Concrete beam-column joint cassette connection structure with self-resetting SMA energy dissipator

Abstract

The present invention discloses a concrete beam-column node box-type connection structure with a self-resetting SMA energy absorber, comprising: a precast reinforced concrete lower column and a precast reinforced concrete upper column fixedly connected by a column end connector; a precast reinforced concrete beam and a precast reinforced concrete lower column fixedly connected by a steel box; and a plurality of self-resetting SMA energy absorbers including a self-resetting device and an energy dissipation device, as well as an energy dissipation connection key, are symmetrically provided at the connection between the precast reinforced concrete beam and the precast reinforced concrete lower column. The concrete beam-column node box-type connection structure with a self-resetting SMA energy absorber provided by the present invention meets the needs of the actual design and construction of prefabricated buildings. The assembled beam-column node has a high bearing capacity, a clear and reasonable damage mode, and can effectively avoid the appearance of plastic hinges at the column ends. Under the action of an earthquake, it can continue to exert a stable energy dissipation effect, and the structure can achieve self-reset after the earthquake.

Description

Technical Field

[0001] The present invention belongs to the technical field of prefabricated concrete buildings, and in particular relates to a concrete beam-column node box-type connection structure with a self-resetting SMA energy absorber. Background Art

[0002] The core area of the beam-column joint is crucial for ensuring the frame's load-bearing capacity and anti-collapse capability. Failure in this area can cause progressive structural damage, even life-threatening serious damage, and has a crucial impact on the seismic performance of the entire structure. Therefore, the performance of prefabricated beam-column joints is key to the widespread application of prefabricated frame structures.

[0003] Traditional beam-column joints mainly use wet operation connection methods. Due to the constraints of working space, construction technology and other aspects, they will face various difficulties when fully applied to prefabricated beam-column joints, and cannot meet the development concept of green, environmental protection, energy saving and high efficiency of prefabricated buildings.

[0004] With the continuous development of prefabricated buildings, various dry connection technologies have gradually emerged in beam-column joints, such as sleeve grouting connection, slurry anchor connection and post-cast strip connection. Among them, the sleeve grouting connection has a significantly increased cost in engineering applications due to the complex processing technology and the special nature of the product, and its quality is difficult to detect, which restricts its application and development; the slurry anchor connection has an eccentric force transmission mechanism, and its mechanical properties, especially the safety of the core area of the beam-column joint in seismic-resistant structures, are difficult to guarantee; the post-cast strip connection is prone to steel bar corrosion, and slag inclusions are difficult to clean. At the same time, due to the dense distribution of steel bars in the core area of the node, the quality of post-casting is difficult to guarantee, and the weak surface formed by splicing will reduce the reliability of the structure.

[0005] It can be seen from this that the existing connection methods often delay the structure from entering the plastic working stage and reduce plastic deformation by increasing the bearing capacity. Therefore, the energy dissipation capacity is relatively poor and does not meet the performance design objectives of the structure's seismic resistance. In addition, plastic hinges are prone to appear in grouting or post-casting, and brittle failure is prone to occur under repeated seismic loads.

[0006] Therefore, it is necessary to research and develop a dry-type connection structure for beam-column nodes that has clear force, simple assembly, can continuously exert a stable energy dissipation effect under earthquake action, and can achieve self-reset after the earthquake. Summary of the Invention

[0007] In order to solve the above problems existing in the prior art, the present invention provides a concrete beam-column node box-type connection structure with a self-resetting SMA energy dissipator. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0008] In a first aspect, the present invention provides a self-resetting SMA energy dissipator, comprising two semicircular outer cylinders, a self-resetting device, and an energy dissipation device; the two outer cylinders are fixedly connected; the self-resetting device is arranged inside the outer cylinders, and the energy dissipation device is arranged outside the two outer cylinders and in close contact with the outer cylinders;

[0009] The self-resetting device includes two limit devices, two movable baffles, an inner rod and several SMA rods;

[0010] The two limiting devices are respectively arranged at the upper and lower ends of the outer cylinder;

[0011] The two movable baffles are respectively arranged on the outside of the two limiting devices and are movably connected to the limiting devices; and each of the two movable baffles is provided with a first through hole for the inner rod to pass through;

[0012] A protrusion is also provided on the inner side of the junction of the inner rod and the movable baffle to push and pull the movable baffle to move when the inner rod is subjected to force;

[0013] The outer edge of each movable baffle is further provided with a plurality of second through holes, and a plurality of SMA rods pass through the second through holes and are fixedly connected to the movable baffle.

