SMA material-based assembled self-centering RC frame beam-column joint

Abstract

The application relates to the technical field of structural engineering, in particular to an assembled self-resetting RC frame beam-column joint based on SMA material, which comprises an RC prefabricated column, an RC prefabricated beam and a reset energy dissipation damper and a friction energy dissipation damper arranged between the RC prefabricated column and the RC prefabricated beam; the reset energy dissipation damper comprises an SMA inner core, an upper constraint cover plate, a lower constraint cover plate, a column end connecting reinforcing plate and a beam end connecting reinforcing plate which are assembled together, and a set energy dissipation gap is reserved between the SMA inner core and the upper constraint cover plate; the friction energy dissipation damper comprises a column middle embedded connecting plate and a beam end embedded connecting plate, the column middle embedded connecting plate and the beam end embedded connecting plate are provided with corresponding primary connecting holes and secondary connecting holes, and each secondary connecting hole on the beam end embedded connecting plate is an arc-shaped long hole. The application can simultaneously consider energy dissipation, self-resetting capacity and safety, can be applied to different seismic intensity conditions, and realizes no damage under small earthquakes, easy repair under medium earthquakes, repairable under large earthquakes and no collapse under giant earthquakes.

Description

Technical Field

[0001] This invention belongs to the field of structural engineering technology, and in particular relates to a prefabricated self-resetting RC frame beam-column joint based on SMA material. Background Technology

[0002] Prefabricated construction has experienced rapid development worldwide in recent years, becoming a viable alternative to traditional cast-in-place construction. Compared to traditional cast-in-place concrete structures, prefabricated buildings offer advantages such as high efficiency, energy saving, and environmental friendliness, and can be integrated with intelligent construction, exhibiting industrialized characteristics. The factory prefabrication construction mode of prefabricated buildings determines that the seismic behavior of prefabricated concrete frame structures differs from that of traditional cast-in-place concrete frame structures. Therefore, developing prefabricated concrete structural systems with good seismic performance has become an important research direction.

[0003] When an earthquake occurs, partial or complete collapse of buildings is one of the most significant causes of casualties and property damage. Over the past century, structural seismic resistance research has made considerable progress. From initial static method research to later response spectrum methods, the primary goals have been to prevent structural collapse and reduce casualties. At this stage, structural seismic design focused on controlling the instantaneous performance of structures under seismic loads, the commonly accepted "no collapse under major earthquakes" requirement. Rigorous seismic design ensured that structures would not collapse under earthquake loads, thereby reducing casualties and economic losses. However, some major earthquakes at the end of the last century provided new warnings for seismic resistance research. In the 1994 Northridge earthquake in the United States and the 1995 Kobe earthquake in Japan, while building collapse and casualties were relatively few, the economic losses were enormous. The Northridge earthquake caused over $50 billion in economic losses, and the Kobe earthquake caused over $170 billion, with extremely severe social impacts. This led to the realization that the traditional approach of solely focusing on whether a structure would collapse after an earthquake as the goal of seismic resistance design is no longer sufficient to meet the demands of modern society. Against this backdrop, performance-based earthquake engineering (PBEE) has gradually developed, and performance-based seismic design (PBSD) has slowly become the mainstream of international earthquake engineering research.

[0004] The fundamental principle of Seismic Shock Displacement (PBSD) is to ensure that the structural response under seismic loading is controlled within the expected target range. The first generation of PBSD used deterministic structural response as the performance target, resulting in deterministic performance estimations that did not adequately consider the randomness and uncertainty of seismic motion and the nonlinear behavior of the structure. The second generation of PBSD used overall structural reliability as the performance target, considering the seismic demands of the structure and the randomness and uncertainty of its capacity, presenting the structural performance level in the form of overall reliability. The third generation of PBSD focuses on seismic risk control as the ultimate performance target, encompassing not only the assessment of the structural collapse risk itself but also the analysis of post-earthquake economic loss risks. Based on probability theory, it incorporates seismic hazard analysis, seismic vulnerability analysis, and seismic loss analysis into its core analytical framework, resulting in a relatively complete theoretical system. However, in today's highly urbanized world, human society still faces the challenge of difficult, time-consuming, and costly post-earthquake reconstruction. There is a growing desire for structures to possess good seismic resilience, maintaining or quickly restoring normal functionality after a major earthquake, thereby minimizing the economic and social impact of earthquakes. Therefore, researching the resilience of structures after disasters has become a key focus in recent years. Against this backdrop, research on the "seismic resilience" of structures and cities has gradually gained attention from scholars. Seismic resilience characterizes the ability of a structure or city to withstand seismic disturbances and to recover rapidly from earthquake disasters.

