Self-resetting fabricated steel-wood hybrid frame structure based on shape memory alloy (SMA)

Abstract

The application discloses a self-resetting assembled steel-wood hybrid frame structure based on a shape memory alloy (SMA), which comprises an assembled steel-wood composite column, an assembled steel-wood composite beam and a self-resetting energy dissipation beam-column joint connected between the two; the joint comprises a beam connecting piece and a column connecting piece, the two are connected through an SMA-steel combined screw rod and a metal energy dissipation piece, and a sliding limiting mechanism is arranged, so that the step response to frequent earthquakes, fortification earthquakes, rare earthquakes and extremely rare earthquakes is realized; the composite column is wrapped by a steel sleeve and is internally provided with a cross-shaped steel column and a wood column core, and a through-length tensioned steel bar screw rod is used to apply a pre-tightening force; the composite beam is provided with a wood flange and a wood web embedded in an open T-shaped steel pipe; the application is fast assembled through modular dry connection, provides self-resetting capacity by using SMA super-elasticity, realizes controllable damage by using an external replaceable metal energy dissipation piece, effectively solves the problems of large post-earthquake residual deformation and difficult repair of traditional steel-wood structures, and has high construction efficiency, excellent mechanical properties, good durability and excellent post-earthquake functional recoverability.

Description

Technical Field

[0001] This invention belongs to the field of building structure technology, specifically relating to a self-resetting prefabricated steel-wood hybrid frame structure based on shape memory alloy SMA. Background Technology

[0002] To improve the load-bearing performance of pure wood structures, the academic and engineering communities have proposed steel-wood composite structural systems. This system utilizes the high strength and high elastic modulus of steel to compensate for the insufficient stiffness and connection strength of wood, enhancing the overall load-bearing capacity of the structure through the synergistic work of steel and wood components. However, existing steel-wood composite systems still have significant shortcomings in terms of seismic toughness: traditional joints often use bolts or nails, relying mainly on the expansion and compression of the wood pores or the plastic yielding of the steel components to dissipate energy under strong earthquakes. While this energy dissipation mechanism can prevent structural collapse, it is often accompanied by significant residual deformation. Post-earthquake repair is not only difficult, but the structure may even fail due to excessive deformation, failing to meet the urgent requirement of "functional recoverability" in modern seismic design.

[0003] Furthermore, existing steel-wood composite structures also have significant shortcomings in terms of component cross-sectional forms and material utilization efficiency. On the one hand, traditional heavy timber structures often rely on large-sized glued laminated timber or logs, which not only significantly increases project costs but also limits the effective utilization of small-diameter fast-growing timber, failing to meet the principle of resource conservation. On the other hand, existing simple steel-wood composite sections often do not fully consider the long-term deformation characteristics of wood. Under changes in environmental temperature and humidity and long-term loads, the shrinkage and expansion of wood, as well as creep, can cause separation or slippage at the wood-steel interface. This results in a significant reduction in the synergistic working capacity of the composite section over time, leading to structural stiffness degradation and an inability to fully utilize the mechanical properties of both materials.

[0004] Existing improvement measures, such as post-tensioned prestressing technology, can provide some degree of restoring capacity, but due to the creep and shrinkage / swelling characteristics of wood, long-term prestress loss is very likely, and the problem of stress concentration at the wood-steel contact surface is difficult to solve.

[0005] Invention application CN114575567A discloses a "prestressed self-resetting glued laminated timber-steel composite beam-column joint," which utilizes prestressed steel strands at the ends of the timber beams, passing through the column and applying initial tension to provide a restoring moment through prestress. However, this solution has significant drawbacks: the prestressed steel strands act on the timber over a long period, making them susceptible to prestress loss due to timber shrinkage, creep, and creep effects, thus weakening or even eliminating the self-resetting ability; simultaneously, energy dissipation relies on timber compression or the addition of soft steel dampers, damage is uncontrollable and difficult to replace, and post-earthquake repair costs are high. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, the present invention aims to provide a self-resetting prefabricated steel-wood hybrid frame structure based on shape memory alloy (SMA). By combining steel and wood materials and introducing a self-resetting mechanism and replaceable energy-consuming components into the frame nodes, the contradiction between energy consumption and resetting in traditional structures is resolved, thereby achieving controllable structural damage and rapid recovery of post-earthquake functions, and improving material utilization efficiency.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A self-resetting prefabricated steel-wood hybrid frame structure based on shape memory alloy (SMA) includes: prefabricated steel-wood composite columns 3, prefabricated steel-wood composite beams 2, and a self-resetting energy-dissipating beam-column node 1 connecting the prefabricated steel-wood composite columns 3 and the prefabricated steel-wood composite beams 2; the self-resetting energy-dissipating beam-column node 1 includes beam connectors 101 and column connectors 102, and n SMA-steel composite bolts 103 and n+1 metal energy-dissipating components 104 are connected between the beam connectors 101 and the column connectors 102 to provide a graded response to earthquakes of different magnitudes, where n is a positive integer.