[0014] In a second aspect, the present invention provides a concrete beam-column node box-type connection structure with a self-resetting SMA energy absorber, comprising a plurality of self-resetting SMA energy absorbers, a precast reinforced concrete upper column, a precast reinforced concrete beam, a precast reinforced concrete lower column, a column end connector, and a steel box; wherein,

[0015] The precast reinforced concrete lower column and the precast reinforced concrete upper column are fixedly connected by the column end connector;

[0016] The precast reinforced concrete beam and the precast reinforced concrete lower column are vertically and fixedly connected by the steel box;

[0017] A plurality of self-resetting SMA energy absorbers are symmetrically arranged at the connection between the precast reinforced concrete beam and the precast reinforced concrete lower column; one end of the self-resetting SMA energy absorber is fixedly connected to the precast reinforced concrete beam, and the other end is fixedly connected to the precast reinforced concrete lower column;

[0018] Wherein, the self-resetting SMA energy absorber is the self-resetting SMA energy absorber provided in the above embodiment.

[0019] Beneficial effects of the present invention:

[0020] 1. The self-resetting SMA energy absorber provided by the present invention, on the one hand, adopts a plurality of SMA rods to design a self-resetting device structure, ensuring that the SMA rods are always in a tensile state during the tensile and compressive loading of the energy absorber, thus preventing the SMA rods from buckling under compression. The superelasticity of the SMA rods under tension enables the connected objects that have been deformed after being stressed to return to their original state, thus realizing the self-resetting function. On the other hand, the energy dissipation device is designed to be in close contact with the outer cylinder. When the device is subjected to an earthquake, the friction between the energy dissipation device and the outer cylinder dissipates the seismic energy, thus realizing the energy dissipation function. In addition, the self-resetting SMA energy absorber does not need to be replaced after the earthquake, and the residual deformation after the earthquake can be restored to the original state by heating the SMA rods or supplementing prestressing.

[0021] 2. The concrete beam-column node box-type connection structure with a self-resetting SMA energy absorber provided by the present invention is further provided with an energy-dissipating connection key at the beam-column connection. Under the action of a major earthquake, a large relative rotation occurs between the prefabricated beams and columns. When the SMA rod in the self-resetting SMA energy absorber reaches the ultimate tensile state and cannot dissipate energy, it will enter a second-stage energy dissipation state. The weakened opening of the energy dissipation connection key can enter the yield stage, exerting the role of buckling energy dissipation. Through the two-stage energy dissipation, the expected structural deformation is controlled, so that the main components of the beam-column node will not be destroyed or slightly damaged during a major earthquake, achieving a higher level of structural seismic performance goals.

[0022] 3. The concrete beam-column node box-type connection structure with a self-resetting SMA energy absorber provided by the present invention realizes a box-type connection between precast reinforced concrete beams and precast reinforced concrete columns, meeting the needs of actual design and construction. The assembled beam-column node has a high bearing capacity, a clear and reasonable damage mode, and can effectively avoid the formation of plastic hinges at the column ends. Under the action of an earthquake, it can continue to exert a stable energy dissipation effect and can achieve self-reset after the earthquake.

[0023] 4. The present invention adopts measures such as pre-embedded U-shaped steel bars at the column ends in the core area of the beam-column joint, pre-embedded U-shaped steel bars at the beam ends, and internal stirrups, which effectively transmit the shear force of the node area, enhance the shear bearing capacity of the node area, and realize the "strong shear and weak bending" damage mode. At the same time, the core area of the node column adopts external steel, which has a great restraining effect on the concrete in the core area of the node, significantly improves the bearing capacity of the node, and realizes the "strong node and weak component" damage mode; the four-corner spiral ring reinforcement of the column end has a strong restraining effect on the corner concrete, and at the same time, the column end adopts parallel reinforcement, which jointly improves the bearing capacity of the column, while the energy-consuming connection key at the beam end is opened to weaken the bearing capacity of the beam, realizing the "strong column and weak beam" damage mode. The structural damage is mainly concentrated on the replaceable components at the beam end, reducing the internal force demand of the adjacent beam components, so that the beam components can also be in a low-damage state under the action of a large earthquake;

[0024] 5. The present invention uses spiral ring reinforcement at the upper column end to exert a strong restraint on the corner concrete, which can effectively avoid the occurrence of plastic hinges at the column end. At the same time, the energy-dissipating connection key opening at the beam end weakens its bearing capacity and transfers the deformation of the beam-column node to the beam end. The plastic hinge in the node area is controlled at the location of the energy-dissipating key opening. The opening position can be flexibly adjusted according to actual conditions, realizing the controllable location of the plastic hinge.

[0025] 6. The prefabricated reinforced concrete columns, prefabricated reinforced concrete beams and self-resetting SMA energy absorbers in the present invention can all be manufactured in the factory and assembled directly on site. The process is simple and the requirements for construction personnel are not high. It can greatly reduce on-site wet concrete work and various complex grouting processes, meet the development concept of green and environmental protection of prefabricated buildings, have high construction efficiency, and strong engineering applicability.

