X-shaped support with replaceable energy-dissipating connection and design method thereof

Abstract

The present invention discloses an X-shaped support with a replaceable energy-absorbing connection and a design method thereof. The X-shaped support with a replaceable energy-absorbing connection comprises a box-section support, a node plate, a connecting plate, high-strength bolts and a variable-section round-end metal energy-absorbing part. A slot is provided at the end of the box-section support. The node plate and the box-section support are assembled and welded by plug-in. The other side of the node plate is welded to the connecting plate to form a T-shape. The box-section support, the node plate and the connecting plate are in a left-right symmetrical relationship. The variable-section round-end metal energy-absorbing part is arranged between the connecting plates and connected by high-strength bolts. Under the action of an earthquake, the variable-section round-end metal energy-absorbing part yields in shear to dissipate energy. After the earthquake, the high-strength bolts on the variable-section round-end metal energy-absorbing part can be removed to achieve the replacement of the energy-absorbing part. The present invention has a simple structural form, clear force, convenient design, good performance, is easy to replace after an earthquake, is easy to maintain, and has good economic benefits.

Description

Technical Field

[0001] The invention belongs to the field of structural engineering in civil engineering, and in particular relates to an X-shaped support with replaceable energy-dissipating connections and a design method thereof. Background Art

[0002] Since the 21st century, significant progress has been made in concepts and technologies for structural energy dissipation and shock absorption. Structural energy dissipation and shock absorption technology aims to improve the performance of structures under earthquakes by setting up energy dissipation components. These energy dissipation components can first undergo plastic deformation when an earthquake occurs, thereby providing additional damping for the structure and effectively dissipating the energy generated by the earthquake. This helps to reduce the impact of earthquakes on the main structure and reduce the risk of structural damage. As a type of energy dissipation component, the damper has a simple structure, is convenient to design, and has good hysteresis performance. It is widely used in structural shock absorption and energy dissipation.

[0003] The steel frame support system has a large lateral stiffness in the elastic stage, and its energy dissipation capacity is weak under the action of rare earthquakes. After the support is compressed and buckled, the lateral stiffness of the structure is significantly reduced, which can easily lead to the loss of bearing capacity and damage of the structure. By combining the damper with the ordinary steel support to form an energy dissipation support, additional stiffness can be provided for the structure, and the damper can also first dissipate plastic energy under the action of an earthquake without buckling the support body, thus protecting the overall performance of the structure.

[0004] Xu Liyan and other scholars proposed a new type of shear steel plate damper in the article "Research on Mechanical Properties and Theoretical Model of Low Yield Point Steel Shear Damper". The effects of test parameters including web width-to-thickness ratio, stiffening rib arrangement, web opening structure, and cyclic loading system were studied, proving the excellent seismic performance of this shear steel plate damper. However, the steel beam connected to the damper needs to bear a relatively large load.

[0005] Gray et al. proposed a central support system (YBS) with a triangular stiffening metal damper in the article "Design and Full-Scale Testing of a Cast Steel Yielding Brace System in a Braced Frame". The damper is installed at the end of the central support and connected to the frame column through a node plate. The damper is relatively complex in structure and has certain difficulties in construction. Summary of the invention

[0006] The purpose of the present invention is to solve the current engineering needs and propose an X-shaped support with replaceable energy-absorbing connection and a design method thereof, which is simple in structure and design. In view of the stress characteristics of the variable-section circular-end metal energy-absorbing part when used for the X-shaped support, the structural form and design method proposed in the present invention have strong engineering application value.

[0007] The X-shaped support with replaceable energy-absorbing connection comprises a box-section support, a node plate, a connection plate and a variable-section circular-end metal energy-absorbing part.

[0008] The ends of the box-section supports are provided with slots, and the node plates and the box-section supports are assembled and welded by means of plug-in.

[0009] The other side of the node plate is welded to the connecting plate to form a T-shape, and the box-type support, node plate and connecting plate are in a bilaterally symmetrical relationship;

[0010] The variable-section round-end metal energy-absorbing parts are arranged between the connecting plates.

