Low-damage self-resetting beam-column joint based on double-order sliding-starting friction damper

Abstract

A low-damage self-resetting beam-column joint based on a double-step sliding-starting friction damper comprises a concrete-filled steel tube column, the concrete-filled steel tube column is connected with an outer ring plate in a welded mode, the outer ring plate is connected with upper flanges of steel beams on the two sides through cover plate connecting plates, and the outer ring plate is connected with webs of the steel beams through shear connecting plates. A double-step sliding self-resetting friction damper is mounted at the joint of the outer ring plate and the lower flange of the steel beam; under the action of a horizontal earthquake, the joint deforms, the cover plate connecting plate of the upper flange rotates and deforms, the shearing connecting plate of the web plate generates friction energy consumption, the double-step sliding self-resetting friction damper connected to the lower flange is stretched or compressed and deforms, and in the first stage, the double-step sliding self-resetting friction damper firstly performs friction energy consumption, and in the second stage, the double-step sliding self-resetting friction damper performs friction energy consumption; after entering the second stage of deformation, the SMA bolt is stretched, and after the external force is unloaded, the second stage of self-resetting can be realized; the self-resetting anti-seismic energy-dissipation and self-resetting structure has the defense level of energy dissipation in small earthquakes and medium earthquakes and self-resetting in large earthquakes and rare earthquakes.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy dissipation and vibration reduction of building structures, and in particular relates to a low-damage self-resetting beam-column node based on a double-order sliding friction damper. Background Art

[0002] Earthquakes have a devastating impact on infrastructure structures. Traditional building structures primarily resist earthquakes by dissipating energy through inelastic deformation of beams, columns, and other components. However, this approach can lead to severe damage to structural components, especially during major earthquakes, rendering the structure unusable. This leads to high post-earthquake repair costs and significant economic losses.

[0003] Steel tube concrete composite structures are mainly used in high-rise and super-high-rise structures. Earthquake damage is the main factor affecting the safety of steel tube concrete composite structures throughout their service life. However, the current seismic resistance and vibration reduction methods of steel tube concrete composite structures still rely on deformation energy dissipation of components or single energy-absorbing dampers for seismic resistance and vibration reduction.

[0004] In order to reduce and avoid post-earthquake damage to building structures, self-resetting technology is introduced into building structures. This technology mainly achieves the post-earthquake self-resetting ability of building structures through self-resetting devices (such as steel strands, SMA, etc.) and self-resetting dampers.

[0005] The patent application document with publication number CN 110924539A discloses a self-resetting steel tube concrete column-steel beam node connection device. The reset device of this node is provided by prestressed tendons. Under long-term reciprocating action, the prestressed tendons will experience prestress loss, which will seriously affect the reset ability of the node. When the node is subjected to horizontal earthquake action, the deformation of the beam-column connection in this invention node is concentrated at the center position of the web of the I-beam, which causes the upper floor slab to suffer greater damage under seismic conditions.

[0006] The patent application document with publication number CN 107675800 B discloses a self-resetting deformation coordinated floor node structure. The connecting cover plate and web connecting plate of this invention are not prefabricated connections. If the components are damaged after an earthquake, they are difficult to replace, which affects the post-earthquake recovery speed. The damper is a self-resetting damper with a single stiffness and cannot achieve multi-order variable stiffness to cope with the uncertainty of earthquakes. In addition, the connection method of the steel structure of this invention cannot be directly applied to steel tube concrete composite structures.

[0007] Installing a single energy-absorbing damper in a steel tube concrete composite structure can achieve the seismic fortification goal during small and moderate earthquakes. However, in the event of large and rare earthquakes, the structure will experience large residual deformation, affecting the continued use of the structure and causing significant property losses and life safety to society.

