A fabricated three-order yield buckling-restrained brace device

Abstract

The application relates to an assembled three-order yield buckling-restrained brace device and belongs to the technical field of building anti-seismic devices. The device comprises two lateral restraint units, a bending energy dissipation unit, an H-shaped steel, a gasket, an upper cover plate and a lower cover plate. The two lateral restraint units are in U shapes and are arranged in two side grooves of the H-shaped steel along the length direction of the H-shaped steel. One bending energy dissipation unit is welded to each end of each lateral restraint unit. The part of the bending energy dissipation unit located outside the lateral restraint unit is fastened to the H-shaped steel through high-strength bolts. The upper cover plate and the lower cover plate cover the upper side and the lower side of the H-shaped steel. The gasket is arranged in the gap between the cover plate and the lateral restraint unit. The lateral restraint unit, the cover plate and the gasket are fastened into an integrated whole through high-strength bolts. The application has a three-order yield function. When applied to a building structure, the application can effectively improve the anti-seismic performance of the main structure, and has the technical advantages of low maintenance and repair cost during use.

Description

Technical Field

[0001] This invention relates to a prefabricated three-stage yield buckling-resistance brace, belonging to the technical field of seismic devices for buildings. Background Technology

[0002] With economic and social development, the economic losses caused by earthquakes are showing a non-linear, accelerating growth trend. Traditional seismic design methods rely on strengthening the main structure to rigidly resist earthquakes. Therefore, traditional structures often experience structural damage to major load-bearing components such as beams and columns after a major earthquake, affecting the building's continued use and repair value. Energy dissipation and damping technology, by placing dampers in the main structure, absorbs seismic energy, effectively protecting the main structure and significantly improving the building's seismic resistance and disaster reduction capabilities. Among various dampers, buckling-resisted braces are widely used due to their stable mechanical properties, outstanding damping capacity, and ease of processing and installation.

[0003] Conventional buckling-restrained braces are typically designed only for moderate and major earthquakes, and are generally not allowed to yield and dissipate energy under minor earthquakes. However, in reality, most structures rarely experience moderate and major earthquakes during their service life, and are more likely to experience minor earthquakes. If the design is based on minor earthquakes, causing the buckling-restrained braces to yield and dissipate energy under minor earthquakes, the main structure will have insufficient energy dissipation capacity under moderate and major earthquakes, and the buckling-restrained braces may also experience fatigue fracture due to excessive accumulation of plastic damage.

[0004] Therefore, stepped yield buckling-restrained braces are an effective technical means to solve the above problems. This type of buckling-restrained brace has multiple yield loads, which can take into account the seismic resistance and disaster reduction requirements of the main structure under different levels of earthquake loading. However, existing stepped yield buckling-restrained braces have the following main shortcomings: 1. It only has two-stage yielding function. After designing the first-stage yielding load based on the action of a small earthquake, the second-stage yielding load can only consider the action of a moderate or large earthquake. At the same time, the key part of the existing stepped yielding buckling-resistance brace that determines its axial stiffness and ultimate bearing capacity—the yielding energy dissipation section—is usually made of a straight steel plate, which makes the design tonnage easy to limit.

[0005] 2. Many components of existing stepped yield-type buckling-restrained braces need to be welded together to form a whole. If a local failure occurs during use, the entire component needs to be replaced, which increases the cost of use, inspection and maintenance.

[0006] Therefore, there is an urgent need for a prefabricated third-order yield buckling-resistant brace that can solve the above-mentioned technical problems. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a prefabricated three-stage yield buckling brace. This device can comprehensively take into account the energy dissipation and vibration reduction requirements of the main structure under small, moderate and large earthquakes, while also being easy to inspect and maintain. Thus, it can effectively improve the seismic performance and reliability of the main structure while also having good economic efficiency.

