Wooden column foot connecting structure with swinging self-resetting function and design method of wooden column foot connecting structure

Abstract

The invention provides a swing self-resetting wooden column foot connecting structure and a design method thereof, a cross-shaped groove is formed in the bottom of a wooden column, a cross-shaped steel inserting plate is fixedly connected through a bolt, a steel column foundation structure composed of a connecting steel plate, a steel pipe column foundation and a plurality of arc-shaped soft steel sheets is arranged at the bottom of the cross-shaped steel inserting plate, the column end is lifted, and the cross-shaped groove is fixedly connected with the cross-shaped steel inserting plate. The maximum bending moment part of the column end is transferred to the position of the steel column foundation structure; according to the steel pipe column foundation of the hollow steel pipe structure and the arc-shaped soft steel sheet of the arc-shaped sheet soft steel structure, the outer diameter of the steel pipe column foundation is smaller than the side length of the upper wooden column, so that the steel pipe column foundation is bent under the action of an earthquake to achieve swinging of the wooden column, and the arc-shaped sheet soft steel arranged on the periphery of the steel pipe column foundation plays a role in limiting and self-resetting. Therefore, the wooden column foot connecting structure can realize swinging and self-resetting during an earthquake; in addition, the column foot connecting structure of the wooden column can prevent wood of the wooden column from being affected by the natural environment of invasion of ground moisture and corrosion of microorganisms.

Description

Technical Field

[0001] The present invention belongs to the technical field of building structures, and relates to a connection structure for the column foot of a wooden column and its design method. Background Art

[0002] Wooden structures not only have the characteristics of environmental protection and high carbon sequestration, but also the prefabricability and high degree of assembly of engineered glued wood products make wooden structures widely used in China. The connection structure between the bottom glued wooden column and the foundation, that is, the connection structure of the column foot of the wooden column, is a commonly used wooden frame structure in wooden structures. The column foot connection structure is one of the key connection structures that affect the lateral stiffness and bearing capacity of the structure. In the commonly used steel filling plate - bolt column foot connection, the steel insert plate is fixedly connected to the concrete foundation. The column end moment is mainly borne by the part where the glued wooden column end is connected to the bolt. On one side of the column end wood, it is under extrusion, and on the other side, it will be separated from the concrete foundation. And at the joint, the bolt is in close contact with the hole circumference and is mutually extruded, generating a tensile stress in the cross grain direction of the wood. Moreover, due to the local jacking restraint effect on the compression side of the lower wooden column, the rotation of the column foot is restricted, resulting in cross grain cracking of the wood at the bolt connection, leading to a decrease in the lateral resistance ability.

[0003] In order to improve the lateral resistance ability and ductility of the connection structure of the column foot of the wooden column, various methods have been adopted to reinforce the connection, such as adding self - tapping screws, using carbon fiber cloth to wrap, adding support members, adding energy - dissipating elements, etc. Although these attempts have significantly improved the bearing capacity and ductility of the connection structure of the column foot of the wooden column, they are still not satisfactory in terms of aesthetics, construction technology, factory production, and economy. Fundamentally, they have not changed the force - bearing mode of the connection structure of the column foot of the wooden column. Eventually, it is still mainly damaged by wood, and there are problems such as being difficult to repair after damage and too high maintenance costs. Summary of the Invention

[0004] In order to solve the problems of low lateral resistance ability and ductility of the connection structure of the column foot of the wooden column described in the background art, being difficult to repair after damage, and too high maintenance costs, the present invention proposes a rocking self - reset connection structure for the column foot of a wooden column and its design method.

[0005] The connection structure of the column foot of the wooden column of the present invention includes a wooden column. A cross - shaped groove is provided at the center of the bottom of the wooden column, and a plurality of screw holes are provided on the wooden column along the horizontal and vertical directions; a cross - shaped steel insert plate is embedded in the cross - shaped groove, and a plurality of connection screw holes coinciding with the screw holes are provided on the cross - shaped steel insert plate; bolts are provided in the screw holes and the connection screw holes; a square connection steel plate is provided at the bottom of the cross - shaped steel insert plate; a steel pipe column foundation and a plurality of arc - shaped mild steel sheets are provided at the bottom of the connection steel plate; the middle of the steel pipe column foundation is hollow, the outer diameter of the steel pipe column foundation is smaller than the side length of the wooden column, and the top of the steel pipe column foundation is fixedly connected to the middle of the bottom of the connection steel plate; the arc - shaped mild steel sheets are evenly arranged along the periphery of the steel pipe column foundation, and the top ends of the arc - shaped mild steel sheets are fixedly connected to the bottom of the connection steel plate.

[0006] The present invention also provides a design method for a rocking self - resetting connection structure of a wooden column base, including the following steps:

[0007] Step 1: According to the seismic design requirements of the wooden structure in the "Code for Design of Wood Structures" (GB50005 - 2017), calculate the bending moment, shear force and axial force at the bottom of the wooden column, and check the compression - bending and shear - resistance bearing capacities of the wooden column to determine the size and material grade of the wooden column;

[0008] Step 2: Initially determine the height, cross - sectional dimensions and material grade of the steel pipe column base according to the size of the wooden column, and ensure that the axial compressive strength of the steel pipe column base is greater than or equal to the axial force of the wooden column;

[0009] Step 3: Under the action of frequent earthquakes, the rocking angle at the top of the steel pipe column base of the wooden column base connection structure is set to 50% - 60% of the elastic inter - story drift angle limit value. The value of the elastic inter - story drift angle limit is 1 / 250. Based on this, check the rotation angle at the top of the steel pipe column base and check the compression - bending bearing capacity of the steel pipe column base at the same time; if the compression - bending bearing capacity of the steel pipe column base does not meet the corresponding requirements in the "Code for Design of Steel Structures" (GB50017 - 2017) and / or the rocking angle at the top of the steel pipe column base cannot meet 50% - 60% of the elastic inter - story drift angle limit value of 1 / 250, then return to Step 2 to re - determine the height, cross - sectional dimensions and material grade of the steel pipe column base until the steel pipe column base can meet the requirements of the "Code for Design of Steel Structures" (GB50017 - 2017) for the compression - bending bearing capacity and the rocking angle at the top is within the range of 50% - 60% of the elastic inter - story drift angle limit value of 1 / 250;

[0010] Step 4: Under the action of rare earthquakes, the rocking angle at the top of the steel pipe column base of the wooden column base connection structure is set to 50% - 70% of the plastic inter - story drift angle limit value. The value of the plastic inter - story drift angle limit is 1 / 50, and at the same time, it meets the overall drift angle limit of the wooden column base connection structure. Based on this, determine the number, position, radian and material grade of the arc - shaped mild steel sheets; regard the steel pipe column base as a cantilever member. When the internal force transmitted from the upper structure of the wooden column base connection structure causes horizontal displacement and rotation angle at the top of the steel pipe column base, one side of the arc - shaped mild steel sheet is just straightened, and based on this, determine its maximum radian value; with the condition that the stress generated when one side of the arc - shaped mild steel sheet is in tension as it rocks with the steel pipe column base just reaches the yield stress of the arc - shaped mild steel sheet, determine its minimum radian value;

[0011] If the radian of the initially determined arc-shaped soft steel sheet is greater than the aforementioned maximum radian or less than the aforementioned minimum radian, repeat Step 4 to adjust the quantity, position and radian of the arc-shaped soft steel sheet; if after repeatedly adjusting the quantity, position and radian of the arc-shaped soft steel sheet, the swing angle of the steel pipe column foundation cannot meet 50%-70% of the plastic inter-story drift angle limit value of 1 / 50, return to Step 2 to re-determine the height, cross-sectional dimension and material grade of the steel pipe column foundation until the swing angle of the steel pipe column foundation is within 50%-70% of the plastic inter-story drift angle limit value of 1 / 50;

[0012] Step 5: Perform a lateral displacement resistance check on the entire wooden column including the connection structure of the wooden column foot, and check whether the inter-story drift angles under frequent earthquake actions and rare earthquake actions meet the requirements of the elastic and plastic inter-story displacement angles in the "Code for Seismic Design of Buildings"; if the inter-story displacement angles meet the requirements of the elastic and plastic inter-story displacement angles in the "Code for Seismic Design of Buildings", the design is completed; if not, return to Step 2 to adjust the height, cross-sectional dimension and material grade of the steel pipe column foundation until the above requirements are met.