[0008] The prefabricated steel-wood composite column 3 includes a steel sleeve column 301, with column end steel plate flanges 305 at both ends of the steel sleeve column 301, a cross-shaped steel column 302 inside the steel sleeve column 301, and a wooden column core 303 filling the space between the steel sleeve column 301 and the cross-shaped steel column 302 inside to form the wooden column core 303. A continuous tensile steel bar bolt 304 passes through the wooden column core 303 and connects to the space between the column end steel plate flanges 305 on both sides of the steel sleeve column 301. The prefabricated steel-wood composite beam 2 includes two opposing open T-shaped steel beams 201. The flanges of the open T-shaped steel beams 201 have built-in flange wooden boards 202, and the webs 205 of the open T-shaped steel beams 201 have built-in wooden webs 203. After installation, the prefabricated steel-wood composite beam 2 is an I-beam as a whole. The I-beam prefabricated steel-wood composite beam 2 is connected as a whole by arranging tie rods 204 at the webs.

[0009] The beam connector 101 of the self-resetting energy-dissipating beam-column node 1 is an integrally formed steel component, including a back plate 115. The back plate 115 is provided with a parallel connecting plate 113 on the back side away from the prefabricated steel-wood composite column 3. The parallel connecting plate 113 is connected to the web 205 and the wooden web 203 at the end of the prefabricated steel-wood composite beam 2 through tie rods 204.

[0010] The column connector 102 is an integrally formed steel component, including a back plate 2 116. A triangular connecting plate 114 is provided on the back side of the back plate 2 away from the prefabricated steel-wood composite beam 2. The triangular connecting plate 114 is connected to the column end steel plate flange 305 of the prefabricated steel-wood composite column 3 via a tension reinforcing bar bolt 304. Multiple SMA-steel composite bolts 103 and multiple metal energy-dissipating components 104 are connected between the back plate 115 of the beam connector 101 and the back plate 2 116 of the column connector 102. Cover plates 105 are respectively attached to both sides of the surface of the metal energy-dissipating component 104. The side of the metal energy-dissipating component 104 and the cover plate 105 closest to the prefabricated steel-wood composite beam 2 is connected to the limiting device 108 via screws 106 and a first nut 107. The side of the metal energy-dissipating component 104 and the cover plate 105 closest to the prefabricated steel-wood composite column 3... The side is connected to the limiting device 109 by screws 106 and first nut 107; the back plate 115 of beam connector 101 and the back plate 116 of column connector 102 are also provided with matching ear pins 112 to connect beam connector 101 and column connector 102 with a pin that allows rotation; the metal energy dissipation component 104 has an elongated sliding bolt hole 110 on the side near the column end, and the back of the cover plate 105 has a limiting block 111 that cooperates with it on the side near the column end; the metal energy dissipation component (104) is a rectangular flat steel. When the self-resetting energy dissipation beam-column node is rotated by external force, causing the SMA-steel combined screw 103 to be stretched and deformed to 3% to 5%, the limiting block 111 slides to the end of the sliding bolt hole 110 and locks, forcing the metal energy dissipation component 104 to participate in the force and undergo plastic yielding.

[0011] The column connector 102 is connected to the column end steel plate flange 305 of the prefabricated steel-wood composite column 3 from all sides of the column end via triangular connecting plates 114 and continuous tension steel rods 304. The triangular connecting plates 114 on all sides form a square.

[0012] The SMA-steel composite screw 103 includes an SMA short screw 117, with threaded steel sleeves 118 threaded to both ends of the SMA short screw 117. One end of the threaded steel sleeve 118 passes through the back plate 115 of the beam connector 101 and is fixed by the second nut 119. The other end of the threaded steel sleeve 118 passes through the back plate 116 of the column connector 102 and is fixed by the second nut 119.

[0013] The wooden core 303 is connected in the height direction by a stapling method: the wooden core 303 is inserted into the stapling steel sleeve 306 and fixed by the stapling screw 307.

[0014] The column end steel plate flange 305 is composed of two steel plates 308, and the two ends of the tension steel bar screw 304 pass through the screw holes on the two steel plates 308 and are tightened and fixed by nuts 309.

