Frame structure provided with variable cross-section segmented swing wall and design method thereof

Abstract

The invention discloses a design method of a frame structure with variable cross-section segmented swing walls, which relates to structural members, and comprises the following steps: determining a target displacement improvement coefficient according to structural performance design indexes of the frame structure, and selecting corresponding BRB energy consumption coefficients for wall bodies of the swing walls at different height sections in the frame structure; a displacement control requirement curve graph of the target displacement improvement coefficient and the target BRB energy consumption coefficient is obtained, intersection point coordinate values corresponding to all the sections of wall bodies are obtained, and the swing wall rigidity ratio and the BRB relative rigidity ratio of all the sections of wall bodies are determined; and according to the swing wall rigidity ratio of each section of wall and the relative rigidity ratio of the BRB, the section size of each section of wall and the configuration area of the energy-consuming BRB are determined. The invention further discloses a frame structure provided with the variable-cross-section segmented swing wall. Cross section design can be carried out on the wall bodies with different heights according to different performance targets, variable cross section design of the segmented swing wall is achieved, the top additional earthquake effect of the structure can be reduced, and the size of the cross section of the wall body can be reduced.

Description

Technical Field

[0001] The present invention relates to structural members, and more particularly, to a frame structure provided with variable cross-section segmented rocking walls and a design method thereof. Background Art

[0002] In traditional frame structures, weak stories are prone to occur in the middle and lower floors during earthquakes, resulting in a story damage mechanism. By adding rocking walls with relatively large lateral stiffness, the inter-story displacement of the frame can be made more uniform, which is beneficial to the uniform dispersion and development of plastic hinges in the overall frame and the suppression of the generation of weak stories. Various rocking wall members have been studied at home and abroad, and some research results have been obtained. However, most of the existing rocking walls have the following three main problems: First, irreversible plastic damage will occur in the corner areas of the wall after an earthquake, and the difficulty and cost of post-earthquake repair are high; Second, considering the convenience of transportation and construction of precast walls, the rocking wall is segmented, but this will lead to a reduction in the displacement control effect of the rocking wall on the frame; Third, the current segmented rocking walls all adopt a constant cross-section design, without considering that the lateral deformation of the frame is concentrated in the middle and lower parts of the floors, and the flexural stiffness of the cross-section of the rocking wall required for the upper floors of the structure is relatively small, and the additional mass at the top of the floor will further increase the additional seismic action at the top of the structure. The cross-sectional dimensions of traditional frame columns will decrease along the height direction. Under the dual influence of the reduction of the column cross-section and the amplification of the seismic action, the column members on the upper floors of the structure with rocking walls are prone to form plastic hinges, and the upper floors are prone to develop into weak stories.

[0003] Therefore, it is urgent and particularly meaningful to develop a variable cross-section segmented rocking wall-frame structure with fast post-earthquake function recovery, strong energy dissipation capacity, simple design method and convenient construction. Summary of the Invention

[0004] In order to overcome the deficiencies of existing rocking wall structures, such as irreversible damage to the wall corners, limited energy dissipation capacity, and difficult wall transportation, the present invention provides a frame structure provided with variable cross-section segmented rocking walls and a design method thereof, which has strong energy dissipation capacity, small wall damage and residual displacement, and can be quickly restored for use after an earthquake.

[0005] The design method of a frame structure provided with variable cross-section segmented rocking walls according to the present invention includes the following steps: Step 1: Determine the target displacement improvement coefficient according to the structural performance design index of the frame structure, and select the corresponding BRB energy dissipation coefficient for the walls of the rocking walls in different height segments of the frame structure; Step 2: Obtain the displacement control requirement curve graph of the target displacement improvement coefficient and the target BRB energy dissipation coefficient, and obtain the intersection coordinate values corresponding to each section of the wall according to the displacement control requirement curve graph, and determine the rocking wall stiffness ratio and the BRB relative stiffness ratio of each section of the wall; Step 3. Determine the cross-sectional dimensions of each section of the wall and the area of the energy-dissipating BRB according to the sway wall stiffness ratio and the BRB relative stiffness ratio of each section of the wall.