[0013] Furthermore, in Step 2, the height of the steel pipe column foundation is initially determined to be 1 / 15 - 1 / 10 of the total height of the wooden column, the outer diameter of the cross-section of the steel pipe column foundation is initially determined to be 1 / 2 of the length or width of the rectangular cross-section of the wooden column, and the material grades of the steel pipe column foundation include low Q420 alloy high-strength structural steel and Q460 alloy high-strength structural steel;

[0014] The formula for the axial compressive strength of the steel pipe column foundation being greater than or equal to the axial force of the wooden column is:

[0015]

[0016] Among them, N is the axial force transmitted by the wooden column; A is the cross-sectional area of the steel pipe column foundation; f is the material strength of the steel pipe column foundation.

[0017] Even further, in Step 3, the flexural-compressive bearing capacity of the steel pipe column foundation includes cross-sectional strength and cross-sectional stability;

[0018] The cross-sectional strength of the steel pipe column foundation should meet the following requirements:

[0019]

[0020] Among them, N and M are respectively the axial force and bending moment transmitted by the wooden column; A n 、W n are respectively the net cross-sectional area and net cross-sectional modulus of the steel pipe column foundation; γ m is the cross-sectional plastic development coefficient; f is the material strength of the steel pipe column foundation;

[0021] The cross-sectional stability of the steel pipe column foundation should meet the following requirements:

[0022]

[0023] Among them, N and M are the axial force and bending moment transmitted by the wooden column respectively; A and W are the cross-sectional area and section modulus of the steel pipe column foundation respectively; φ is the overall stability coefficient of the axially compressed member in the plane of the bending moment action; f is the material strength of the steel pipe column foundation; γ m is the section plastic development coefficient; β is the equivalent bending moment coefficient used when calculating the overall stability of the compression-bending member; N′ Ex is the calculation parameter determined by the equivalent slenderness ratio in the plane of the bending moment action;

[0024] The swing angle θ at the top of the steel pipe column foundation is calculated according to the following formula by using the graphical multiplication method:

[0025]

[0026] Among them, θ is the swing angle at the top of the steel pipe column foundation respectively; are the relevant calculation parameters in the bending moment diagram corresponding to applying a unit moment at the top of the steel pipe column foundation when using the graphical multiplication method; E is the elastic modulus of the corresponding steel used; I is the cross-sectional moment of inertia of the steel pipe column foundation; M and V are the bending moment and shear force transmitted by the wooden column respectively; l is the height of the steel pipe column foundation.

[0027] Furthermore, in the fourth step, the number of arc-shaped mild steel sheets is at least 4, and the arc-shaped mild steel sheets are evenly arranged on the concentric circles with the center of the steel pipe column foundation as the center. The diameter D of the concentric circles is 0.9 - 1.1 times the width of the rectangular cross-section of the wooden column; the material grade of the arc-shaped mild steel sheets includes carbon structural steel Q235; the radian of the arc-shaped mild steel sheets is determined according to the length and radius of the arc-shaped mild steel sheets;

[0028] The swing angle θ and lateral displacement Δ of the steel pipe column foundation are calculated according to the following formula by using the graphical multiplication method:

[0029]

[0030]

[0031] Among them, Δ and θ are the lateral displacement and swing angle at the top of the steel pipe column foundation respectively; are the relevant calculation parameters in the bending moment diagrams corresponding to applying a unit horizontal force and a unit moment at the top of the steel pipe column foundation when using the graphical multiplication method; E is the elastic modulus of the corresponding steel used; I is the cross-sectional moment of inertia of the steel pipe column foundation; M and V are the bending moment and shear force transmitted by the wooden column respectively; l is the height of the steel pipe column foundation;

[0032] After determining the number, position, and material grade of the arc-shaped mild steel sheets, the swing angle and lateral displacement at the top of the steel pipe column foundation can be obtained based on the above, and assuming that the arc-shaped mild steel sheets are just completely straightened at this time, the straightened length of the arc-shaped mild steel sheets can be calculated from the geometric relationship according to the magnitudes of the swing angle and lateral displacement, and then the radian value of the arc-shaped mild steel sheets can be determined from the chord length in the initial state, i.e., the height of the steel pipe column foundation, and the maximum radian value can be determined with this radian value;

[0033] When determining the minimum radian value of the arc-shaped mild steel sheets, assume that the arc-shaped mild steel sheets have no radian and are a flat steel sheet. The arc-shaped mild steel sheets will deform and generate stress as the steel pipe column foundation swings. When the stress of the arc-shaped mild steel sheets reaches the elastic limit, i.e., its material yield strength, a certain elongation deformation will also occur. Take the length in this state as the straightened length of the arc-shaped mild steel sheets, and then determine the minimum radian value of the arc-shaped mild steel sheets from the chord length in the initial state, i.e., the height of the steel pipe column foundation.

[0034] Furthermore, in step five, the total inter-story displacement of the entire wooden column including the connection structure at the column foot of the wooden column consists of three parts: ① the lateral displacement Δ1 generated by the wooden column under the action of the horizontal load; ② the lateral displacement Δ2 generated by the steel pipe column foundation under the action of the horizontal load; ③ the geometric lateral displacement Δ3 generated due to the reset swing angle of the steel pipe column foundation;

[0035] Under the action of an earthquake, the anti-lateral stiffness of the wooden column is calculated using the inflection point method or the D-value method, and thus the lateral displacement value is calculated. The lateral stiffness D′ of the wooden column is:

[0036]

[0037] where, i t is the linear stiffness of the wooden column; l t is the length of the wooden column;

[0038] The lateral displacement Δ1 is:

[0039]

[0040] where, V is the shear force generated by the wooden column under the action of an earthquake;

[0041] The lateral displacement Δ3 is:

[0042] Δ3 = l t sinθ,

[0043] where, l t is the length of the wooden column; θ is the swing angle at the top of the steel pipe column foundation;

[0044] Under the action of a frequently-occurring earthquake, the total inter-story displacement should satisfy:

[0045] Δ1 + Δ2 + Δ3 ≤ [θ e h,

[0046] Among them, [θ e is the elastic inter-story drift angle limit value under frequent earthquake action, taking 1 / 250; h is the overall floor height, including the length l of the wooden column t and the height l of the steel pipe column foundation;

[0047] Under rare earthquake action, the total inter-story displacement should satisfy:

[0048] Δ1 + Δ2 + Δ3 ≤ [θ p h,

[0049] Among them, [θ p is the plastic inter-story displacement angle limit value under rare earthquake action, taking 1 / 50; h is the overall floor height, including the length l of the wooden column t and the height l of the steel pipe column foundation.

