A frame structure with variable-section segmented rocking walls and its design method

Abstract

The present invention discloses a design method for a frame structure provided with a variable-section segmented rocking wall. The method involves structural components, determining a target displacement improvement coefficient based on the structural performance design index of the frame structure, and selecting corresponding BRB energy dissipation coefficients for the rocking walls at different height segments in the frame structure; obtaining a displacement control demand curve diagram of the target displacement improvement coefficient and the target BRB energy dissipation coefficient, obtaining the intersection coordinate values ​​corresponding to each wall segment, and determining the rocking wall stiffness ratio and BRB relative stiffness ratio of each wall segment; determining the cross-sectional dimensions of each wall segment and the configuration area of ​​the energy dissipation BRB based on the rocking wall stiffness ratio and BRB relative stiffness ratio of each wall segment. The present invention also discloses a frame structure provided with a variable-section segmented rocking wall. The present invention can perform cross-sectional design on walls of different heights according to different performance targets, realizing a variable cross-sectional design of the segmented rocking wall, which can not only reduce the additional seismic action at the top of the structure, but also reduce the cross-sectional dimensions of the wall.

Description

Technical Field

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

[0002] Traditional frame structures are prone to developing weak layers in the lower floors during earthquakes, leading to a layer damage mechanism. Adding rocking walls with greater lateral stiffness can make the inter-story displacements of the frame more uniform, facilitating the uniform distribution of plastic hinges throughout the entire frame and suppressing the development of weak layers. Various rocking wall components have been studied both domestically and internationally, yielding some promising results. However, most rocking walls studied in previous studies suffer from three major issues: First, irreversible plastic damage occurs in the corners of the wall after an earthquake, making post-earthquake repair difficult and costly. Second, considering the ease of transport and construction of prefabricated walls, rocking walls are segmented, but this reduces their ability to control frame displacement. Third, current segmented rocking walls are designed with a uniform cross-section, failing to account for the fact that lateral deformation of the frame is concentrated in the lower and middle floors. Consequently, the rocking wall sections required for the upper and middle floors have lower flexural stiffness, and the added mass at the top of the floors further increases the additional seismic action at the top of the structure. The cross-sectional dimensions of traditional frame columns decrease along the height direction. Under the dual influence of the reduced column cross-section and the amplified seismic action, plastic hinges are easily formed in the column components of the upper floors of the structure with rocking walls, and the upper floors are easily developed into weak layers.

[0003] Therefore, it is urgent and particularly meaningful to develop a variable-section segmented rocking wall-frame structure that can quickly restore post-earthquake functions, has strong energy dissipation capacity, is simple in design method, and is convenient in construction. Summary of the Invention

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

[0005] The present invention provides a design method for a frame structure with segmented rocking walls having variable cross-sections, the method comprising the following steps:

[0006] 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;

[0007] 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;

[0008] 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.

[0009] Preferably, in step 2, the method for obtaining the displacement control demand curve is:

[0010] 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;

[0011] 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;

[0012] 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.

[0013] Preferably, 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:

[0014] ,

[0015] Where, represents the displacement improvement coefficient, Indicates the number of segments, represents the rocking wall stiffness ratio, Represents the BRB relative stiffness ratio.

[0016] Preferably, the BRB relative stiffness ratio under the BRB energy dissipation coefficient is calculated according to the following BRB energy dissipation coefficient formula:

[0017] ,

[0018] Where, represents the BRB energy consumption coefficient, Represents the BRB relative stiffness ratio.

[0019] Preferably, in step three, the bending stiffness of the rocking wall is calculated according to the rocking wall stiffness ratio of the wall, thereby determining the cross-sectional dimensions of the wall:

[0020] ,

[0021] Where, represents the rocking wall stiffness ratio, Indicates the structure height, represents the bending stiffness of the rocking wall, represents the lateral stiffness of the frame, Indicates the number of segments.

[0022] Preferably, in step three, the configuration area of ​​the energy-consuming BRB is calculated according to the BRB relative stiffness ratio:

[0023] ,

[0024] Where, 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] Beneficial effects

[0029] The advantages of the present invention are:

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 4. The recoverable BRB in the frame remains elastic after a major earthquake, providing self-recovery force for the structure, reducing the residual displacement of the structure and achieving the goal of post-earthquake recovery function.

[0034] 5. The segmented design of the swing wall not only reduces the internal force of the wall, but also makes transportation and lifting convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A displacement control demand curve diagram for a design method of a frame structure with a variable-section segmented rocking wall according to the present invention;

[0036] Figure 2 This is a schematic diagram of the overall structure of a frame structure with variable-section segmented swing walls according to the present invention;

[0037] Figure 3 This is a structural diagram of the ear plate pin connections between each wall section and between the lower wall and the foundation of the present invention;

[0038] Figure 4 Schematic diagram of the planar layout of the recoverable BRB of the present invention;

[0039] Figure 5 FIG. 4 is a structural diagram of the recoverable BRB of the present invention.