[0006] Preferably, in Step 2, the method for obtaining the displacement control demand curve graph is as follows: Calculate the combined value of the sway wall stiffness ratio and the BRB relative stiffness ratio under the target displacement improvement coefficient, and obtain the performance curve of the target displacement improvement coefficient according to the combined value; Calculate the BRB relative stiffness ratio under the BRB energy dissipation coefficient, and obtain the performance curve of the target BRB energy dissipation coefficient according to the BRB relative stiffness ratio; Place the performance curve of the target displacement improvement coefficient and the performance curve of the BRB energy dissipation coefficient in the same coordinate system to obtain the displacement control demand curve graph.

[0007] Preferably, calculate the combined value of the sway wall stiffness ratio and the BRB relative stiffness ratio under the target displacement improvement coefficient according to the following target displacement improvement coefficient formula: , In the formula, represents the displacement improvement coefficient, represents the number of segments, represents the sway wall stiffness ratio, represents the BRB relative stiffness ratio.

[0008] Preferably, calculate the BRB relative stiffness ratio under the BRB energy dissipation coefficient according to the following BRB energy dissipation coefficient formula: , In the formula, represents the BRB energy dissipation coefficient, represents the BRB relative stiffness ratio.

[0009] Preferably, in Step 3, calculate the flexural stiffness of the sway wall according to the sway wall stiffness ratio of the wall, so as to determine the cross-sectional dimensions of the wall: , In the formula, represents the sway wall stiffness ratio, represents the structural height, represents the flexural stiffness of the sway wall, represents the lateral stiffness of the frame, represents the number of segments.

[0010] Preferably, in Step 3, calculate the area of the energy-dissipating BRB according to the BRB relative stiffness ratio: , In the formula, represents the BRB relative stiffness ratio, is the elastic modulus of BRB, is the core area of the BRB, is the distance between the BRB centers on both sides of the wall, Indicates the structure height, represents the bending stiffness of the rocking wall, is the length of the BRB core segment.

[0011] A frame structure with a variable-section segmented rocking wall comprises a frame, a rocking wall, an energy-absorbing BRB, a restorable BRB, a rigid connecting beam, and a foundation. The frame and the rocking wall are both arranged on the foundation, the restorable BRB is arranged in the frame, and the frame and the rocking wall are connected by a rigid connecting beam. The rocking wall is composed of multiple wall sections arranged from bottom to top, and the wall sections and the wall and the foundation are hingedly connected by buried steel lugs. Energy-absorbing BRBs are symmetrically bolted on both sides of the wall. The cross-sectional dimensions of each wall section and the configuration area of the energy-absorbing BRBs are designed using the above-mentioned design method.

[0012] Preferably, a main ear plate is embedded in the bottom of the wall, and auxiliary ear plates are embedded in the foundation and the top of the wall. The main ear plate and the auxiliary ear plate are connected via a distribution shaft to form a support.

[0013] Preferably, a plurality of recoverable BRB arrangement layers are provided in the frame, and recoverable BRBs are arranged at the four end corners of each recoverable BRB arrangement layer, and the recoverable BRBs are arranged obliquely in the corresponding recoverable BRB arrangement layer, and the two ends of the recoverable BRBs are respectively connected to the beam-column ends in the corresponding recoverable BRB arrangement layer through node plates.

[0014] Beneficial effects The advantages of the present invention are: 1. The design method of the present invention can design the cross-section of walls of different heights according to different performance targets, realizing the variable cross-section design of segmented rocking walls, which can not only effectively reduce the additional seismic action on the top of the structure, but also reduce the cross-sectional size of the wall.

[0015] 2. The vacant design at the corners of the wall can not only ensure the free swing of the wall, but also avoid damage to the corner area of the wall, reducing the cost and time of post-earthquake repair.

[0016] 3. The energy-absorbing BRBs on both sides of the wall can realize the concept of “damage control” of the structure and reduce the damage to the main structure during earthquakes.

[0017] 4. The recoverable BRB in the frame remains elastic after a major earthquake, providing self-centering force for the structure, reducing the residual displacement of the structure, and achieving the goal of recoverable function after an earthquake.

[0018] 5. The segmented design of the rocking wall can not only reduce the internal force of the wall, but also facilitate transportation and hoisting. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a displacement control demand curve diagram for the design method of the frame structure with variable cross-section segmented rocking walls of the present invention; Figure 2 It is a schematic diagram of the overall structure of the frame structure with variable cross-section segmented rocking walls of the present invention; Figure 3 It is a structural diagram of the lug plate pin connection between each section of the wall and between the lower wall and the foundation of the present invention; Figure 4 It is a schematic plan layout diagram of the recoverable BRB of the present invention; Figure 5 It is a structural diagram of the recoverable BRB of the present invention.