[0011] Furthermore, the variable-section circular-end metal energy-absorbing part is a variable-section energy-absorbing part, including two semicircular end plates for assuming energy absorption, and two relatively arranged variable-section straight plates. A semicircular end plate is arranged at each end of the variable-section straight plate, and the two variable-section straight plates are fixedly connected to the connecting plate by high-strength bolts.

[0012] Furthermore, the support may be a box-shaped structure, or may be a channel steel or H-shaped steel structure.

[0013] Preferably, the variable cross-section round end metal energy dissipation part is constructed as follows: given the geometric parameters of the energy dissipation part, including the thickness t of the steel plate, the width b′ of the variable cross-section straight plate end, the outer diameter R of the semicircular end, and the total length d of the variable cross-section straight plate, such as Figure 3 As shown. A single variable-section circular end metal energy-absorbing component includes four parts, including: two semicircular end plates ABC and DEF, two variable-section straight plates AF and CD, and a semicircular end plate is welded at each end of the variable-section straight plate, forming a semicircular shape. The variable-section straight plates AF and CD are connected to the connection plates through high-strength bolts in the above-mentioned nodes, and are the non-energy-absorbing connection parts of the component; the semicircular arc segments ABC and DEF are the parts of the component that bear the energy-absorbing function.

[0014] Furthermore, the variable-section circular end metal energy-absorbing part is made of Q235 steel, low-yield steel LY225 or LY160, the semicircular end plate is made of straight plate cold-bent, and the bolt hole is a standard hole, a large circular hole or a slotted hole.

[0015] A design method for an X-shaped support with a variable-section round-end metal energy dissipation member comprises the following steps:

[0016] The variable-section circular end metal energy dissipation part includes two semicircular end plates for absorbing energy and two relatively arranged variable-section straight plates. Since the bending moment is the largest at the intersection of the variable-section straight plate and the semicircular end plate of the variable-section circular end metal energy dissipation part, and the variable-section straight plate may bend and deform, the semicircular section of the variable-section circular end metal energy dissipation part after deformation is not a strictly standard semicircular arc. The variable-section circular end metal energy dissipation part is two semicircular arcs working together. According to this force deformation, the modified yield load F of the variable-section circular end metal energy dissipation part is obtained. y , the expressions of initial stiffness K0 and second stiffness K′, the restoring force model of the variable-section circular end metal energy dissipation part is determined by the following parameters: the outer diameter R of the variable-section circular end metal energy dissipation part, the thickness t, the middle width b of the variable-section straight plate, the yield strength f y , yield load correction factor α, initial stiffness correction factor β and second stiffness correction factor γ;

[0017] Under the action of earthquake, the frame shifts horizontally, and the supports bear different internal forces. The two diagonal supports are subjected to tension, while the other two diagonal supports are subjected to compression. The axial forces generated by the horizontal loads of the four steel supports meet at the energy dissipation connection. After the force is decomposed, the horizontal forces are balanced in the horizontal direction, and shear forces act on the variable-section circular end metal energy dissipation parts in the vertical direction. In this case, the variable-section circular end metal energy dissipation parts are controlled to yield in shear first to dissipate energy. At this time, the yield load of the support is multiplied by the safety factor η1 so that the yield load of the support is greater than the yield load of the energy dissipation parts. Considering the influence of the compressive stability coefficient of the support, 0.7P is taken. y As the support yield load, considering the unbalanced tension and compression of the support, take η2F y is the yield load of the energy dissipation part; then the design of the X-shaped support with replaceable energy dissipation connection must meet the following requirements: the vertical component of the support yield load should be greater than the yield load of the variable-section circular end metal energy dissipation part so that the energy dissipation part yields first, that is,

[0018] 2×η1×0.7P y sinα>η2F y

[0019] Where α is the angle between the support and the horizontal plane, F y is the yield load of the variable cross-section circular end metal energy dissipation part, η2 is the safety magnification factor of the energy dissipation part, P y =A zc ·f y ;

[0020] Determine the component performance of the X-shaped support with replaceable energy-absorbing connection, and use stiffness ratio and strength ratio to describe the component performance of the X-shaped support with replaceable energy-absorbing connection: perform elastic-plastic time-history analysis on the X-shaped support steel frame structure with replaceable energy-absorbing connection, and obtain the inter-story displacement angle, base shear force and vertex displacement corresponding to the target performance segment of the X-shaped support steel frame with replaceable energy-absorbing connection under X- and Y-direction earthquakes, so as to calculate the equivalent stiffness of the structure and its corresponding additional damping ratio and stiffness ratio.