[0008] The existing dampers are installed in the steel tube concrete column-steel beam connection nodes. The dampers only undergo a single self-resetting deformation, which reduces the initial stiffness of the structure and has a weak energy dissipation capacity. Severe response problems will occur in the high-order modes of the structure, and it cannot meet the requirements of earthquake uncertainty. Summary of the Invention

[0009] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a low-damage self-resetting beam-column node based on a double-stage sliding friction damper. In the node design, the rotation center of the node connection is transferred from the web to the upper flange, which can better protect the floor from damage in an earthquake. The node is an assembled node. A double-stage sliding self-resetting friction damper is installed on the outer ring plate and the lower flange of the steel beam. The shear connection plate of the web adopts a special structural design with one bolt on the upper part and multiple bolts on the lower part. The outer ring plate and the upper flange of the steel beam are connected by a cover plate connection plate, which concentrates the damage on the upper cover plate connection plate. It can be quickly replaced after the earthquake to realize the recovery ability of the self-resetting node after the earthquake. A double-stage sliding self-resetting friction damper is installed in the node, which can achieve good energy dissipation capacity under small and medium earthquakes, and can achieve self-resetting effect under large earthquakes and rare earthquakes. All components of the node can be assembled and constructed, and the purpose of rapid construction can be achieved during the construction process.

[0010] In order to achieve the above object, the present invention adopts the following technical solutions:

[0011] A low-damage self-resetting beam-column node based on a double-stage sliding friction damper includes a steel tube concrete column 1, which is welded to an outer ring plate 3. The connection between the outer ring plate 3 and the upper flanges of the steel beams 2 on both sides is connected by a cover plate connecting plate 5, and the connection between the outer ring plate 3 and the web of the steel beam 2 is connected by a shear connecting plate 6. A double-stage sliding self-resetting friction damper 7 is installed at the connection between the outer ring plate 3 and the lower flange of the steel beam 2.

[0012] The double-stage sliding self-resetting friction damper 7 includes a first clamping plate 14 and a second clamping plate 15. One end of the first clamping plate 14 and the second clamping plate 15 are both flat sections, and the other ends of the first clamping plate 14 and the second clamping plate 15 are both variable sections. The upper and lower surfaces of the flat section end of the first clamping plate 14 are symmetrically connected to one end of the flat section cover plate 12, the upper and lower surfaces of the variable section end of the first clamping plate 14 are symmetrically connected to one end of the variable section cover plate 13, and the upper and lower surfaces of the variable section end of the second clamping plate 15 are symmetrically connected to the other end of the variable section cover plate 13.

[0013] The flat section cover plate 12 is connected to the flat section end of the first clamping plate 14 via a first high-strength bolt 171 , and the variable section ends of the first clamping plate 14 and the second clamping plate 15 are connected to the variable section cover plates 13 on the upper and lower surfaces via SMA bolts 18 , respectively.

[0014] A spacer 19 is provided between the contact surface between the SMA bolt 18 and the variable-section cover plate 13 .

[0015] Notches 20 are respectively provided on both sides of the cover connecting plate 5 .

[0016] A first connecting plate 161 is connected between the end of the flat-section cover plate 12 that is not connected to the first splint 14, and a second connecting plate 162 and a third connecting plate 163 are symmetrically connected to the upper and lower surfaces of the flat-section end of the second splint 15. Connecting end plates 8 are installed on the steel beam 2 and the outer ring plate 3, and the first connecting plate 161, the second connecting plate 162 and the third connecting plate 163 are hingedly connected to the connecting end plates 8 on the steel beam 2 and the outer ring plate 3 respectively.

[0017] The end of the flat section cover plate 12 not connected to the first clamping plate 14 is connected to the first connecting plate 161 via a second high-strength bolt 172 , and the second connecting plate 162 and the third connecting plate 163 are connected to the flat section end of the second clamping plate 15 via a third high-strength bolt 173 .

