A multi-stage buckling-restrained brace based on bamboo-joint shape memory alloy bars

Abstract

The present invention relates to a multi-stage buckling-restrained brace based on a bamboo-joint-shaped shape memory alloy bar, belonging to the technical field of structural vibration control. It includes a restraint plate a, a restraint plate b, and a bamboo-joint-shaped shape memory alloy bar core; a plurality of irregular circular arc-shaped grooves are formed on the inner sides of the restraint plate a and the restraint plate b; the bamboo-joint-shaped shape memory alloy bar core is a shape memory alloy bar, which is placed in the irregular circular arc-shaped grooves of the restraint plate a and the restraint plate b, and is provided with a central limit bolt, an end limit bolt, a first yield section a, a first yield section b, a second yield section a, a second yield section b, a threaded end a, and a threaded end b. By setting yield sections with different diameters, the present invention achieves the effect of staged yielding and can realize multi-stage seismic design.

Description

Technical Field

[0001] The invention relates to a multi-stage buckling-resistance brace based on a bamboo-shaped shape memory alloy rod, and belongs to the technical field of structural vibration control. Background Art

[0002] Earthquakes are the most significant threat to buildings during their use. Under strong earthquakes, buildings may suffer severe plastic damage. After an earthquake, although structures designed according to current ductile design concepts can avoid collapse, large residual displacements cause the building to lose its function, and the repair or reconstruction of the building often results in huge property losses. In order to reduce the residual displacement of the structure and enable it to resume function as quickly as possible after an earthquake, self-resetting technology is considered one of the most promising solutions. Its principle is to organically combine the self-resetting device with the structure to effectively reduce or even eliminate the residual displacement of the structure, thereby achieving post-earthquake functional recovery of the structure. Within this category, many self-resetting dampers, connections, and support devices have been successfully proposed. Among them, anti-buckling braces based on superelastic shape memory alloys are widely used in the field of self-resetting technology due to their excellent energy dissipation and reset capabilities.

[0003] In order to make the anti-buckling support of shape memory alloy move towards practical engineering applications, scholars have conducted a series of studies, which are mainly divided into two categories: anti-buckling support based on superelastic shape memory alloy plates and anti-buckling support based on superelastic shape memory alloy rods. The results show that the anti-buckling support based on superelastic shape memory alloy plates cannot undergo multi-waveform buckling due to the significant notch effect of superelastic shape memory alloy plates, and has poor deformation capacity. The anti-buckling support based on superelastic shape memory alloy rods can undergo multi-waveform buckling due to the insignificant notch effect of superelastic shape memory alloy rods, and has strong deformation capacity, which can meet the needs of actual engineering.

[0004] The study also found that the superelastic shape memory alloy rod anti-buckling support designed for small earthquakes would be destroyed in advance when encountering a strong earthquake, and the main structure may be at risk of collapse. The superelastic shape memory alloy rod anti-buckling support designed for strong earthquakes cannot enter the working state in advance when the structure is slightly deformed due to its large initial stiffness and strength, resulting in poor seismic resistance to small and medium earthquakes. Summary of the Invention

[0005] In response to the above-mentioned defects of the above-mentioned prior art, the present invention proposes a multi-stage anti-buckling support based on a bamboo-type shape memory alloy rod. The inner core of the bamboo-type shape memory alloy rod is composed of multiple energy-absorbing sections with different diameters. The inner diameter is small and the outer diameter is large. The small diameter part yields in advance and plays a role in small and medium earthquakes, and the large diameter part plays a role in strong earthquakes, which can realize multi-stage seismic design.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A multi-stage buckling-resistant brace based on a bamboo-joint-shaped shape memory alloy bar, the multi-stage buckling-resistant brace comprising a restraint plate a, a restraint plate b, and a bamboo-joint-shaped shape memory alloy bar core;

[0008] Both the restraint plate a and the restraint plate b are perforated steel plates, on which a counterbore a and a counterbore b are respectively provided, and a plurality of irregular circular arc-shaped grooves are opened at the center of the surface perpendicular to the counterbore and on the inner sides of the restraint plate a and the restraint plate b; bolts are arranged in the counterbore a and the counterbore b;

[0009] The bamboo-joint-shaped shape memory alloy bar core is a shape memory alloy bar, on which a central limit bolt, end limit bolts, a first yield section a, a first yield section b, a second yield section a, a second yield section b, a threaded end a, and a threaded end b are provided; the end limit bolts are arranged on both sides of the central limit bolt; the first yield section a and the first yield section b are respectively located between the central limit bolt and the end limit bolts on both sides; the second yield section a and the second yield section b are respectively located between the end limit bolts and the threaded end a and the threaded end b;

[0010] The bamboo-joint-shaped shape memory alloy bar core is placed in the irregular circular arc-shaped grooves of the restraint plate a and the restraint plate b, and sufficient deformation space is reserved at its ends; wherein, the central limit bolt of the bamboo-joint-shaped shape memory alloy bar core is in matching contact with the irregular circular arc-shaped grooves at the centers of the restraint plate a and the restraint plate b, ensuring that the bamboo-joint-shaped shape memory alloy bar core is always at the center of the restraint plate a and the restraint plate b, while there is an axial gap between the end limit bolts and the irregular circular arc-shaped grooves of the restraint plate a and the restraint plate b, the left gap is L1, the right gap is L2, L1 = L2, and the radial gap is T1.