[0040] Among them: 1: frame with recoverable BRB; 2: swing wall; 3: energy-absorbing BRB; 4: recoverable BRB; 5: rigid connecting beam; 6: foundation; 7: hinged steel lug; 4-1: high-strength steel plate; 4-2: reinforced concrete; 4-3: connector; 4-4: high-strength bolt; 4-5: embedded steel plate of beam-column node; 7-1: main lug; 7-2: auxiliary lug; 7-3: pin. DETAILED DESCRIPTION

[0041] The present invention will be further described below in conjunction with the embodiments, but this does not constitute any limitation to the present invention. Any limited number of 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.

[0042] Example 1

[0043] The present invention provides a design method for a frame structure with a segmented rocking wall having a variable cross-section. The variable cross-section design of the segmented rocking wall is performed using a displacement control demand curve. The specific design steps are as follows:

[0044] Step 1: Determine the target displacement improvement factor based on the frame structure performance design index, and select different BRB (buckling restrained brace) energy dissipation coefficients for walls at different height segments in the rocking wall.

[0045] Step 2: Draw the displacement control demand curve of the target displacement improvement coefficient and the target BRB energy consumption coefficient, obtain the coordinate value of the intersection 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.

[0046] Specifically, the target displacement improvement coefficient formula below can be used to calculate the combined values ​​of the rocking wall stiffness ratio and the BRB relative stiffness ratio of the structure under different target displacement improvement coefficients. This allows the plotting of multiple performance curves for different target displacement improvement coefficients.

[0047] ,

[0048] Where, represents the displacement improvement coefficient, Indicates the number of segments, represents the rocking wall stiffness ratio, Represents the BRB relative stiffness ratio.

[0049] According to the following BRB energy dissipation coefficient formula, the BRB relative stiffness ratio under different BRB energy dissipation coefficients can be calculated, thereby drawing multiple performance curves of BRB energy dissipation coefficients with different targets.

[0050] ,

[0051] Where, represents the BRB energy consumption coefficient, Represents the BRB relative stiffness ratio.

[0052] like Figure 1 As shown in Figure 2, by plotting the performance curves for the target displacement improvement factor and the BRB energy dissipation factor in the same coordinate system, we can obtain the displacement control demand curve for the variable-section segmented rocking wall. Find the two corresponding curves in the displacement control demand curve and determine their intersection. The horizontal and vertical coordinates of the intersection are the rocking wall stiffness ratio and the BRB relative stiffness ratio, respectively.

[0053] Step 3: Determine the cross-sectional dimensions of each wall section and the configuration area of ​​the energy-absorbing BRB based on the rocking wall stiffness ratio and the BRB relative stiffness ratio of each wall section.

[0054] Specifically, the cross-sectional dimensions of each wall segment are first determined according to the following rocking wall stiffness ratio formula, and then the configuration area of ​​the energy-dissipating BRB is calculated using the BRB relative stiffness ratio formula.

[0055] ,

[0056] ,

[0057] Where, Indicates the structure height, represents the bending stiffness of the rocking wall, represents the lateral stiffness of the frame, is the rotational stiffness of the BRB around the bottom hinged support; 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, is the length of the BRB core segment.

[0058] The above design method can design the cross-section of walls of different heights according to different performance targets, realizing the variable cross-section design of the swing wall, which can not only reduce the additional seismic action on the top of the structure, but also reduce the cross-sectional size of the wall.

[0059] Example 2

[0060] like Figure 2 As shown, the present invention presents a frame structure with a variable-section segmented rocking wall, comprising a frame 1 with a restorable BRB, a rocking wall 2 with multiple energy-absorbing BRBs on either side, an energy-absorbing BRB 3, a restorable BRB 4, a rigid coupling beam 5, and a foundation 6. The restorable BRBs 4 in the frame 1 are arranged layer by layer, and the frame 1 and rocking wall 2 are connected by a rigid coupling beam 5. The rocking wall 2 is composed of multiple segments of variable-section walls. Each segment and the lower segment are hingedly connected to the foundation 6 by embedded steel lugs 7. Vertical energy-absorbing BRBs 3 are symmetrically bolted to each side of the wall, allowing each segment to dissipate seismic energy through the energy-absorbing BRBs 3 on both sides, protecting the wall from damage. In the rocking wall 2 with multiple segments of variable-section walls, the structural performance design requirements can be achieved by varying the wall cross-sectional dimensions and the stiffness parameters of the energy-absorbing BRBs 3. Furthermore, the cross-sectional dimensions of each segment and the area allocated for the energy-absorbing BRBs 3 are designed using the aforementioned design method.