[0021] Furthermore, the additional damping ratio and additional stiffness ratio of the X-shaped braced steel frame structure with replaceable energy-absorbing connection were integrated and analyzed. The results showed that the ratio of the vertical shear stiffness of the energy-absorbing connection, i.e. the initial stiffness K0 of the energy-absorbing part, to the vertical stiffness component of the support was between 0.50 and 0.85, and the ratio of the shear yield strength of the energy-absorbing connection to the vertical component of the support yield strength was between 0.35 and 0.65.

[0022] Furthermore, in the structural design, the limit displacement d of the variable cross-section circular end metal energy dissipation part u It is 0.2 to 0.5 times the outer diameter R of the semicircular end plate. The value range of η1 is between 0.50 and 0.60, and the value range of η2 is between 1.05 and 1.15.

[0023] Furthermore, the yield load F of the variable cross-section circular end metal energy dissipation part y , initial stiffness K0, expressed as:

[0024]

[0025] In the formula, R is the outer diameter of the variable cross-section circular end metal energy dissipation part, t is the thickness of the variable cross-section circular end metal energy dissipation part, b is the middle width of the variable cross-section straight plate, and f is the y is the yield strength, λ is the amplification factor, which is the square of the difference in width of the variable-section straight plate of the variable-section round-end metal energy-absorbing part, α is the yield load correction factor, which ranges from 4.45 to 4.46, and β is the initial stiffness correction factor, which ranges from 1.40 to 1.50.

[0026] Furthermore, when the shear force on the variable-section energy-absorbing part is greater than the yield load, the variable-section circular-end metal energy-absorbing part is in the elastic-plastic stage, and the stiffness at this time is the second stiffness, which is expressed as:

[0027] K′=γK0

[0028] Where γ is the second stiffness correction coefficient, and its value range is between 0.014 and 0.016.

[0029] Furthermore, the width b′ of the end portion of the variable-section straight plate of the variable-section round-end metal energy-absorbing part is 1.1 to 1.2 times the width b of the middle portion of the straight plate.

[0030] Furthermore, according to design requirements, it is recommended that the middle width b of the variable-section straight plate range from 60 to 300 mm, the end width b′ of the variable-section straight plate range from 74 to 360 mm, the height 2R of the variable-section round-end metal energy-absorbing part range from 80 to 240 mm, and the thickness t of the variable-section round-end metal energy-absorbing part range from 6 to 32 mm.

[0031] Compared with the prior art, the present invention has at least the following advantages and effects:

[0032] Compared with the circular-end metal damper with equal cross-section, the variable-section circular-end metal energy-absorbing part has greater initial stiffness and yield load, good elastic-plastic properties, a fuller load-displacement hysteresis curve, stronger energy-absorbing capacity, and can absorb more seismic energy during earthquakes. Compared with ordinary support frames, the X-support with replaceable energy-absorbing connection will not have a sudden drop in stiffness after the support is buckled. The energy consumption of the structure is concentrated on the variable-section circular-end metal energy-absorbing part, and the energy-absorbing part can be quickly replaced after the earthquake. Compared with a pure frame, the X-support with a replaceable energy-absorbing connection has better hysteresis performance and greater stiffness. The present invention has a simple structure, clear force transmission, and good economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of an X-shaped support with replaceable energy-dissipating connections used in the present invention.

[0034] Figure 2 It is an exploded view of an X-shaped support with replaceable energy-dissipating connection used in the present invention.

[0035] Figure 3 It is a schematic diagram of the geometric dimensions of the variable-section round-end metal energy-absorbing part used in the present invention.

[0036] Figure 4 It is a mechanical diagram of an X-shaped support with replaceable energy-dissipating connection used in the present invention.

