Prefabricated buckling-restrained brace with displacement amplification mechanism and its design method

Abstract

This invention relates to the field of building vibration reduction technology, specifically a prefabricated buckling-restrained brace with a displacement amplification mechanism and its design method. Addressing the problem that buckling-restrained braces cannot fully utilize their energy dissipation performance under small-amplitude vibrations or seismic excitation, this invention proposes an all-steel prefabricated buckling-restrained brace with a displacement amplification mechanism. By introducing a displacement amplification mechanism, the small inter-story deformation of the structure can be effectively amplified and transferred to the energy-dissipating core plate, significantly improving the response displacement of the core plate. Thus, even with small structural deformation, good energy dissipation can still be achieved, effectively improving the vibration reduction efficiency and applicability of the buckling-restrained brace under normal and minor earthquake conditions.

Description

Technical Field

[0001] This invention relates to the field of building vibration reduction technology, specifically a prefabricated buckling-resistance brace with a displacement amplification mechanism and its design method. Background Technology

[0002] With the continuous improvement of the country's industrial level, there is an increasing number of high-precision and high-value equipment in industrial plants, which puts forward higher requirements for the vibration resistance of building structures under various dynamic forces such as earthquakes and wind loads.

[0003] The damping mechanism of buckling-restrained braces lies in dissipating the seismic energy input to the structure through the elastoplastic hysteretic deformation of their internal energy-dissipating core plates, thereby reducing the seismic forces borne by the main structure. The greater the relative deformation at both ends of the energy-dissipating core plate, the more significant its energy dissipation capacity and damping effect.

[0004] However, in practical engineering, the deformation of the energy-dissipating core panel is usually closely related to the inter-story displacement of the main structure. Structural design codes require that the inter-story deformation of the main structure under design earthquake conditions be controlled within a small range to ensure structural safety and functionality. This limitation restricts the deformation range of the buckling-restrained brace, making it difficult for its energy-dissipating core panel to fully utilize its hysteretic energy dissipation potential. Therefore, buckling-restrained braces generally suffer from prominent problems in practical applications, such as low energy dissipation efficiency and insignificant damping effect. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a prefabricated buckling-resistance brace with a displacement amplification mechanism and its design method.

[0006] The technical solution adopted by this invention to solve its technical problem is:

[0007] A prefabricated buckling-restrained brace with a displacement amplification mechanism includes a core plate, a restrained square steel tube, a transition H-beam, and an amplification lever; wherein,

[0008] The outer surfaces of the upper and lower sidewalls of the constrained square steel tube are provided with core plate limiting grooves. The shape of the core plate limiting grooves is adapted to the core plate. Two core plates are respectively set in the core plate limiting grooves of the upper and lower sidewalls. Both ends of the constrained square steel tube are inserted into transition H-beams, and the transition H-beams slide with the constrained square steel tube. Both ends of the constrained square steel tube and the upper and lower sides of the web of the transition H-beams are provided with amplifying levers. The far end of the amplifying lever is hinged to the end of the core plate, the middle part of the amplifying lever is hinged to the constrained square steel tube, and the near end of the amplifying lever is hinged to the wing plate of the transition H-beam. The distance between the far end and the middle part of the amplifying lever is greater than the distance between the near end and the middle part.

[0009] As a preferred embodiment, a further technical solution of the present invention is:

[0010] Preferably, the core board adopts a three-section structure, including a low yield section core board in the middle, the two ends of the low yield section core board are connected to the middle yield section core board, and the outer end of the middle yield section core board is connected to the high yield section core board.

[0011] Preferably, the outer end of the high-yield section core plate is provided with a hollow end constraint sleeve for hinged connection with the amplifying lever.

[0012] Preferably, both ends of the constrained square steel tube and the inner surfaces of the upper and lower side walls are provided with enlarged support plates, and the enlarged support plates are provided with enlarged support plate through holes for hinged connection with the enlarged lever.

[0013] Preferably, guide rails are provided at both ends of the constrained square steel tube and on the inner surfaces of the upper and lower side walls, and guide rail grooves adapted to the guide rails are provided on the flanges of the transition H-beam.

[0014] Preferably, a smooth cylindrical connecting rod is provided between the flanges of the transition H-beam for hinged connection with the amplifying lever.

[0015] Preferably, the outer surfaces of the upper and lower sidewalls of the constrained square steel pipe are provided with cover plates, the yield strength of the cover plate material is not lower than the yield strength of the core plate of the high yield section, and the thickness of the cover plate is not less than 1.5 times the thickness of the core plate.

[0016] Preferably, it also includes a connector connected to the outer end of the transition H-beam, wherein the inner end of the connector is a flat end adapted to the end face of the transition H-beam, and the outer end is a variable cross-section H-beam with an enlarged opening.

[0017] This invention also discloses a design method applied to the above-mentioned prefabricated buckling-restrained brace with a displacement amplification mechanism, the specific steps of which are as follows:

[0018] S1: Based on the floor plans and building functions, determine the cross-sectional dimensions of the load-bearing structural members and calculate the inter-story drift angles for each floor. :

[0019] ;

[0020] in, This represents the maximum horizontal displacement between the i-th floor of the building structure under vibration. This represents the height of the i-th floor of the building structure under vibration.