[0015] The step-by-step response to earthquakes of different magnitudes includes: Under frequent earthquakes: θ < [1 / 250], where θ is the inter-story drift angle, the SMA-steel composite screw 103 is in the elastic stage, the metal energy dissipation component 104 does not participate in the stress, and the structure is undamaged. Under the design earthquake action: 1 / 250<θ<1 / 50, the strain of SMA-steel composite screw 103 reaches the design threshold of 3%~5%, enters the hyperelastic deformation stage, and the metal energy dissipation component 104 begins to yield and dissipate energy. Under rare earthquake action: θ=1 / 50, the SMA-steel composite screw 103 exhibits superelastic recovery capability, significantly reducing residual deformation, and the metal energy-dissipating component 104 fully enters the plastic strengthening section to dissipate energy, while the main component remains elastic or suffers only minor damage. Under extremely rare earthquake conditions: θ>1 / 50, limit device 108 and limit device 2109 activate the secondary protection mechanism, the connector undergoes plastic deformation to absorb the remaining energy, and at the same time, the continuous tensile steel rod 304 inside the column acts as the last line of defense to prevent structural collapse.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. Convenient component fabrication and high standardization facilitate transportation and rapid installation: This invention achieves industrialized building production through modular design. Small-sized timber is assembled into large-sized column cores using a pier-jointing method, which not only improves timber utilization but also achieves uniformity and standardization of component dimensions. Compared to traditional concrete components, this composite component is lightweight, reducing the requirements for transportation and hoisting equipment, making it particularly suitable for construction areas with inconvenient transportation or where large machinery cannot access. The entire structural system uses dry connections such as bolts and pins, eliminating on-site wet work and gluing processes. All components can be prefabricated with high precision in the factory, requiring only simple assembly on-site, significantly shortening the construction cycle and meeting the requirements for efficient construction of prefabricated buildings.

[0017] 2. Optimized component cross-section design, combining excellent mechanical properties and durability: This invention employs a composite cross-section design, rationally partitioning materials according to stress characteristics. The cross-section of the outer steel sleeve column plus the cross-shaped steel column effectively constrains the inner wooden core, significantly improving the compressive strength and ductility of the wood. The steel bears the main tensile and shear forces, while the wood bears the compressive forces, fully leveraging the mechanical advantages of both materials and enhancing the overall load-bearing capacity. In terms of durability, the rigid constraint of the steel sleeve column limits the macroscopic deformation and cracking of the wood caused by creep and shrinkage / swelling characteristics, effectively solving the problem of loose joint connections caused by changes in material properties in traditional wood structures, ensuring the stiffness and safety of the structure throughout its entire life cycle.

[0018] 3. Excellent Post-Earthquake Functional Recoverability: This invention constructs a dual seismic resistance mechanism of "self-resetting + energy dissipation" by setting SMA-steel composite bolts and replaceable metal energy-dissipating components at beam-column joints. Under earthquake action, the metal energy-dissipating components yield first, dissipating energy and suppressing damage to the main structure. After the earthquake, the superelastic effect of the SMA material generates a restoring force, driving the structure back to its initial position. This effectively solves the problem of traditional steel-wood structures being difficult to repair due to excessive residual deformation, achieving the seismic fortification goal of "no damage in small earthquakes, self-resetting in moderate earthquakes, repairable in large earthquakes, and no collapse in extremely rare earthquakes." In addition, the energy-dissipating components are externally mounted and connected by bolts, eliminating the need to repair the main beams and columns after an earthquake. Only the damaged components need to be replaced to quickly restore the building's function, significantly reducing the total life-cycle cost.

[0019] In summary, this invention achieves a prefabricated steel-wood hybrid frame structure that combines high construction efficiency, excellent mechanical properties, long-term durability, and outstanding post-earthquake functional recoverability through modular and standardized component design and innovative node construction. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the self-resetting assembled steel-wood hybrid frame structure of the present invention.

[0021] Figure 2 This is a schematic diagram of the connection between the beam connector 101 and the column connector 102 in this invention.

[0022] Figure 3 This is a schematic diagram of the prefabricated steel-wood composite column (3) in this invention.

[0023] Figure 4 This is an exploded structural diagram of the core component of the prefabricated steel-wood composite column (3) in this invention.

[0024] Figure 5 This is a schematic diagram of the connection between the prefabricated steel-wood composite beam (2) and the beam connector (101) in this invention.

[0025] Figure 6 This is a schematic diagram of the connection between the prefabricated steel-wood composite column (3) and the column connector (102) in this invention.

[0026] Figure 7 This is a schematic diagram of the cross-sectional structure of the prefabricated steel-wood composite beam (2) in this invention.

