T =2nmax(M c )+M sy (7)

[0074]

[0075] Where M T is the total bending capacity of the damper, n is the number of bending steel bars, M c The bending resistance provided by the bent steel bar, M sy The bending resistance provided by the shear plate.

[0076] Shear plate shear strength F sy It can be calculated by formula (9), the shear strength of the bent steel bar is F fy It can be calculated by formula (10). The combined force of the shear plate and the bending steel bar is T , satisfying Q T =F sy +nF fy .like Figure 8 shown.

[0077]

[0078] In addition to meeting the strength requirements, the damper must also meet the stiffness requirements to ensure that the pier structure has a certain ability to resist deformation. The damper stiffness includes the shear plate stiffness K sy and bending steel bar stiffness K dy For the shear plate K sy In terms of stiffness, the size of the central shear steel block directly determines the stiffness of the shear plate, so its stiffness can be seen in formula (11). dy Visible formula (12)

[0079]

[0080] In the formula, t 1 is the shear plate thickness; k is the shear shape coefficient, which is taken as 1.2; τ sy is the shear stress of the material; G s is the shear strain modulus of the steel plate, which can be taken as 0.385E s , where E s is the elastic modulus of steel; I s is the moment of inertia of the bent steel bar.

[0081] The schematic diagram of stiffness calculation is as follows Fig. 9 shown.

[0082] The stiffness of the entire damper K dyIt is equivalent to the sum of n curved steel bars connected in parallel with the shear plate, so it can be calculated using formula (13). Furthermore, the stiffness of the tie beam segment K can be replaced P It can be calculated by formula (14), where K c is the segment stiffness of the tie beam, which can refer to the cast-in-place tie beam stiffness K CIP Calculate as formula (15). Finally, use formula (16) to verify whether the damper value meets the stiffness requirements, where β d is the tie beam stiffness reduction factor, when β d When it is 1, it is considered that the stiffness is not reduced, and the stiffness of the replacement tie beam is equal to the stiffness of the cast-in-place tie beam.

[0083] K dy =nK fy +K sy (13)

[0084]

[0085] K P =β d K CIP (16)

[0086] Where, ΔM and ΔV are bending deformation and shear deformation under unit load, respectively; L is the length of the tie beam of the cast-in-place part; E t and I t and A t They are the elastic modulus, moment of inertia and cross-sectional area of ​​the concrete tie beam; G is the shear modulus of concrete, which can be taken as 0.425E t .

[0087] Based on the preliminarily determined values, the shear strength and stiffness of the damper are verified to determine whether they meet the design requirements. If not, repeated iterative calculations are required until the requirements are met.

[0088] Example 2

[0089] The damper design calculation is carried out based on the reinforcement of the tie beam of a highway pier in a high-intensity area:

[0090] The height and width of the tie beam are 650mm and 550mm respectively. The main reinforcement of the tie beam is HRB steel bar with a diameter of 14mm.

[0091] According to the formula for shear calculation of inclined sections of beams in the Code for Design of Concrete Structures GB 50010-2010:

[0092]

[0093] α cv =0.7f t =1.71MPa f yv=400MPa A sv =314mm 2 h 0 =608mm

[0094] s=80mm

[0095] V y =1354.836kN

[0096] According to the relevant parameters, we can get:

[0097] V=2032.254kN (considering safety factor 1.5)

[0098] Calculate the flexural yield capacity of the tie beam:

[0099] M y =n×f y ×A S ×h 0

[0100] n=14f y =400MPa A S =153.94mm 2 h 0 =608mm

[0101] According to the relevant parameters, we can get: M y =524.134 kN·m, the maximum bending moment M of the tie beam corresponding to the damper position is 389.95 kN·mm.

[0102] 1. Selecting the strength reduction factor as 0.8, the reasonable internal force requirement M of the combined energy-absorbing structure can be determined T , Q T :

[0103] M T =β×M=0.8×389.95=311.96kN·m

[0104] Q T =β×V=0.8×2032255=1625.8kN

[0105] Where β is the strength reduction factor, M and V represent the bending and shear capacity of the concrete tie beam at the damper position respectively. Since the energy dissipation structure yields before the ordinary concrete section of the tie beam, a number less than 1 can be taken, which is determined according to the requirements of the actual project. In this example, the reduction factor is calculated as 0.8.

[0106] 2. Determine the size and quantity of the bent steel bars

[0107] According to the previous calculation results, the Pareto frontier of a single bending steel bar is obtained by Pareto optimization, and the preliminary bending moment M of the bending steel bar is obtained. c and volume V o , and 5 dimensional parameters include l, r, t, h, b, corresponding to the length, radius, half thickness, sagitta, and width of the bent steel bar.