[0026] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the structure of a self-resetting SMA energy dissipator provided by an embodiment of the present invention;

[0028] Figure 2 This is a partial enlarged view of the self-resetting SMA energy dissipator provided by an embodiment of the present invention;

[0029] Figure 3 Schematic diagram of a concrete beam-column node box-type connection structure with a self-resetting SMA energy absorber provided by an embodiment of the present invention;

[0030] Figure 4 Schematic diagram of the structure of the prefabricated reinforced concrete lower column provided by an embodiment of the present invention;

[0031] Figure 5 Schematic diagram of the structure of the prefabricated reinforced concrete upper column provided by an embodiment of the present invention;

[0032] Figure 6 A schematic structural diagram of a column end connector provided by an embodiment of the present invention;

[0033] Figure 7 A schematic structural diagram of a prefabricated reinforced concrete beam provided in an embodiment of the present invention;

[0034] Figure 8 1 is a schematic structural diagram of a steel box provided in an embodiment of the present invention;

[0035] Figure 9 A schematic structural diagram of an energy-consuming connection key provided by an embodiment of the present invention;

[0036] Description of reference numerals:

[0037] 1- Self-resetting SMA energy dissipator;

[0038] 101-outer cylinder, 102-limiting device, 103-movable baffle, 104-inner rod, 105-SMA rod, 106-bump, 107-limiting card, 108-limiting baffle, 109-non-asbestos friction plate, 110-friction plate, 111-bolt, 112-bottom cylinder, 113-ear plate;

[0039] 2-Precast reinforced concrete upper columns;

[0040] 201-U-shaped reinforcement at the upper column end, 202-parallel reinforcement, 203-spiral ring reinforcement, 204-upper column longitudinal reinforcement;

[0041] 3- Precast reinforced concrete beams;

[0042] 301- longitudinal reinforcement in beam, 302- weldment, 303- beam-column fixing bolt rod, 304- inner stirrups at beam end, 305- U-shaped reinforcement at beam end, 306- bolt hole, 307- fixing steel plate;

[0043] 4- Precast reinforced concrete lower column;

[0044] 401-U-shaped steel bar at the lower column end, 402-outer steel, 403-steel bar connection sleeve, 404-upper and lower column fixing bolt rod, 405-lower column longitudinal reinforcement;

[0045] 5-column end connector; 6-steel box; 7-energy dissipation connection key; 8-angle steel. DETAILED DESCRIPTION

[0046] The present invention will be further described in detail below with reference to specific examples, but the embodiments of the present invention are not limited thereto.

[0047] Example 1

[0048] See Figure 1 , Figure 1 1 is a schematic structural diagram of a self-resetting SMA energy dissipator provided by an embodiment of the present invention, which includes two semicircular outer cylinders 101, a self-resetting device, and an energy dissipation device; the two outer cylinders 101 are fixedly connected; the self-resetting device is disposed inside the outer cylinders 101, and the energy dissipation device is disposed outside the two outer cylinders 101 and in close contact with the outer cylinders 101;

[0049] The self-resetting device includes two limit devices 102, two movable baffles 103, an inner rod 104 and a plurality of SMA rods 105;

[0050] Two limiting devices 102 are respectively provided at the upper and lower ends of the outer cylinder 101;

[0051] The two movable baffles 103 are respectively arranged on the outside of the two limiting devices 102 and are movably connected to the limiting devices 102; and each of the two movable baffles 103 is provided with a first through hole for the inner rod 104 to pass through;

[0052] A protrusion 106 is provided on the inner side of the junction of the inner rod 104 and the movable baffle 103 to push or pull the movable baffle 103 to move when the inner rod 104 is subjected to force;

[0053] The outer edge of each movable baffle 103 is further provided with a plurality of second through holes, and a plurality of SMA rods 105 pass through the second through holes and are fixedly connected to the movable baffle 103 .

[0054] For further information, see Figure 2 , Figure 2 This is a partial enlarged view of the self-resetting SMA energy dissipator provided by an embodiment of the present invention. In this embodiment, the limiting device 102 includes two limiting cards 107 and a limiting baffle 108; the two limiting cards 107 are respectively fixed on the inner walls of the two outer cylinders 101; the limiting baffle 108 is set between the two limiting cards 107; wherein,

[0055] The limiting baffle 108 is an annular baffle, and is provided with a third through hole corresponding to the second through hole for the SMA rod 105 to pass through.

[0056] Optionally, as an implementation method, the limit card 107 is welded to the outer cylinder 101 , and under the action of the limit card 107 , the outer cylinder 101 cannot be displaced in the radial direction.