[0027] Figure 8 This is an enlarged schematic diagram of the connection structure of the self-resetting energy-dissipating beam-column node (1) in this invention.

[0028] Figure 9 This is a front view of the beam connector 101 of the present invention.

[0029] Figure 10 This is a side view of the beam connector 101 of the present invention.

[0030] Figure 11 This is a side view of the column connector 102 of the present invention.

[0031] Figure 12 This is a top view of the column connector 102 of the present invention.

[0032] Figure 13 This is an exploded view of the self-resetting energy-dissipating beam-column joint of the present invention.

[0033] Figure 14 This is a schematic diagram of the SMA-steel composite screw 103 of the present invention.

[0034] Figure 15 This is an enlarged schematic diagram of the metal energy-dissipating component 104 of the self-resetting energy-dissipating beam-column node in this invention.

[0035] Figure 16 This is a front view of the cover plate 105 in the metal energy-consuming component 104 of the present invention.

[0036] Figure 17 This is a schematic diagram of the back side of the cover plate 105 in the metal energy-consuming component 104 of the present invention.

[0037] Wherein, 1—self-resetting energy-dissipating beam-column node, 101—beam connector, 102—column connector, 103—SMA-steel composite screw, 104—metal energy-dissipating component, 105—cover plate, 106—screw, 107—first nut, 108—limiting device one, 109—limiting device two, 110—sliding bolt hole, 111—limiting block, 112—ear plate pin; 113—parallel connecting plate; 114—triangular connecting plate; 115—back plate one; 116—back plate two; 117—SMA short screw; 118—screw 119—Second nut; 2—Assembled steel-wood composite beam; 201—Open T-shaped steel beam; 202—Flanged wooden board; 203—Wooden web; 204—Tie rod; 205—Web; 3—Assembled steel-wood composite column; 301—Steel sleeve column; 302—Built-in cross-shaped steel column; 303—Small-sized wooden column; 304—Continuous tensile reinforcing bar tie rod; 305—Column end steel plate flange; 306—Bottomed steel sleeve; 307—Bottomed tie rod; 308—Steel plate; 309—Nut; 310—Self-tapping screw. Detailed Implementation

[0038] The following detailed description is provided with reference to the accompanying drawings. This embodiment aims to achieve a prefabricated steel-wood hybrid frame structure that combines high construction efficiency, excellent mechanical properties, long-term durability, and outstanding post-earthquake functional recoverability through modular and standardized component design and innovative node construction.

[0039] 1. Prefabrication and assembly of prefabricated steel-wood composite columns 3 (e.g.) Figure 3 , Figure 4 ) Wooden column core 303 splicing: First, several wooden columns are spliced ​​together in the height direction using a stud connection method, and then reinforced with stud steel sleeves 306 and stud bolts 307 to form a complete wooden column core 303. This method not only significantly improves the utilization rate of small-diameter fast-growing timber and reduces project costs, but also achieves the regularization and standardization of component dimensions, facilitating industrialized production and transportation.

[0040] Column core frame assembly: The assembled wooden column cores 303 are filled into the four spatial areas separated by the built-in cross-shaped steel columns 302, completing the core filling. The cross-shaped steel columns serve as the core frame, providing strong lateral restraint for the internal wooden columns.

[0041] Longitudinal restraint is applied: Tension-reinforcing steel rods 304 are inserted into two pre-drilled holes in the middle of the wooden column. Subsequently, column end flanges 305, consisting of upper and lower steel plates, are fitted onto both ends of the column. The ends of the tension-reinforcing steel rods 304 pass through the threaded holes on the flanges and are tightened in the enlarged grooves using nuts 309, thus connecting the wooden column core, the built-in cross-shaped steel column, and the flanges into a single, stable column core assembly. This continuous tension-reinforcing steel rod serves as a last line of defense under extreme earthquake conditions, preventing complete column separation and ensuring life safety.

[0042] Sleeve Encapsulation: The assembled column core assembly is embedded inside the steel sleeve column 301. Self-tapping screws 310 are used to penetrate the wall panel of the steel sleeve column 301 and drive into the internal wooden column core, achieving a tight and fixed connection between the outer steel cylinder and the inner column core, thus completing the fabrication of the prefabricated steel-wood composite column 3.