[0018] The cover plate connecting plate 5 is connected to the connection between the outer ring plate 3 and the upper flange of the steel beam 2 through the fourth high-strength bolt 4; the shear connecting plate 6 is connected to the connection between the outer ring plate 3 and the web of the steel beam 2 through bolts, and the bolts on the shear connecting plate 6 are arranged in a distribution form of one bolt at the top and multiple bolts at the bottom.

[0019] The first splint 14 , the second splint 15 and the variable-section cover plate 13 are all designed with sloped variable sections, and the sloped variable sections of the first splint 14 and the second splint 15 fit in with the sloped variable sections of the upper and lower variable-section cover plates 13 .

[0020] The frictional sliding force between the flat-section cover plate 12 and the flat-section end of the first clamping plate 14 is smaller than the frictional sliding force between the variable-section cover plate 13 and the variable-section ends of the first clamping plate 14 and the second clamping plate 15 .

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The present invention will solve the problem of beams and columns being damaged under earthquakes. Through a deformation-coordinated structural design, the outer ring plate 3 is connected to the upper flange of the steel beam 2 through a cover plate connecting plate 5 and a fourth high-strength bolt 4. The outer ring plate 3 and the lower flange of the steel beam 2 are installed with a double-stage sliding self-resetting friction damper 7, so that the deformation and damage of the steel tube concrete column-steel beam connection node under earthquakes are concentrated on the cover plate connecting plate 5, so that other components are in an elastic state, and the purpose of rapid replacement can be achieved after the earthquake, greatly reducing the post-earthquake repair work.

[0023] 2. Under the action of an earthquake, the present invention installs a double-stage sliding self-resetting friction damper 7 at the connection between the outer ring plate 3 and the lower flange of the steel beam 2, and the shear connection plate 6 of the outer ring plate 3 and the web of the steel beam 2 adopts a special structural design with one bolt on the top and multiple bolts on the bottom. The rotation center of the node under the action of an earthquake is moved from the center position of the web of the steel beam 2 to the upper flange of the connection, thereby reducing the deformation and damage of the upper floor slab and minimizing the damage to other components.

[0024] 3. The double-stage sliding self-resetting friction damper 7 of the present invention is applied to the self-resetting node. The double-stage sliding self-resetting friction damper 7 is designed in two stages. The first stage is flat section friction and the second stage is a variable section friction device. This allows the node to have a two-stage working mechanism under the action of earthquake resistance. During small and medium earthquakes, the node only consumes energy through friction between the flat section cover plate 12 and the first clamping plate 14. Under the action of large and rare earthquakes, the node can achieve self-resetting through the coordinated coupling of the sloped variable section design of the variable section cover plate 13, the first clamping plate 14 and the second clamping plate 15 and the SMA bolt 18, so that the node has no large residual deformation. Therefore, this node has a two-level earthquake protection level, and the node has a protection level of "energy consumption in small and medium earthquakes, and self-resetting in large and rare earthquakes."

[0025] 4. The node of the present invention adopts a deformation-coordinated structural design. The connection between the outer ring plate 3 and the upper flange of the steel beam 2 is connected by a cover plate connecting plate 5 and a fourth high-strength bolt 4. The outer ring plate 3 and the lower flange of the steel beam 2 are installed with a double-stage sliding self-resetting friction damper 7. The rotation center of the beam-column node is moved from the web center of the steel beam 2 to the upper flange, thereby increasing the deformation of the lower flange to 2 times the original value, achieving a displacement amplification effect, so as to better play the effect of the displacement damper. Therefore, the deformation under the action of the earthquake is mainly concentrated on the double-stage sliding self-resetting friction damper 7, the energy consumption of the two-stage sliding self-resetting friction damper 7 in the first stage is achieved by the friction of the flat-section damper, and the self-resetting of the two-stage sliding self-resetting friction damper 7 in the second stage is achieved through the coordinated action of the sloped variable-section design of the variable-section cover plate 13, the first clamping plate 14 and the second clamping plate 15 and the SMA bolt 18. During the loading process, the design of the inclined surface makes the damper have a larger output force, and the SMA bolt 18 is stretched. During the unloading process, the SMA has a reset ability, so that the two-stage sliding self-resetting friction damper 7 is reset without residual deformation.