[0005] Currently, seismic resilience research primarily focuses on self-centering structures. Under strong earthquakes, self-centering structures utilize their own weight, prestressed components, or high-performance materials to achieve deformation recovery, mitigating or even completely eliminating residual post-earthquake deformation. Simultaneously, they utilize damping elements to dissipate seismic energy, exhibiting a "flag-shaped" hysteretic behavior. Compared to traditional structures, the most significant characteristic of self-centering structures is their minimal or even zero residual post-earthquake deformation. Theoretically, because they return to their initial shape after an earthquake, the main body of a self-centering structure can continue to function without repair. This feature greatly increases the likelihood of continued use of individual structures after an earthquake, mitigating the high economic costs and significant social impacts of strong earthquakes, promoting rapid recovery of life and production after an earthquake, and aligning with the goal of developing earthquake-resistant cities.

[0006] Currently, research on prefabricated self-centering reinforced concrete (RC) frame structures mainly focuses on precast / prestressed self-centering (PPSC) structural systems. In PPSC systems, prefabricated components (frame beams, frame columns, wall segments, etc.) are connected by unbonded post-tensioning (PT) prestressing tendons. Under seismic loading, the prefabricated components can rotate relative to each other, forming openings. The stretched PT prestressing tendons provide the structure with self-centering capability, mitigating residual deformation after an earthquake and allowing the structure to return to its initial position. During this process, the seismic energy absorbed by the structure is dissipated primarily through energy dissipation (ED) elements at the nodes (such as built-in energy dissipation tendons or external damping devices), resulting in a typical "flag-shaped" hysteretic behavior. Despite the very "attractive" advantages of this new structural system in terms of seismic performance (less damage after an earthquake and the ability to restore the structure to its usability in a short time), it has not yet been applied on a large scale after more than 20 years of research. The main reason for this is that the safety redundancy of this structural system is less than that of traditional cast-in-place RC frames. In terms of system composition, it mainly relies on unbonded prestressed tendons to connect precast components in series. The failure of the prestressed tendons will lead to devastating consequences. Summary of the Invention

[0007] In view of this, the purpose of the present invention is to provide a prefabricated self-resetting RC frame beam-column joint based on SMA material, which avoids the potential problems of the connection method of series prefabricated components and the small safety redundancy when using prestressed tendons to provide restoring force in the existing prefabricated prestressed self-resetting structural system. While ensuring the energy consumption and self-resetting capability of the RC frame joint, the safety of the RC frame joint is improved.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: Prefabricated self-resetting RC frame beam-column joints based on SMA material include: RC precast columns; RC precast beams; The reset energy dissipation damper is installed between the RC precast column and the RC precast beam, with two sets spaced vertically. The reset energy dissipation damper includes an SMA core, an upper constraint cover plate, a lower constraint cover plate, a column end connecting reinforcement plate, and a beam end connecting reinforcement plate. The SMA core is connected between the upper constraint cover plate and the lower constraint cover plate, and a set energy dissipation gap is left between the SMA core and the upper constraint cover plate. The column end connecting reinforcement plate is connected to both the SMA core and the RC precast column through column end high-strength bolts, and the beam end connecting reinforcement plate is connected to both the SMA core and the RC precast beam through beam end high-strength bolts. The friction energy dissipation damper includes a column-embedded connecting plate partially embedded in the RC precast column and a beam-end embedded connecting plate partially embedded in the RC precast beam. The column-embedded connecting plate and the beam-end embedded connecting plate are provided with corresponding main connecting holes and secondary connecting holes. Multiple secondary connecting holes are distributed along the circumference of the main connecting holes. Each secondary connecting hole on the beam-end embedded connecting plate is an arc-shaped elongated hole. Shear bolts are inserted into the corresponding main connecting holes and the corresponding secondary connecting holes on the column-embedded connecting plate and the beam-end embedded connecting plate.

[0009] Preferably, the SMA core is a variable cross-section structure, including a middle energy-dissipating section and connecting sections at both ends. The width of the energy-dissipating section is smaller than the width of the connecting sections. The energy-dissipating section is connected to the upper constraint cover plate and the lower constraint cover plate, and the connecting sections are connected to the corresponding column end connecting reinforcement plate or beam end connecting reinforcement plate.