[0057] Furthermore, the first through hole on the movable baffle 103 is a rectangular hole so that the inner rod 104 can just pass through, and the second through holes are a plurality of small round holes so that the SMA rods 105 can pass through accordingly. The two ends of the SMA rods 105 are fixedly connected to the movable baffle 103 by anchors.

[0058] In this embodiment, parameters such as the diameter, length, and number of the SMA rods 105 can be flexibly set according to the requirements of energy consumption and self-resetting performance.

[0059] For further information, please see Figure 2 The energy dissipation device includes a non-asbestos friction plate 109 and a friction plate 110. These are positioned at the ends of the two outer cylinders 101 from the inside out and secured to the outer cylinders 101 using bolts 111 connecting the two cylinders 101. The preload from the bolts 111 at the front of the outer cylinders 101 ensures tight contact between the friction plate 110 and the outer cylinder 101. The non-asbestos friction plate 109 is inserted inside the friction plate 110. When subjected to vibration, friction between the friction plate 109 and the outer cylinder dissipates vibration energy.

[0060] In this embodiment, the self-resetting SMA energy absorber further includes a bottom cylinder 112, which is connected to the outer cylinder 101 via a thread. Figure 1 shown.

[0061] It is understandable that the lower portion of the bottom tube 112 and the upper portion of the inner rod 104 are further provided with ear plates 113 for connecting to an object that needs to be fixed.

[0062] The following combination Figure 1 The force-bearing process of the self-resetting SMA energy absorber provided in this embodiment is introduced.

[0063] When no force is applied, the inner rod 104 is in the middle position and the plurality of SMA rods 105 are in a natural state. Figure 1 As shown in Figure b.

[0064] When subjected to pressure, the inner rod 104 pushes and pulls the movable baffle 103 to move downward. Limited by the upper limit device 102, the SMA rod 105 will stretch downward. Figure 1 As shown in Figure a.

[0065] When subjected to a pulling force, the inner rod 104 pushes and pulls the movable baffle 103 to move upwards. Limited by the limit device 102 at the lower end, the SMA rod 105 will stretch upwards. Figure 1 As shown in Figure c.

[0066] Thus, when the self-resetting SMA energy dissipator is subjected to force, the SMA rod 105 is kept in tension, preventing the SMA rod from buckling under compression. When the pressure or tension disappears, the superelasticity of the SMA rod in tension is utilized to restore the connected object to its original state after structural deformation.

[0067] The self-resetting SMA energy absorber provided in this embodiment, on the one hand, adopts a plurality of SMA rods to design a self-resetting device structure, ensuring that the SMA rods are always in a tensile state during the tensile and compressive loading process of the energy absorber, avoiding the compressive buckling of the SMA rods, and utilizing the superelasticity of the SMA rods under tension to restore the connection objects deformed after being stressed to their initial state, thereby realizing the self-resetting function; on the other hand, an energy dissipation device in close contact with the outer cylinder is designed, and when the device is subjected to an earthquake, the friction between the device and the outer cylinder dissipates the earthquake energy, thereby realizing the energy dissipation function; in addition, the self-resetting SMA energy absorber does not need to be replaced after the earthquake, and the residual deformation after the earthquake can be restored to the original state by heating the SMA rods or supplementing prestress.

[0068] Example 2

[0069] Based on the above embodiment, this embodiment provides a concrete beam-column node box-type connection structure with a self-resetting SMA energy absorber. Figure 3 , Figure 3Schematic diagram of a concrete beam-column node box-type connection structure with a self-resetting SMA energy dissipator provided by an embodiment of the present invention, comprising:

[0070] Several self-resetting SMA energy absorbers 1, precast reinforced concrete upper columns 2, precast reinforced concrete beams 3, precast reinforced concrete lower columns 4, column end connectors 5 and steel boxes 6; wherein,

[0071] The precast reinforced concrete lower column 4 and the precast reinforced concrete upper column 2 are fixedly connected by a column end connector 5;

[0072] The precast reinforced concrete beam 3 and the precast reinforced concrete lower column 4 are vertically and fixedly connected by a steel box 6;

[0073] Several self-resetting SMA energy absorbers 1 are symmetrically arranged at the connection between the precast reinforced concrete beam 3 and the precast reinforced concrete lower column 4; one end of the self-resetting SMA energy absorber 1 is fixedly connected to the reinforced concrete beam 3, and the other end is fixedly connected to the precast reinforced concrete lower column 4;

[0074] The self-resetting SMA energy absorber 1 is the self-resetting SMA energy absorber provided in the above-mentioned embodiment. In this embodiment, one end of the self-resetting SMA energy absorber 1 is connected to the precast reinforced concrete beam 3 via an angle steel 8 welded to the steel box 6, and the other end is connected to the precast reinforced concrete lower column 4 via an angle steel 8 welded to the outer steel cladding 402.