[0026] In summary, the present invention is a fully assembled steel tube concrete column-steel beam self-resetting node. Through the node structural design, that is, a sliding friction damper 7 is installed on the lower flange, the web is connected to the upper flange of the high-strength bolts 4 with one bolt and multiple bolts at the lower end, and the outer ring plate 3 is connected to the upper flange of the steel beam 2 through the cover plate connecting plate 5 and the fourth high-strength bolt 4. The rotation center is moved from the web of the steel beam to the upper flange, which reduces the damage to the upper floor slab and concentrates the damage to the component on the cover plate connecting plate connected to the upper flange to protect other components from damage. In addition, this structural design can increase the deformation of the lower flange to twice the original value. This amplification effect can better play the role of a double-stage sliding damper. The damper is a two-stage structural design, which can enable the node to have better energy dissipation capacity under small and medium earthquakes, and can achieve self-resetting effect under large earthquakes and rare earthquakes. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0028] Figure 2 It is a front view of the present invention.

[0029] Figure 3 It is a top view of the present invention.

[0030] Figure 4 Schematic diagram of the connection structure between the steel tube concrete column 1 and the outer ring plate 3 of the present invention.

[0031] Figure 5 Schematic diagram of the structure of the outer ring plate 3 of the present invention.

[0032] Figure 6 It is a structural schematic diagram of the steel beam 2 of the present invention.

[0033] Figure 7 Schematic diagram of the structure of the double-stage sliding self-resetting friction damper 7 of the present invention.

[0034] Figure 8 This is a high-strength bolt group of the high-strength bolt 4 of the present invention.

[0035] Figure 9 It is a schematic diagram of the connection structure of the steel beam 2 and the cover plate connecting plate 5 of the present invention.

[0036] Figure 10 It is a structural schematic diagram of the connecting end plate 8 of the present invention.

[0037] Figure 11 It is a structural schematic diagram of the cover connecting plate 5 of the present invention.

[0038] Figure 12 It is a structural schematic diagram of the stiffening rib plate 9 of the present invention.

[0039] Figure 13 The steel tube and core concrete 11 of the steel tube concrete column 1 of the present invention.

[0040] Figure 14 It is a structural schematic diagram of the variable cross-section cover plate 13 of the present invention.

[0041] Figure 15 Schematic diagram of the structure of the first splint 14 of the present invention.

[0042] Figure 16 Schematic diagram of the structure of the cushion block 19 of the present invention.

[0043] Figure 17 Schematic diagram of the structure of the SMA bolt 18 of the present invention.

[0044] Among them, 1. Steel tube concrete column; 2. Steel beam; 3. Outer ring plate; 4. Fourth high-strength bolt; 5. Cover plate connecting plate; 6. Shear connecting plate; 7. Double-stage sliding self-resetting friction damper; 8. Connecting end plate; 9. Stiffening rib plate; 10. Loading plate; 11. Core concrete; 12. Flat section cover plate; 13. Variable section cover plate; 14. First splint; 15. Second splint; 161. First connecting plate; 162. Second connecting plate; 163. Third connecting plate; 171. First high-strength bolt; 172. Second high-strength bolt; 173. Third high-strength bolt; 18. SMA bolt; 19. Spacer; 20. Notch. DETAILED DESCRIPTION

[0045] The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0046] In order to meet the requirements of resilient urban development, the steel tube concrete composite structure is given the ability to self-reset, the residual deformation of the structure is reduced, and the main damage of the steel tube concrete column-beam connection is concentrated in a certain component so that it can be quickly replaced after an earthquake. Therefore, the present invention proposes a low-damage self-resetting beam-column node based on a double-order sliding friction damper.