[0010] Furthermore, the energy-consuming section is provided with an elongated hole extending along its length direction, and the lower constraint cover plate is provided with pads at positions corresponding to the elongated hole and the edge of the energy-consuming section in the width direction. The thickness of the pads is greater than the thickness of the energy-consuming section, and the upper constraint cover plate is provided with perforations at positions corresponding to the pads.

[0011] Preferably, the thickness of the pad is 1 mm greater than the thickness of the energy-consuming section.

[0012] Preferably, the SMA core is a copper-based shape memory alloy.

[0013] Preferably, the friction energy dissipation damper also includes hard friction plates attached to both sides of the end of the embedded plate in the column.

[0014] Furthermore, four secondary connection holes are provided on both the column-embedded connection plate and the beam-end embedded connection plate; in the column-embedded connection plate and the beam-end embedded connection plate, the two secondary connection holes on the upper side and the two secondary connection holes on the lower side are symmetrical about the main connection hole, and the two secondary connection holes on the left side and the two secondary connection holes on the right side are symmetrical about the main connection hole.

[0015] Furthermore, the corresponding column end connecting reinforcement plates in the reset energy dissipation dampers at the same positions on both sides of the same RC precast column are interconnected.

[0016] The beneficial effects of this invention are: 1. The RC frame beam-column joint of this invention adopts a dry, all-bolted assembly connection method, fully leveraging the efficient construction characteristics of prefabricated structures. Simultaneously, it employs a high-performance, low-cost copper-based SMA core to provide energy dissipation and self-resetting capabilities for the RC frame beam-column joint. Furthermore, a plastic hinge is constructed at the beam end of the RC precast beam, which improves the shear bearing capacity of the joint while allowing relative rotation between the RC precast column and the RC precast beam. This also limits the maximum displacement angle of the RC frame beam-column joint, prevents the axial displacement of the reset energy-dissipating damper from exceeding limits, and promotes the participation of the RC precast beam in plastic deformation to jointly dissipate energy when the joint displacement angle is large. This invention avoids the potential problems of existing precast prestressed self-resetting structural systems that use prestressed tendons to provide restoring force in the connection method of series precast components and have relatively low safety redundancy.

[0017] 2. The RC frame beam-column joint of the present invention can simultaneously take into account energy dissipation, self-resetting capability and safety, and can be applied to different earthquake intensities. It can achieve no damage in small earthquakes, easy repair in moderate earthquakes, repairable in large earthquakes, and no collapse in mega earthquakes, thereby increasing the possibility of continued use of individual structures after earthquakes. It can reduce the high economic cost and significant social impact caused by strong earthquakes and promote the rapid recovery of life and production after earthquakes. Attached Figure Description

[0018] Figure 1 This is a three-dimensional schematic diagram of the prefabricated self-resetting RC frame beam-column joint based on SMA material according to the present invention; Figure 2 yes Figure 1 The main view; Figure 3 This is a schematic diagram of the resetting energy dissipation damper in the prefabricated self-resetting RC frame beam-column joint based on SMA material according to the present invention. Figure 4 yes Figure 3 Exploded view; Figure 5 yes Figure 3 A schematic diagram of the structure of the SMA kernel in China; Figure 6 This is a schematic diagram of the friction energy dissipation damper in the prefabricated self-resetting RC frame beam-column joint based on SMA material according to the present invention. Figure 7 yes Figure 5 Exploded view; Figure 8 This is a schematic diagram of the seismic response of the prefabricated self-resetting RC frame beam-column joint based on SMA material according to the present invention.

[0019] Reference numerals: 1-RC precast column, 2-RC precast beam, 3-SMA core, 4-upper constraint cover plate, 5-lower constraint cover plate, 6-column end connection reinforcement plate, 7-beam end connection reinforcement plate, 8-column end high-strength bolt, 9-beam end high-strength bolt, 10-column embedded connection plate, 11-beam end embedded connection plate, 12-column main connection hole, 13-column secondary connection hole, 14-beam main connection hole, 15-beam secondary connection hole, 16-main shear bolt, 17-secondary shear bolt, 18-shield block, 19-elongated hole, 20-energy dissipation section, 21-connection section, 22-hard friction plate, 23-reset energy dissipation damper, 24-friction energy dissipation damper, 25-fastening high-strength bolt. Detailed Implementation

[0020] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0021] Specific embodiments of the prefabricated self-resetting RC frame beam-column joint based on SMA material of the present invention: like Figure 1 and Figure 2 As shown, the prefabricated self-resetting RC frame beam-column joint based on SMA material includes RC precast column 1, RC precast beam 2, and a reset energy dissipation damper 23 and a friction energy dissipation damper 24 disposed between RC precast column 1 and RC precast beam 2.