[0020] Wherein: 1: Frame containing recoverable BRB; 2: Rocking wall; 3: Energy-dissipating BRB; 4: Recoverable BRB; 5: Rigid coupling beam; 6: Foundation; 7: Hinged steel lug plate; 4-1: High-strength steel plate; 4-2: Reinforced concrete; 4-3: Connector; 4-4: High-strength bolt; 4-5: Embedded steel plate at beam-column joint; 7-1: Main lug plate; 7-2: Sub-lug plate; 7-3: Pin shaft. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] The following is a further description of the present invention in conjunction with embodiments, but it does not constitute any limitation to the present invention. Any limited modifications made by anyone within the scope of the claims of the present invention are still within the scope of the claims of the present invention.

[0022] Embodiment 1 A design method of a frame structure with variable cross-section segmented rocking walls of the present invention conducts variable cross-section design of the segmented rocking walls through a displacement control demand curve diagram. The specific design steps are as follows: Step 1: Determine the target displacement improvement coefficient according to the performance design index of the frame structure, and select different BRB (Buckling Restrained Brace) energy-dissipating coefficients for the walls in different height segments of the rocking wall.

[0023] Step 2: Draw a displacement control demand curve diagram of the target displacement improvement coefficient and the target BRB energy-dissipating coefficient, obtain the intersection coordinate values of the two curves of each section of the rocking wall, and determine the rocking wall stiffness ratio and BRB relative stiffness ratio of each section of the wall.

[0024] Specifically, according to the following formula for the target displacement improvement coefficient, the combined values of the sway wall stiffness ratio and the BRB relative stiffness ratio under different target displacement improvement coefficients can be calculated, and thus multiple performance curves with different target displacement improvement coefficients can be plotted.

[0025] , wherein, represents the displacement improvement coefficient, represents the number of segments, represents the sway wall stiffness ratio, represents the BRB relative stiffness ratio.

[0026] According to the following formula for the BRB energy dissipation coefficient, the BRB relative stiffness ratio under different BRB energy dissipation coefficients can be calculated, and thus multiple performance curves with different target BRB energy dissipation coefficients can be plotted.

[0027] , wherein, represents the BRB energy dissipation coefficient, represents the BRB relative stiffness ratio.

[0028] As Figure 1 shown, by plotting the performance curves of the target displacement improvement coefficient and the BRB energy dissipation coefficient in the same coordinate system, the displacement control requirement curve of the variable cross-section segmented sway wall can be obtained. Find the corresponding two curves in the displacement control requirement curve, and determine the intersection point of the two curves. The abscissa and ordinate of the intersection point coordinates are the sway wall stiffness ratio and the BRB relative stiffness ratio respectively.

[0029] Step 3: Determine the cross-sectional dimensions of each segment of the wall and the configuration area of the energy-dissipating BRB according to the sway wall stiffness ratio and the BRB relative stiffness ratio of each segment of the wall.

[0030] Specifically, first determine the cross-sectional dimensions of each segment of the wall according to the following sway wall stiffness ratio formula, and then calculate the configuration area of the energy-dissipating BRB from the BRB relative stiffness ratio formula.

[0031] , , wherein, represents the structural height, represents the flexural stiffness of the sway wall, represents the lateral stiffness of the frame, is the rotational stiffness of the BRB around the bottom hinge support; is the elastic modulus of the BRB, is the core section area of the BRB, is the distance between the centers of the BRBs on both sides of the wall, is the length of the core segment of the BRB.

[0032] The above design method can perform cross-section design on walls of different heights according to different performance goals, realizing the variable cross-section design of the split rocking wall, which can not only reduce the additional seismic action at the top of the structure, but also reduce the cross-section size of the wall.

[0033] Embodiment 2 As Figure 2 shown, a frame structure with a variable cross-section segmented rocking wall of the present invention includes a frame 1 containing recoverable BRBs, rocking walls 2 with multiple energy-dissipating BRBs on both sides, energy-dissipating BRBs 3, recoverable BRBs 4, rigid coupling beams 5, and a foundation 6. Among them, the recoverable BRBs 4 in the frame 1 are arranged layer by layer, and the frame 1 is connected to the rocking wall 2 through the rigid coupling beam 5. The rocking wall 2 is composed of multiple segments of variable cross-section walls. The walls between each segment and between the lower wall and the foundation 6 are hinged through pre-embedded steel ear plates 7. At the same time, vertical energy-dissipating BRBs 3 are symmetrically bolted on both sides of the wall, so that each segment of the wall can dissipate seismic energy through the energy-dissipating BRBs 3 on both sides to protect the wall from damage. In the rocking wall 2 with multiple segments of variable cross-section walls, the performance design requirements of the structure can be achieved by changing the cross-section size of the wall and the stiffness parameters of the energy-dissipating BRBs 3. In addition, the cross-section size of each segment of the wall and the configuration area of the energy-dissipating BRBs 3 are designed using the above design method.