[0037] Figure 5 Schematic diagram of the force of an X-shaped support with replaceable energy-dissipating connection in an embodiment of the present invention.

[0038] Figure 6 is a stress diagram of the structure in an embodiment of the present invention.

[0039] Figure 7 1 is a stress diagram of a variable cross-section circular end metal energy dissipating part in an embodiment of the present invention.

[0040] Figure 8 is a load-displacement hysteresis curve diagram of the structure in the embodiment of the present invention.

[0041] Fig. 93 is a load-displacement hysteresis curve diagram of the variable-section circular-end metal energy-absorbing part in an embodiment of the present invention.

[0042] In the figure, 1 is support, 2 is node plate, 3 is connection plate, 4 is variable-section circular end metal energy-absorbing part, and 5 is high-strength bolt. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solution and advantages of the present invention clearer and more specific, the following will be further described in detail in conjunction with the embodiments of the present invention and the accompanying drawings. However, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0044] The present invention provides an X-shaped support with replaceable energy-dissipating connection, the specific structure is as follows Figure 1 As shown, it includes a support 1, a node plate 2, a connecting plate 3, and a variable-section circular end metal energy dissipation part 4. The specific structural form is: a slot is provided at the end of the support 1, the node plate 2 and the support 1 are assembled and welded by plugging, the other side of the node plate 2 is welded to the connecting plate 3 to form a T shape, the support 1, the node plate 2, and the connecting plate 3 are in a bilaterally symmetrical relationship, and the variable-section circular end metal energy dissipation part 4 is arranged between the connecting plates 3, and is connected by high-strength bolts 5.

[0045] In some embodiments of the present invention, the support 1 is a central support with a box-shaped cross section.

[0046] In some embodiments of the present invention, the variable-section circular end metal energy dissipation part 4 is made of LY225 steel. A single variable-section circular end metal energy dissipation part includes four parts, including: two semicircular end plates ABC and DEF, two variable-section straight plates AF and CD, and one of the semicircular end plates is welded at each end of the variable-section straight plate. The variable-section straight plates AF and CD are connected to the connection plate 3 in the above-mentioned node by high-strength bolts 5.

[0047] The X-shaped support with replaceable energy-absorbing connection provided above is connected with steel columns and steel beams to form a steel frame with X-shaped support to bear the force together, which is safer, more reliable, and simpler and more convenient to install.

[0048] Next, we establish a finite force situation:

[0049] 1. Model establishment

[0050] In some embodiments of the present invention, an X-shaped support with a replaceable energy-absorbing connection is connected to a steel column and a steel beam. The finite element software ANASY is used to perform finite element simulation on the structure after the X-shaped support with a replaceable energy-absorbing connection provided by the aforementioned embodiments of the present invention is connected. The parameters of the variable-section round-end metal energy-absorbing part are set as follows: the middle width b of the variable-section straight plate is 210 mm, the end width b′ of the straight plate is 260 mm, the outer diameter R is 60 mm, the thickness t is 16 mm, and the dimensions of the remaining components are shown in the following table:

[0051] Table 1 Geometric dimensions of model components (unit: mm)

[0052]

[0053]

[0054] The parameter design related to the finite element model is shown in the following table:

[0055] Table 2 Model related parameter design

[0056]

[0057] The steel beams, steel bottom beams and steel columns are made of Q355 steel, the box supports are made of Q235 steel, and the variable-section circular end metal energy-absorbing parts are made of LY225 steel; the elastic modulus E is 2.0×10 5 MPa.

[0058] The finite element solid model is subjected to pseudo-static analysis, and the mesh of the connection parts is refined to ensure the accuracy of the calculation. During loading, the two column bottoms are constrained by fixed supports, and lateral constraints are applied to the frame column node domain to prevent out-of-plane instability. An axial force of 265kN is applied to the column top. Friction contact is set between the bolts and the energy dissipation parts, the bolts and the connecting plates, and the energy dissipation parts and the connecting plates. The friction coefficient is taken as 0.35. The bolts are 10.9-grade M24 high-strength bolts, and a preload of 225kN is applied. Figure 5 shown.