[0050] Compared with the prior art, the present invention sets a cross-shaped groove at the bottom of the wooden column, fixedly connects a cross-shaped steel insert plate through bolts, sets a connecting steel plate, a steel pipe column foundation and a plurality of arc-shaped mild steel sheets at the bottom of the cross-shaped steel insert plate, raises the column end, and transfers the maximum bending moment part of the column end to the position of the steel pipe column foundation; the steel pipe column foundation of the hollow steel pipe structure and the arc-shaped mild steel sheets of the arc-shaped thin sheet mild steel structure, the outer diameter of the steel pipe column foundation is smaller than the side length of the upper wooden column, so that the steel pipe column foundation is bent under earthquake action to realize the swaying of the wooden column, and the arc-shaped mild steel sheets arranged around the steel pipe column foundation play a role of limiting and self-resetting, that is, the arc-shaped mild steel sheets allow the steel pipe column foundation to sway, and during the swaying process, the arc-shaped mild steel sheets restrain the steel pipe column foundation and the connection structure of the wooden column column foot to reset, so that the connection structure of the wooden column column foot can realize swaying self-resetting during an earthquake, thereby reducing the bending moment at the bottom end of the wooden column and preventing the brittle failure of the wooden column from occurring along the grain splitting around the screw holes; in addition, the connection structure of the wooden column column foot can also protect the wooden column from the influence of the natural environment such as the intrusion of ground moisture and the corrosion of microorganisms. The connection structure of the wooden column column foot of the present invention can reduce the bending moment borne by the end of the wooden column, improve the flexural stiffness at the column end, avoid premature cross-grain splitting at the column end, has good earthquake reduction effect and self-resetting ability, and at the same time has the characteristics of being replaceable, easy to repair and low maintenance cost. The structure of the present invention is simple, low in economic cost, can reduce earthquake action, change the failure form of the structure, improve the ductility of the structure, has stable and reliable performance, and is highly practical, and has good engineering application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 is an exploded view of the connection structure of the wooden column column foot of the present invention.

[0052] Figure 2 is a perspective view of the connection structure of the wooden column column foot of the present invention.

[0053] Figure 3 are the three views of the connection structure of the wooden column column foot of the present invention,Figure 3 (a) is the front view, Figure 3 (b) is the left view, Figure 3 (c) is the top view.

[0054] Figure 4 This is the working principle diagram of the connection structure of the wooden column footing of the present invention, Figure 4 (a) is before loading, Figure 4 (b) is under positive loading, Figure 4 (c) is for positive reset, Figure 4 (b) is under reverse loading, Figure 4 (c) is for reverse reset.

[0055] Figure 5 This is the schematic diagram of the detailed dimensions of the steel insertion plate used in the embodiment, Figure 5 (a) is the front view, Figure 5 (b) is the side view.

[0056] Figure 6 This is the dimension and layout diagram of the mild steel and steel pipe in the embodiment.

[0057] Figure 7 This is the diagram for determining the radian of the arc-shaped mild steel in the embodiment.

[0058] Figure 8 This is the schematic diagram of the coordinate system for calculating the elongation length of the arc-shaped mild steel in the embodiment.

[0059] Figure 9 This is the design flow chart of the connection structure of the wooden column footing of the present invention.

[0060] Explanation of reference numerals: 1 - wooden column, 11 - screw hole, 12 - cross-shaped groove; 2 - cross-shaped steel insertion plate, 21 - connecting screw hole; 3 - arc-shaped mild steel sheet; 4 - steel pipe column foundation; 5 - bolt; 6 - connecting steel plate. Detailed implementation manners

[0061] The following will describe in detail the implementation of the present invention with reference to the accompanying drawings. However, they do not constitute a limitation to the present invention, but are only for example. At the same time, through the description, the advantages of the present invention will be more clearly understood. All deformations that can be directly derived or associated by those of ordinary skill in the art from the content disclosed in the present invention should be considered as within the protection scope of the present invention. The positional relationships described in the embodiments are all consistent with those shown in the accompanying drawings. Other parts not described in detail in the embodiments are all prior arts.

[0062] The working mechanism of the new type of column base joint mainly includes two aspects: one is that in the elastic stage, the reciprocating swing of the wooden column is mainly used to release energy and reduce the transmission of seismic energy to the upper structure; the other is that in the plastic stage, the nonlinearity of the material, that is, the yield energy dissipation of the steel insert plate, is utilized. At the same time, the column base produces reciprocating swing rotation to release seismic energy, while the arc-shaped mild steel plays a role in limiting position and self-resetting. The special structural form of the new type of column base joint, that is, the four arc-shaped mild steels are symmetrically arranged on the concentric circumference of the steel pipe, enables it to play a role in limiting position in different directions and can adapt to the randomness of the direction of seismic action.

[0063] The working schematic diagram of the new type of column base joint under cyclic load is shown in Figure 4 the figure. When the external load is small, the structure is in the elastic stage. Due to the reasonable design of the cross-sectional dimensions of the glued wooden column and the steel pipe column base, a certain rotation can be generated at the lower wooden column base under the action of the horizontal load, as shown in Figure 4 (a). At this time, the arc-shaped mild steels R1 and R4 are in tension, and R2 and R3 are in compression, restricting the column base from generating excessive rotational deformation and providing a restoring force after unloading to reset the wooden column; when the structure is reversely loaded, the arc-shaped mild steels R1 and R4 are in compression, and R2 and R3 are in tension, as shown in Figure 4 (c). The arc-shaped mild steel also has a limiting effect on the lower column base in this stage and provides a restoring force to reset the wooden column after unloading. Under the action of the reciprocating load, the wooden column will undergo reciprocating swing, release energy, and reduce the input of external energy. In this process, the arc-shaped mild steel is in an elastic state. As the external load increases, the rotation angle of the bottom plate of the steel insert plate at the column base further increases. Due to the bidirectional constraint of the bolts on the steel insert plate, the steel insert plate connector begins to yield at the cross center position, generating a certain amount of plastic deformation to play an energy dissipation role. The yield position is only concentrated in the central area at the bottom of the steel insert plate and does not spread to the surrounding of the bolt holes. At this time, the column bottom rotation angle increases, but due to the limiting effect of the arc-shaped mild steel on the upper wooden column, excessive rotational deformation of the wooden column is avoided, thus ensuring the safety of the main structure. At the same time, it can effectively avoid or delay the splitting failure of the wood at the column bottom and provide a certain restoring force after unloading to reset the wooden column.

[0064] The connection structure of the wooden column base is shown in Figure 1 , Figure 2 and Figure 3As shown in the figure, a cross-shaped groove 12 is provided at the center of the bottom of the wooden column 1, and a plurality of screw holes 11 are provided on the wooden column 1 along the horizontal and vertical directions; a cross-shaped steel insert plate 2 is embedded in the cross-shaped groove 12, and a plurality of connecting screw holes 21 coinciding with the screw holes 11 are provided on the cross-shaped steel insert plate 2; bolts 5 are provided in the screw holes 11 and the connecting screw holes 21; a square connecting steel plate 6 is provided at the bottom of the cross-shaped steel insert plate 2; a steel pipe column base 4 and a plurality of arc-shaped mild steel sheets 3 are provided at the bottom of the connecting steel plate 6; the middle of the steel pipe column base 4 is hollow, the outer diameter of the steel pipe column base 4 is smaller than the side length of the wooden column 1, and the top of the steel pipe column base 4 is fixedly connected to the middle of the bottom of the connecting steel plate 6; the arc-shaped mild steel sheets 3 are uniformly arranged along the periphery of the steel pipe column base 4, and the top ends of the arc-shaped mild steel sheets 3 are fixedly connected to the bottom of the connecting steel plate 6.

[0065] When designing the connection structure of the wooden column foot, the following requirements should be met:

[0066] (1) The lower column foot joint has sufficient flexural bearing capacity and can swing to a certain extent, effectively reducing the relative deformation at the connection between the end of the wooden column 1 and the bolt 5, thereby delaying or avoiding the cross-grain splitting of the wooden column 1.