[0075] Optionally, as an implementation method, the self-resetting SMA energy absorber 1 is connected to the angle steel 8 by bolts.

[0076] Therefore, the concrete beam-column node box-type connection structure with self-resetting SMA energy absorber provided in this embodiment realizes the box-type connection between precast reinforced concrete beams and precast reinforced concrete columns, meeting the needs in actual design and construction. The assembled beam-column node has high bearing capacity, clear and reasonable damage mode, and can effectively avoid the appearance of plastic hinges at the column ends. Under the action of earthquake, it can continue to exert a stable energy dissipation effect and can achieve self-reset after the earthquake.

[0077] For further information, see Figure 4 , Figure 4 Schematic diagram of the structure of the prefabricated reinforced concrete lower column provided by an embodiment of the present invention, which includes a U-shaped steel bar 401 at the lower column end, an outer steel bar 402, a steel bar connecting sleeve 403, upper and lower column fixing bolt rods 404 and a lower column longitudinal bar 405; wherein,

[0078] The lower column longitudinal reinforcement 405 is tied and connected with the stirrups to form a reinforcement skeleton, and the lower column end U-shaped reinforcement 401 is tied and connected with the stirrups;

[0079] One end of the steel bar connecting sleeve 403 is screwed into the upper part of the lower column longitudinal reinforcement 405, and the other end is screwed into the upper and lower column fixing bolt rods 404;

[0080] The upper and lower column fixing bolt rods 404 are connected to the column end connector 5;

[0081] The outer steel cladding 402 is arranged outside the core area of the prefabricated reinforced concrete lower column 4.

[0082] For further information, see Figure 5 , Figure 5 : is a structural diagram of a prefabricated reinforced concrete upper column provided by an embodiment of the present invention, which includes a U-shaped steel bar 201 at the upper column end, parallel bars 202, spiral ring bars 203 and upper column longitudinal bars 204; wherein,

[0083] The spiral ring reinforcement 203 is passed through the upper column longitudinal reinforcement 204 and the parallel reinforcement 202, and is tied with stirrups to form a reinforcement skeleton;

[0084] The U-shaped steel bar 201 at the upper column end is connected with the stirrups by tying;

[0085] The upper column longitudinal reinforcement 204 and the parallel reinforcement 202 are welded to the column end connector 5, as shown in FIG. Figure 6 shown.

[0086] For further information, see Figure 7 , Figure 7 301, a weldment 302, a beam-column fixing bolt rod 303, a beam-end inner stirrup 304, a beam-end U-shaped steel bar 305, a bolt hole 306, and a fixing steel plate 307; wherein,

[0087] The longitudinal reinforcement 301 in the beam is welded to the steel box 6 through the weldment 302 and the stirrups are tied;

[0088] The steel box 6 is fixedly mounted on one end of the prefabricated reinforced concrete beam 3.

[0089] The U-shaped steel bars 305 and the inner stirrups 304 at the beam end are arranged at one end of the inner longitudinal reinforcement 301 of the beam, and the steel box 6 is fixedly arranged on the outside of the side beam end;

[0090] The beam column fixing bolt rod 303 is fixedly set on the top of the steel box 6; the fixing steel plate 307 is fixedly set on the side of the steel box 6 and is fixedly connected to the steel box 6 up and down.

[0091] Optionally, as an implementation method, the steel box 6 in this embodiment can be used as follows Figure 8 The structure shown.

[0092] Under normal working conditions, the present invention uses the beam end fixing screw and the steel box to jointly provide bending stiffness for the node, and its bending stiffness is better than that of traditional nodes; under the action of small or moderate earthquakes, it is in the first stage of energy consumption period, which is mainly provided by the energy absorber; under the action of large earthquakes, it is in the second stage of energy consumption period, and the energy is consumed by the buckling of the energy-consuming connecting key. At the same time, the overall seismic response of the structure is reduced by relying on the characteristic of reduced stiffness after yielding. The deformation of the structure is mainly concentrated on the energy-consuming connecting key, while the main components such as beams and columns are in a low-damage mode and continue to maintain an elastic state. The energy absorber and the energy-consuming connecting key are fixed by bolt connection. If damage occurs after the earthquake, repair and replacement are convenient and quick, and the structure's use function and mechanical properties are restored simultaneously, showing the two major advantages of optimization of damage mechanism and easy repair after the earthquake.