[0043] This composite column design achieves optimized material zoning—the outer steel sleeve and cross-shaped steel column effectively constrain the inner wooden core, significantly improving the compressive strength and ductility of the wood. The steel primarily bears tensile and shear forces, while the wood primarily bears compressive forces, fully leveraging the mechanical advantages of both materials and enhancing the overall load-bearing capacity. Simultaneously, the rigid constraint of the steel sleeve effectively suppresses macroscopic deformation and cracking of the wood due to creep and shrinkage / swelling, solving the problem of joint loosening caused by changes in material properties in traditional wood structures, and ensuring the stiffness and safety of the structure throughout its entire life cycle. The entire component is lightweight, facilitating transportation and hoisting, making it particularly suitable for areas with poor transportation access.

[0044] 2. Prefabrication and assembly of prefabricated steel-wood composite beams 2 (e.g.) Figure 7 ) Flange connection: Insert the flange board 202 into the flange gap of the open T-shaped steel beam 201 and use self-tapping screws to firmly connect it to the steel flange.

[0045] Web connection: The wooden web 203 is placed inside the web 205 area of ​​the open T-shaped steel beam 201, and the tie rods 204 are used to penetrate the wooden web and tie and lock it to the steel web 205, thus completing the fabrication of the prefabricated steel-wood composite beam 2.

[0046] The beam component is also prefabricated in the factory with high precision. Its combined cross-section effectively improves the beam's bending stiffness and load-bearing capacity. Working together with the composite columns, it forms a main frame with high initial stiffness, which can effectively resist wind loads and frequent earthquakes.

[0047] 3. Overall assembly and node connection of the frame structure Node positioning: The column connector 102 in the self-resetting energy-dissipating beam-column node 1 is precisely aligned with the column end steel plate flange 305 at the end of the prefabricated steel-wood composite column 3, and then fixed to the tension steel bar threaded rod 304 inside the column using nuts (see...). Figure 1 , Figure 2 , Figure 6 ).

[0048] Beam-column connection: The beam connector 101 is installed at the end of the prefabricated steel-wood composite beam 2 using the reinforced zone screws. Subsequently, using the ear plate pin 112 connection method, the beam connector 101 and the column connector 102 are connected by a rotatable pin connection, forming a basic beam-column connection (see...). Figure 1 , Figure 2 , Figure 8 ).

[0049] The column connector 102 includes a back plate 2 116. A triangular connecting plate 114 is provided on the back side of the back plate 2 away from the prefabricated steel-wood composite beam 2. The triangular connecting plate 114 is connected to the column end steel plate flange 305 of the prefabricated steel-wood composite column 3 via a tension steel rod 304. Multiple SMA-steel composite rods 103 and multiple metal energy-dissipating components 104 are connected between the back plate 115 of the beam connector 101 and the back plate 2 116 of the column connector 102. Cover plates 105 are respectively attached to both sides of the surface of the metal energy-dissipating component 104. The side of the metal energy-dissipating component 104 and the cover plate 105 closest to the prefabricated steel-wood composite beam 2 is connected to the limiting device 108 via screws 106 and a first nut 107. The side of the metal energy-dissipating component 104 and the cover plate 105 closest to the prefabricated steel-wood composite column 3 is connected to the limiting device 2 109 via screws 106 and a first nut 107. Figure 7 , Figure 8 A matching lug pin 112 is also provided between the back plate 115 of beam connector 101 and the belly side of the back plate 116 of column connector 102 to connect beam connector 101 and column connector 102 with a pin that allows rotation (see...). Figure 2 , Figure 6 , Figure 8 ).

[0050] like Figure 9 , Figure 10 The column connector 102 is connected to the column end steel plate flange 305 of the prefabricated steel-wood composite column 3 from all sides of the column end via triangular connecting plates 114 and continuous tension steel rods 304. The triangular connecting plates 114 on all sides form a square.

[0051] Installation of functional components: At the limiting device 106 of the node ear plate, the SMA-steel combined screw 103 and the metal energy dissipation component 104 are installed sequentially. The metal energy dissipation component 104 is connected to the upper and lower sides of the limiting device 108 and limiting device 209 of the beam / column connector via screws 106 and a first nut 107. The cover plate 105 is tightly attached to the metal energy dissipation component 104, and its end limiting block 111 is initially located within the elongated sliding bolt hole 110 of the metal energy dissipation component on the column end side, in a slidable state. (Example...) Figures 11 to 17 .

[0052] Assembly complete: Repeat the above steps until the entire frame structure is assembled on-site. All connections use dry connections such as bolts and pins, eliminating the need for wet on-site work.