[0067] (2) The column foot joint has a compressive bearing capacity and compressive stiffness equivalent to those of the wooden column 1.

[0068] (3) The self-resetting arc-shaped mild steel sheet 3 has a two-way resetting ability, but it cannot prematurely restrain the deformation of the column foot, nor can it prematurely fail and lose its function. Therefore, it should have an appropriate lateral stiffness and a large bearing capacity.

[0069] Based on this, the present invention proposes a design method for the connection structure of the wooden column foot. The flowchart is as Figure 9 shown, and the steps are as follows:

[0070] Step 1: According to the seismic design requirements of the timber structure in the "Code for Design of Timber Structures" GB50005-2017, calculate the bending moment, shear force and axial force at the bottom of the wooden column 1, and check the flexural and shear bearing capacities of the wooden column 1 to determine the size and material grade of the wooden column 1.

[0071] Step 2: Initially determine the height, cross-sectional dimensions and material grade of the steel pipe column base 4 according to the size of the wooden column 1, and ensure that the axial compressive strength of the steel pipe column base 4 is greater than or equal to the axial force of the wooden column 1.

[0072] Specifically, the height of the steel pipe column base 4 is initially determined to be 1 / 15 - 1 / 10 of the total height of the wooden column 1, the outer diameter of the cross-section of the steel pipe column base 4 is initially determined to be 1 / 2 of the length or width of the rectangular cross-section of the wooden column 1, and the material grades of the steel pipe column base 4 include low Q420 alloy high-strength structural steel and Q460 alloy high-strength structural steel.

[0073] The formula for the axial compressive strength of the steel pipe column foundation 4 being greater than or equal to the axial force of the wooden column 1 is:

[0074]

[0075] Wherein, N is the axial force transmitted from the wooden column 1; A is the cross-sectional area of the steel pipe column foundation 4; f is the material strength of the steel pipe column foundation 4.

[0076] Step 3: Under the action of frequent earthquakes, the swing angle at the top of the steel pipe column foundation 4 of the connection structure of the wooden column foot is set to 50%-60% of the elastic inter-story drift angle limit value, and the value of the elastic inter-story drift angle limit is 1 / 250. Based on this, the top rotation angle of the steel pipe column foundation 4 is checked, and at the same time, the flexural-compressive bearing capacity of the steel pipe column foundation 4 is checked; if the flexural-compressive bearing capacity of the steel pipe column foundation 4 does not meet the corresponding requirements in the "Steel Structure Design Standard" GB50017-2017 and / or the swing angle at the top of the steel pipe column foundation 4 cannot meet 50%-60% of the elastic inter-story drift angle limit value of 1 / 250, then return to Step 2 to re-determine the height, cross-sectional dimensions, and material grade of the steel pipe column foundation 4 until the steel pipe column foundation 4 can meet the requirements of the "Steel Structure Design Standard" GB50017-2017 for the flexural-compressive bearing capacity and the swing angle at the top is within the range of 50%-60% of the elastic inter-story drift angle limit value of 1 / 250.

[0077] Specifically, the flexural-compressive bearing capacity of the steel pipe column foundation 4 includes cross-sectional strength and cross-sectional stability.

[0078] The cross-sectional strength of the steel pipe column foundation 4 should meet the following requirements:

[0079]

[0080] Wherein, N and M are respectively the axial force and bending moment transmitted from the wooden column 1; A n , W n are respectively the net cross-sectional area and net cross-sectional modulus of the steel pipe column foundation 4; γ m is the cross-sectional plastic development coefficient; f is the material strength of the steel pipe column foundation 4.

[0081] The cross-sectional stability of the steel pipe column foundation 4 should meet the following requirements:

[0082]

[0083] Wherein, N and M are respectively the axial force and bending moment transmitted from the wooden column 1; A and W are respectively the cross-sectional area and cross-sectional modulus of the steel pipe column foundation 4; is the overall stability coefficient of the axially compressed member in the plane of the bending moment; f is the material strength of the steel pipe column foundation 4; γ m is the cross-sectional plastic development coefficient; β is the equivalent bending moment coefficient used when calculating the overall stability of the flexural-compressive member; N′ Exis the calculation parameter determined by the equivalent slenderness ratio in the plane of bending moment action.

[0084] The swing angle θ at the top of the steel pipe column foundation 4 is calculated according to the following formula by the graphical multiplication method:

[0085]

[0086] where θ is the swing angle at the top of the steel pipe column foundation 4 respectively; are the relevant calculation parameters in the bending moment diagram corresponding to applying a unit moment at the top of the steel pipe column foundation 4 when using the graphical multiplication method; E is the elastic modulus of the corresponding steel used; I is the sectional moment of inertia of the steel pipe column foundation 4; M and V are the bending moment and shear force transmitted from the wooden column 1 respectively; l is the height of the steel pipe column foundation 4.

[0087] Step 4: Under the action of rare earthquake, the swing angle at the top of the steel pipe column foundation 4 of the connection structure at the column foot of the wooden column is set to 50%-70% of the plastic inter-story drift angle limit value, and the value of the plastic inter-story drift angle limit is 1 / 50, and at the same time, it meets the overall drift angle limit value of the connection structure at the column foot of the wooden column. Based on this, determine the quantity, position, radian and material grade of the arc-shaped mild steel sheet 3; regard the steel pipe column foundation 4 as a cantilever member. When the internal force transmitted from the superstructure of the connection structure at the column foot of the wooden column causes horizontal displacement and rotation at the top of the steel pipe column foundation 4, one side of the arc-shaped mild steel sheet 3 is just straightened, and thus determine its maximum radian value; take the condition that the stress generated when one side of the arc-shaped mild steel sheet 3 is in tension as it swings with the steel pipe column foundation 4 just reaches the yield stress of the arc-shaped mild steel sheet 3 to determine its minimum radian value;

[0088] If the radian of the arc-shaped mild steel sheet 3 initially determined is greater than the aforementioned maximum radian value or less than the aforementioned minimum radian value, repeat Step 4 to adjust the quantity, position and radian of the arc-shaped mild steel sheet 3; if after repeatedly adjusting the quantity, position and radian of the arc-shaped mild steel sheet 3, the swing angle of the steel pipe column foundation 4 cannot meet 50%-70% of the plastic inter-story drift angle limit value of 1 / 50, then return to Step 2 to determine the height, cross-sectional size and material grade of the steel pipe column foundation 4 again until the swing angle of the steel pipe column foundation 4 is within 50%-70% of the plastic inter-story drift angle limit value of 1 / 50.

[0089] Specifically, the quantity of the arc-shaped mild steel sheet 3 is at least 4 pieces, and the arc-shaped mild steel sheet 3 is evenly arranged on the concentric circles with the center of the steel pipe column foundation 4 as the center. The diameter D of this concentric circle is 0.9-1.1 times the width of the rectangular cross-section of the wooden column 1; the material grade of the arc-shaped mild steel sheet 3 includes carbon structural steel Q235; the radian of the arc-shaped mild steel sheet 3 is determined according to the length and radius of the arc-shaped mild steel sheet 3.

[0090] The swing angle θ and displacement Δ of the steel pipe column foundation 4 are calculated according to the following formula by the graphical multiplication method:

[0091]

[0092]

[0093] Among them, Δ and θ are the lateral displacement and swing angle at the top of the steel pipe column foundation 4 respectively; They are the relevant calculation parameters in the bending moment diagrams corresponding to applying a unit horizontal force and a unit moment at the top of the steel pipe column foundation 4 when using the moment distribution method; E is the elastic modulus of the corresponding steel used; I is the sectional moment of inertia of the steel pipe column foundation 4; M and V are the bending moment and shear force transmitted from the wooden column 1 respectively; l is the height of the steel pipe column foundation 4.