[0093] In addition, the damage mode of the present invention is clear and reasonable. Measures such as pre-embedded U-shaped steel bars at the column ends in the core area of the beam-column joint, pre-embedded U-shaped steel bars at the beam ends, and internal stirrups effectively transfer the shear force in the node area, enhance the shear bearing capacity of the node area, and realize the damage mode of "strong shear and weak bending". At the same time, the columns in the core area of the node are covered with external steel, which has a great restraining effect on the concrete in the core area of the node, significantly improves the bearing capacity of the node, and realizes the damage mode of "strong node and weak component"; the spiral ring reinforcement at the four corners of the column end has a strong restraining effect on the corner concrete. At the same time, the column end adopts parallel reinforcement to jointly improve the bearing capacity of the column, while the energy-consuming connection key at the beam end is opened to weaken the bearing capacity of the beam, realizing the damage mode of "strong column and weak beam". The structural damage is mainly concentrated on the replaceable components at the beam end, reducing the internal force demand of the adjacent beam components. Under the action of a large earthquake, the beam component can also be in a low-damage state.

[0094] At the same time, the spiral ring reinforcement at the column end has a strong restraining effect on the corner concrete, and can also effectively avoid the occurrence of plastic hinges at the column end. At the same time, the energy-absorbing connection key opening at the beam end weakens its bearing capacity and transfers the deformation of the beam-column node to the beam end. The plastic hinge in the node area is controlled at the position of the energy-absorbing key opening. The opening position can be flexibly adjusted according to actual conditions, so that the position of the plastic hinge can be controlled.

[0095] For further information, please see Figure 3 , wherein, an energy-absorbing connection key 7 is also provided at the connection between the prefabricated reinforced concrete beam 3 and the prefabricated reinforced concrete lower column 4.

[0096] For details, see Figure 9 , Figure 9 A schematic structural diagram of the energy-absorbing connecting key provided in an embodiment of the present invention shows that the energy-absorbing connecting key 7 is L-shaped, one side of which is fixed to the reinforced concrete beam 3, and the other side is fixed to the precast reinforced concrete lower column 4; and a plurality of openings are provided on the side fixed to the reinforced concrete beam 3 to achieve a buckling energy-absorbing effect when a large structural deformation occurs at the beam-column node.

[0097] In this embodiment, the energy dissipation connection key 7 connects the precast reinforced concrete beam and the precast reinforced concrete lower column through the angle steel 8 welded to the outer steel 402 and the steel box 6.

[0098] As a preferred implementation, in this embodiment, the energy dissipation connection key 7 is positioned in the middle of the two self-resetting SMA energy absorber installation positions so as to better exert its function.

[0099] Specifically, under the action of a major earthquake, a large relative rotation occurs between the prefabricated beams and columns. When the SMA rod in the self-resetting SMA energy absorber reaches the ultimate tensile state and cannot dissipate energy, it will enter the second-stage energy dissipation state. The weakened opening of the energy-dissipating connection key can enter the yield stage, playing the role of buckling energy dissipation. The expected structural deformation is controlled through two-stage energy dissipation, so that the main components of the beam-column node will not be destroyed or will be slightly damaged under a major earthquake, achieving a higher level of structural seismic performance goals.

[0100] Example 3

[0101] Based on the above-mentioned embodiment 2, this embodiment provides a preparation process of a concrete beam-column node box-type connection structure with a self-resetting SMA energy absorber, which mainly includes the following aspects:

[0102] (1) Preparation of self-resetting SMA energy dissipator:

[0103] The limit clamps 107 are welded on the two half outer cylinders 101 respectively, and the limit baffle 108 is placed inside the limit clamp 107. The limit baffle 108 is annular and cannot be displaced along the radial direction of the outer cylinder 101 under the action of the limit clamp 107; the movable baffle 103 is placed on the outside of the limit baffle 108, and a rectangular hole is opened in the middle of the movable baffle 103. The inner rod 104 is inserted along the rectangular hole. A small circular hole is opened on the outer edge of the movable baffle 103. The SMA rod 10 is inserted along the circular hole. 5. Use anchors to fix the two ends of the SMA rod 105, weld a protrusion 106 on the inner rod 104 along the inner side of the movable baffle 103, and use the inner rod 104 to push and pull the movable baffle 103 when the force is applied to it. Snap the two half outer cylinders 101 together, place non-asbestos (NAO) friction plates 109 and friction plates 110 at their ends in sequence, and fix them with bolts 111. Connect the bottom cylinder 112 to the outer cylinder 101 through threads to complete the preparation of the self-resetting SMA energy absorber 1.

[0104] (2) Precast reinforced concrete lower and upper columns

[0105] Lower column: Tie and connect the lower column longitudinal reinforcement 405 with the stirrups to form a reinforcement skeleton, screw the reinforcement connection sleeve 403 into the upper connection area of the longitudinal reinforcement at the column end, screw the other end of the sleeve into the upper and lower column fixing bolt rods 404, tie and connect the U-shaped reinforcement 401 at the lower column end with the stirrups, and then start supporting the formwork. At the same time, replace the formwork at the corresponding position with the core area outer steel 402, and then pre-embed the beam-column fixing bolt rods 303 at the corresponding position in advance. Finally, pour concrete, and the prefabrication of the lower column is completed.