[0047] See also Figures 1 to 6 A low-damage self-resetting beam-column joint based on a double-stage sliding friction damper comprises a steel tube concrete column 1, the steel tube concrete column 1 is welded to an outer ring plate 3 (see Figure 4 ), the connection between the outer ring plate 3 and the upper flange of the steel beam 2 is connected by the cover plate connection plate 5 and the fourth high-strength bolt 4 (see Figure 8 、 Figure 9 ), the connection between the outer ring plate 3 and the web of the steel beam 2 is connected by a shear connection plate 6, and the connection between the outer ring plate 3 and the lower flange of the steel beam 2 is installed with a double-stage sliding self-resetting friction damper 7.

[0048] A loading plate 10 is disposed on the top of the concrete-filled steel tube column 1 .

[0049] See also Figure 13 The steel tube concrete column 1 and the outer ring plate 3 are welded and prefabricated in the factory, and the core concrete 11 is poured into the steel tube concrete column 1 on site. The steel beam 2, the double-stage sliding self-resetting friction damper 7 and the remaining components are prefabricated in the factory and assembled on site to achieve the purpose of rapid construction.

[0050] The purpose of designing the shear connection plate 6 is to increase the energy dissipation capacity of the node under earthquake action.

[0051] See also Figure 7 The double-stage sliding self-resetting friction damper 7 includes a first clamping plate 14 and a second clamping plate 15. One end of the first clamping plate 14 and the second clamping plate 15 are both flat sections, and the other ends of the first clamping plate 14 and the second clamping plate 15 are both variable sections. The upper and lower surfaces of the flat section end of the first clamping plate 14 are symmetrically connected to one end of the flat section cover plate 12, the upper and lower surfaces of the variable section end of the first clamping plate 14 are symmetrically connected to one end of the variable section cover plate 13, and the upper and lower surfaces of the variable section end of the second clamping plate 15 are symmetrically connected to the other end of the variable section cover plate 13.

[0052] See also Figure 17 The flat section cover plate 12 is connected to the flat section end of the first clamp plate 14 through the first high-strength bolt 171, and the variable section ends of the first clamp plate 14 and the second clamp plate 15 are respectively connected to the variable section cover plates 13 on the upper and lower surfaces through SMA bolts 18.

[0053] The two-stage sliding self-resetting friction damper 7 has a flat-section friction device and a variable-section friction device. The flat-section device is fixed by a flat-section cover plate 12 and a first clamping plate 14 through a first high-strength bolt 171. The variable-section device is connected to the variable-section cover plates 13 on the upper and lower sides by SMA bolts 18 at the variable-section ends of the first clamping plate 14 and the second clamping plate 15 respectively. The energy dissipation capacity and self-resetting ability of the two-stage sliding self-resetting friction damper 7 are achieved by changing the pre-tightening force of the first high-strength bolt 171 and the SMA bolt 18.

[0054] See also Figure 16 A spacer 19 is provided between the contact surface of the SMA bolt 18 and the variable-section cover plate 13. The length of the SMA bolt 18 is increased, and the deformation of the SMA bolt 18 is controlled by adjusting the thickness of the spacer 19. This prevents the SMA bolt 18 from entering the strengthening stage and generating residual deformation, which would affect the self-resetting function of the damper.

[0055] See also Figure 10A first connecting plate 161 is connected to the end of the flat-section cover plate 12 not connected to the first clamping plate 14. A second connecting plate 162 and a third connecting plate 163 are symmetrically connected to the upper and lower surfaces of the flat-section end of the second clamping plate 15, facilitating installation and connection with the node. Connecting end plates 8 are installed between the upper and lower flanges of the steel beam 2, on the web, and on the outer ring plate 3. The first connecting plate 161, second connecting plate 162, and third connecting plate 163 at both ends of the double-stage sliding self-resetting friction damper 7 are hingedly connected to the connecting end plates 8 on the steel beam 2 and the outer ring plate 3, respectively.