[0053] This node structure is the core of the dual seismic resistance mechanism of "self-resetting + energy dissipation". Under frequent earthquakes, the SMA-steel composite screw 103 provides initial rotational stiffness, and the structure remains elastic and undamaged. When the earthquake intensity increases to the design or rare level, the node rotation causes the SMA screw to stretch into the hyperelastic stage, while the cover plate limiting block 111 slides to the end of the sliding bolt hole 110 and locks, forcing the metal energy dissipation component 104 to yield and enter the plastic state, dissipating a large amount of seismic energy. After the earthquake, the hyperelastic effect of the SMA material generates a strong restoring force, driving the structure to automatically reset and significantly reducing residual deformation. Because the energy dissipation component is external and bolted, only the damaged metal energy dissipation component 104 needs to be replaced after the earthquake (e.g., Figure 15 This system allows for rapid restoration of building functionality without the need to repair the main beams and columns, significantly reducing life-cycle costs and perfectly achieving the high-performance seismic resistance goals of "no damage in minor earthquakes, self-resetting in moderate earthquakes, repairable in major earthquakes, and no collapse in extremely rare earthquakes." The modular and dry-connection characteristics of the entire system also make on-site construction extremely convenient and efficient, greatly shortening the construction period. Furthermore, to reduce the use of SMA materials and address the issue of uneconomical application of SMA in structural engineering, SMA-steel composite bolts 103 (such as...) are used. Figure 14This design can be used when the node rotation capability requirement is not high or the steel column cross-section is large. The SMA-steel composite screw 103 includes a short screw 117, with threaded steel sleeves 118 threaded to both ends of the short screw 117. One end of the threaded steel sleeve 118 passes through the back plate 115 of the beam connector 101 and is fixed by a second nut 119. The other end of the threaded steel sleeve 118 passes through the back plate 116 of the column connector 102 and is fixed by a second nut 119. The threaded steel sleeve 118 is made of high-strength alloy structural steel and is threaded along its entire length and inside and out. The construction of the SMA short screw remains unchanged, except that threads are machined only on the anchoring sections on both sides. The two materials are connected by threads.

[0054] The working principle of this invention is as follows: First, an internal cross-shaped steel column and an external steel sleeve are used in the column to form multiple constraints on the internal wooden column core, and pre-tensioning force is applied by a continuous tensile steel bolt; in the beam, an open T-shaped steel section is combined with wooden flanges and wooden webs. This design allows the steel to mainly bear the tensile, shear, and constraint forces, while the wood mainly bears the compressive forces, giving full play to the mechanical advantages of both materials, improving the load-bearing capacity, stiffness, and dimensional stability of the components, while achieving lightweighting and standardized factory prefabrication (see [reference]). Figure 1 , Figure 4 , Figure 6 ).

[0055] Secondly, by employing self-resetting energy-dissipating beam-column joints, the load-bearing, resetting, and energy-dissipating functions of the structure are decoupled (see [link]). Figure 1 , Figure 8 , Figure 13 ): The load-bearing function is provided by the basic force transmission path through the ear plate-pin connection that allows rotation. Figures 10 to 13 ); The self-resetting function is achieved by the SMA-steel composite screw. Figure 14 The structure utilizes the superelastic deformation of shape memory alloy (SMA) under seismic loading to generate restoring force, driving the structure to automatically reset after the earthquake and reducing residual deformation. The energy-consuming function is achieved by an external metal energy-consuming component ( Figure 15 When the earthquake intensity exceeds the design flood level, the cover plate limit block slides to the end of the sliding bolt hole and locks, forcing the metal energy-dissipating component into a plastic yield state, thus dissipating a large amount of earthquake energy. Figure 16 , Figure 17 ).

[0056] By matching the parameters constructed from the nodes, the following graded response was achieved: 1. Under frequent earthquake action (θ < [1 / 250], elastic working stage): The inter-story drift angle remains within the elastic limit. At this time, the displacement of the node cover plate limiting block in the sliding bolt hole is less than the preset sliding distance, and the metal energy dissipation component 104 is in a completely stress-free "quiet" state. Utilizing the high lateral stiffness provided by the steel-wood composite section, the inter-story drift angle is strictly controlled within 1 / 250. Under this small deformation, the SMA-steel composite bolt 103 only undergoes elastic tension, and the node stiffness does not degrade, ensuring that the structure meets the code's "no damage under minor earthquakes" requirement and normal functional requirements.

[0057] 2. Under the design earthquake action (1 / 250 < θ < 1 / 50, damage initiation and control stage): When the interlayer displacement angle exceeds the elastic limit, the node rotation causes the cover plate limiting block to slide to the end of the elongated hole and lock (i.e., the sliding travel is exhausted). At this point, the strain of the SMA-steel composite screw 103 reaches 3% of the design value. At the 5% threshold, it enters the hyperelastic plateau segment; the metal energy-dissipating component 104 is then forced to yield, dissipating energy through hysteretic deformation. This is achieved by precisely designing the length of the sliding bolt hole to 1 / 200th of its original length. The displacement at 1 / 150th of the original value allows energy-dissipating components to intervene precisely in the early stages of the structure's nonlinear phase. This mechanism effectively curbs the amplification of acceleration response, keeps the inter-story drift angle within a safe range, and avoids premature failure of non-structural components.