[0021] S2: If the calculated inter-story drift angle does not exceed the code limit, there is no need to add prefabricated buckling-restrained braces; if the inter-story drift angle exceeds the code limit but does not exceed twice the code limit, it is determined that prefabricated buckling-restrained braces are needed for structural reinforcement design; if the inter-story drift angle exceeds twice the code limit, the dimensions of the structural load-bearing members should be readjusted until the inter-story drift angle is controlled within twice the code limit.

[0022] S3: For situations requiring structural reinforcement by adding prefabricated buckling-restrained braces, based on the inter-story drift angles of each floor of the building structure and according to the pre-set relationship between the inter-story drift angles and the lateral stiffness ratio, select the required lateral stiffness ratio for each floor. ;

[0023] S4: Calculate the structural stiffness of each floor of the building structure. And calculate the total stiffness of the prefabricated buckling-restrained braces required for each floor based on the structural stiffness. :

[0024] ;

[0025] in, This represents the ratio of the lateral stiffness of the i-th floor of the building structure. This represents the structural stiffness between the i-th floors of a building structure.

[0026] S4: Calculate the stiffness required to be provided by a single prefabricated buckling-restrained brace arranged in the i-th layer. :

[0027] ;

[0028] in, This indicates the number of prefabricated buckling-restrained braces designed and arranged in the i-th floor of the building structure.

[0029] S5: Calculate the required cross-sectional area of ​​the core plate for a single prefabricated buckling-restrained brace:

[0030] ;

[0031] ;

[0032] in, This represents the cross-sectional area of ​​a prefabricated buckling-restrained brace arranged in a herringbone pattern. This represents the cross-sectional area of ​​a prefabricated buckling-restrained brace with a single diagonal brace arrangement. This indicates the angle between the prefabricated buckling-restrained brace and the horizontal direction. Indicates the core board stiffness;

[0033] S6: Based on the parameters determined in S1-S5, perform building structure modeling and simulation to verify whether the inter-story drift angle meets the code limit after setting prefabricated buckling-restrained braces. If it does, the design is complete. If it does not, reselect the lateral stiffness ratio and return to S4 until the inter-story drift angle does not exceed the code limit.

[0034] Preferably, in the case of a three-section core plate structure consisting of a low-yield section core plate, a medium-yield section core plate, and a high-yield section core plate, since the cross-sectional areas of the three sections are different, to ensure the reliability of the design, the cross-sectional area of ​​the low-yield section core plate is considered as a key parameter determining the overall stiffness and effective load-bearing area of ​​the core plate. This represents the stiffness of the core plate in the low yield section;

[0035] The yield strength of each segment in the three-segment core plate satisfies:

[0036] ;

[0037] ;

[0038] ;

[0039] ;

[0040] in, , This represents the yield strength and cross-sectional area of ​​the core plate in the low yield section. , This represents the yield strength and cross-sectional area of ​​the core plate in the middle yield section. , This represents the yield strength and cross-sectional area of ​​the high-yield section core plate. , This represents the magnification factor, a real number between 2 and 5; ]、 Let be a Gaussian function, and represent taking values ​​of less than or equal to the real number . , The largest integer part;

[0041] In a prefabricated buckling-restrained brace, the stiffness of the components other than the three-section core plate satisfies the following requirements:

[0042] ;

[0043] ;

[0044] ;

[0045] in, This refers to the stiffness of components other than the three-section core plate in a prefabricated buckling-restrained brace. The magnification factor is a real number between 3 and 5. The equivalent stiffness of the three-segment core plate. , These represent the stiffness of the low-yield-section core plate, the medium-yield-section core plate, and the high-yield-section core plate, respectively. , , These refer to the lengths of the low-yield-section core plate, the medium-yield-section core plate, and the high-yield-section core plate, respectively. The corresponding values ​​are d, g, and z in sequence.

[0046] The dimensions between the core board limiting groove and the core board meet the following requirements:

[0047] ;

[0048] in, This indicates the difference in size between the core board limiting groove and the core board. This indicates the maximum design working deformation of the prefabricated buckling-restrained brace. The coefficient represents an integer between 2 and 5. Let be a Gaussian function, representing the expression that takes values ​​not exceeding the real number . The largest integer part.

[0049] The present invention, which adopts the above technical solution, has the following prominent features compared with the prior art:

[0050] To address the issue that buckling-restrained braces (BRBs) cannot fully utilize their energy dissipation performance under small-amplitude vibrations or seismic excitation, a prefabricated all-steel BRB with a displacement amplification mechanism is proposed. By introducing the displacement amplification mechanism, the small inter-story deformation of the structure can be effectively amplified and transferred to the energy-dissipating core plate, significantly improving the response displacement of the core plate. Thus, even with small structural deformation, good energy dissipation can still be achieved, effectively improving the damping efficiency and applicability of BRBs under normal and minor earthquake conditions. Attached Figure Description

[0051] Figure 1 This is an exploded structural diagram of a prefabricated buckling-resistance brace with a displacement amplification mechanism in an embodiment of the present invention;

[0052] Figure 2 yes Figure 1 Enlarged schematic diagram of the structure at point I;

[0053] Figure 3 This is a schematic diagram of the core board structure in an embodiment of the present invention;

[0054] Figure 4 yes Figure 3 A magnified schematic diagram of the structure at point II in the middle;

[0055] Figure 5 This is a schematic diagram of the structure of the constrained square steel tube in an embodiment of the present invention;

[0056] Figure 6 yes Figure 5 A magnified view of section III in the diagram;

[0057] Figure 7 This is a schematic diagram of the transition H-beam structure in an embodiment of the present invention;