[0059] 2. Results Analysis

[0060] Cyclic reciprocating loads are applied to the X-shaped support steel frame with replaceable energy dissipation connection of the present invention, and the obtained structural stress diagram, energy dissipation component stress diagram, structural hysteresis curve and hysteresis curve of the energy dissipation component are as follows: Figure 6 , 7 , 8, and 9.

[0061] In the stress diagram, the color changes from light white to darker, indicating that the stress is getting bigger and bigger. Figure 6 , Figure 7It can be seen that the stress at the intersection of the variable-section straight plate and the semicircular end plate is the largest, with a value of 347.94MPa, indicating that the variable-section circular end metal energy dissipation parts have yielded, and the main structure and support stress range is between 0 and 300MPa, both of which remain elastic and unyielding. The energy dissipation is concentrated on the variable-section circular end metal energy dissipation parts, which can be replaced after the earthquake.

[0062] The energy dissipation coefficient E and equivalent viscous damping coefficient ξ of the energy dissipation component when the displacement is 62 mm can be calculated from the hysteresis curve. eq :

[0063]

[0064]

[0065] From the analysis of the figure, it can be seen that the hysteresis curve is full, and the equivalent viscous damping coefficient ξ eq It is also relatively large, indicating that its hysteresis curve performance is good and the initial stiffness is large.

[0066] The above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. An X-shaped support with replaceable energy-dissipating connections, characterized in that: It comprises a box-section support (1), a node plate (2), a connection plate (3) and a variable-section circular-end metal energy-absorbing part (4); A slot is provided at the end of the box-section support (1), and the node plate (2) and the box-section support (1) are assembled and welded in a plug-in manner; The other side of the node plate (2) is welded to the connecting plate (3) to form a T-shape, and the box-section support (1), the node plate (2) and the connecting plate (3) are in a bilaterally symmetrical relationship; The variable-section round-end metal energy-absorbing part (4) is arranged between the connecting plates (3); The X-shaped support is designed by the following steps: The variable-section circular end metal energy dissipation part (4) comprises two semicircular end plates for absorbing energy and two oppositely arranged variable-section flat plates. Since the bending moment is the largest at the intersection of the variable-section flat plate and the semicircular end plate of the variable-section circular end metal energy dissipation part (4), and the variable-section flat plate may bend and deform, the semicircular end plate of the variable-section circular end metal energy dissipation part (4) is not a strictly standard semicircular arc after deformation. The variable-section circular end metal energy dissipation part (4) is a combination of two semicircular end plates working together. According to the force deformation, the modified yield load of the variable-section circular end metal energy dissipation part (4) is obtained. , initial stiffness and the second stiffness The restoring force model of the variable cross-section circular end metal energy dissipation part (4) is determined by the following parameters: the outer diameter of the variable cross-section circular end metal energy dissipation part ,thickness , Middle width of variable cross-section straight plate , yield strength , yield load correction factor α, initial stiffness correction factor β and second stiffness correction factor ; Among them, the yield load of the variable cross-section circular end metal energy dissipation part (4) is , initial stiffness The expression is: In the formula, is the outer diameter of the variable-section circular-end metal energy-absorbing part, is the thickness of the variable-section circular end metal energy dissipation part, The middle width of the straight plate of the variable-section round-end metal energy-absorbing part. is the yield strength, is the magnification factor, which is the square of the width difference of the variable-section straight plate of the variable-section round-end metal energy dissipation part. is the yield load correction factor, β is the initial stiffness correction factor; When the shear force on the variable-section circular end metal energy dissipation part is greater than the yield load, the variable-section circular end metal energy dissipation part is in the elastic-plastic stage, and the stiffness at this time is the second stiffness, which is expressed as: In the formula, is the second stiffness correction coefficient, and its value range is between 0.014 and 0.016; Under the action of an earthquake, the frame shifts horizontally, and the box-section supports (1) bear different internal forces. The two diagonal box-section supports (1) are subjected to tension, while the other two diagonal box-section supports (1) are subjected to compression. The axial forces generated by the horizontal load on the four steel box-section supports (1) converge at the energy-absorbing connection. After the force is decomposed, the horizontal forces are balanced in the horizontal direction, and a shear force acts on the variable-section circular end metal energy-absorbing part (4) in the vertical direction. In this case, the variable-section circular end metal energy-absorbing part (4) is controlled to yield and dissipate energy first. At this time, the yield load of the box-section support (1) is multiplied by the safety factor. Make the yield load of the box section support (1) greater than the yield load of the energy dissipation component; consider the influence of the compressive stability coefficient of the box section support (1) and take 0.7 As the yield load of the box section support (1), consider the unbalanced tension and compression of the box section support (1). is the yield load of the energy dissipation part; then the design of the X-shaped support with replaceable energy dissipation connection must meet the following requirements: the vertical component of the yield load of the box-section support (1) should be greater than the yield load of the variable-section circular end metal energy dissipation part (4) so ​​that the energy dissipation part yields first, that is, In the formula, is the angle between the box section support (1) and the horizontal plane, is the yield load of the variable cross-section circular end metal energy dissipation part, is the safety magnification factor of energy-consuming parts, ; Determine the component performance of the X-shaped support with replaceable energy-absorbing connection, and use stiffness ratio and strength ratio to describe the component performance of the X-shaped support with replaceable energy-absorbing connection: perform elastic-plastic time-history analysis on the X-shaped support steel frame structure with replaceable energy-absorbing connection, and obtain the inter-story displacement angle, base shear force and vertex displacement corresponding to the target performance segment of the X-shaped support steel frame with replaceable energy-absorbing connection under X- and Y-direction earthquakes, so as to calculate the equivalent stiffness of the structure and its corresponding additional damping ratio and stiffness ratio.