[0022] Specifically, such as Figure 2 , Figure 3 and Figure 4 As shown, two sets of reset energy dissipation dampers 23 are arranged vertically and horizontally. Each set of reset energy dissipation dampers 23 includes an SMA core 3, an upper constraint cover plate 4, a lower constraint cover plate 5, a column end connecting reinforcement plate 6, and a beam end connecting reinforcement plate 7. In this embodiment, the SMA core 3 is a copper-based shape memory alloy, connected between the upper constraint cover plate 4 and the lower constraint cover plate 5. Figure 5As shown, the SMA core 3 has a variable cross-section structure, including a central energy-dissipating section 20 and connecting sections 21 at both ends. The width of the energy-dissipating section 20 is smaller than the width of the connecting sections 21. An elongated hole 19 extending along the length direction is provided in the middle of the energy-dissipating section 20, with pointed ends at both ends. A row of pads 18 is provided on the lower constraint cover plate 5 at positions corresponding to the elongated hole 19 and the edges of the energy-dissipating section 20 in the width direction. Each row includes three spaced pads 18. A through hole is provided on the upper constraint cover plate 4 at the position corresponding to each pad 18. The upper constraint cover plate 4 is connected to the energy-dissipating section 20 and the lower constraint cover plate by multiple high-strength bolts 25. In this embodiment, a predetermined energy-dissipating gap is maintained between the SMA core 3 and the upper constraint cover plate 4 because the thickness of the pad 18 is greater than the thickness of the energy-dissipating section 20. In practical applications, it is optimal for the thickness of the pad 18 to be 1 mm greater than the thickness of the energy dissipation section 20. This gap allows the SMA core to exhibit a tendency for lateral deformation, followed by multi-wave deformation under the constraint of the upper constraint cover plate 4. Of course, this gap should not be too large; in other embodiments, it can fluctuate around 1 mm.

[0023] Two L-shaped column-end connecting reinforcement plates 6 are provided, symmetrically arranged on the upper and lower sides of one of the connecting sections. Fixing holes are provided on both the horizontal and vertical sections of the L-shaped plates. Both column-end connecting reinforcement plates 6 are connected to the corresponding connecting sections of the SMA core 3 and the RC precast column 1 via column-end high-strength bolts 8. Two beam-end connecting reinforcement plates 7 are also provided, symmetrically arranged on the upper and lower sides of the other connecting section. Of the two beam-end connecting reinforcement plates 7 in the same reset energy-dissipating damper 23, one is attached to the surface of the RC precast beam 3, and the other is attached to the surface of the corresponding connecting section of the SMA core. All four end-connecting reinforcement plates 7 are simultaneously connected to the corresponding connecting sections of the SMA core 3 and the RC precast beam 2 via beam-end high-strength bolts 9.

[0024] like Figure 6 and Figure 7As shown, the friction energy dissipation damper 24 includes a column-embedded connecting plate 10 partially embedded in the RC precast column 1 and a beam-end embedded connecting plate 11 partially embedded in the RC precast beam 2. Two beam-end embedded connecting plates 11 are provided, arranged opposite each other and spaced apart within the RC precast beam 2, forming an installation groove between them. The column-embedded connecting plate 10 partially extends into the aforementioned installation groove. Hard friction plates 22 are attached to both sides of the ends of the column-embedded connecting plate 10, which can increase the initial stiffness of the node and its energy dissipation capacity after rotation. The column-embedded connecting plate 10 has a main column connecting hole 12 and four secondary column connecting holes 13 distributed in the circumferential direction of the main column connecting hole 12; similarly, the beam-end embedded connecting plate 11 has a main beam connecting hole 14 corresponding to the main column connecting hole 12 and secondary beam connecting holes 15 corresponding one-to-one with the secondary column connecting holes 13. Among them, the secondary beam connection holes 15 are arc-shaped elongated holes. Of the four secondary beam connection holes 15, the two upper and two lower ones are symmetrical about the main beam connection hole 14, while the two left and two right ones are symmetrical about the main beam connection hole 14. The distribution of the main column connection holes 12 and secondary column connection holes 13 also follows the above pattern. The main column connection holes 12 and the main beam connection holes 14 have the same diameter, and both are fitted with matching main shear bolts. Secondary shear bolts 17 are fitted into the secondary column connection holes 13 and their corresponding secondary beam connection holes 15. While increasing the number of shear bolts and improving the shear bearing capacity of the joint, relative rotation between the RC precast beam 1 and the RC precast column 2 is still allowed. Simultaneously, it can limit the maximum displacement angle of the beam-column joint, prevent the SC-BRD axial displacement from exceeding the limit, and promote the RC precast beam 2 to participate in plastic deformation and jointly dissipate energy when the joint displacement angle is large.