[0058] 3. Under rare earthquake conditions (θ≈1 / 50, self-resetting and functional preservation stage): The inter-story drift angle approaches or reaches the elasto-plastic drift angle limit of 1 / 50 specified in the code. At this point, the metal energy-dissipating component 104 enters the plastic strengthening stage, fully utilizing its "fuse" function to concentrate energy dissipation; while the SMA-steel composite screw 103 utilizes its superelasticity to provide restoring force. Compared to traditional steel-wood joints that may produce irreversible and huge residual deformation at a drift angle of 1 / 50, this invention can control the residual inter-story drift angle to below 0.2% (i.e., 1 / 500) after earthquake unloading, allowing the structure to essentially return to its initial position. The main steel-wood components remain elastic or suffer only minor damage, achieving the transcendent goal of "repair without correction after a major earthquake."

[0059] 4. Under extremely rare earthquake conditions (θ>1 / 50, collapse-resistant limit stage): When subjected to an extreme earthquake exceeding the design expectations, with the inter-story drift angle significantly exceeding 1 / 50 or even reaching 1 / 30, external energy dissipation components may fail. In this situation, the beam-column connection limiting device activates secondary protection, and the continuous tension steel rods 304 within the column provide axial tension force using the catenary effect. Even if the wooden column core is partially crushed or the joint rotation is excessive, the tension steel rods can still limit the axial separation displacement of the beam-column joint, preventing floor collapse and ensuring that the structure does not collapse entirely under extreme deformation, thus meeting the bottom-line requirement of "life safety."

[0060] The entire structural system can be quickly assembled on-site using dry connections (bolts, pins), eliminating the need for wet work. After an earthquake, only the yielded metal energy-absorbing components need to be replaced, and the main structure remains largely undamaged, allowing it to regain its functionality. This achieves the high-performance earthquake-resistant goal of "no damage in minor earthquakes, recoverable in moderate earthquakes, repairable in major earthquakes, and no collapse in extremely rare earthquakes."

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A self-resetting prefabricated steel-wood hybrid frame structure based on shape memory alloy SMA, characterized in that, include: The prefabricated steel-wood composite column (3), the prefabricated steel-wood composite beam (2), and the self-resetting energy-dissipating beam-column node (1) connecting the prefabricated steel-wood composite column (3) and the prefabricated steel-wood composite beam (2); the self-resetting energy-dissipating beam-column node (1) includes a beam connector (101) and a column connector (102). There are n SMA-steel composite screws (103) and n+1 metal energy-dissipating components (104) between the beam connector (101) and the column connector (102) to perform graded response to earthquakes of different levels, where n is a positive integer.

2. The self-resetting prefabricated steel-wood hybrid frame structure based on shape memory alloy (SMA) according to claim 1, characterized in that, The prefabricated steel-wood composite column (3) includes a steel sleeve column (301), with column end steel plate flanges (305) at both ends of the steel sleeve column (301). The steel sleeve column (301) has a built-in cross-shaped steel column (302), and a wooden column core (303) is filled between the steel sleeve column (301) and the built-in cross-shaped steel column (302) to form the wooden column core (303). A continuous tensile steel bar thread (304) passes through the wooden column core (303) and connects to the column end steel plate flanges (305) at both ends of the steel sleeve column (301).

3. The self-resetting prefabricated steel-wood hybrid frame structure based on shape memory alloy SMA according to claim 1, characterized in that, The prefabricated steel-wood composite beam (2) includes two opposing open T-shaped steel beams (201). The flanges of the open T-shaped steel beams (201) have built-in flange wooden boards (202), and the webs (205) of the open T-shaped steel beams (201) have built-in wooden webs (203). After installation, the prefabricated steel-wood composite beam (2) is an I-beam as a whole. The whole is connected by tie rods (204) arranged at the webs of the I-beam prefabricated steel-wood composite beam (2).

4. A self-resetting prefabricated steel-wood hybrid frame structure based on shape memory alloy SMA according to claim 1, characterized in that, The beam connector (101) of the self-resetting energy-dissipating beam-column node (1) is an integrally formed steel component, including a back plate (115). The back plate (115) is provided with a parallel connecting plate (113) on the back side away from the prefabricated steel-wood composite column (3). The parallel connecting plate (113) is connected to the web plate (205) and the wooden web plate (203) at the end of the prefabricated steel-wood composite beam (2) through tie rods (204).