[0008] To achieve the above objectives, the present invention provides the following technical solution: A prefabricated three-stage yield buckling-resistance brace is characterized by comprising two lateral restraint units 1, a bending energy dissipation unit 2, an H-beam 3, a pad 4, an upper cover plate 5, and a lower cover plate 6. The two lateral restraint units 1 are U-shaped and arranged along the length of the H-beam 3 in the grooves on both sides of the H-beam 3. Each lateral restraint unit 1 has a bending energy dissipation unit 2 welded to both ends. The portion of the bending energy dissipation unit 2 located outside the lateral restraint unit 1 is fastened to the H-beam 3 by high-strength bolts. The upper cover plate 5 and the lower cover plate 6 cover the upper and lower sides of the H-beam 3. The pad 4 is located in the gap between the cover plate and the lateral restraint unit 1. The lateral restraint unit 1, the cover plate, and the pad 4 are fastened together as a whole by high-strength bolts. Preferably, the lateral restraint unit 1 is made of cold-formed channel steel (a channel steel formed by processing steel plate by a bending machine, i.e., cold-formed steel channel), and multiple bolt holes are provided along the length of the cold-formed channel steel; Preferably, the bending energy dissipation unit 2 includes multiple X-shaped steel plates 7, an upper end plate 8, a lower end plate 10, and an intermediate plate 9. The multiple X-shaped steel plates 7 are respectively welded to the upper and lower sides of the intermediate plate 9. The upper end plate 8 is welded to the top of the upper X-shaped steel plate 7, and the lower end plate 10 is welded to the bottom of the lower X-shaped steel plate 7. The bending energy dissipation unit 2 is welded to both ends of the web of the lateral restraint unit 1 through the intermediate plate 9. The upper surface of the upper end plate 8 and the lower surface of the lower end plate 10 are provided with a friction material layer 11, and the surface of the friction material layer 11 is in contact with the H-beam 3. Preferably, the number of high-strength bolts installed between the upper end plate 8, the lower end plate 10, and the H-beam 3 is... n The formula for calculating 1 (1) is: (1) in n 1 represents the required number of bolts and must be a multiple of 4. The coefficient of friction between friction material layer 11 and H-beam 3 is denoted as 0.3~0.45. P To determine the preload of the high-strength bolts to be used, F 1 represents the design value of the first-order yield load determined based on the action of a minor earthquake; Preferably, the formula (2) for calculating the total number n2 of the X-shaped steel plates 7 is: n 2=3F 2 h / bt 2 f y1 (2) In the formula, h , b , t These are the height, root width, and thickness of the X-shaped steel plate 7, respectively. f y1 F1 represents the yield strength of X-shaped steel plate 7, and F2 represents the design value of the second-order yield load determined based on the moderate earthquake action. Preferably, the H-beam 3 includes an upper flange 3-1 and a lower flange 3-2 as an integral structure, and a web 3-3 located between the two flanges. The middle section of the flange is cut with a notch 3-4, the shape of the notch 3-4 matches the shape of the pad 4, and bolt holes are provided at both ends of the flange. Preferably, the cross-sectional area of ​​the intermediate section A Based on the design value of yield load under a major earthquake F 3. Through strength calculation, it was determined that the net cross-sectional area at the ends of the H-beam is greater than the cross-sectional area in the middle section. A 1.8 times, the formula for calculating A (3) is: A = F 3 / f y2 (3) in f y2 This represents the design value of the yield strength of H-beam 3. F 3 represents the design value of the third-order yield load determined based on the action of a major earthquake; Preferably, the bolt holes at both ends of the flange of the H-beam 3 are oblong, and the slot length of the oblong holes is... L The formula for calculating 2 (4) is: (4) in d The diameter of the high-strength bolt. This represents the maximum design displacement under minor earthquake conditions. Preferably, both the cover plate and the pad plate 4 are provided with bolt holes corresponding to the lateral restraint units 1. The thickness of the pad plate 4 is 1-2 mm thicker than the flange thickness of the H-beam 3, so as to ensure that the lateral expansion deformation caused by the Poisson effect when the H-beam is under pressure can be effectively released.

[0009] The beneficial effects of this invention are as follows: 1. The prefabricated three-stage yield buckling-resistance brace of the present invention has a three-stage yield function. Its three-stage yield loads are designed for minor earthquakes, moderate earthquakes and major earthquakes respectively, which can comprehensively take into account the energy dissipation and vibration reduction requirements of the main structure under different seismic actions.

[0010] 2. The prefabricated three-stage yield buckling-restrained brace of the present invention uses H-beams as the inner core. Compared with the existing straight inner core, it can provide greater initial stiffness and yield bearing capacity in a limited space, and can be used to manufacture large-tonnage buckling-restrained braces.