[0056] The end of the flat section cover plate 12 not connected to the first clamping plate 14 is connected to the first connecting plate 161 via a second high-strength bolt 172 , and the second connecting plate 162 and the third connecting plate 163 are connected to the flat section end of the second clamping plate 15 via a third high-strength bolt 173 .

[0057] The two ends of the two-stage sliding self-resetting friction damper 7 are respectively installed with a first connecting plate 162, a second connecting plate 162 and a third connecting plate 163, which can be connected to the connecting end plate 8 of the outer ring plate 3 and the steel beam 2 through a pin shaft. The hinged connection can prevent the node from affecting the operation of the two-stage sliding self-resetting friction damper 7 during the deformation process.

[0058] See also Figure 11 Notches 20 are respectively provided at the middle positions on both sides of the cover connecting plate 5.

[0059] The cover plate connecting plate 5 is designed with a dog-bone notch 20 so that the rotation center of the node is located at the notch 20 and the stress caused by deformation is concentrated at the notch 20 .

[0060] See also Figure 12 The connection between the end plates 8 is connected with a stiffening rib plate 9.

[0061] In order to prevent deformation of the connection of the end plate 8, which would cause the double-stage sliding self-resetting friction damper 7 to fail to fully exert its effect, a stiffening rib plate 9 is welded at the connection of the end plate 8.

[0062] The shear connection plate 6 is connected to the connection between the outer ring plate 3 and the web of the steel beam 2 by bolts. The bolts on the shear connection plate 6 are arranged in a distribution form of one bolt at the top and multiple bolts at the bottom.

[0063] See also Figure 14 、 Figure 15 The first plywood 14, the second plywood 15 and the variable-section cover plate 13 are all designed with sloped variable sections, and the sloped variable sections of the first plywood 14 and the second plywood 15 are in line with the sloped variable sections of the upper and lower variable-section cover plates 13.

[0064] The frictional sliding force between the flat-section cover plate 12 and the flat-section end of the first clamping plate 14 is smaller than the frictional sliding force between the variable-section cover plate 13 and the variable-section ends of the first clamping plate 14 and the second clamping plate 15. To enable the node to achieve a two-stage seismic fortification effect, the frictional sliding force of the flat-section friction device of the dual-stage self-resetting friction damper 7 must be smaller than that of the variable-section friction device.

[0065] Under the action of the reciprocating load of the earthquake, the two-stage sliding self-resetting friction damper 7 performs reciprocating tension and compression work. During this process, the SMA bolts 18 of the variable-section friction device of the two-stage sliding self-resetting friction damper 7 are all in a tension state, which changes the previous working mode of the SMA bolts 18 that were both tensile and compressive. This design reduces the prestress loss of the SMA bolts 18.

[0066] Under the action of an earthquake, the steel tube concrete column 1 rotates, with the cover plate connecting plate 5 at the connection between the outer ring plate 3 and the steel beam 2 as the rotation center. The shear connecting plate 6 at the web connecting plate and the web of the steel beam 2 dissipate energy through friction, and the deformation is mainly concentrated on the double-stage sliding self-resetting friction damper 7 of the lower flange. The cover plate connecting plate 5 is designed with a dog-bone notch, so that the deformation of the cover plate connecting plate 5 connected to the upper flange is concentrated at the notch. The design of concentrating the deformation of the node on the upper flange is to reduce the damage to the floor slab of the upper flange.

[0067] The working mechanism of the double-stage sliding self-resetting friction damper 7 is divided into two stages. The first stage is the pure energy consumption stage, and the second stage is the self-resetting stage. In the first stage, the flat-section cover plate 12 and the first clamping plate 14 consume energy through friction. In the second stage, the sloped variable-section design of the variable-section cover plate 13, the first clamping plate 14 and the second clamping plate 15 and the SMA bolt 18 work together to achieve the self-resetting effect. The first clamping plate 14 and the second clamping plate 15 move relative to each other, and the inclined surface drives the variable-section cover plate 13 to move outward, causing the SMA bolt 18 to be stretched.