[0058] Figure 8 This is a schematic diagram showing the relative assembly positions of the constrained square steel tube and the transition H-beam in an embodiment of the present invention;

[0059] Figure 9 yes Figure 8 Enlarged view of a portion of point IV in the middle;

[0060] Figure 10 This is a schematic diagram of the overall assembly of the assembled anti-buckling brace with displacement amplification mechanism in an embodiment of the present invention;

[0061] Figure 11 yes Figure 10 Enlarged view of section V;

[0062] Figure 12 This is a schematic diagram of the structure of the magnifying lever in an embodiment of the present invention;

[0063] Figure 13 This is a schematic diagram of the structure of the large roller in an embodiment of the present invention;

[0064] Figure 14 This is a schematic diagram of the interior of the static position assembled buckling-resistance brace in an embodiment of the present invention;

[0065] Figure 15 This is a schematic diagram of the internal structure of the assembled buckling-resistance brace at the deformation position in an embodiment of the present invention;

[0066] Figure 16 This is an installation effect diagram of the assembled anti-buckling brace in an embodiment of the present invention;

[0067] Figure 17 This is the loading regime curve of the finite element analysis in the embodiments of the present invention;

[0068] Figure 18 This is the finite element model of the prefabricated buckling-restrained brace in this embodiment of the invention. Figure 1 ;

[0069] Figure 19 This is the finite element model of the prefabricated buckling-restrained brace in this embodiment of the invention. Figure 2 ;

[0070] Figure 20 This is the hysteresis curve of finite element analysis in the embodiments of the present invention;

[0071] Figure 21 This is a schematic diagram of the long span direction of the structure with a displacement amplification mechanism for buckling-resistance bracing in an embodiment of the present invention;

[0072] Figure 22 This is a schematic diagram of the short span direction of the structure with a displacement amplification mechanism for buckling-restrained bracing in an embodiment of the present invention;

[0073] Figure 23 This is the selected time history curve of the natural seismic wave ELcentro wave in the embodiments of the present invention;

[0074] Figure 24 This refers to the selected natural seismic wave Qian'an wave time history curve in this embodiment of the invention;

[0075] Figure 25 This refers to the selected artificial seismic wave time history curve in this embodiment of the invention;

[0076] Figure 26 These are comparison diagrams of the maximum horizontal displacement in the X and Y directions of the two structures in the embodiments of the present invention under the ELcentro wave, wherein, Figure a is the X direction and Figure b is the Y direction;

[0077] Figure 27 These are comparison diagrams of the maximum inter-layer displacement angles in the X and Y directions of the two structures in the embodiments of the present invention under ELcentro wave, wherein Figure c is the X direction and Figure d is the Y direction;

[0078] Figure 28 These are comparison diagrams of the maximum horizontal displacement in the X and Y directions of the two structures in the embodiments of the present invention under the Qian'an wave, wherein Figure e is in the X direction and Figure f is in the Y direction;

[0079] Figure 29 These are comparison diagrams of the maximum inter-story drift angles in the X and Y directions of the two structures in the embodiments of the present invention under the Qian'an wave, wherein Figure g is in the X direction and Figure h is in the Y direction;

[0080] Figure 30 These are comparison diagrams of the maximum horizontal displacement in the X and Y directions of the two structures in the embodiments of the present invention under artificial waves, wherein Figure i represents the X direction and Figure j represents the Y direction;

[0081] Figure 31 These are comparison diagrams of the maximum interlayer displacement angles in the X and Y directions of a structure in an embodiment of the present invention under artificial waves, wherein Figure k represents the X direction and Figure l represents the Y direction.

[0082] Explanation of reference numerals in the attached drawings: 1. Core plate; 2. Constraint square steel tube; 3. Transition H-beam; 4. Enlarging lever; 5. Core plate limiting groove; 6. Low yield section core plate; 7. Medium yield section core plate; 8. High yield section core plate; 9. End constraint sleeve; 10. Enlarging support plate; 11. Enlarging support plate through hole; 12. Guide rail; 13. Guide rail groove; 14. Connecting rod; 15. Cover plate; 16. Connector; 17. Far end hole; 18. Support hole; 19. Proximal end hole; 20. Small roller; 21. Large roller; 22. Bolt; 23. Nut; 24. Smooth rod segment; 25. Threaded rod segment. Detailed Implementation

[0083] The present invention will be further illustrated below with reference to specific embodiments. The purpose of this illustration is solely to provide a better understanding of the invention. Therefore, the examples given do not limit the scope of protection of the present invention.

[0084] like Figures 1 to 13 As shown in the figure, this embodiment presents a prefabricated buckling-restrained brace with a displacement amplification mechanism, including a core plate 1, a restrained square steel tube 2, a transition H-beam 3, and an amplification lever 4; wherein,

[0085] The outer surfaces of the upper and lower sidewalls of the constrained square steel tube 2 are provided with core plate limiting grooves 5. The shape of the core plate limiting grooves 5 is adapted to the core plate 1. The two core plates 1 are respectively set in the core plate limiting grooves 5 on the upper and lower sidewalls. The two ends of the constrained square steel tube 2 are respectively inserted into the transition H-beams 3, and the transition H-beams 3 and the constrained square steel tube 2 are in sliding fit. The two ends of the constrained square steel tube 2 and the upper and lower sides of the web of the transition H-beams 3 are provided with amplifying levers 4. The far end of the amplifying levers 4 is hinged to the end of the core plate 1, the middle part of the amplifying levers 4 is hinged to the constrained square steel tube 2, and the near end of the amplifying levers 4 is hinged to the wing plate of the transition H-beams 3. The distance between the far end and the middle part of the amplifying levers 4 is greater than the distance between the near end and the middle part.