[0108] According to the bending strength equation and the volume equation of the bent steel bar, a multi-objective equation group is obtained, such as equation (6). Approximate ranges are set for the length l, radius r, half thickness t, sagittal height h, and width b of the bent steel bar, respectively. A preliminary range can be determined based on actual conditions, and the results that meet the above objective functions are obtained using MATLAB multi-objective optimization, in which a genetic algorithm is used for analysis. Fig.10 As shown, the Pareto optimization curve is obtained, and the points in the curve are the target values ​​M of the corresponding parameters. c and V o Assuming the number of bending steel bars n, and considering the actual size of the tie beam layout space and other structural factors, it is proposed to select the parameter value with a bending moment value closer to the internal force demand as the preliminary design value for subsequent verification.

[0109] According to the optimization results, the final value is [200, 1340, 40, 60, 40], specifically: length l = 200mm, radius r = 1340mm, half of the thickness is t = 40mm, sagitta h = 60mm, width b = 200mm. Assuming that 10 bending steel bars are required to meet the bending moment requirements, the subsequent size calculation is performed.

[0110] The shear bearing capacity of a single curved steel bar is:

[0111]

[0112] The total shear bearing capacity V is:

[0113] V=nf fy =132.267×10=1322.67kN

[0114] The required shear capacity of the shear plate is

[0115] F sy =Q T -V=1625.8-1322.67kN=303.13kN

[0116]

[0117] Assume t 1 The same thickness as the bent steel bar, then b can be calculated 2 is 50mm, b 1 It is necessary to further determine after comparing the stiffness.3 It can be determined according to the structural requirements. If it is required that no buckling occurs, it can be taken as b 1 Same size parameters.

[0118] 3. Calculation of cast-in-place tie beam stiffness:

[0119]

[0120] Where L is the length of the tie beam extension, which is 500mm, k is the shape coefficient related to the cross section, which is 1.2 for a rectangular cross section, E and G are the elastic modulus and shear modulus of the tie beam concrete, and concrete G = 0.425E. The stiffness of the cast-in-place tie beam with a length of L can be obtained to be 4.4843kN·m.

[0121] 4. Calculation of series connection beam-damper stiffness:

[0122] The stiffness of the concrete tie beam is K C

[0123]

[0124] make

[0125] K P =β d K CIP

[0126] where β d is the stiffness reduction factor, which can be 1 or less and is determined based on actual needs. In this example, it is 0.65.

[0127] Then there is b 1 =5mm.

[0128] During the calculation, multiple iterations are required to verify whether the damper bending moment, shear force and stiffness meet the requirements until the final parameter calculation is completed when the design requirements are met.

[0129] Example 3

[0130] The installation method of the replaceable bent steel bar-shear plate combined metal damper of the above-mentioned embodiment 1 and embodiment 2 comprises the following steps:

[0131] S1. Piers and concrete tie beams are manufactured in the processing plant. Screws are embedded inside the concrete tie beams to reserve installation positions for combined metal dampers.

[0132] S2. The left connecting steel plate 1, the right connecting steel plate 2 and the bolt fixing plate 3 are processed and manufactured in the processing plant, and the bolt fixing plate reserved bolt holes 7 are set on the bolt fixing plate 3. The left connecting steel plate 1 and the right connecting steel plate 2 are bolted together by screws embedded in the concrete tie beam, and a reserved position is ensured between the left connecting steel plate 1 and the right connecting steel plate 2 to facilitate the installation of energy-consuming components.

[0133] S3. The bending steel bar 5 and the shear plate 6 are manufactured in the processing plant, and the bolt holes 8 for the bending steel bar are reserved at both ends of the bending steel bar 5. The bolt holes 8 for the bending steel bar on the bending steel bar 5 and the shear plate 6 are aligned with the bolt holes 7 for the bolt fixing plate 3, and they are connected with high-strength bolts 4. When the shear plate 6 is subjected to load and the pier column concrete tie beam moves relative to each other, the left and right limbs of the middle "H" steel can shift relative to each other, forming plastic deformation and consuming energy.

[0134] S4. When the bent steel bar 5 or the shear plate 6 is deformed and damaged under the action of an earthquake, it can be replaced, the high-strength bolts 4 can be disassembled and reinstalled, and a new bent steel bar 5 or shear plate 6 can be replaced, so that the replaceable bent steel bar-shear plate combined metal damper can achieve sustainable working ability, restore the temporary working capacity of the bridge pier, and facilitate the development of post-earthquake rescue work.

[0135] The above is only a preferred embodiment of the present invention, and does not impose any formal limitation on the structure of the present invention. The layout type and the number of uses of the present invention are not limited to this example, and can be optimized and selected according to the actual project. Any modification, equivalent change and decoration of the above embodiment based on the technical principle of the present invention that does not deviate from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A replaceable bent steel bar-shear plate combined metal damper, characterized in that: It comprises a left connecting steel plate (1), a right connecting steel plate (2), a bolt fixing plate (3), high-strength bolts (4) and an energy dissipation component; The left connecting steel plate (1) and the right connecting steel plate (2) are respectively connected to the concrete tie beam, and bolt fixing plates (3) are fixed to the left connecting steel plate (1) and the right connecting steel plate (2), and are connected to the energy dissipation component through high-strength bolts (4); wherein four groups of bolt fixing plates (3) are provided, and are respectively located at the upper and lower ends of the inner sides of the left connecting steel plate (1) and the right connecting steel plate (2), and each group of bolt fixing plates (3) includes two bolt fixing plates (3) at the upper and lower ends; The energy dissipation component is installed between the left connecting steel plate (1) and the right connecting steel plate (2), and comprises a bent steel bar (5) and a shear plate (6); the shear plate (6) is a combination of an "H"-shaped steel plate and bent steel bars (5) at the upper and lower ends; a plurality of groups of bent steel bars (5) and at least one shear plate (6) are arranged side by side; both ends of the bent steel bar (5) are provided with bent steel bar reserved bolt holes (8), and the bolt fixing plate (3) is also provided with bolt fixing plate reserved bolt holes (7) correspondingly; the two ends of the bent steel bar (5) are fixed to each group of bolt fixing plates (3) through the bent steel bar reserved bolt holes (8), the bolt fixing plate reserved bolt holes (7) and the high-strength bolts (4).