[0011] Further, the bolts are high-strength bolts, which are placed in the counterbore a and the counterbore b to fix the restraint plate a and the restraint plate b, ensuring that the two do not have relative displacement and providing reliable restraint for the bamboo-joint-shaped shape memory alloy bar core.

[0012] Further, the diameters of the first yield section a, the first yield section b, the second yield section a, and the second yield section b are D1, D2, D3, and D4 respectively, and both D3 and D4 are greater than D1 and D2.

[0013] Further, the number of each yield section and the parameters L1, L2, T1, D1, D2, D3, and D4 can all be designed according to the seismic requirements of the actual structure.

[0014] Further, the threaded end a and the threaded end b are respectively connected to the structures on both sides.

[0015] Further, the counterbores a, counterbores b, and bolts avoid the inner core of the bamboo-joint-shaped shape memory alloy bar and are arranged on both sides of the inner core of the bamboo-joint-shaped shape memory alloy bar.

[0016] When the structure vibrates due to earthquake action, it will drive the relative movement of the threaded end a and the threaded end b, thereby causing the first yield segments a, first yield segments b, second yield segments a, and second yield segments b of the inner core of the bamboo-joint-shaped shape memory alloy bar to yield, consuming earthquake energy while providing the structure with the ability to reset; during small and medium earthquakes, the first yield segments a and first yield segments b of the inner core of the bamboo-joint-shaped shape memory alloy bar with a smaller diameter yield first and enter the hysteretic energy dissipation state, providing damping force for the structure and improving the energy dissipation ability and reset ability of the structure under small and medium earthquakes, while the second yield segments a and second yield segments b do not enter the yield state due to their larger diameter and only undergo elastic deformation; under strong earthquake action, when the deformation of the structure is large enough to reach L1, the end limit bolts of the first yield segments a and first yield segments b contact the irregular circular arc-shaped grooves of the restraint plate a and the restraint plate b, and the first yield segments a and first yield segments b stop deforming, while the second yield segments a and second yield segments b continue to deform, ensuring the seismic effect of the structure under strong earthquakes.

[0017] The present invention can achieve the following technical effects:

[0018] (1) Using the shape memory alloy bar as the main energy dissipation and reset material, it has a good reset effect and strong deformation ability;

[0019] (2) By setting yield segments with different diameters in the inner core of the bamboo-joint-shaped shape memory alloy bar of the multi-stage buckling-resistant support of the shape memory alloy bar, the effect of staged yielding is achieved, realizing multi-stage seismic design;

[0020] (3) The device can achieve multi-stage seismic design and has good seismic effects under small, medium, and large earthquakes;

[0021] (4) Under earthquake action, the probability of the device undergoing small deformation is greater. If the first yield segment of the device breaks due to fatigue damage, the device will not fail immediately and can still protect the structure well, having the outstanding advantage of controllable risk;

[0022] (5) The whole device is assembled, easy to install and maintain, and has a wide application prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is the front view of the multi-stage buckling-resistant support based on the bamboo-joint-shaped shape memory alloy bar of the present invention.

[0024] Figure 2 It is the top view of the multi-stage buckling-resistant support based on the bamboo-joint-shaped shape memory alloy bar of the present invention.

[0025] Figure 3 This is a side view of the multi-stage buckling-restrained brace based on a bamboo-joint-shaped shape memory alloy bar of the present invention.

[0026] Figure 4 This is the bamboo-joint-shaped shape memory alloy bar inner core of the multi-stage buckling-restrained brace based on a bamboo-joint-shaped shape memory alloy bar of the present invention.

[0027] Figure 5 This is the local positional relationship between the bamboo-joint-shaped shape memory alloy bar inner core and the restraint of the multi-stage buckling-restrained brace based on a bamboo-joint-shaped shape memory alloy bar of the present invention. Detailed implementation manners

[0028] The following combines the appended Figures 1-5 drawings and specific embodiments to further elaborate on the present invention, facilitating a clear understanding of the present invention, but they do not limit the present invention.