[0034] Specifically, the walls between each segment and between the lower wall and the foundation 6 are connected through energy-dissipating BRBs 3. The end plates on both sides of the brace are connected to the pre-embedded steel plates of the wall and the foundation 6 through high-strength bolts to ensure the rotation ability of the wall during the earthquake. The pre-embedded steel plate is a low-strength steel plate wrapped by reinforced concrete, and the cross-section shape of the steel plate can be selected as a straight shape, a cross shape, etc.

[0035] In this embodiment, the lower regions of each segment of the wall of the rocking wall 2 are in a V shape, and main ear plates for pin connection are pre-embedded at the bottom. The foundation 6 and the top of each segment of the wall are pre-embedded with sub-ear plates. The main ear plate uses a double ear plate, and the sub-ear plate uses a triple ear plate. The support connected by the pin can rotate freely, but cannot have relative movement in the vertical or horizontal directions.

[0036] Specifically, as Figure 3 shown, it shows the main ear plates 7-1 pre-embedded at the bottom of each segment of the wall for connecting the pin, and the sub-ear plates 7-2 pre-embedded at the top of the lower wall of the foundation 6. The support connected by the pin 7-3 can rotate freely, that is, rotate along the axis of the pin 7-3, but cannot have relative movement in the vertical or horizontal directions.

[0037] Figure 4A layout method of the recoverable BRB4 on a plane can enhance the torsional stiffness of the frame. However, its layout method is not fixed, and it can also be arranged separately at the mid-span of the outer bay of the frame or symmetrically arranged on both sides along the central axis. Specifically, there are multiple recoverable BRB layout layers in the frame 1, and recoverable BRB4s are arranged at the four end corners of each recoverable BRB layout layer, but it is not limited to being arranged at the four end corners, and can also be arranged at other positions in the recoverable BRB layout layer. The recoverable BRB4 is inclinedly arranged in its corresponding recoverable BRB layout layer, and the two ends of the recoverable BRB4 are respectively connected to the beam-column ends in its corresponding recoverable BRB layout layer through gusset plates. That is, the recoverable BRB4s in the four corner areas of the frame are arranged in an inclined manner, so that the whole frame remains elastic after a major earthquake, provides a self-restoring force for the structure, reduces the residual displacement of the structure, and achieves the goal of recoverable function after an earthquake.

[0038] As Figure 5 shown, the whole section of the recoverable BRB4 is a high-strength steel plate 4-1 wrapped by reinforced concrete 4-2. The cross-sectional shape of the steel plate can be selected as a straight shape, a cross shape, etc., and the cross-sectional area of the core material is increased to improve the yield bearing capacity of the brace. It is connected to the embedded steel plate 4-5 of the beam-column joint through high-strength bolts 4-4 to ensure its elasticity during an earthquake. The cross-sectional area of its core material needs to be significantly larger than that of the energy-dissipating BRB3 to ensure that the recoverable BRB4 maintains an elastic working state under earthquake action and provides a post-earthquake restoring force for the segmented rocking wall-frame structure; at the same time, the cross-sections of the beam-column members connected to the BRB can be appropriately increased to avoid plastic damage caused by the additional axial force of the BRB.

[0039] The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which will not affect the implementation effect of the present invention and the practicality of the patent.

Claims

1. A design method for a frame structure with a variable cross-section segmented sway wall, characterized in that, The method comprises the following steps: Step 1: Determine a target displacement improvement coefficient based on the structural performance design index of the frame structure, and select corresponding BRB energy dissipation coefficients for the rocking walls at different height segments in the frame structure; Step 2: Obtain a displacement control demand curve of the target displacement improvement coefficient and the target BRB energy consumption coefficient, and obtain the coordinate values of the intersection points corresponding to each wall segment based on the displacement control demand curve to determine the rocking wall stiffness ratio and BRB relative stiffness ratio of each wall segment; Step 3: Determine the cross-sectional dimensions of each wall section and the configuration area of the energy dissipation BRB according to the rocking wall stiffness ratio and the BRB relative stiffness ratio of each wall section.