[0094] After determining the number, position and material grade of the arc-shaped mild steel sheets 3, the swing angle and lateral displacement at the top of the steel pipe column foundation 4 at this time are obtained according to the above, and assuming that the arc-shaped mild steel sheets 3 are just completely straightened at this time, the straightened length of the arc-shaped mild steel sheets 3 can be obtained from the geometric relationship based on the magnitudes of this swing angle and lateral displacement, and then from the chord length in the initial state, that is, the height of the steel pipe column foundation 4, the radian size of the arc-shaped mild steel sheets 3 can be determined, and this radian value is taken as the maximum radian value.

[0095] When determining the minimum radian value of the arc-shaped mild steel sheets 3, assume that the arc-shaped mild steel sheets 3 have no radian and are a straight steel sheet. The arc-shaped mild steel sheets 3 will deform and generate stress as the steel pipe column foundation 4 swings. When the stress of the arc-shaped mild steel sheets 3 reaches the elastic limit, that is, its material yield strength, a certain elongation deformation will also occur. The length in this state is taken as the straightened length of the arc-shaped mild steel sheets 3, and then from the chord length in the initial state, that is, the height of the steel pipe column foundation 4, the minimum radian value of the arc-shaped mild steel sheets 3 is determined.

[0096] Step Five: Conduct a lateral displacement check on the entire wooden column including the connection structure of the wooden column foot, and check whether the inter-story lateral displacement angles under frequent earthquake action and rare earthquake action meet the requirements of the elastic and plastic inter-story displacement angles in the "Code for Seismic Design of Buildings"; if the inter-story displacement angles meet the requirements of the elastic and plastic inter-story displacement angles in the "Code for Seismic Design of Buildings", the design is completed; if not, return to Step Two to adjust the height, cross-sectional dimensions and material grade of the steel pipe column foundation 4 until the above requirements are met.

[0097] Specifically, the total bottom-story inter-story displacement of the entire wooden column including the connection structure of the wooden column foot consists of three parts: ① the lateral displacement Δ1 generated by the wooden column 1 under the action of horizontal load; ② the lateral displacement Δ2 generated by the steel pipe column foundation 4 under the action of horizontal load; ③ the geometric lateral displacement Δ3 generated due to the reset swing angle of the steel pipe column foundation 4.

[0098] Under earthquake action, the anti-lateral stiffness of the wooden column is calculated using the inflection point method or the D-value method to calculate the lateral displacement value. The lateral stiffness D' of the wooden column 1 is:

[0099]

[0100] Among them, i t is the linear stiffness of the wooden column 1; l t is the length of the wooden column 1;

[0101] The lateral displacement Δ1 is:

[0102]

[0103] Among them, V is the shear force generated by the wooden column 1 under the earthquake action;

[0104] The lateral displacement Δ3 is:

[0105] Δ3 = l t sinθ,

[0106] Among them, l t is the length of the wooden column 1; θ is the swing angle at the top of the steel pipe column foundation 4;

[0107] Under the action of frequent earthquakes, the total inter-story displacement should satisfy:

[0108] Δ1 + Δ2 + Δ3 ≤ [θ e h,

[0109] Among them, [θ e is the limit value of the elastic inter-story lateral displacement angle under the action of frequent earthquakes, taking 1 / 250; h is the total story height, including the length l of the wooden column 1 t and the height l of the steel pipe column foundation 4;

[0110] Under the action of rare earthquakes, the total inter-story displacement should satisfy:

[0111] Δ1 + Δ2 + Δ3 ≤ [θ p h,

[0112] Among them, [θ p is the limit value of the plastic inter-story displacement angle under the action of rare earthquakes, taking 1 / 50; h is the total story height, including the length l of the wooden column 1 t and the height l of the steel pipe column foundation 4.

[0113] Embodiment

[0114] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. The following embodiments are implemented on the premise of the technical solution of the present invention, and the detailed implementation manners and specific operation processes are given, but the protection scope of the present invention is not limited to the following embodiments.

[0115] Step 1. According to the seismic design requirements of the timber structure in the "GB50005-2017 Timber Structure Design Standard", calculate the bending moment, shear force and axial force at the bottom of the wooden column 1, and check the flexural and shear bearing capacities of the wooden column 1 to determine the size and material grade of the wooden column 1.

[0116] Since this step is a routine check of the bearing capacity of wooden columns, according to the "Code for Design of Timber Structures" (GB50005-2017), the checking process is omitted and only the calculation results are given.

[0117] As Figure 5 shown, according to the seismic design requirements of timber structures in the "Code for Design of Timber Structures" (GB50005-2017), the cross-sectional dimensions of wooden column 1 are set as 305 mm × 305 mm, and the strength grade is TC T 36, f c = 21.1 N / mm 2 , f m = 25.1 N / mm 2 ; the dimensions of the cruciform steel insert plate 2 are 310 mm × 305 mm × 10 mm, and the dimensions of the connecting steel plate 6 are 305 mm × 305 mm × 18 mm; the diameter of the bolt 5 is 20 mm, the length is 341 mm, the diameter of the nut is 36 mm, and the thickness is 18 mm.

[0118] The bolt 5 adopts the 8.8-grade friction-type high-strength bolt specified in the "Code for Design of Steel Structures" (GB50017-2017). When the strain reaches 0.00321, it is considered to yield, and the yield stress is 640 MPa. When the strain reaches 0.1, the ultimate stress is reached, and the ultimate stress is 800 MPa; the steel pipe column foundation 4 adopts an ideal elastoplastic material, and the yield strength is 460 MPa; the yield strength of the cruciform steel insert plate 2 is 390 MPa, Q235B grade steel, the yield strength f y = 235 N / mm 2 , the ultimate strength f u = 375 N / mm 2 , the yield strain ε1 = 0.1114%, the elastic modulus E = 2.06×10 5 N / mm 2 , and the Poisson's ratio ν = 0.3.

[0119] According to the conventional calculation, at room temperature of 20 °C, under the action of frequent earthquakes, the internal forces at the bottom of the wooden column 1 are the bending moment M = 13.1 kN·m, the axial force N = 99.7 kN, and the shear force V = 4.5 kN. Under the action of rare earthquakes, the internal forces at the bottom of the column are the bending moment M = 73.5 kN·m, the axial force N = 13.5 kN, and the shear force V = 23.5 kN.

[0120] Step 2: Based on the dimensions of the wooden column 1, preliminarily determine the height, cross-sectional dimensions, and material grade of the steel pipe column foundation 4 to ensure that the axial compressive strength of the steel pipe column foundation 4 is greater than or equal to the axial force of the wooden column 1.

[0121] The preliminarily determined dimensions of the steel pipe column foundation 4 are the outer diameter d2 = 120 mm, the inner diameter d1 = 70 mm, and the height l = 200 mm; the yield strength f of the steel pipe column foundation 4y = 460 N / mm 2 , the strength design value is taken as f = 410 N / mm according to Table 4.4.1 of the "Steel Structure Design Standard" GB50017-2017 2 , the axial compressive strength of the steel pipe column foundation 4 needs to be greater than or equal to the axial force of the wooden column 1. The ratio of the axial compressive strength of the steel pipe column foundation 4 to the axial force of the wooden column 1 is the axial compression ratio, and its calculation formula is:

[0122]

[0123] Among them, N is the axial force transmitted by the wooden column 1; A is the cross-sectional area of the steel pipe column foundation 4; f is the material strength of the steel pipe column foundation 4.