5. A self-resetting prefabricated steel-wood hybrid frame structure based on shape memory alloy (SMA) according to claim 1, characterized in that, The column connector (102) is an integrally formed steel component, including a back plate two (116). A triangular connecting plate (114) is provided on the back side of the back plate two (116) away from the prefabricated steel-wood composite beam (2). The triangular connecting plate (114) is connected to the column end steel plate flange (305) of the prefabricated steel-wood composite column (3) through a tension steel rod (304). Multiple SMA-steel composite rods (103) and multiple metal energy-consuming parts (104) are connected between the back plate one (115) of the beam connector (101) and the back plate two (116) of the column connector (102). Cover plates (105) are respectively tightly attached to both sides of the surface of the metal energy-consuming parts (104). The side of the metal energy-consuming parts (104) and the cover plates (105) close to the prefabricated steel-wood composite beam (2) is connected to the limiting device one (105) through screws (106) and nuts (107). 108) The metal energy-consuming component (104) and the cover plate (105) are connected to the limiting device two (109) on the side of the prefabricated steel-wood composite column (3) by screws (106) and nuts (107); the back plate one (115) of the beam connector (101) and the back plate two (116) of the column connector (102) are also provided with a matching ear plate pin (112) to connect the beam connector (101) and the column connector (102) with a pin that allows rotation; the metal energy-consuming component (104) is a rectangular flat steel. When the self-resetting energy-consuming beam-column node is subjected to external force and rotates, causing the SMA-steel composite screw (103) to stretch and deform to 3% to 5%, the limiting block (111) slides to the end of the sliding bolt hole (110) and locks, forcing the metal energy-consuming component (104) to participate in the force and undergo plastic yielding.

6. A self-resetting prefabricated steel-wood hybrid frame structure based on shape memory alloy (SMA) according to claim 1, characterized in that, The prefabricated steel-wood composite column (3) is connected to the column end steel plate flange (305) by a continuous tensile steel rod (304) passing through a triangular connecting plate (114). The four triangular connecting plates (114) form a square.

7. A self-resetting prefabricated steel-wood hybrid frame structure based on shape memory alloy (SMA) according to claim 1, characterized in that, The SMA-steel composite screw (103) includes an SMA short screw (117), with threaded steel sleeves (118) threaded to both ends of the SMA short screw (117). One end of the threaded steel sleeve (118) passes through the back plate one (115) of the beam connector (101) and is fixed by a nut (119). The other end of the threaded steel sleeve (118) passes through the back plate two (116) of the column connector (102) and is fixed by a nut (119).

8. A self-resetting prefabricated steel-wood hybrid frame structure based on shape memory alloy (SMA) according to claim 1, characterized in that, The wooden core (303) is connected in the height direction by a stapling method: the wooden core (303) is inserted into the stapling steel sleeve (306) and fixed by the stapling screw (307).

9. A self-resetting prefabricated steel-wood hybrid frame structure based on shape memory alloy SMA according to claim 1, characterized in that, The column end steel plate flange (305) is composed of two steel plates (308), and the two ends of the tensioned steel bar threaded rod (304) pass through the threaded rod holes on the two steel plates (308) and are tightened by nuts (309).

10. A self-resetting prefabricated steel-wood hybrid frame structure based on shape memory alloy (SMA) according to claim 1, characterized in that, The step-by-step response to earthquakes of different magnitudes includes: Under the action of frequent earthquakes: θ < [1 / 250], where θ is the inter-story drift angle, the SMA-steel composite screw (103) is in the elastic stage, the metal energy dissipation component (104) does not participate in the force, and the structure is undamaged; Under the design earthquake action: 1 / 250<θ<1 / 50, the strain of the SMA-steel composite screw (103) reaches the design threshold of 3%~5%, enters the hyperelastic deformation stage, and the metal energy-consuming component (104) begins to yield and consume energy; Under rare earthquake action: θ=1 / 50, the SMA-steel composite screw (103) exerts superelastic recovery capability, significantly reduces residual deformation, the metal energy dissipation component (104) fully enters the plastic strengthening section to dissipate energy, and the main component remains elastic or only slightly damaged; Under extremely rare earthquake action: θ>1 / 50, limit device one (108) and limit device two (109) activate the secondary protection mechanism, the connector undergoes plastic deformation to absorb the remaining energy, and at the same time the tension steel rod (304) running through the column serves as the last line of defense to prevent the structure from collapsing.

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