[0106] Upper column: Pass the spiral ring reinforcement 203 through the upper column longitudinal reinforcement 204 and the parallel reinforcement 202, then tie the stirrups to form a steel skeleton, tie and connect the U-shaped steel bar 201 at the upper column end with the stirrups, weld the upper column longitudinal reinforcement 204 and the parallel reinforcement 202 to the column end connector 5, then support the formwork, and finally pour concrete, and the upper column prefabrication is completed.

[0107] (3) Prefabricated reinforced concrete beams

[0108] The weldment 302 is welded to the steel box 6, and the longitudinal reinforcement 301 inside the precast concrete beam 3 is welded to the weldment 302. Then the stirrups are tied, and the U-shaped steel bars 305 and the inner stirrups 304 at the beam ends are embedded. The fixed steel plate 307 is welded between the upper and lower steel boxes, and the beam prefabrication is completed.

[0109] (4) Assembling precast reinforced concrete columns and precast reinforced concrete beams

[0110] Hoist the prefabricated reinforced concrete upper column 2 to the corresponding position of the lower column 4, align the holes of the column end connector 5 with the pre-embedded upper and lower column fixing bolt rods 404, insert and fix them with nuts to achieve the assembly of the upper column 2 and the lower column 4; hoist the prefabricated reinforced concrete beam 3 to the corresponding position of the column, align the holes of the steel box 6 with the pre-embedded beam-column fixing bolt rods 303, insert and fix them with nuts to achieve the assembly of the beam and column.

[0111] (5) Assemble the self-resetting SMA energy absorber and energy dissipation connection key

[0112] Weld the connecting angle steel 8 to the corresponding positions of the steel box 6 and the outer steel 402 in the core area of the beam column, and bolt the self-resetting SMA energy absorber 1 to the angle steel 8. Place the energy dissipation connection key 7 on the outside of the fixed steel plate 307 and the outer steel 402 at the corresponding position and secure them with bolts.

[0113] At this point, the preparation of the concrete beam-column node box connection structure with self-resetting SMA energy absorber is completed.

[0114] The prefabricated reinforced concrete columns, prefabricated reinforced concrete beams and self-resetting SMA energy absorbers in the present invention can all be manufactured in the factory and directly assembled on site. The process is simple and the requirements for construction personnel are not high. It can greatly reduce on-site wet concrete work and various complex grouting processes, meet the development concept of green and environmentally friendly prefabricated buildings, have high construction efficiency, and strong engineering applicability.

[0115] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0116] Furthermore, terms such as "mounted," "connected," "connect," and "fixed" should be interpreted broadly. For example, they may refer to fixed or detachable connections, or integration; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of these terms in the present invention based on specific circumstances.

[0117] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. A concrete beam-column node box-type connection structure with a self-resetting SMA energy absorber, characterized in that: It comprises a plurality of self-resetting SMA energy absorbers (1), a prefabricated reinforced concrete upper column (2), a prefabricated reinforced concrete beam (3), a prefabricated reinforced concrete lower column (4), a column end connector (5) and a steel box (6); wherein, The precast reinforced concrete lower column (4) and the precast reinforced concrete upper column (2) are fixedly connected via the column end connector (5); The precast reinforced concrete beam (3) and the precast reinforced concrete lower column (4) are fixedly connected via the steel box (6); A plurality of the self-resetting SMA energy absorbers (1) are symmetrically arranged at the connection between the precast reinforced concrete beam (3) and the precast reinforced concrete lower column (4); one end of the self-resetting SMA energy absorber (1) is fixedly connected to the precast reinforced concrete beam (3), and the other end is fixedly connected to the precast reinforced concrete lower column (4); An energy-dissipating connection key (7) is also provided at the connection between the prefabricated reinforced concrete beam (3) and the prefabricated reinforced concrete lower column (4); The energy dissipation connection key (7) is L-shaped, with one side fixed to the precast reinforced concrete beam (3) and the other side fixed to the precast reinforced concrete lower column (4); and the side fixed to the precast reinforced concrete beam (3) is provided with a plurality of openings to achieve a buckling energy dissipation effect when a large structural deformation occurs at the beam-column node; The self-resetting SMA energy dissipator (1) comprises two semicircular outer cylinders (101), a self-resetting device and an energy dissipation device; the two outer cylinders (101) are fixedly connected; the self-resetting device is arranged inside the outer cylinders (101), and the energy dissipation device is arranged outside the two outer cylinders (101) and is in close contact with the outer cylinders (101); The self-resetting device comprises two limiting devices (102), two movable baffles (103), an inner rod (104) and a plurality of SMA rods (105); The two limiting devices (102) are respectively arranged at the upper and lower ends of the outer cylinder (101); The two movable baffles (103) are respectively arranged on the outside of the two limiting devices (102) and are movably connected to the limiting devices (102); and the two movable baffles (103) are each provided with a first through hole for the inner rod (104) to pass through; A protrusion (106) is also provided on the inner side of the portion where the inner rod (104) meets the movable baffle (103) to push or pull the movable baffle (103) to move when the inner rod (104) is subjected to force; The outer edge of each movable baffle (103) is further provided with a plurality of second through holes, and a plurality of SMA rods (105) pass through the second through holes and are fixedly connected to the movable baffle (103).