[0068] The purpose of designing a two-stage working mechanism of the double-stage sliding self-resetting friction damper 7 is to enable the node to consume energy under the action of small and medium earthquakes, improve the initial stiffness of the node, and enable the node to have the ability to self-reset under large and rare earthquakes. The two-stage earthquake-resistant concept forms an efficient earthquake-resistant system.

[0069] Except for the cover connecting plate 5, the other components of the node of the present invention are in an elastic state under the action of an earthquake, so that the deformation and damage of the node are mainly concentrated on the cover connecting plate 5. Such a design can quickly replace the cover connecting plate 5 after the earthquake, so as to achieve the purpose of rapid restoration of the structure, which meets the requirements of resilient urban development.

[0070] Under the action of an earthquake, the load of the node of the present invention is transferred from the steel tube concrete column 1 to the steel beam 2, and the connection becomes the most critical position. In the node of the present invention, the rotation center of the node is moved up to the upper flange, increasing the deformation of the lower flange, which can better play the effect of the double-stage sliding self-resetting friction damper 7.

[0071] The present invention provides a low-damage self-resetting beam-column node based on a double-stage sliding friction damper, which solves the problems currently faced by steel tube concrete composite structures in earthquake resistance, and enables the structure to have multi-level earthquake resistance. In small and medium earthquakes, the node mainly consumes energy, and in large and rare earthquakes, the node mainly self-resets, and the rotation center of the node is moved from the middle position of the web to the upper flange, concentrating the damage of the components on a certain component. The components can be quickly replaced after the earthquake to achieve the purpose of rapid restoration of the structure to use. The present invention provides a low-damage self-resetting beam-column node based on a double-stage sliding friction damper, which has multi-level earthquake resistance and can achieve energy consumption in small and medium earthquakes and self-reset in large and rare earthquakes.

[0072] The design concept of this node makes up for the shortcomings of the traditional steel tube concrete composite structure in terms of seismic resistance. While ensuring the structural safety performance, it minimizes the damage caused by earthquakes to the building structure and has multi-level seismic defense capabilities.

[0073] The present invention provides a low-damage, self-resetting beam-column joint based on a dual-stage sliding friction damper. This novel joint design can transform the seismic design concept of steel tube concrete composite structures, improve their seismic fortification, and construct a highly efficient seismic-resistant system. The joint of the present invention allows for the rapid replacement of locally damaged components after an earthquake, saving time and money, and achieving rapid post-earthquake recovery. Therefore, the present invention provides a novel seismic-resistant solution for future seismic-resistant steel tube concrete composite structures and for the development of resilient cities.

[0074] The working principle of the present invention is as follows: under the action of horizontal earthquake, the node is deformed, the cover plate connecting plate 5 of the upper flange is rotationally deformed, the shear connecting plate 6 of the web consumes friction energy, and the two-stage sliding self-resetting friction damper 7 connected to the lower flange is stretched or compressed and deformed. The two-stage sliding self-resetting friction damper 7 first consumes friction energy in the first stage. After entering the second stage of deformation, the SMA bolt 18 of the two-stage sliding self-resetting friction damper 7 is stretched. After the external force is unloaded, due to the reset ability of the SMA bolt 18, self-reset can be achieved in the second stage.

Claims

1. A low-damage self-resetting beam-column joint based on a double-stage sliding friction damper, comprising a steel tube concrete column (1), the steel tube concrete column (1) being welded to an outer ring plate (3), characterized in that: The connection points between the outer ring plate (3) and the upper flanges of the steel beams (2) on both sides are connected via cover plate connection plates (5), the connection points between the outer ring plate (3) and the web of the steel beam (2) are connected via shear connection plates (6), and a double-stage sliding self-resetting friction damper (7) is installed at the connection point between the outer ring plate (3) and the lower flange of the steel beam (2).