[0086] In practice, the core plate 1 adopts a three-section structure, including the low yield section core plate 6 located in the middle, the two ends of the low yield section core plate 6 are connected to the middle yield section core plate 7, and the outer end of the middle yield section core plate 7 is connected to the high yield section core plate 8; the cross-sectional area of ​​the low yield section core plate 6, the middle yield section core plate 7, and the high yield section core plate 8 increases sequentially.

[0087] In practice, the outer end of the high yield section core plate 8 is provided with a hollow end constraint sleeve 9, which is used to hinge with the amplifying lever 4.

[0088] In practice, both ends of the constrained square steel pipe 2 and the inner surfaces of the upper and lower side walls are provided with enlarged support plates 10. The enlarged support plates 10 are provided with enlarged support plate through holes 11 for hinged connection with the enlarged lever 4.

[0089] In practice, guide rails 12 are provided at both ends of the constrained square steel pipe 2 and on the inner surfaces of the upper and lower side walls. The guide rails 12 are provided along the entire length, and guide rail grooves 13 adapted to the guide rails 12 are provided on the flanges of the transition H-beam 3.

[0090] In practice, a smooth cylindrical connecting rod 14 is provided between the flanges of the transition H-beam 3 for hinged connection with the amplifying lever 4.

[0091] In practice, cover plates 15 are provided on the outer surfaces of the upper and lower side walls of the constrained square steel pipe 2. The yield strength of the material of the cover plate 15 is not lower than the yield strength of the core plate 8 in the high yield section, and the thickness of the cover plate 15 is not less than 1.5 times the thickness of the core plate 1.

[0092] In implementation, it also includes a connector 16 connected to the outer end of the transition H-beam 3. The inner end of the connector 16 is a flat end adapted to the end face of the transition H-beam 3, and the outer end is a variable cross-section H-beam with an enlarged opening; such as Figure 16 The connector 16 shown is connected at one end to the transition H-beam 3 and at the other end to the building structure to form a support system.

[0093] The enlarging lever 4 is provided with a distal hole 17, a support hole 18, and a proximal hole 19. The size of the distal hole 17 is adapted to the inner diameter of the end constraint sleeve 9. After the end constraint sleeve 9 and the distal hole 17 are aligned, the small roller 20 is inserted to achieve hinge. The size of the support hole 18 is matched with the through hole 11 of the enlarged support plate. After the two are aligned, the large roller 21 is inserted to achieve hinge. The size of the proximal hole 19 is matched with the outer diameter of the connecting rod 14, allowing the connecting rod 14 to pass freely through the proximal hole 19. The large roller 21 includes a bolt 22 and a nut 23. The upper part of the bolt 22 is provided with a smooth rod section 24 and a threaded rod section 25. The small roller 20 has the same structure as the large roller 21, but the size is different.

[0094] In practice, the assembly process of the prefabricated buckling-restrained brace with displacement amplification mechanism of the present invention is as follows:

[0095] Step 1: Install the three-section core plate 1 into the core plate limiting groove 5 on the constrained square steel tube 2. Then, insert the transition H-beam 3 into the inner cavity of the constrained square steel tube 2, so that the guide rail 12 on the constrained square steel tube 2 is accurately embedded in the guide rail groove 13 of the transition H-beam 3, realizing the sliding connection between the two.

[0096] Step 2: Assemble the displacement amplification mechanism. First, pass the small roller 20 through the end constraint sleeve 9 and the distal hole 17 of the amplification lever 4 respectively; then, pass the large roller 21 through the support hole 18 of the amplification lever 4 and the through hole 11 of the amplification support plate on the constraint square steel tube 2 to achieve hinged support of the amplification lever 4; finally, pass the connecting rod 14 through the proximal hole 19 of the amplification lever 4, and weld the two ends of the connecting rod 14 to the two flanges of the transition H-beam 3 to complete the connection between the amplification mechanism and the transition H-beam 3.

[0097] Step 3: Weld connector 16 to transition H-beam 3 to complete the overall assembly. At this point, the all-steel prefabricated buckling-restrained brace with displacement amplification mechanism is installed.

[0098] Now combined Figure 14 and Figure 15 To illustrate the working principle of the all-steel prefabricated buckling-restrained brace with displacement amplification mechanism of the present invention:

[0099] like Figure 14 As shown, when the building structure is in a static state and has not deformed, the enlarged lever 4 inside the support remains in its initial position perpendicular to the support axis, as... Figure 15 As shown, when structural deformation occurs, resulting in a relative displacement U between the connecting parts at both ends of the buckling-restrained brace, this displacement is transmitted to the connecting rod 14 through the transition H-beam 3, which in turn drives the amplifying lever 4 to rotate around the support point. After displacement conversion and amplification by the lever mechanism, the final displacement transmitted to both ends of the three-section core plate is:

[0100] ;

[0101] LB1 represents the length of the distal end (force arm) of the lever, and LB2 represents the length of the proximal end (resistance arm). By adjusting the ratio of LB1 to LB2, the displacement amplification factor of the support can be flexibly designed, thereby changing the performance of the support.