2. The concrete beam-column node box-type connection structure with a self-resetting SMA energy absorber according to claim 1 is characterized in that: The limiting device (102) includes two limiting cards (107) and a limiting baffle (108); the two limiting cards (107) are respectively fixed on the inner walls of the two outer cylinders (101); the limiting baffle (108) is arranged between the two limiting cards (107); wherein, The limiting baffle (108) is a circular baffle, and is provided with a third through hole corresponding to the second through hole for the SMA rod (105) to pass through.

3. The concrete beam-column node box-type connection structure with a self-resetting SMA energy absorber according to claim 1 is characterized in that: Both ends of the SMA rod (105) are fixedly connected to the movable baffle (103) via anchors.

4. The concrete beam-column node box-type connection structure with a self-resetting SMA energy absorber according to claim 1 is characterized in that: The energy dissipation device includes a non-asbestos friction plate (109) and a friction plate (110); the non-asbestos friction plate (109) and the friction plate (110) are arranged at the ends of the two outer cylinders (101) from the inside to the outside, and are fixed to the outer cylinders (101) by bolts (111) connecting the two outer cylinders (101).

5. The concrete beam-column node box-type connection structure with a self-resetting SMA energy absorber according to claim 1 is characterized in that: The self-resetting SMA energy dissipator further comprises a bottom cylinder (112), wherein the bottom cylinder (112) is connected to the outer cylinder (101) via threads.

6. The concrete beam-column node box-type connection structure with a self-resetting SMA energy absorber according to claim 1 is characterized in that: The prefabricated reinforced concrete lower column (4) comprises a lower column end U-shaped steel bar (401), an outer steel bar (402), a steel bar connection sleeve (403), upper and lower column fixing bolt rods (404) and a lower column longitudinal bar (405); wherein, The lower column longitudinal reinforcement (405) is tied and connected with the stirrups to form a reinforcement skeleton, and the lower column end U-shaped reinforcement (401) is tied and connected with the stirrups; One end of the steel bar connecting sleeve (403) is screwed into the upper portion of the lower column longitudinal reinforcement (405), and the other end is screwed into the upper and lower column fixing bolt rods (404); The upper and lower column fixing bolt rods (404) are connected to the column end connecting piece (5); The outer steel (402) is arranged outside the core area of the prefabricated reinforced concrete lower column (4).

7. The concrete beam-column node box-type connection structure with a self-resetting SMA energy absorber according to claim 1 is characterized in that: The prefabricated reinforced concrete upper column (2) comprises upper column end U-shaped steel bars (201), parallel bars (202), spiral ring bars (203) and upper column longitudinal bars (204); wherein, The spiral ring reinforcement (203) is passed through the upper column longitudinal reinforcement (204) and the parallel reinforcement (202), and is tied with stirrups to form a reinforcement skeleton; The upper column end U-shaped steel bar (201) is connected to the stirrup by binding; The upper column longitudinal reinforcement (204) and the parallel reinforcement (202) are welded to the column end connector (5).

8. The concrete beam-column node box-type connection structure with a self-resetting SMA energy absorber according to claim 1 is characterized in that: The prefabricated reinforced concrete beam (3) comprises longitudinal reinforcement (301) in the beam, weldment (302), beam-column fixing bolt rods (303), stirrups (304) in the beam ends, U-shaped reinforcement (305) at the beam ends, bolt holes (306) and fixing steel plates (307); wherein, The longitudinal reinforcement (301) in the beam is welded to the steel box (6) through the weldment (302), and the stirrups are tied; The steel box (6) is fixedly arranged at one end of the prefabricated reinforced concrete beam (3). The U-shaped steel bar (305) at the beam end and the inner stirrup (304) at the beam end are arranged at one end of the inner longitudinal reinforcement (301) of the beam, and the steel box (6) is fixedly arranged outside the beam end on the side where the U-shaped steel bar (305) at the beam end and the inner stirrup (304) at the beam end are located; The beam column fixing bolt rod (303) is fixedly arranged on the top of the steel box (6); the fixing steel plate (307) is fixedly arranged on the side of the steel box (6) and is fixedly connected to the steel box (6) up and down.

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