2. A low-damage self-resetting beam-column joint based on a dual-order sliding friction damper according to claim 1, characterized in that: The double-stage sliding self-resetting friction damper (7) comprises a first clamping plate (14) and a second clamping plate (15), one end of the first clamping plate (14) and the second clamping plate (15) are both flat sections, and the other ends of the first clamping plate (14) and the second clamping plate (15) are both variable sections. The upper and lower surfaces of the flat section end of the first clamping plate (14) are symmetrically connected to one end of the flat section cover plate (12), the upper and lower surfaces of the variable section end of the first clamping plate (14) are symmetrically connected to one end of the variable section cover plate (13), and the upper and lower surfaces of the variable section end of the second clamping plate (15) are symmetrically connected to the other end of the variable section cover plate (13).

3. The low-damage self-resetting beam-column joint based on a dual-stage sliding friction damper according to claim 2, characterized in that: The flat-section cover plate (12) is connected to the flat-section end of the first clamping plate (14) via a first high-strength bolt (171), and the variable-section ends of the first clamping plate (14) and the second clamping plate (15) are connected to the variable-section cover plates (13) on the upper and lower surfaces via SMA bolts (18), respectively.

4. The low-damage self-resetting beam-column joint based on a dual-order sliding friction damper according to claim 3, characterized in that: A spacer (19) is provided between the contact surface between the SMA bolt (18) and the variable-section cover plate (13).

5. The low-damage self-resetting beam-column joint based on a dual-order sliding friction damper according to claim 1, characterized in that: Notches (20) are respectively provided on both sides of the cover plate connecting plate (5).

6. The low-damage self-resetting beam-column joint based on a dual-stage sliding friction damper according to claim 2, characterized in that: A first connecting plate (161) is connected between the end of the flat section cover plate (12) not connected to the first clamping plate (14), and a second connecting plate (162) and a third connecting plate (163) are symmetrically connected to the upper and lower surfaces of the flat section end of the second clamping plate (15). Connecting end plates (8) are installed on the steel beam (2) and the outer ring plate (3), and the first connecting plate (161), the second connecting plate (162) and the third connecting plate (163) are respectively hingedly connected to the connecting end plates (8) on the steel beam (2) and the outer ring plate (3).

7. The low-damage self-resetting beam-column joint based on a dual-stage sliding friction damper according to claim 6, characterized in that: The end of the flat-section cover plate (12) not connected to the first clamping plate (14) is connected to the first connecting plate (161) via a second high-strength bolt (172), and the second connecting plate (162) and the third connecting plate (163) are connected to the flat-section end of the second clamping plate (15) via a third high-strength bolt (173).

8. The low-damage self-resetting beam-column joint based on a dual-order sliding friction damper according to claim 1, characterized in that: The cover plate connecting plate (5) is connected to the connection between the outer ring plate (3) and the upper flange of the steel beam (2) through the fourth high-strength bolt (4); the shear connecting plate (6) is connected to the connection between the outer ring plate (3) and the web of the steel beam (2) through bolts, and the bolts on the shear connecting plate (6) are arranged in a distribution form of one bolt at the top and multiple bolts at the bottom.

9. A low-damage self-resetting beam-column joint based on a dual-stage sliding friction damper according to claim 2 or 3, characterized in that: The first clamping plate (14), the second clamping plate (15) and the variable-section cover plate (13) are all designed with sloped variable sections, and the sloped variable sections of the first clamping plate (14) and the second clamping plate (15) fit in with the sloped variable sections of the upper and lower variable-section cover plates (13).

10. The low-damage self-resetting beam-column joint based on a dual-stage sliding friction damper according to claim 2, characterized in that: The frictional sliding force between the flat-section cover plate (12) and the flat-section end of the first clamping plate (14) is smaller than the frictional sliding force between the variable-section cover plate (13) and the variable-section ends of the first clamping plate (14) and the second clamping plate (15).

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