[0124] The verification shows that the requirements are met, and proceed to Step Three.

[0125] Step Three: According to the relevant provisions of the "Steel Structure Design Standard" GB50017-2017, the steel pipe column foundation 4 is subjected to the combined action of axial force, bending moment and shear force. It is checked according to the flexural-compression member, and the calculated value of A n = 7.46×10 3 mm 2 ,

[0126] W n = 1.5×10 5 mm 3 , then the cross-sectional strength check is as follows:

[0127]

[0128] Among them, N and M are the axial force and bending moment transmitted by the wooden column 1 respectively; A n , W n are the net cross-sectional area and net cross-sectional modulus of the steel pipe column foundation 4 respectively; γ m is the section plastic development coefficient. For flexural-compression members that need to check the fatigue strength, it is advisable to take 1.0; f is the material strength of the steel pipe column foundation 4.

[0129] When checking the stability of the steel pipe column foundation 4, its section classification is type b, the slenderness ratio λ x = 5.76 mm, the steel strength grade correction coefficient is ε k = 1.4, the overall stability coefficient φ = 0.999, and the Euler force and related calculation parameters are calculated as follows:

[0130]

[0131]

[0132]

[0133] Among them, NE is the Euler force calculated according to the maximum slenderness ratio of the component; N′ Ex is the calculation parameter determined by the equivalent slenderness ratio in the plane of the bending moment; E is the elastic modulus of the material of the steel pipe column foundation 4; A is the cross-sectional area of the steel pipe; λ, λ x are both the slenderness ratios of the steel pipe column foundation 4, β is the equivalent bending moment coefficient used in the calculation of the overall stability of the biaxial compression and bending, and its subscripts x and y represent directions. Only uniaxial compression and bending are considered, so β y = β x ; N is the design value of the axial force of the steel pipe column foundation 4; M 1x , M 2x are the end bending moments on the x-axis, |M 1x | ≥ |M 2x |. When there is an inflection point, opposite signs are taken, and when there is no inflection point, the same sign is taken.

[0134] Then its overall stability check is as follows:

[0135]

[0136] Among them, N and M are the axial force and bending moment transmitted from the wooden column 1 respectively; A and W are the cross-sectional area and section modulus of the steel pipe column foundation 4 respectively; φ is the overall stability coefficient of the axially compressed member in the plane of the bending moment; f is the design value of the material strength of the steel pipe column foundation 4; γ m is the section plastic development coefficient; β is the equivalent bending moment coefficient used in the calculation of the overall stability of the compression-bending member; N′ Ex is the calculation parameter determined by the equivalent slenderness ratio in the plane of the bending moment.

[0137] Therefore, the compression-bending bearing capacity of the steel pipe column foundation 4 meets the design requirements.

[0138] Check whether the deformation of the steel pipe column foundation 4 meets the requirements under the previously determined size and strength conditions. It can be calculated that the moment of inertia of the cross-section of the steel pipe column foundation 4 is I = 9.0×10 6 mm 4 . Regarding the steel pipe column foundation 4 as a cantilever member, under the internal force combination in the case of frequent earthquakes, the calculation of its rotation angle θ and displacement Δ by the graphical multiplication method is as follows:

[0139]

[0140]

[0141] where Δ and θ are the lateral displacement and swing angle at the top of the steel pipe column foundation 4 respectively; and are the relevant calculation parameters in the bending moment diagram corresponding to the application of unit horizontal force and unit moment at the top of the steel pipe column foundation 4 when using the moment distribution method; E is the elastic modulus of the corresponding steel; I is the section moment of inertia of the steel pipe column foundation 4; M and V are the design values of the bending moment and shear force transmitted from the wooden column 1; l is the height of the steel pipe column foundation 4; [θ e is the limit value of the elastic inter-story drift angle, which is 1 / 250.

[0142] The rotation angle under frequent earthquakes meets the limit requirements.

[0143] Step 4: First, check whether the rotation angle θ of the steel pipe column foundation 4 meets the requirements under the internal force combination of M = 73.5 kN·m, N = 13.7 kN, and V = 23.5 kN in rare earthquakes: p Whether it meets the requirements:

[0144]

[0145]

[0146] where [θ p is the limit value of the plastic inter-story drift angle, which is 1 / 50.

[0147] Therefore, the swing angle of the steel pipe column foundation 4 under rare earthquakes meets the limit requirements.

[0148] Then, based on the lateral displacement Δ and rotation angle θ generated by the steel pipe column foundation 4 under rare earthquake actions obtained, assuming that the arc-shaped mild steel 3 is just straightened at this time, determine the maximum radian value of the arc-shaped mild steel 3. There are four pieces of arc-shaped mild steel 3, which are arranged on a circle with a diameter of D = 300 mm centered on the center and symmetrically arranged at the four corners, as p shown, and at the same time, the height l of the steel pipe column foundation 4 is 200 mm, as p shown. From the geometric relationship, the length of the completely straightened arc-shaped mild steel 3 can be obtained as 200.872 mm. If the radius of the arc-shaped mild steel 3 is set as r and the corresponding radian is 2α, the following system of equations can be established: Figure 6 shown, and at the same time, the height l of the steel pipe column foundation 4 is 200 mm, as Figure 7 shown. From the geometric relationship, the length of the completely straightened arc-shaped mild steel 3 can be obtained as 200.872 mm. If the radius of the arc-shaped mild steel 3 is set as r and the corresponding radian is 2α, the following system of equations can be established:

[0149]

[0150] It can be solved that α = 0.1615, and thus the maximum radian value α max = 0.323 rad can be determined.

[0151] Taking the elongation length when the arc-shaped mild steel 3 reaches the yield strength without considering the radian of the arc-shaped mild steel 3 as the basis for determining the minimum radian of the arc-shaped mild steel 3. As Figure 8As shown, the arc-shaped mild steel 3 has a variable cross-section from top to bottom. The width at both the upper and lower ends is 40 mm, the width in the middle is 20 mm, and the thickness is t = 4 mm. The arc-shaped mild steel 3 is made of Q235B grade steel with a yield strength of f y = 235 MPa.

[0152] When the weakest cross-section in the middle yields, the tensile force on the mild steel is:

[0153] N = f y A = 235 × 4 × 20 = 18.8 kN

[0154] Among them, f y is the yield strength of Q235 steel; A is the cross-sectional area of the arc-shaped mild steel 3.

[0155] Establish a coordinate system as shown in Figure 8 , and let the position of the dimension line on one side of the arc-shaped mild steel 3 be f(x) = b(x) / 2.

[0156] From the known dimension information, the equation of the circle where the arc is located is:

[0157] x 2 +(y - 515) 2 = 505 2 , that is

[0158] According to the Taylor series expansion, neglecting the higher-order infinitesimals, we get:

[0159]

[0160] The tensile length is:

[0161]

[0162] Substituting the expression of f(x), we can solve:

[0163]

[0164] Among them, δ is the tensile length of the mild steel; l is the height of the steel pipe column foundation 4; N is the magnitude of the tensile force on the arc-shaped mild steel 3; E is the elastic modulus of the arc-shaped mild steel 3; t is the thickness of the arc-shaped mild steel 3.

[0165] Then the elongation of the arc-shaped mild steel 3 when it reaches yield is δ = 0.179 mm, that is, the minimum length of the arc-shaped mild steel 3 is (200 + 0.179) mm, and the minimum radian value α min = 0.147 rad.

[0166] The radian value α of the arc-shaped mild steel 3 is between the maximum radian value α max and the minimum radian value α min , meeting the requirements.