[0011] 3. The assembled three-stage yield buckling-resistance brace of the present invention is assembled with high-strength bolts. After a minor or moderate earthquake, the damage to the friction unit and bending energy dissipation unit can be directly observed. If necessary, the lateral restraint unit can be removed and replaced. The key H-shaped steel core can continue to be used, thus effectively reducing the difficulty and cost of post-earthquake inspection and repair, thereby improving the economy of seismic design for building structures.

[0012] 4. The components of this invention are assembled using high-strength bolts. The related technologies proposed in this invention can not only be used to construct new buckling-restrained bracing components, but also to modify and upgrade existing H-beam steel components in the structure, thereby improving the seismic performance of the main structure. Therefore, it has a wider range of applications.

[0013] 5. The prefabricated third-order yield buckling-resistance brace of the present invention has an H-shaped cross section at the end, similar to ordinary braces, which facilitates connection with the node plate of the main structure and reduces the difficulty of designing and constructing the connection section. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of a prefabricated third-order yield buckling-resistance brace according to the present invention; Figure 2 for Figure 1 Exploded view; Figure 3 This is a side view of an assembled three-stage yielding buckling-resistance brace according to the present invention; Figure 4 This is an assembly diagram of the lateral restraint unit, bending energy dissipation unit, and H-beam in a prefabricated third-order yield buckling-resistance brace of the present invention. Figure 5 for Figure 3 Exploded view; Figure 6 This is a structural schematic diagram of the lateral restraint unit and the bending energy dissipation unit; Figure 7 This is a schematic diagram of the bending energy dissipation unit. Figure 8 This is a structural schematic diagram of an X-shaped steel plate. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example 1

[0016] This embodiment describes a prefabricated three-stage yield buckling-resistance brace. Please refer to [link to relevant documentation]. Figure 1-8 It includes two lateral restraint units 1, a bending energy dissipation unit 2, an H-beam 3, a pad 4, an upper cover plate 5, and a lower cover plate 6. The two lateral restraint units 1 are U-shaped and are arranged in the grooves on both sides of the H-beam 3 along the length of the H-beam 3. A bending energy dissipation unit 2 is welded to both ends of each lateral restraint unit 1. The part of the bending energy dissipation unit 2 located outside the lateral restraint unit 1 is fastened to the H-beam 3 by high-strength bolts. The upper cover plate 5 and the lower cover plate 6 cover the upper and lower sides of the H-beam 3. The pad 4 is located in the gap between the cover plate and the lateral restraint unit 1. The lateral restraint unit 1, the cover plate, and the pad 4 are fastened together as a whole by high-strength bolts.

[0017] The lateral restraint unit 1 is made of cold-formed channel steel and has multiple bolt holes along its length.

[0018] The bending energy dissipation unit 2 includes multiple X-shaped steel plates 7, an upper end plate 8, a lower end plate 10, and an intermediate plate 9. The multiple X-shaped steel plates 7 are respectively welded to the upper and lower sides of the intermediate plate 9. The upper end plate 8 is welded to the top of the upper X-shaped steel plate 7, and the lower end plate 10 is welded to the bottom of the lower X-shaped steel plate 7. The bending energy dissipation unit 2 is welded to both ends of the web of the lateral restraint unit 1 through the intermediate plate 9. The upper surface of the upper end plate 8 and the lower surface of the lower end plate 10 are provided with friction material layers 11, and the surface of the friction material layers 11 is in contact with the H-beam 3. H-beam 3 includes an upper flange 3-1 and a lower flange 3-2, which are integral structures, and a web 3-3 located between the two flanges. The middle section of the flange is cut with a notch 3-4, the shape of which matches the shape of the pad 4. Bolt holes are provided at both ends of the flange.

[0019] The specific design is as follows: The first step is the design of the friction element. Through seismic analysis, the design value of the first-order yield load is determined based on the action of minor earthquakes. F 1. According to F 1. Based on the friction characteristics of the friction material to be used (usually brass or brake pads), the number of high-strength bolts required to connect the upper end plate 8 and lower end plate 10 of the bending energy dissipation unit 2 to the flange of the H-beam 3 is calculated. The calculation formula is as follows: ,inn 1 represents the required number of bolts, and it must be a multiple of 4 to facilitate subsequent assembly. This is the coefficient of friction between the friction material and the steel plate, typically ranging from 0.3 to 0.45. P To determine the preload of the high-strength bolts to be used, the preload can be determined based on the bolt diameter. d The performance level can be determined by consulting the mechanical design manual.