[0061] Specifically, each wall segment and the lower wall and foundation 6 are connected via energy-dissipating BRBs 3. The end plates on either side of these supports are connected to the wall and pre-embedded steel plates of foundation 6 via high-strength bolts, ensuring the wall's ability to rotate during earthquakes. The pre-embedded steel plates are low-strength steel plates encased in reinforced concrete, and their cross-sections can be either straight or cross-shaped.

[0062] In this embodiment, the lower sections of each wall of the rocking wall 2 are V-shaped, with pre-embedded main lugs at the bottom for pinned connection. Auxiliary lugs are pre-embedded between the foundation 6 and the top of each wall section. The main lugs are double-lug, while the auxiliary lugs are triple-lug. The supports connected by the pins can rotate freely but cannot undergo vertical or horizontal relative movement.

[0063] Specifically, such as Figure 3 The diagram shows the main lugs 7-1 embedded at the bottom of each wall section for connecting the pins, and the auxiliary lugs 7-2 embedded at the top of the foundation 6 and the lower wall. The support, connected by the pin 7-3, can rotate freely, that is, rotate along the axis of the pin 7-3, but cannot undergo relative vertical or horizontal movement.

[0064] Figure 4 It is a way of arranging the recoverable BRB4 on the plane, which can enhance the torsional stiffness of the frame. However, its arrangement is not fixed, and it can also be arranged separately at the middle span of the outer frame of the frame or symmetrically on both sides along the central axis. Specifically, a plurality of recoverable BRB arrangement layers are provided in the frame 1, and recoverable BRB4 are arranged at the four end corners of each recoverable BRB arrangement 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 arrangement layer. The recoverable BRB4 is arranged obliquely in its corresponding recoverable BRB arrangement layer, and the two ends of the recoverable BRB4 are respectively connected to the beam column ends in its corresponding recoverable BRB arrangement layer through node plates. That is, the recoverable BRB4 in the four corners of the frame, and the inclined arrangement method is adopted, so that the frame as a whole still maintains elasticity after a large earthquake, provides self-recovery force for the structure, reduces the residual displacement of the structure, and achieves the goal of post-earthquake recoverable function.

[0065] like Figure 5 As shown, the entire restorable BRB4 section consists of high-strength steel plates 4-1 encased in reinforced concrete 4-2. The steel plates can be shaped in a straight or cross-shaped pattern, increasing the core cross-sectional area to enhance the yield bearing capacity of the support. High-strength bolts 4-4 connect the BRB4 to the embedded steel plates 4-5 at the beam-column joints to ensure its elasticity during earthquakes. The core cross-sectional area must be significantly larger than that of the energy-absorbing BRB3 to ensure that the restorable BRB4 maintains its elastic working state during earthquakes, providing post-seismic restorative force for the segmented rocking wall-frame structure. Simultaneously, the cross-sectional area of ​​the beam-column components connected to the BRBs can be increased accordingly to avoid plastic damage caused by the additional axial force acting on the BRBs.

[0066] The above is only a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present invention. These modifications and improvements will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. A design method for a frame structure with variable-section segmented rocking walls, 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 target 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 segment and the configuration area of ​​the energy dissipation BRB based on the rocking wall stiffness ratio and the BRB relative stiffness ratio of each wall segment; 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; Placing the performance curve of the target displacement improvement coefficient and the performance curve of the BRB energy consumption coefficient in the same coordinate system to obtain the displacement control demand curve; 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: ， Where, represents the displacement improvement coefficient, Indicates the number of segments, represents the rocking wall stiffness ratio, represents the BRB relative stiffness ratio; The BRB relative stiffness ratio under the BRB energy dissipation coefficient is calculated according to the following BRB energy dissipation coefficient formula: ， Where, represents the BRB energy consumption coefficient, Represents the BRB relative stiffness ratio.

2. The design method of a frame structure with variable-section segmented rocking walls 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: ， Where, represents the rocking wall stiffness ratio, Indicates the structure height, represents the bending stiffness of the rocking wall, represents the lateral stiffness of the frame, Indicates the number of segments.

3. The design method of a frame structure with variable-section segmented rocking walls 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: ， Where, 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.

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

5. A frame structure with variable cross-section segmented rocking walls according to claim 4, 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.

6. A frame structure with variable cross-section segmented rocking walls according to claim 4, 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 arranged obliquely in the recoverable BRB arrangement layers corresponding thereto, and both ends of the recoverable BRBs (4) are connected to the beam-column ends in the recoverable BRB arrangement layers corresponding thereto through node plates.

Images