[0029] As shown in the appended Figures 1-2 drawings, a multi-stage buckling-restrained brace based on a bamboo-joint-shaped shape memory alloy bar in this embodiment includes a restraint plate a1, a restraint plate b2, and a bamboo-joint-shaped shape memory alloy bar inner core 4. Both the restraint plate a1 and the restraint plate b2 are perforated steel plates, on which a counterbore a11 and a counterbore b21 are respectively provided. On the center of the surface perpendicular to the counterbore and on the inner sides of the restraint plate a1 and the restraint plate b2, a plurality of irregular circular arc-shaped grooves are opened. Bolts 3 are arranged in the counterbore a11 and the counterbore b21. The bolts 3 are high-strength bolts, which are placed in the counterbore a11 and the counterbore b21 to fix the restraint plate a1 and the restraint plate b2, ensuring that there is no relative displacement between the two, and providing a reliable restraint for the bamboo-joint-shaped shape memory alloy bar inner core 4. In addition, the counterbore a11, the counterbore b21, and the bolts 3 avoid the bamboo-joint-shaped shape memory alloy bar inner core 4 and are arranged on both sides of the bamboo-joint-shaped shape memory alloy bar inner core 4.

[0030] As Figure 1 shown, the bamboo-joint-shaped shape memory alloy bar inner core 4 is a shape memory alloy bar, on which a center limit bolt 41, end limit bolts 42, a first yield section a43, a first yield section b44, a second yield section a45, a second yield section b46, a threaded end a47, and a threaded end b48 are provided. The end limit bolts 42 are arranged on both sides of the center limit bolt 41. The first yield section a43 and the first yield section b44 are respectively located between the center limit bolt 41 and the end limit bolts 42 on both sides. The second yield section a45 and the second yield section b46 are respectively located between the end limit bolts 42 and the threaded end a47, the threaded end b48, and the threaded end a47, the threaded end b48 are respectively connected to the structures on both sides.

[0031] As Figure 4As shown in the figure, the diameters of the first yield segment a43, the first yield segment b44, the second yield segment a45, and the second yield segment b46 are D1, D2, D3, and D4 respectively, and both D3 and D4 are greater than D1 and D2. The core 4 of the bamboo-joint shape memory alloy bar is placed in the irregular circular arc-shaped grooves of the restraint plate a1 and the restraint plate b2, and sufficient deformation space is reserved at its ends. Among them, the central limit bolt 41 of the core 4 of the bamboo-joint shape memory alloy bar is in matching contact with the irregular circular arc-shaped grooves at the centers of the restraint plate a1 and the restraint plate b2, ensuring that the core 4 of the bamboo-joint shape memory alloy bar is always at the centers of the restraint plate a1 and the restraint plate b, while there is a gap reserved axially between the end limit bolt 42 and the irregular circular arc-shaped grooves of the restraint plate a1 and the restraint plate b2. The left gap is L1, the right gap is L2, L1 = L2, and the radial gap is T1. The number of each of the above yield segments and the parameters L1, L2, T1, D1, D2, D3, and D4 can be designed according to the seismic requirements of the actual structure.

[0032] The multi-stage buckling-restrained brace based on the bamboo-joint shape memory alloy bar is connected to the structure through the threaded ends a47 and b48 at both ends of the core 4 of the bamboo-joint shape memory alloy bar. When the structure vibrates due to earthquake action, it will drive the threaded ends a47 and b48 to move relatively, thereby causing the first yield segment a43, the first yield segment b44, the second yield segment a45, and the second yield segment b46 of the core 4 of the bamboo-joint shape memory alloy bar to yield, consuming earthquake energy while providing the structure with the ability to reset. When small and medium earthquakes occur, the first yield segment a43 and the first yield segment b44 of the core 4 of the bamboo-joint shape memory alloy bar with a small diameter yield first and enter the hysteretic energy dissipation state, providing damping force for the structure and improving the energy dissipation capacity and reset ability of the structure under small and medium earthquakes, while the second yield segment a45 and the second yield segment b46 do not enter the yield state due to their large diameters and only undergo elastic deformation. Under strong earthquake action, when the deformation of the structure reaches L1, the end limit bolts 42 of the first yield segment a43 and the first yield segment b44 contact the irregular circular arc-shaped grooves of the restraint plate a1 and the restraint plate b2, and the first yield segment a43 and the first yield segment b44 stop deforming, while the second yield segment a45 and the second yield segment b46 continue to deform, ensuring the seismic effect of the structure under strong earthquakes.

[0033] In this embodiment, the buckling restraint device has obvious advantages. The shape memory alloy bar is used as the main energy dissipation and reset material, with small residual displacement and strong deformation ability. By setting yield sections with different diameters in the bamboo-joint-shaped shape memory alloy bar inner core of the multi-stage buckling restraint of the shape memory alloy bar, the effect of staged yielding is achieved, and multi-stage seismic design is realized. The device can achieve multi-stage seismic design and has good seismic effects under small, medium and large earthquakes. Under the action of an earthquake, the probability of small deformation of the device is greater. If the first yield section of the device breaks due to fatigue damage, the device will not fail immediately and can still protect the structure well, having the prominent advantage of controllable risk. The whole device is assembled, easy to install and maintain, with clear mechanism and reliable performance, and has a wide application prospect.