2. An X-shaped support with replaceable energy-dissipating connection according to claim 1, characterized in that: The variable cross-section circular end metal energy absorbing part (4) comprises two semicircular end plates for absorbing energy and two oppositely arranged variable cross-section flat plates, one semicircular end plate being arranged at each end of the variable cross-section flat plate, and the two variable cross-section flat plates are fixedly connected to the connecting plate (3) by high-strength bolts (5).

3. An X-shaped support with replaceable energy-dissipating connection according to claim 2, characterized in that: The variable-section circular end metal energy dissipation part (4) is made of Q235 steel, low-yield steel LY225 or LY160, the semicircular end plate is made of a straight plate by cold bending, and the bolt hole is a standard hole, a large circular hole or a slotted hole.

4. An X-shaped support with replaceable energy-dissipating connection according to claim 1, characterized in that: Under the action of an earthquake, the variable-section circular end metal energy absorbing part (4) dissipates energy by yielding under shear. After the earthquake, the high-strength bolts on the variable-section circular end metal energy absorbing part can be removed to achieve replacement of the energy absorbing part.

5. A design method for an X-shaped support with replaceable energy-dissipating connections, characterized in that: The following steps are involved: The variable-section circular end metal energy dissipation part (4) comprises two semicircular end plates for absorbing energy and two oppositely arranged variable-section flat plates. Since the bending moment is the largest at the intersection of the variable-section flat plate and the semicircular end plate of the variable-section circular end metal energy dissipation part (4), and the variable-section flat plate may bend and deform, the semicircular end plate of the variable-section circular end metal energy dissipation part (4) is not a strictly standard semicircular arc after deformation. The variable-section circular end metal energy dissipation part (4) is a combination of two semicircular end plates working together. According to the force deformation, the modified yield load of the variable-section circular end metal energy dissipation part (4) is obtained. , initial stiffness and the second stiffness The restoring force model of the variable cross-section circular end metal energy dissipation part (4) is determined by the following parameters: the outer diameter of the variable cross-section circular end metal energy dissipation part ,thickness , Middle width of variable cross-section straight plate , yield strength , yield load correction factor α, initial stiffness correction factor β and second stiffness correction factor ; Among them, the yield load of the variable cross-section circular end metal energy dissipation part (4) is , initial stiffness The expression is: In the formula, is the outer diameter of the variable-section circular-end metal energy-absorbing part, is the thickness of the variable-section circular end metal energy dissipation part, The middle width of the straight plate of the variable-section round-end metal energy-absorbing part. is the yield strength, is the magnification factor, which is the square of the width difference of the variable-section straight plate of the variable-section round-end metal energy dissipation part. is the yield load correction factor, β is the initial stiffness correction factor; When the shear force on the variable-section circular end metal energy dissipation part is greater than the yield load, the variable-section circular end metal energy dissipation part is in the elastic-plastic stage, and the stiffness at this time is the second stiffness, which is expressed as: In the formula, is the second stiffness correction coefficient, and its value range is between 0.014 and 0.016; Under the action of an earthquake, the frame shifts horizontally, and the box-section supports (1) bear different internal forces. The two diagonal box-section supports (1) are subjected to tension, while the other two diagonal box-section supports (1) are subjected to compression. The axial forces generated by the horizontal load on the four