[0025] like Figure 8 As shown, the corresponding column end connecting reinforcing plates 6 in the reset energy dissipation dampers at the same positions on the left and right sides of the same RC precast column 1 are connected to each other.

[0026] Combination Figure 8 The design expected deformation of the prefabricated self-resetting RC frame beam-column joint based on SMA material, the energy dissipation principle of each component's reset, and the seismic performance target of its frame structure system under various levels of seismic loading are as follows: (1) When the frame is under long-term design conditions such as frequent earthquakes, the RC precast beam 1, RC precast column 2, and the reset energy dissipation dampers 23 on both sides of the node all remain elastic. At the same time, the hard friction plate 22 at the connection between the RC precast beam 1 and the RC precast column 2 does not rotate relative to the pre-embedded connection plate 11 at the beam end. The frame as a whole uses elastic stiffness to resist vibration deformation. The structure is undamaged and has no residual deformation after a minor earthquake; the structure can continue to be used without repair after the earthquake.

[0027] (2) When the frame is subjected to an excitation intensity exceeding that of a frequent earthquake but below that of a rare earthquake, the RC precast beam 1 and RC precast column remain elastic. The hard friction plate 22 at the connection between the RC precast beam 1 and the RC precast column 2 begins to rotate relative to the pre-embedded connecting plate 11 at the beam end to enhance the energy dissipation capacity of the "beam hinge". Meanwhile, the copper-based SMA core in the reset energy dissipation damper 23 is in a hyperelastic deformation range with a small strain amplitude where the axial residual strain is almost zero. At this time, the energy dissipation capacity of the copper-based SMA core is small, but the recovery stress after unloading is sufficient, thereby providing additional energy dissipation capacity and good post-earthquake self-resetting capacity for the beam hinge, thereby reducing or even eliminating the post-earthquake residual deformation of the precast frame structure. That is, after a moderate earthquake, the RC precast beam 2, RC precast column 1 and other components are undamaged, the residual deformation of the reset energy dissipation damper 23 is almost zero, and there is a small residual displacement angle between the hard friction plate 22 and the pre-embedded connection plate 11 at the beam end; the post-earthquake structure does not need to be repaired, or only needs to release the prestress in the local shear bolts and correct the small residual displacement angle between some of the hard friction plates 22 and the pre-embedded connection plate 11 at the beam end before it can continue to be used.

[0028] (3) When the frame structure is subjected to an excitation of rare earthquake intensity, the RC precast beam 1 and RC precast column 2 are still expected to remain elastic. The hard friction plate 22 at the connection of RC precast beam 1 and RC precast column 2 undergoes a large relative rotation with the pre-embedded connecting plate 11 at the beam end, further enhancing the energy dissipation capacity of the "beam hinge". The copper-based SMA core in the reset energy dissipation damper 23 undergoes large and nearly symmetrical axial tensile and compressive yield deformation and hysteretic energy dissipation under the constraint of the constraint member on its out-of-plane deformation. At this time, the energy dissipation capacity of the copper-based SMA core is significantly improved, the recovery stress after unloading decreases, and the residual deformation increases, thereby providing sufficient hysteretic energy dissipation and good post-earthquake self-resetting capacity for the beam hinge, thus reducing its post-earthquake residual deformation while controlling the seismic response of the frame structure. That is, after a major earthquake, the main beams and columns of the structure are undamaged, the reset energy dissipation damper 23 has small residual deformation, and there is a certain residual displacement angle between the hard friction plate 22 and the pre-embedded connection plate 11 at the beam end; the post-earthquake structure can continue to be used after replacing the reset energy dissipation damper with large axial deformation and correcting the displacement angle of the shear bolt connection with large residual deformation.