[0020] The second step involves the design and assembly of bending energy dissipation unit 2. This is based on the design value of the second-order yield load determined by the moderate earthquake. F 2. According to F 2. Determine the geometric dimensions and total number of X-shaped plates 7 based on the material to be used. The specific design formula is as follows: n 2=3 F 2 h / bt 2 f y1 In the formula n 2 represents the total number of X-shaped plates required. h , b , t These are the height, root width, and thickness of the X-shaped plate 7, as shown in the attached figure. Figure 8 (as shown) f y1 The yield strength of the X-shaped steel plate. After the design of the X-shaped plate 7 is completed, the X-shaped plate 7 is welded together with the upper end plate 8, the lower end plate 10 and the middle plate 9 to form the bending energy dissipation unit 2 (as shown in the attached figure). Figure 7 As shown in the figure, bolt holes need to be drilled in advance on the upper and lower end plates. The diameter of the bolt holes should be the same as the diameter of the high-strength bolts to be used in the first step (the upward deviation should be controlled within 0.5mm). The number of holes on each end plate is as follows. n 1 / 4.

[0021] The third step is to assemble the lateral constraint unit 1. (See attached image.) Figure 6 As shown, bolt holes need to be pre-drilled on the cold-formed channel steel. The number and diameter of the bolt holes need to be determined after local stability analysis and calculation of the H-beam 3. Then, the intermediate plates 9 of the two bending energy dissipation units 2 are respectively centered and welded to both ends of the web of the cold-formed channel steel. Friction material layers 11 are laid on the upper and lower end plates of the bending energy dissipation units to form lateral constraint units 1. The distance between the upper and lower end plates of the bending energy dissipation units 2 and the cold-formed channel steel should be ensured. L 1 is greater than the maximum design displacement of the prefabricated third-order yield buckling-restrained brace. This is to prevent the upper and lower end plates from directly contacting the cold-formed channel steel during operation, which would affect the smooth realization of its third-order yield mechanism.

[0022] Step four: Assembly of lateral restraint unit 1 and H-beam 3. (See attached diagram) Figure 4 As shown, a variable cross-section H-beam 3 is required. The middle section can be formed by locally cutting the flanges. The cross-sectional area of ​​the middle section is... A The design value of the third-order yield load needs to be determined based on the action of a major earthquake. F 3. Determined through strength verification, the calculation formula is as follows: A = F 3 / f y2 ,in f y2 This refers to the design value of the yield strength of the H-beam. The net cross-sectional area at the three ends of the H-beam must be greater than the cross-sectional area of ​​the middle section. A The length is 1.8 times that of the H-beam to ensure that the ends of the H-beam remain in the elastic stage throughout the entire working process, thus ensuring reliable force transmission. The bolt holes at both ends of the flange of H-beam 3 are oblong, and the slot length of the oblong holes is... ,in d The diameter of the connecting bolt. This represents the maximum design displacement under minor earthquake conditions. The lateral restraint unit 1 and the variable cross-section H-beam 3 are connected by tightening high-strength bolts, completing the assembly of the lateral restraint unit 1 and the H-beam 3. It should be noted that at this point, the component already possesses a double-yield function and can be directly used as a double-yield type metal damper, representing a variant of this invention.

[0023] Step 5: Design and assembly of the vertical constraint elements. (See attached document) Figure 2 As shown, the vertical restraint unit mainly consists of an upper cover plate 5, a lower cover plate 6, and four pads 4. Bolt holes corresponding to the cold-formed channel steel are opened on the cover plates and pads 4. The pads 4 should be 1-2 mm thicker than the flange of the H-beam 3 to ensure that the lateral deformation caused by the Poisson effect after the H-beam 3 yields under compression can be effectively released. The thickness of the cover plate needs to be determined by calculation based on the spacing of the connecting bolts and the maximum design load of the prefabricated third-order yield buckling-restrained brace. The cover plates, pads 4, and cold-formed channel steel are connected as a whole by high-strength bolts, ultimately forming a prefabricated third-order yield buckling-restrained brace device, as shown in the attached diagram. Figure 1 As shown.