[0167] Step 5: Conduct a lateral displacement check on the entire wooden column including the connection structure of the wooden column base. The total inter-story displacement at the bottom layer of the entire wooden column including the connection structure of the wooden column base consists of three parts: ① The lateral displacement Δ1 generated by the wooden column 1 under the action of the horizontal load; ② The lateral displacement Δ2 generated by the steel pipe column foundation 4 under the action of the horizontal load; ③ The geometric lateral displacement Δ3 generated due to the reset swing angle of the steel pipe column foundation 4.

[0168] Under the action of an earthquake, the action of the horizontal earthquake on the frame structure can generally be simplified as a horizontal force on the frame joints, and the inflection point method is used to estimate the lateral displacement of the wooden column.

[0169] It is known that under the action of a frequently-occurring earthquake, the shear force magnitude received by the bottom-layer wooden column 1 is V = 4.5 kN. The geometric dimensions of the wooden column 1 are 305 mm × 305 mm, and its moment of inertia is I = 305 4 / 12 = 7.2×10 8 mm 4 , the column length l t = 2.8 m, and the elastic modulus of the glued laminated timber of strength grade TC T 36 is E = 11000 N / mm 2 . Then the linear stiffness of the wooden column 1 is:

[0170]

[0171] Then the lateral stiffness of the bottom layer is:

[0172]

[0173] Then the lateral displacement of the wooden column (1) is:

[0174]

[0175] It has been obtained that the horizontal lateral displacement Δ2 = 0.148 mm at the top of the steel pipe column foundation (4) under a frequently-occurring earthquake, and the rotation angle θ = 1 / 684. Then the lateral displacement generated due to the swing reset is:

[0176] Δ3 = l t sinθ = 2800×sin(1 / 684) = 4.1 mm,

[0177] Therefore, its total inter-story displacement is:

[0178] Δ1 + Δ2 + Δ3 = 1.05 + 0.148 + 4.1 = 5.3 mm ≤ [θ e h = 3000 / 250 = 12 mm,

[0179] Among them, [θ eis the limit value of elastic inter-story drift ratio, taking 1 / 250; h is the total floor height, including the length l of the wooden column (1) t and the height l of the steel pipe column foundation (4).

[0180] The elastic inter-story drift ratio under frequent earthquakes meets the requirements of the seismic code.

[0181] Under rare earthquakes, the corresponding shear force magnitude is V = 23.5 kN. Similarly, Δ1 = 5.47 mm, Δ2 = 0.827 mm, and Δ3 = 2800×sin(1 / 122) = 22.95 mm can be obtained. The total inter-story displacement is:

[0182] Δ1 + Δ2 + Δ3 = 5.47 + 0.827 + 22.95 = 29.25 mm ≤ [θ p h = 3000 / 50 = 60 mm

[0183] Among them, [θ p is the limit value of plastic inter-story drift ratio, taking 1 / 50; h is the total floor height, including the length l of the wooden column (1) t and the height l of the steel pipe column foundation (4).

[0184] The plastic inter-story drift ratio under rare earthquakes also meets the requirements of the seismic code.

[0185] The preferred embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings and specific embodiments. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A swing self-resetting connection structure for a wooden column base, comprising a wooden column (1), characterized in that: A cross-shaped groove (12) is provided at the center of the bottom of the wooden column (1), and a plurality of screw holes (11) are provided on the wooden column (1) along the transverse and longitudinal directions; a cross-shaped steel insert plate (2) is embedded in the cross-shaped groove (12), and a plurality of connecting screw holes (21) coinciding with the screw holes (11) are provided on the cross-shaped steel insert plate (2); bolts (5) are provided in the screw holes (11) and the connecting screw holes (21); a square connecting steel plate (6) is provided at the bottom of the cross-shaped steel insert plate (2); a steel pipe column base (4) and a plurality of arc-shaped soft steel sheets (3) are provided at the bottom of the connecting steel plate (6); the middle of the steel pipe column base (4) is hollow, the outer diameter of the steel pipe column base (4) is smaller than the side length of the wooden column (1), and the top of the steel pipe column base (4) is fixedly connected to the middle of the bottom of the connecting steel plate (6); the arc-shaped soft steel sheets (3) are uniformly arranged along the periphery of the steel pipe column base (4), and the top ends of the arc-shaped soft steel sheets (3) are fixedly connected to the bottom of the connecting steel plate (6).

2. A design method for the swing self-resetting connection structure of the wooden column base described in claim 1, characterized in that, It includes the following steps: Step 1: According to the seismic design requirements of the wooden structure in the "Code for Design of Timber Structures" (GB50005 - 2017), calculate the bending moment, shear force and axial force at the bottom of the wooden column (1), and check the flexural compression and shear bearing capacities of the wooden column (1) to determine the size and material grade of the wooden column (1). Step 2: Initially determine the height, cross-sectional dimensions and material grade of the steel pipe column base (4) according to the size of the wooden column (1), and ensure that the axial compressive strength of the steel pipe column base (4) is greater than or equal to the axial force of the wooden column (1). Step 3: Under the action of frequent earthquakes, the swing angle at the top of the steel pipe column base (4) of the column foot connection structure of the wooden column is set to 50% - 60% of the elastic inter-story drift angle limit value, and the value of the elastic inter-story drift angle limit is 1 / 250. Based on this, check the top rotation angle of the steel pipe column base (4), and at the same time check the flexural compression bearing capacity of the steel pipe column base (4); if the flexural compression bearing capacity of the steel pipe column base (4) does not meet the corresponding requirements in the "Code for Design of Steel Structures" (GB50017 - 2017) and / or the swing angle at the top of the steel pipe column base (4) cannot meet 50% - 60% of the elastic inter-story drift angle limit value of 1 / 250, then return to Step 2 to re-determine the height, cross-sectional dimensions and material grade of the steel pipe column base (4) until the steel pipe column base (4) can meet the requirements for flexural compression bearing capacity in the "Code for Design of Steel Structures" (GB50017 - 2017) and the swing angle at the top is within the range of 50% - 60% of the elastic inter-story drift angle limit value of 1 / 250. Step 4: Under the action of rare earthquakes, the swing angle at the top of the steel pipe column foundation (4) of the wooden column footing connection structure is set to 50%-70% of the plastic inter-story drift angle limit value. The value of the plastic inter-story drift angle limit is taken as 1 / 50, and at the same time, it meets the overall drift angle limit of the wooden column footing connection structure. Based on this, determine the quantity, position, radian, and material grade of the arc-shaped mild steel sheet (3); regard the steel pipe column foundation (4) as a cantilever member. When the internal force transmitted from the superstructure of the wooden column footing connection structure causes horizontal displacement and rotation at the top of the steel pipe column foundation (4), one side of the arc-shaped mild steel sheet (3) is just straightened, and thus determine its maximum radian value; Taking the condition that the stress generated when the arc-shaped mild steel sheet (3) is in tension on one side as it swings with the steel pipe column foundation (4) just reaches the yield stress of the arc-shaped mild steel sheet (3), determine its minimum radian value; If the radian of the preliminarily determined arc-shaped mild steel sheet (3) is greater than the aforementioned maximum radian value or less than the aforementioned minimum radian value, repeat Step 4 to adjust the quantity, position, and radian of the arc-shaped mild steel sheet (3); If after repeatedly adjusting the quantity, position, and radian of the arc-shaped mild steel sheet (3), the swing angle of the steel pipe column foundation (4) cannot meet 50%-70% of the plastic inter-story drift angle limit value of 1 / 50, then return to Step 2 to re-determine the height, cross-sectional dimensions, and material grade of the steel pipe column foundation (4) until the swing angle of the steel pipe column foundation (4) is within 50%-70% of the plastic inter-story drift angle limit value of 1 / 50; Step 5: Conduct a lateral displacement resistance check on the entire wooden column including the wooden column footing connection structure to see if the inter-story drift angles under frequent earthquake actions and rare earthquake actions meet the requirements of the elastic and plastic inter-story displacement angles in the Code for Seismic Design of Buildings; if the inter-story displacement angles meet the requirements of the elastic and plastic inter-story displacement angles in the Code for Seismic Design of Buildings, the design is completed; if not, return to Step 2 to adjust the height, cross-sectional dimensions, and material grade of the steel pipe column foundation (4) until the above requirements are met.