[0029] (4) When the frame structure is subjected to an excitation of extremely rare earthquake intensity, the RC precast column 1 is still expected to remain elastic. Under the control of the secondary beam connection hole 15 at the left end of the beam end pre-embedded connection plate 11, the shear bolt connection of the RC precast beam 2 and the RC precast column 1 reaches the maximum displacement angle limit, the reset energy dissipation damper 23 reaches the maximum axial deformation limit, and the RC precast beam 2 begins to participate in plastic deformation in order to maximize the energy dissipation capacity of the beam hinge plastic deformation, control the seismic response of the structure and the plastic damage of the precast column components, so that the structure still yields according to the overall mechanism and prevents the structure from collapsing.

[0030] The prefabricated self-resetting RC frame beam-column joint based on SMA material of the present invention can simultaneously take into account energy dissipation, self-resetting capability and safety. It can be applied to different earthquake intensities, achieving no damage in minor earthquakes, easy repair in moderate earthquakes, repairable in major earthquakes, and no collapse in mega-earthquakes. It increases the possibility of continued use of individual structures after earthquakes, can reduce the high economic cost and significant social impact caused by strong earthquakes, and promote the rapid recovery of life and production after earthquakes.

[0031] In other embodiments, without considering cost, the SMA core may also be made of nickel-titanium SMA material or iron-manganese-silicon alloy material.

[0032] The embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A fabricated self-centering RC frame beam-column joint based on SMA material, characterized in that, include: RC precast columns; RC precast beams; The reset energy dissipation damper is installed between the RC precast column and the RC precast beam, with two sets spaced vertically. The reset energy dissipation damper includes an SMA core, an upper constraint cover plate, a lower constraint cover plate, a column end connecting reinforcement plate, and a beam end connecting reinforcement plate. The SMA core is connected between the upper constraint cover plate and the lower constraint cover plate, and a set energy dissipation gap is left between the SMA core and the upper constraint cover plate. The column end connecting reinforcement plate is connected to both the SMA core and the RC precast column through column end high-strength bolts, and the beam end connecting reinforcement plate is connected to both the SMA core and the RC precast beam through beam end high-strength bolts. The friction energy dissipation damper includes a column-embedded connecting plate partially embedded in the RC precast column and a beam-end embedded connecting plate partially embedded in the RC precast beam. The column-embedded connecting plate and the beam-end embedded connecting plate are provided with corresponding main connecting holes and secondary connecting holes. Multiple secondary connecting holes are distributed along the circumference of the main connecting holes. Each secondary connecting hole on the beam-end embedded connecting plate is an arc-shaped elongated hole. Shear bolts are inserted into the corresponding main connecting holes and the corresponding secondary connecting holes on the column-embedded connecting plate and the beam-end embedded connecting plate. The SMA core is a variable cross-section structure, including a middle energy-dissipating section and connecting sections at both ends. The width of the energy-dissipating section is smaller than the width of the connecting section. The energy-dissipating section is connected to the upper constraint cover plate and the lower constraint cover plate. The connecting sections are connected to the corresponding column end connecting reinforcement plate or beam end connecting reinforcement plate. The energy-consuming section is provided with an elongated hole extending along its length direction. The lower constraint cover plate is provided with pads at positions corresponding to the elongated hole and the edge of the energy-consuming section in the width direction. The thickness of the pads is greater than the thickness of the energy-consuming section. The upper constraint cover plate is provided with perforations at positions corresponding to the pads.

2. The SMA material based fabricated self-centering RC frame beam-column joint of claim 1, wherein, The thickness of the pad is 1 mm greater than the thickness of the energy-consuming section.

3. The prefabricated self-resetting RC frame beam-column joint based on SMA material according to claim 1 or 2, characterized in that, The SMA core is a copper-based shape memory alloy.

4. The prefabricated self-resetting RC frame beam-column joint based on SMA material according to claim 1 or 2, characterized in that, The friction energy dissipation damper also includes hard friction plates attached to both sides of the end of the pre-embedded connecting plate in the column.

5. The prefabricated self-resetting RC frame beam-column joint based on SMA material according to claim 1 or 2, characterized in that, There are four secondary connection holes on both the column-embedded connection plate and the beam-end embedded connection plate. In the column-embedded connection plate and the beam-end embedded connection plate, the two secondary connection holes on the upper side and the two secondary connection holes on the lower side are symmetrical about the main connection hole, and the two secondary connection holes on the left side and the two secondary connection holes on the right side are symmetrical about the main connection hole.

6. The prefabricated self-resetting RC frame beam-column joint based on SMA material according to claim 1 or 2, characterized in that, The corresponding column end connecting reinforcement plates in the reset energy dissipation dampers at the same positions on both sides of the same RC precast column are connected to each other.

Images