[0102] When the two ends of the three-section core plate receive an amplified displacement L, core plate 1 begins to deform under stress. Since the low-yield section core plate 6 has the lowest yield strength and the smallest cross-sectional area, it yields first in the initial loading stage, entering the energy dissipation phase. As deformation continues to increase, the medium-yield section core plate 7 and the high-yield section core plate 8 successively enter the yield state, achieving multi-stage energy dissipation. When the deformation exceeds the design limit of the support, failure first occurs in the low-yield section core plate 6, achieving controllability and replaceability of the damaged area and ensuring the safety of the main structure.

[0103] It should be noted that the actual displacement L at both ends of the three-section core plate includes two components: a deformation component us parallel to the support axis and a small offset Δh perpendicular to the support axis. Since the overall deformation of the support under normal working conditions is small, the value of Δh is much smaller than us, and its impact on mechanical properties can be ignored. In terms of structural design, it is only necessary to ensure that the size of the core plate limiting groove 5 is slightly larger than the cross-sectional size of the three-section core plate, reserving sufficient vertical deformation space, to avoid unnecessary constraint or friction between the constrained square steel pipe 2 and the core plate 1.

[0104] In practice, for all-steel prefabricated buckling-restrained braces equipped with displacement amplification mechanisms, the core load-bearing component is a three-section core plate. Since the cross-sectional area and yield strength of core plate 1 are lower than those of other components, the middle low-yield section becomes the area that deforms first. Under axial tensile force, the yield bearing capacity of the brace is determined by the yield strength of the material and the net cross-sectional area of ​​this low-yield section.

[0105] Under axial pressure, the support deforms. The core plate 6, with the largest deformation (low yield section), first contacts the inner surface of the external constraint and enters a low-order buckling mode. As the pressure continues to increase, the middle and high yield sections of the core plate successively enter the low-order buckling state, ultimately achieving a low-order buckling mode for the entire three-section core plate. If the pressure further increases, under the action of the external constraint, core plate 1 will gradually transition from a low-order buckling mode to a high-order buckling mode. Since the yield strength of other components is several times higher than that of core plate 1, these components remain in the elastic stage and will not fail. As buckling progresses, the contact area between core plate 1 and the external constraint structure gradually expands, eventually achieving full-section yielding of the three-section core plate.

[0106] Because the brace introduces a displacement amplification mechanism (amplification factor LB1 / LB2), its end displacement is significantly amplified, rendering traditional displacement-based design methods inapplicable. Therefore, the performance-based design approach centered on displacement should be abandoned in favor of a performance-based seismic design philosophy. The overall stiffness requirements of the target building structure should be used as the functional basis during design, avoiding direct reliance on brace displacement parameters. This leads to a novel design method for buckling-restrained braces with this amplified displacement, the specific steps of which are as follows:

[0107] S1: Based on the floor plans and building functions, determine the cross-sectional dimensions of the load-bearing structural members and calculate the inter-story drift angles for each floor. :

[0108] ;

[0109] in, This represents the maximum horizontal displacement between the i-th floor of the building structure under vibration. This represents the height of the i-th floor of the building structure under vibration.

[0110] S2: If the calculated inter-story drift angle does not exceed the code limit, there is no need to add prefabricated buckling-restrained braces; if the inter-story drift angle exceeds the code limit but does not exceed twice the code limit, it is determined that prefabricated buckling-restrained braces are needed for structural reinforcement design; if the inter-story drift angle exceeds twice the code limit, the dimensions of the structural load-bearing members should be readjusted until the inter-story drift angle is controlled within twice the code limit.

[0111] S3: For situations requiring structural reinforcement by adding prefabricated buckling-restrained braces, based on the inter-story drift angles of each floor of the building structure and according to the pre-set relationship between the inter-story drift angles and the lateral stiffness ratio, select the required lateral stiffness ratio for each floor. ;

[0112] In practice, the selection of lateral stiffness ratios for building structural design is shown in Table 1.

[0113] Table 1 Selection of Lateral Stiffness Ratio for Building Structural Design

[0114]

[0115] For data not listed in the table, interpolation can be used to calculate and select an appropriate lateral stiffness ratio for the building structure that needs reinforcement.

[0116] S4: Calculate the structural stiffness of each floor of the building structure. And calculate the total stiffness of the prefabricated buckling-restrained braces required for each floor based on the structural stiffness. :

[0117] ;

[0118] in, This represents the ratio of the lateral stiffness of the i-th floor of the building structure. This represents the structural stiffness between the i-th floors of a building structure.

[0119] S4: Calculate the stiffness required to be provided by a single prefabricated buckling-restrained brace arranged in the i-th layer. :

[0120] ;

[0121] in, This indicates the number of prefabricated buckling-restrained braces designed and arranged in the i-th floor of the building structure.

[0122] S5: Calculate the required cross-sectional area of ​​the core plate for a single prefabricated buckling-restrained brace:

[0123] ;

[0124] ;

[0125] in, This represents the cross-sectional area of ​​a prefabricated buckling-restrained brace arranged in a herringbone pattern. This represents the cross-sectional area of ​​a prefabricated buckling-restrained brace with a single diagonal brace arrangement. This indicates the angle between the prefabricated buckling-restrained brace and the horizontal direction. Indicates the core board stiffness;

[0126] S6: Based on the parameters determined in S1-S5, perform building structure modeling and simulation to verify whether the inter-story drift angle meets the code limit after setting prefabricated buckling-restrained braces. If it does, the design is complete. If it does not, reselect the lateral stiffness ratio and return to S4 until the inter-story drift angle does not exceed the code limit.