[0024] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A prefabricated three-stage yield buckling-resistance brace, characterized in that... It includes two lateral restraint units, a bending energy dissipation unit, an H-beam, a pad, an upper cover plate, and a lower cover plate. The two lateral restraint units are U-shaped and are set in the grooves on both sides of the H-beam along the length of the H-beam. A bending energy dissipation unit is welded to both ends of each lateral restraint unit. The part of the bending energy dissipation unit located outside the lateral restraint unit is fastened to the H-beam with high-strength bolts. The upper cover plate and the lower cover plate cover the upper and lower sides of the H-beam. The pad is set in the gap between the cover plate and the lateral restraint unit. The lateral restraint unit, the cover plate, and the pad are fastened together as a whole with high-strength bolts. The bending energy dissipation unit includes multiple X-shaped steel plates, an upper end plate, a lower end plate, and an intermediate plate. The multiple X-shaped steel plates are respectively welded to the upper and lower sides of the intermediate plate. The upper end plate is welded to the top of the upper X-shaped steel plate, and the lower end plate is welded to the bottom of the lower X-shaped steel plate. The bending energy dissipation unit is welded to both ends of the web of the lateral restraint unit through the intermediate plate. The upper surface of the upper end plate and the lower surface of the lower end plate are provided with friction material layers, and the surface of the friction material layers is in contact with the H-shaped steel.

2. A prefabricated three-stage yield buckling-resistance brace according to claim 1, characterized in that... The lateral restraint unit is made of cold-formed channel steel, and multiple bolt holes are provided along the length of the cold-formed channel steel.

3. A prefabricated three-stage yield buckling-resistance brace according to claim 1, characterized in that... The number of high-strength bolts installed between the upper end plate, the lower end plate, and the H-beam. n The formula for calculating 1 is: （1） in n 1 represents the required number of bolts and must be a multiple of 4. for The coefficient of friction between the friction material layer and the H-beam ranges from 0.3 to 0.

45. P To determine the preload of the high-strength bolts to be used, F 1 represents the design value of the first-order yield load determined based on the action of a minor earthquake.

4. A prefabricated three-stage yield buckling-resistance brace according to claim 1, characterized in that... The formula for calculating the total number n2 of X-shaped steel plates is: n 2=3 F 2 h / bt 2 f y1 （2） In the formula, h , b , t These are the height, root width, and thickness of the X-shaped steel plate, respectively. f y1 F1 represents the yield strength of the X-shaped steel plate, and F2 represents the design value of the second-order yield load determined based on the moderate earthquake action.

5. A prefabricated three-stage yield buckling-resistance brace according to claim 1, characterized in that... The H-beam includes an upper flange and a lower flange as an integral structure, and a web between the two flanges. The middle section of the flange is cut with a notch, the shape of which matches the shape of the pad. Bolt holes are provided at both ends of the flange.

6. A prefabricated three-stage yield buckling-resistance brace according to claim 5, characterized in that... The cross-sectional area of ​​the middle section of the flange A Based on the design value of yield load under a major earthquake F 3. Through strength calculations, it was determined that the net cross-sectional area at the ends of the H-beam is greater than the cross-sectional area of ​​the middle section of the flange. A 1.8 times, the formula for calculating A is: A = F 3 / f y2 （3） in f y2 This refers to the design value of the yield strength of the H-beam. F 3 represents the design value of the third-order yield load determined based on the action of a major earthquake.

7. A prefabricated three-stage yield buckling-resistance brace according to claim 5, characterized in that... The bolt holes at both ends of the flange of the H-beam are oblong in shape, and the slot length of the oblong holes is... L The formula for calculating 2 is: （4） in d The diameter of the high-strength bolt. This represents the maximum design displacement under minor earthquake conditions.

8. A prefabricated three-stage yield buckling-resistance brace according to claim 1, characterized in that... Both the cover plate and the pad are provided with bolt holes corresponding to the lateral restraint units. The thickness of the pad is 1-2 mm thicker than the flange thickness of the H-beam.

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