2. The design method of a frame structure with a variable cross-section segmented sway wall according to claim 1, characterized in that In step 2, the method for obtaining the displacement control demand curve is: Calculating a combined value of the rocking wall stiffness ratio and the BRB relative stiffness ratio under the target displacement improvement factor, and obtaining a performance curve of the target displacement improvement factor based on the combined value; Calculating a BRB relative stiffness ratio under the BRB energy dissipation coefficient, and obtaining a performance curve of a target BRB energy dissipation coefficient according to the BRB relative stiffness ratio; The performance curve of the target displacement improvement coefficient and the performance curve of the BRB energy consumption coefficient are placed in the same coordinate system to obtain the displacement control demand curve.

3. The design method of a frame structure with a variable cross-section segmented swinging wall according to claim 2, characterized in that The combined value of the rocking wall stiffness ratio and the BRB relative stiffness ratio under the target displacement improvement coefficient is calculated according to the following target displacement improvement coefficient formula: ， In the formula, represents the displacement improvement coefficient, represents the number of segments, represents the stiffness ratio of the rocking wall, represents the relative stiffness ratio of the BRB.

4. The design method of a frame structure with a variable cross-section segmented sway wall according to claim 2, characterized in that, The BRB relative stiffness ratio under the BRB energy dissipation coefficient is calculated according to the following BRB energy dissipation coefficient formula: ， In the formula, represents the BRB energy dissipation coefficient, represents the BRB relative stiffness ratio.

5. The design method of a frame structure with a variable cross-section segmented swinging wall according to claim 1, characterized in that, In step three, the bending stiffness of the rocking wall is calculated based on the rocking wall stiffness ratio of the wall, thereby determining the cross-sectional dimensions of the wall: ， In the formula, represents the stiffness ratio of the rocking wall, represents the structural height, represents the flexural stiffness of the rocking wall, represents the lateral stiffness of the frame, represents the number of segments.

6. The design method of a frame structure with a variable cross-section segmented sway wall according to claim 1, characterized in that, In step 3, the configuration area of the energy-consuming BRB is calculated based on the BRB relative stiffness ratio: ， In the formula, represents the relative stiffness ratio of BRB, is the elastic modulus of BRB, is the cross-sectional area of the core section of BRB, is the distance between the centers of BRBs on both sides of the wall, represents the structural height, represents the flexural stiffness of the rocking wall, is the length of the core section of BRB.

7. A frame structure provided with a variable cross-section segmented sway wall, characterized in that, The invention comprises a frame (1), a rocking wall (2), an energy-absorbing BRB (3), a recoverable BRB (4), a rigid connecting beam (5) and a foundation (6); the frame (1) and the rocking wall (2) are both arranged on the foundation (6); the recoverable BRB (4) is arranged in the frame (1); the frame (1) and the rocking wall (2) are connected by a rigid connecting beam (5); the rocking wall (2) is composed of a plurality of wall sections arranged from bottom to top, and the wall sections and the wall sections and the foundation (6) are hingedly connected by buried steel lugs (7); the energy-absorbing BRB (3) is symmetrically bolted on both sides of the wall, and the cross-sectional dimensions of each wall section and the configuration area of the energy-absorbing BRB (3) are designed by applying the design method described in any one of claims 1 to 6.

8. A frame structure with a variable cross-section segmented sway wall according to claim 7, characterized in that, A main ear plate (7-1) is pre-buried at the bottom of the wall, and auxiliary ear plates (7-2) are pre-buried at the foundation (6) and the top of the wall. The main ear plate (7-1) and the auxiliary ear plate (7-2) are connected via a distribution shaft (7-3) to form a support seat.

9. A frame structure with a variable cross-section segmented sway wall according to claim 7, characterized in that, The frame (1) is provided with a plurality of recoverable BRB arrangement layers, each of the recoverable BRB arrangement layers is provided with a plurality of recoverable BRBs (4), and the recoverable BRBs (4) are obliquely arranged in their corresponding recoverable BRB arrangement layers. The two ends of the recoverable BRB (4) are respectively connected to the beam-column ends in its corresponding recoverable BRB arrangement layer through gusset plates.

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