[0127] In implementation, when the core plate adopts a three-section core plate structure consisting of a low-yield section, a medium-yield section, and a high-yield section, the cross-sectional area of ​​the three sections differs in different areas. To ensure design reliability, the cross-sectional area of ​​the low-yield section core plate is considered a key parameter determining the overall stiffness and effective load-bearing area of ​​the core plate. This represents the stiffness of the core plate in the low yield section;

[0128] The yield strength of each segment in the three-segment core plate satisfies:

[0129] ;

[0130] ;

[0131] ;

[0132] ;

[0133] in, , This represents the yield strength and cross-sectional area of ​​the core plate in the low yield section. , This represents the yield strength and cross-sectional area of ​​the core plate in the middle yield section. , This represents the yield strength and cross-sectional area of ​​the high-yield section core plate. , This represents the magnification factor, a real number between 2 and 5; ]、 Let be a Gaussian function, and represent taking values ​​of less than or equal to the real number . , The largest integer part;

[0134] In a prefabricated buckling-restrained brace, the stiffness of the components other than the three-section core plate satisfies the following requirements:

[0135] ;

[0136] ;

[0137] ;

[0138] in, This refers to the stiffness of components other than the three-section core plate in a prefabricated buckling-restrained brace. The magnification factor is a real number between 3 and 5. The equivalent stiffness of the three-segment core plate. , These represent the stiffness of the low-yield-section core plate, the medium-yield-section core plate, and the high-yield-section core plate, respectively. , , These refer to the lengths of the low-yield-section core plate, the medium-yield-section core plate, and the high-yield-section core plate, respectively. The corresponding values ​​are d, g, and z in sequence.

[0139] The dimensions between the core board limiting groove and the core board meet the following requirements:

[0140] ;

[0141] in, This indicates the difference in size between the core board limiting groove and the core board. This indicates the maximum design working deformation of the prefabricated buckling-restrained brace. The coefficient represents an integer between 2 and 5. Let be a Gaussian function, representing the expression that takes values ​​not exceeding the real number . The largest integer part.

[0142] This invention addresses the problem that buckling-restrained braces (BRBs) cannot fully utilize their energy dissipation performance under small-amplitude vibrations or seismic excitation due to deformation limitations. It proposes an all-steel prefabricated BRB with a displacement amplification mechanism. By introducing this mechanism, minute inter-story deformations can be effectively amplified and transferred to the energy-dissipating core plate, significantly increasing the core plate's response displacement. This allows for good energy dissipation even with small structural deformations, effectively improving the damping efficiency and applicability of BRBs under normal and minor earthquake conditions.

[0143] Example 1: Finite element analysis of the performance of a prefabricated buckling-restrained brace with displacement amplification mechanism

[0144] Based on the geometric parameters in Table 2, a finite element model of an all-steel prefabricated buckling-restrained brace with a displacement amplification mechanism was established. For parts not explicitly marked in the table, 60# steel was used as the material; except for the three-section core plate, only the elastic properties of the other components were considered. Figure 17 The loading regime of the finite element model is as follows: the overall shape and stress distribution of the finite element model are as follows. Figure 18 and 19 As shown.

[0145] Table 2 Key parameters of an all-steel prefabricated buckling-restrained brace with displacement amplification mechanism

[0146]

[0147] like Figure 22 The figure shows the hysteresis performance curve of the all-steel prefabricated buckling-restrained brace with displacement amplification mechanism obtained by finite element simulation in this example. It can be seen that under working conditions, the maximum energy dissipation of the brace reaches 8.36 kN·m, and the hysteresis loop shape is full, indicating that the prefabricated buckling-restrained brace of this invention has strong plastic deformation capacity and excellent energy dissipation performance.

[0148] Example 2: Design Case of Prefabricated Buckling-Restrained Brake with Displacement Amplification Mechanism

[0149] This embodiment

[0150] This study focuses on a four-story office building with a steel-concrete composite frame structure. Structural design was carried out, and prefabricated steel buckling-restrained braces with displacement amplification mechanisms were used for reinforcement within the frame. The complete bracing design process is presented below, and the seismic responses of the structures with and without bracing under frequent earthquakes are compared. The structural finite element analysis was performed using Midas software.

[0151] The building has a floor plan of 5 spans (long side) × 3 spans (short side), with spans of 6m and 4m respectively, and a floor height of 3.6m for each floor. In the Midas modeling, C30 concrete was used for both beams and columns, and Q235B steel was used for the steel frame. The mechanical parameters of both concrete and steel were set to the software's default values. The all-steel prefabricated buckling-restrained brace with displacement amplification mechanism was simulated using Plastic (Wen) connection elements. The architectural design parameters are shown in Table 3 below.

[0152] Table 3 Frame Design Parameters

[0153]

[0154] Step 1: Conduct preliminary structural design.

[0155] Based on the floor plan and building function, the dimensions of the load-bearing components of the structure were initially determined, and the structural information is shown in Table 4 below. The building plan consists of 5 spans on the long side and 3 spans on the short side, with spans of 6m and 4m respectively, and a floor height of 3.6m for each floor. In Midas, the beams and columns in the structure are made of C30 strength grade concrete, and the steel frame is made of Q235B. The mechanical properties of the concrete and steel frame materials are set to the default values ​​provided by the Midas software.