[0034] The above is only a preferred embodiment of the present invention, and does not impose any formal restrictions on the structure of the present invention. The layout type and the number of uses of the present invention are not limited to this example either, and can be optimized according to the actual project. Any modification, equivalent change and decoration made to the above embodiments based on the technical principle of the present invention without departing from the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A multi-stage buckling-restrained brace based on a bamboo-joint-shaped shape memory alloy bar, characterized in that: The multi-stage buckling-restrained brace includes a restraint plate a (1), a restraint plate b (2), and a corrugated shape memory alloy bar core (4); The restraint plate a (1) and the restraint plate b (2) are both perforated steel plates, on which counterbores a (11) and counterbores b (21) are respectively provided. Multiple irregular circular arc-shaped grooves are formed at the centers of the sides perpendicular to the counterbores and on the inner sides of the restraint plate a (1) and the restraint plate b (2); bolts (3) are arranged in the counterbores a (11) and the counterbores b (21); The corrugated shape memory alloy bar core (4) is a shape memory alloy bar, on which a central limit bolt (41), an end limit bolt (42), a first yield section a (43), a first yield section b (44), a second yield section a (45), a second yield section b (46), a threaded end a (47), and a threaded end b (48) are provided; the end limit bolts (42) are arranged on both sides of the central limit bolt (41); the first yield section a (43) and the first yield section b (44) are respectively located between the central limit bolt (41) and the end limit bolts (42) on both sides; the second yield section a (45) and the second yield section b (46) are respectively located between the end limit bolts (42) and the threaded end a (47) and the threaded end b (48); The corrugated shape memory alloy bar core (4) is placed in the irregular circular arc-shaped grooves of the restraint plate a (1) and the restraint plate b (2), and sufficient deformation space is reserved at its ends; among them, the central limit bolt (41) of the corrugated shape memory alloy bar core (4) is in matching contact with the irregular circular arc-shaped grooves at the centers of the restraint plate a (1) and the restraint plate b (2), ensuring that the corrugated shape memory alloy bar core (4) is always at the center of the restraint plate a (1) and the restraint plate b, while there is a gap axially between the end limit bolts (42) and the irregular circular arc-shaped grooves of the restraint plate a (1) and the restraint plate b (2). The left gap is L1, the right gap is L2, and L1 = L2. The radial gap is T1; The counterbores a (11), the counterbores b (21), and the bolts (3) avoid the corrugated shape memory alloy bar core (4) and are arranged on both sides of the corrugated shape memory alloy bar core (4); When the structure vibrates due to seismic action, it will drive the relative movement of the threaded end a (47) and the threaded end b (48), thereby causing the first yield segments a (43), first yield segments b (44), second yield segments a (45) and second yield segments b (46) of the core (4) of the bamboo-jointed shape memory alloy bar to yield, consuming seismic energy while providing the structure with the ability to reset; when a moderate or small earthquake occurs, the first yield segments a (43) and first yield segments b (44) of the bamboo-jointed shape memory alloy bar core (4) with a smaller diameter yield first and enter the hysteretic energy dissipation state, providing damping force for the structure and improving the energy dissipation capacity and reset ability of the structure under moderate or small earthquakes, while the second yield segments a (45) and second yield segments b (46) do not enter the yield state due to their larger diameter and only undergo elastic deformation; under strong seismic action, when the deformation of the structure is large enough to reach L1, the end limit bolts (42) of the first yield segments a (43) and first yield segments b (44) contact the irregular circular arc-shaped grooves of the restraint plate a (1) and the restraint plate b (2), the first yield segments a (43) and first yield segments b (44) stop deforming, and the second yield segments a (45) and second yield segments b (46) continue to deform to ensure the seismic resistance effect of the structure under strong earthquakes; Among them, the bolt (3) is a high-strength bolt, which is placed in the counterbore a (11) and the counterbore b (21) to fix the restraint plate a (1) and the restraint plate b (2), ensuring that there is no relative displacement between the two and providing reliable restraint for the core (4) of the bamboo-jointed shape memory alloy bar; the diameters of the first yield segments a (43), first yield segments b (44), second yield segments a (45) and second yield segments b (46) are D1, D2, D3 and D4 respectively, and both D3 and D4 are greater than D1 and D2; the number of each yield segment and the parameters L1, L2, T1, D1, D2, D3 and D4 can all be designed according to the seismic requirements of the actual structure; the threaded end a (47) and the threaded end b (48) are respectively connected to the structures on both sides.

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