3. The design method of a swing self-resetting connection structure for a wooden column base according to claim 2, characterized in that: In the above Step 2, the height of the steel pipe column foundation (4) is preliminarily determined to be 1 / 15 - 1 / 10 of the total height of the wooden column (1), the outer diameter of the cross-section of the steel pipe column foundation (4) is preliminarily determined to be 1 / 2 of the length or width of the rectangular cross-section of the wooden column (1), and the material grade of the steel pipe column foundation (4) includes low-alloy high-strength structural steel Q420 and alloy high-strength structural steel Q460; The ratio of the axial compressive strength of the steel pipe column foundation (4) to the axial force of the wooden column (1) is the axial compression ratio, and its calculation formula is: Among them, N is the axial force transmitted from the wooden column (1); A is the cross-sectional area of the steel pipe column foundation (4); f is the material strength of the steel pipe column foundation (4).

4. The design method of a rocking self - resetting connection structure for a wooden column base according to claim 3, characterized in that: In the above Step 3, the flexural-compressive bearing capacity of the steel pipe column foundation (4) includes cross-sectional strength and cross-sectional stability; The cross-sectional strength of the steel pipe column foundation (4) should meet the following requirements: Among them, N and M are respectively the axial force and bending moment transmitted from the wooden column (1); A n , W n are respectively the net cross-sectional area and net cross-sectional modulus of the steel pipe column foundation (4); γ m is the sectional plastic development coefficient; f is the material strength of the steel pipe column foundation (4); The cross-sectional stability of the steel pipe column foundation (4) should meet the following requirements: Among them, N and M are respectively the axial force and bending moment transmitted from the wooden column (1); A and W are respectively the cross-sectional area and section modulus of the steel pipe column foundation (4). is the overall stability coefficient of the axially compressed member in the plane of bending moment action; f is the material strength of the steel pipe column foundation (4); γ m is the section plastic development coefficient; β is the equivalent bending moment coefficient used when calculating the overall stability of the flexural-compression member; N′ Ex is the calculation parameter determined by the equivalent slenderness ratio in the plane of bending moment action. The swing angle θ at the top of the steel pipe column foundation (4) is calculated according to the following formula using the graphical multiplication method: Among them, θ is respectively the swing angle at the top of the steel pipe column foundation (4); are the relevant calculation parameters in the bending moment diagram corresponding to applying a unit moment at the top of the steel pipe column foundation (4) when using the graphical multiplication method; E is the elastic modulus of the corresponding steel used; I is the section moment of inertia of the steel pipe column foundation (4); M and V are respectively the bending moment and shear force transmitted from the wooden column (1); l is the height of the steel pipe column foundation (4).

5. The design method of a rocking self - resetting connection structure for a wooden column base according to claim 4, characterized in that: In the fourth step, the number of arc-shaped mild steel sheets (3) is at least 4, and the arc-shaped mild steel sheets (3) are evenly arranged on concentric circles with the center of the steel pipe column foundation (4) as the center. The diameter D of the concentric circles is 0.9 - 1.1 times the width of the rectangular cross-section of the wooden column (1); the material grade of the arc-shaped mild steel sheets (3) includes carbon structural steel Q235; the radian of the arc-shaped mild steel sheets (3) is determined according to the length and radius of the arc-shaped mild steel sheets (3). The swing angle θ and lateral displacement Δ of the steel pipe column foundation (4) are calculated according to the following formula by the moment distribution method:[[]] where Δ and θ are the lateral displacement and swing angle at the top of the steel pipe column foundation (4), respectively; They are the relevant calculation parameters in the bending moment diagrams corresponding to applying a unit horizontal force and a unit moment at the top of the steel pipe column foundation (4) when using the graphical multiplication method; E is the elastic modulus of the corresponding steel used; I is the sectional moment of inertia of the steel pipe column foundation (4); M and V are the bending moment and shear force transmitted from the wooden column (1), respectively; l is the height of the steel pipe column foundation (4). After determining the number, position and material grade of the arc-shaped mild steel sheets (3), the swing angle and lateral displacement at the top of the steel pipe column foundation (4) at this time are obtained according to the above. Assuming that the arc-shaped mild steel sheets (3) are just completely straightened at this time, the straightened length of the arc-shaped mild steel sheets (3) can be obtained from the geometric relationship based on the magnitudes of the swing angle and lateral displacement. Then, from the chord length in the initial state, that is, the height of the steel pipe column foundation (4), the radian size of the arc-shaped mild steel sheets (3) can be determined, and this radian value is used as the maximum radian value.[[]] When determining the minimum radian value of the arc-shaped mild steel sheets (3), assume that the arc-shaped mild steel sheets (3) have no radian and are a straight steel sheet. The arc-shaped mild steel sheets (3) will deform and generate stress as the steel pipe column foundation (4) swings. When the stress of the arc-shaped mild steel sheets (3) reaches the elastic limit, that is, its material yield strength, a certain elongation deformation will also occur. The length in this state is used as the straightened length of the arc-shaped mild steel sheets (3). Then, from the chord length in the initial state, that is, the height of the steel pipe column foundation (4), the minimum radian of the arc-shaped mild steel sheets (3) is determined.[[]] 6. The design method of a rocking self - resetting connection structure for a wooden column base according to claim 5, characterized in that: In the fifth step, the total inter-story displacement of the bottom layer of the entire wooden column including the wooden column footing connection structure is composed of three parts: ① the lateral displacement Δ1 generated by the wooden column (1) under the action of the horizontal load; ② the lateral displacement Δ2 generated by the steel pipe column foundation (4) under the action of the horizontal load; ③ the geometric lateral displacement Δ3 generated due to the reset swing angle of the steel pipe column foundation (4). Under the action of an earthquake, the anti-lateral stiffness of the wooden column is calculated by the inflection point method or the D-value method, and then the lateral displacement value is calculated. The lateral stiffness D' of the wooden column (1) is:[[]] where i t is the linear stiffness of the wooden column (1); l t is the length of the wooden column (1); The lateral displacement Δ1 is:[[]] where V is the shear force generated by the wooden column (1) under the action of an earthquake.[[]] The lateral displacement Δ3 is:[[]] Δ3 = l t sinθ, where l t is the length of the wooden column (1); θ is the swing angle at the top of the steel pipe column foundation (4); Under the action of a frequent earthquake, the total inter-story displacement should satisfy:[[]] Δ1 + Δ2 + Δ3 ≤ [θ e h, Among them, [θ e is the limit value of the elastic inter-story drift angle under the action of frequent earthquakes, taking 1 / 250; h is the height of the entire floor, including the length l t of the wooden column (1) and the height l of the steel pipe column foundation (4); Under the action of a rare earthquake, the total inter-story displacement should satisfy:[[]] Δ1+Δ2+Δ3v[θ p h, Among them, [θ p is the limit value of the plastic inter-story drift angle under rare earthquake action, taking 1 / 50; h is the full-story height, including the length l t of the wooden column (1) and the height l of the steel pipe column foundation (4).

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