[0156] Table 4 Information on Frame Components

[0157]

[0158] According to Midas's calculations, the maximum inter-story drift angle of the frame structure under the response spectrum is 1 / 257. Although the structure exceeds the limit, it does not exceed twice the code limit. The deficiency in its seismic performance can be compensated by arranging buckling-restrained braces.

[0159] Step Two: For building structures where the value exceeds the standard limit but does not exceed twice the standard limit, determine the inter-story drift angle based on the building's floor level. Determine the lateral stiffness ratio of the building structure by referring to the table. The data not shown in the table were determined by interpolation. The inter-story drift angle and lateral stiffness of the building in this case are shown in Table 5 below.

[0160] Table 5 Selection Table for Lateral Stiffness Ratio of Frames

[0161]

[0162] Step 3: Calculate the structural stiffness of each layer Then, based on the structural stiffness, the total stiffness of the supports required for each floor is calculated. The lateral stiffness required for the building in this case is shown in Table 6 below.

[0163] Table 6 requires the provision of lateral stiffness.

[0164]

[0165] Step 4: Determine the stiffness provided by a single buckling-restrained brace for the i-th layer. :

[0166] like Figure 21 and Figure 22 The plan shows that 4 supports are arranged per floor in the X direction (long span direction) and 4 supports are arranged per floor in the Y direction (short span direction), for a total of 8 supports per floor. The stiffness of a single support required for each floor is shown in Table 8.

[0167] Table 7. Lateral stiffness required for each individual support in each layer.

[0168]

[0169] Step 5: Calculate the area required for the low yield segment of the three-segment core plate of a single buckling-restrained brace. The structure is arranged using a single diagonal brace, and the area is shown in Table 8 below.

[0170] Table 8. Low yield section area of ​​a three-section core plate for a single buckling-restrained brace.

[0171]

[0172] Step 6: Complete the structural bracing arrangement according to the bracing parameters in the above steps, and verify the response of the structure with buckling-restrained bracing arranged in Midas under frequent earthquakes.

[0173] Table 9 shows the first six periods of the original structure and the damping structure with supports, calculated as follows. The period of the original structure is significantly longer than that of the damping frame structure. The first three periods of the two structures are extracted: 0.511s, 0.457s, and 0.409s for the traditional frame structure, and 0.371s, 0.252s, and 0.235s for the damping frame structure. The damping rates (damping rate = difference between the period of the original structure and the period of the damping structure / period of the frame structure) of the traditional frame structure are 27.31%, 44.91%, and 42.54%, respectively. The first three periods are reduced by an average of 38.25%.

[0174] Table 9. First 6 Periods of Traditional Frame Structures and Vibration-Resistant Frame Structures

[0175]

[0176] According to the seismic design code, a time history analysis under frequent earthquakes is conducted. Figure 23-25 The maximum seismic acceleration values ​​of the two actual strong earthquake records (S waves) and one artificial wave shown have been adjusted to 70 cm / s².

[0177] Figures 26-31 The study presents the inter-story displacement and inter-story drift angle variations of a frame structure and a damping structure under frequent earthquake intensities, based on two actual strong earthquake records and one artificial wave. The results show that a damping structure with a displacement amplification mechanism, designed and installed according to the patent, exhibits significantly improved seismic performance compared to the original structure: inter-story displacement is reduced by a maximum of 20.91%, and the inter-story drift angle is reduced by a maximum of 35.21% (a value of 1 / 365, less than the code limit), with a maximum damping rate of 25.20% for the top floor acceleration. This demonstrates that a displacement amplification mechanism with a prefabricated all-steel buckling-resistance brace significantly enhances the seismic performance of the structure.

[0178] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. All equivalent changes made based on the description and drawings of the present invention are included within the scope of the present invention.

Claims

1. A prefabricated buckling-restrained brace with a displacement amplification mechanism, characterized in that, This includes a core board, constrained square steel tubes, transition H-beams, and amplifying levers; among which, The outer surfaces of the upper and lower sidewalls of the constrained square steel tube are provided with core plate limiting grooves. The shape of the core plate limiting grooves is adapted to the core plate. Two core plates are respectively set in the core plate limiting grooves of the upper and lower sidewalls. Both ends of the constrained square steel tube are inserted into transition H-beams, and the transition H-beams slide with the constrained square steel tube. Both ends of the constrained square steel tube and the upper and lower sides of the web of the transition H-beams are provided with amplifying levers. The far end of the amplifying lever is hinged to the end of the core plate, the middle part of the amplifying lever is hinged to the constrained square steel tube, and the near end of the amplifying lever is hinged to the wing plate of the transition H-beam. The distance between the far end and the middle part of the amplifying lever is greater than the distance between the near end and the middle part.

2. The prefabricated buckling-resistance brace with displacement amplification mechanism according to claim 1, characterized in that, The core board adopts a three-section structure, including a low yield section core board in the middle, the two ends of the low yield section core board are connected to the middle yield section core board, and the outer end of the middle yield section core board is connected to the high yield section core board.

3. The prefabricated buckling-resistance brace with displacement amplification mechanism according to claim 2, characterized in that, The outer end of the high yield section core plate is provided with a hollow end constraint sleeve for hinge connection with the amplification lever.

4. The prefabricated buckling-restrained brace with displacement amplification mechanism according to claim 1, characterized in that, Both ends of the constrained square steel tube and the inner surfaces of the upper and lower side walls are provided with enlarged support plates, and the enlarged support plates are provided with enlarged support plate through holes for hinge connection with the enlarged lever.