steel box-section supports (1) converge at the energy-absorbing connection. After the force is decomposed, the horizontal forces are balanced in the horizontal direction, and a shear force acts on the variable-section circular end metal energy-absorbing part (4) in the vertical direction. In this case, the variable-section circular end metal energy-absorbing part (4) is controlled to yield and dissipate energy first. At this time, the yield load of the box-section support (1) is multiplied by the safety factor. Make the yield load of the box section support (1) greater than the yield load of the energy dissipation component; consider the influence of the compressive stability coefficient of the box section support (1) and take 0.7 As the yield load of the box section support (1), consider the unbalanced tension and compression of the box section support (1). is the yield load of the energy dissipation part; then the design of the X-shaped support with replaceable energy dissipation connection must meet the following requirements: the vertical component of the yield load of the box-section support (1) should be greater than the yield load of the variable-section circular end metal energy dissipation part (4) so ​​that the energy dissipation part yields first, that is, In the formula, is the angle between the box section support (1) and the horizontal plane, is the yield load of the variable cross-section circular end metal energy dissipation part, is the safety magnification factor of energy-consuming parts, ; Determine the component performance of the X-shaped support with replaceable energy-absorbing connection, and use stiffness ratio and strength ratio to describe the component performance of the X-shaped support with replaceable energy-absorbing connection: perform elastic-plastic time-history analysis on the X-shaped support steel frame structure with replaceable energy-absorbing connection, and obtain the inter-story displacement angle, base shear force and vertex displacement corresponding to the target performance segment of the X-shaped support steel frame with replaceable energy-absorbing connection under X- and Y-direction earthquakes, so as to calculate the equivalent stiffness of the structure and its corresponding additional damping ratio and stiffness ratio.

6. A design method for an X-shaped support with replaceable energy dissipation connection according to claim 5, characterized in that: The additional damping ratio and additional stiffness ratio of the X-shaped braced steel frame structure with replaceable energy-absorbing connections are integrated and analyzed. The results show that the vertical shear stiffness of the energy-absorbing connection is the initial stiffness of the energy-absorbing component. The ratio of the vertical stiffness component of the X-shaped support is between 0.50 and 0.85, and the ratio of the shear yield strength of the energy-dissipating connection to the vertical component of the yield strength of the X-shaped support is between 0.35 and 0.

65.

7. A design method for an X-shaped support with replaceable energy dissipation connection according to claim 5, characterized in that: Limit displacement of the variable cross-section circular end metal energy dissipation part (4) is the outer diameter of the semicircular end plate of the energy dissipating part R 0.2~0.5 times of The value range is between 0.50 and 0.

60. The value range is between 1.05 and 1.

15.

8. The design method of an X-shaped support with replaceable energy dissipation connection according to claim 5, characterized in that: The width of the end of the variable-section straight plate of the variable-section round-end metal energy dissipation part (4) Is the middle width of the straight plate b 1.1~1.2 times of the middle width of the straight plate of the variable cross-section round-end metal energy dissipation part (4) b The value range is 60~300 mm, and the width of the end of the variable cross-section straight plate The value range of is 74~360 mm, and the height of the variable-section round-end metal energy dissipation part (4) is 2 R The value range of is 80~240 mm, and the thickness of the variable-section circular end metal energy dissipation part (4) t The value range is 6~32 mm.

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