2. The replaceable bent steel bar-shear plate combined metal damper according to claim 1, characterized in that: The bent steel bars (5) are divided into two groups, an upper group and a lower group. Both ends of the bent steel bars (5) in the upper group and the lower group are clamped between two bolt fixing plates (3) in each group through high-strength bolts (4).

3. The replaceable bent steel bar-shear plate combined metal damper according to claim 2, characterized in that: The bent steel bars (5) are arc-shaped, and the arc-shaped protruding parts of the upper and lower groups of bent steel bars (5) are arranged opposite to each other.

4. The replaceable bent steel bar-shear plate combined metal damper according to claim 1, characterized in that: The shear plate (6) is arranged in the middle of the multiple groups of bent steel bars (5), and the multiple groups of bent steel bars (5) are symmetrically arranged on both sides of the shear plate (6).

5. The replaceable bent steel bar-shear plate combined metal damper according to claim 1, characterized in that: The number of the shear plates (6) and the bent steel bars (5) is calculated based on the strength and stiffness of the tie beam in the corresponding bridge structure, and the stiffness and strength of the entire damper must be maintained at 0.8 times the corresponding index of the concrete tie beam to ensure that the damper structure is weaker than the tie beam structure so that damage is concentrated at the damper position; the arrangement of the shear plates (6) and the bent steel bars (5) should be adjusted in combination with the number of the shear plates (6) and the bent steel bars (5), but it should be ensured that the shear plates (6) and the bent steel bars (5) of the entire damper are symmetrically distributed to avoid out-of-plane damage caused by improper construction.

6. The replaceable bent steel bar-shear plate combined metal damper according to claim 5, characterized in that: The bent steel bars (5) are in groups of 2, 4, 6 or 8.

7. The replaceable bent steel bar-shear plate combined metal damper according to claim 1, characterized in that: The "H"-shaped steel plate has a middle cross-section between its left and right limbs that is larger than its upper and lower end cross-sections.

8. The replaceable bent steel bar-shear plate combined metal damper according to claim 1, characterized in that: The left connecting steel plate (1) and the right connecting steel plate (2) are both welded together with the bolt fixing plate (3).

9. The replaceable bent steel bar-shear plate combined metal damper according to claim 1, characterized in that: The "H"-shaped steel plate in the shear plate (6) is integrally formed or welded with the bent steel bars (5) at the upper and lower ends.

10. A method for installing the replaceable bent steel bar-shear plate combined metal damper according to any one of claims 1 to 9, characterized in that: The steps include: S1. Piers and concrete tie beams are manufactured in the processing plant. Screws are embedded in the concrete tie beams to reserve installation positions for combined metal dampers. S2. The left connecting steel plate (1), the right connecting steel plate (2) and the bolt fixing plate (3) are processed and manufactured in a processing plant, and a bolt fixing plate reserved bolt hole (7) is set on the bolt fixing plate (3). The left connecting steel plate (1) and the right connecting steel plate (2) are bolted together by means of a screw rod pre-buried in the concrete tie beam, and a reserved position is ensured between the left connecting steel plate (1) and the right connecting steel plate (2) to facilitate the installation of the energy dissipation component. S3, manufacturing the bent steel bar (5) and the shear plate (6) in a processing plant, and reserving bolt holes (8) for the bent steel bar at both ends of the bent steel bar (5), aligning the bolt holes (8) for the bent steel bar on the bent steel bar (5) and the shear plate (6) with the bolt holes (7) for the bolt fixing plate (3), and connecting them with high-strength bolts (4) respectively; ensuring that when the shear plate (6) is subjected to load and the pier column concrete tie beam moves relative to each other, the left and right limbs of the middle "H"-shaped steel can shift relative to each other, forming plastic deformation and consuming energy; S4. When the bent steel bar (5) or the shear plate (6) is deformed and damaged under the action of an earthquake, it can be replaced by disassembling the high-strength bolts (4) and replacing them with new bent steel bars (5) or shear plates (6). This enables the replaceable bent steel bar-shear plate combined metal damper to achieve sustainable working capacity, restore the temporary working capacity of the bridge pier, and facilitate the development of post-earthquake rescue work.

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