5. The prefabricated buckling-restrained brace with displacement amplification mechanism according to claim 4, characterized in that, Guide rails are provided at both ends of the constrained square steel tube and on the inner surface of the upper and lower side walls, and guide rail grooves adapted to the guide rails are provided on the flanges of the transition H-beam.

6. The prefabricated buckling-restrained brace with displacement amplification mechanism according to claim 5, characterized in that, A smooth cylindrical connecting rod is provided between the flanges of the transition H-beam for hinged connection with the amplifying lever.

7. The prefabricated buckling-restrained brace with displacement amplification mechanism according to claim 2, characterized in that, The outer surfaces of the upper and lower side walls of the constrained square steel pipe are provided with cover plates. The yield strength of the cover plate material is not lower than the yield strength of the core plate in the high yield section, and the thickness of the cover plate is not less than 1.5 times the thickness of the core plate.

8. The prefabricated buckling-restrained brace with displacement amplification mechanism according to claim 1, characterized in that, It also includes a connector that connects to the outer end of the transition H-beam. The inner end of the connector is a flat end that matches the end face of the transition H-beam, and the outer end is a variable cross-section H-beam with an enlarged opening.

9. A design method, characterized in that, The specific steps for applying the assembled buckling-restrained brace with displacement amplification mechanism as described in any one of claims 1 to 8 are as follows: S1: Based on the floor plans and building functions, determine the cross-sectional dimensions of the load-bearing structural members and calculate the inter-story drift angles for each floor. : ； in, This represents the maximum horizontal displacement between the i-th floor of the building structure under vibration. This represents the height of the i-th floor of the building structure under vibration. S2: If the calculated inter-story drift angle does not exceed the code limit, there is no need to add prefabricated buckling-restrained braces; if the inter-story drift angle exceeds the code limit but does not exceed twice the code limit, it is determined that prefabricated buckling-restrained braces are needed for structural reinforcement design; if the inter-story drift angle exceeds twice the code limit, the dimensions of the structural load-bearing members should be readjusted until the inter-story drift angle is controlled within twice the code limit. S3: For situations requiring structural reinforcement by adding prefabricated buckling-restrained braces, based on the inter-story drift angles of each floor of the building structure and according to the pre-set relationship between the inter-story drift angles and the lateral stiffness ratio, select the required lateral stiffness ratio for each floor. ; S4: Calculate the structural stiffness of each floor of the building structure. And calculate the total stiffness of the prefabricated buckling-restrained braces required for each floor based on the structural stiffness. : ； in, This represents the ratio of the lateral stiffness of the i-th floor of the building structure. This represents the structural stiffness between the i-th floors of a building structure. S4: Calculate the stiffness required to be provided by a single prefabricated buckling-restrained brace arranged in the i-th layer. : ； in, This indicates the number of prefabricated buckling-restrained braces designed and arranged in the i-th floor of the building structure. S5: Calculate the required cross-sectional area of ​​the core plate for a single prefabricated buckling-restrained brace: ； ； in, This represents the cross-sectional area of ​​a prefabricated buckling-restrained brace arranged in a herringbone pattern. This represents the cross-sectional area of ​​a prefabricated buckling-restrained brace with a single diagonal brace arrangement. This indicates the angle between the prefabricated buckling-restrained brace and the horizontal direction. Indicates the core board stiffness; S6: Based on the parameters determined in S1-S5, perform building structure modeling and simulation to verify whether the inter-story drift angle meets the code limit after setting prefabricated buckling-restrained braces. If it does, the design is complete. If it does not, reselect the lateral stiffness ratio and return to S4 until the inter-story drift angle does not exceed the code limit.

10. The design method according to claim 9, characterized in that, When the core plate adopts a three-section core plate structure consisting of a low-yield section, a medium-yield section, and a high-yield section, the cross-sectional area of ​​the three sections differs in different areas. To ensure design reliability, the cross-sectional area of ​​the low-yield section is considered a key parameter determining the overall stiffness and effective load-bearing area of ​​the core plate. This represents the stiffness of the core plate in the low yield section; The yield strength of each segment in the three-segment core plate satisfies: ； ； ； ； in, , This represents the yield strength and cross-sectional area of ​​the core plate in the low yield section. , This represents the yield strength and cross-sectional area of ​​the core plate in the middle yield section. , This represents the yield strength and cross-sectional area of ​​the high-yield section core plate. , This represents the magnification factor, a real number between 2 and 5; ]、 Let be a Gaussian function, and represent taking values ​​of less than or equal to the real number . , The largest integer part; In a prefabricated buckling-restrained brace, the stiffness of the components other than the three-section core plate satisfies the following requirements: ； ； ； in, This refers to the stiffness of components other than the three-section core plate in a prefabricated buckling-restrained brace. The magnification factor is a real number between 3 and 5. The equivalent stiffness of the three-segment core plate. , These represent the stiffness of the low-yield-section core plate, the medium-yield-section core plate, and the high-yield-section core plate, respectively. , , These refer to the lengths of the low-yield-section core plate, the medium-yield-section core plate, and the high-yield-section core plate, respectively. The corresponding values ​​are d, g, and z in sequence. The dimensions between the core board limiting groove and the core board meet the following requirements: ； in, This indicates the difference in size between the core board limiting groove and the core board. This indicates the maximum design working deformation of the prefabricated buckling-restrained brace. The coefficient represents an integer between 2 and 5. Let be a Gaussian function, representing the expression that takes values ​​not exceeding the real number . The largest integer part.

Images