Steel column base joint structure with folded line anchorage and design method thereof

Abstract

The application relates to the technical field of building construction, in particular to a steel column foot rigid joint structure of a folded line anchoring and a design method thereof. The steel column foot rigid joint structure comprises a concrete foundation, a steel column and a folded line type foot plate. The bottom of the steel column is fixedly connected with the folded line type foot plate on the periphery of the side surface, so as to form a folded line foot at the bottom of the steel column. The folded line type foot plate is an H-shaped steel. The bottom of the steel column and the folded line type foot plate are embedded in the concrete foundation, and the surface of the folded line type foot plate is provided with studs. The rigid joint structure can effectively transmit the internal force of the steel column to the concrete foundation, realize the fine design of the steel column foot strong node requirement, meet the requirement that the column foot node should not be damaged before the column body under the medium and large earthquakes, expand the contact area of the column foot and the concrete foundation, effectively reduce the risk of punching shear failure of the column foundation, and also can reduce the thickness of the bottom plate required by the punching shear, and save the engineering cost.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, and in particular to a steel column base node structure with zigzag anchorage and its design method. Background Technology

[0002] Prefabricated modular buildings, with their advantages of factory processing, rapid on-site construction, and environmental friendliness, have been widely used in public buildings, residential buildings, and industrial plants. Steel structures, as one of the main structural forms, also possess the characteristics of prefabrication, and their use in above-ground buildings has become one of the mainstream trends in domestic building structure development. Steel structures offer significant advantages for above-ground buildings; the foundations of steel columns are generally reinforced concrete structures.

[0003] Above-ground steel structures bear vertical gravity loads, horizontal wind loads, and seismic loads, which are transferred to the foundation below through columns. The safety and reliability of column base joints are a prerequisite for ensuring the safety of the superstructure. Current structural design codes require that the column base joints of steel structures should not fail before the column itself under moderate to major earthquakes.

[0004] To meet the requirements for strong joints in steel structure column bases, the conventional approach in steel column base design is linear anchorage, such as embedded, inserted, or exposed bases. Exposed bases have a large cross-section and often protrude beyond the finished floor level, affecting interior functionality. Exposed bases experience complex stresses, often require prestressing due to their lower stiffness, and their exposure to ground level impacts building functionality. Embedded bases, on the other hand, require deeper foundations to improve the stability of the steel column base connection, significantly increasing the workload—all undesirable outcomes for those skilled in the art. Summary of the Invention

[0005] To address the aforementioned problems, this invention, based on theoretical analysis and full-scale experimental verification, provides a steel column base node structure with zigzag anchorage and its design method. This structure can significantly reduce the amount of work, save construction time, overcome existing technical bottlenecks, and is simple in form and aesthetically pleasing.

[0006] This invention discloses a steel column base node structure with zigzag anchorage, including a concrete foundation, a steel column, and a zigzag column base plate;

[0007] The bottom four sides of the steel column are fixedly connected with the zigzag column base plate to form a zigzag column base at the bottom of the steel column; the zigzag column base plate is H-beam, the bottom of the steel column and the zigzag column base plate are both embedded in the concrete foundation, and the surface of the zigzag column base plate is provided with studs.

[0008] The concrete foundation is provided with top longitudinal bars and bottom longitudinal bars, and stirrups are sleeved between the top longitudinal bars and the bottom longitudinal bars.

[0009] In some of these embodiments, the steel column is a box-shaped steel column, an H-shaped steel column, or a circular tube column;

[0010] When the steel column is a box-shaped steel column, the inner cavity of the box-shaped steel column is provided with horizontal inner partitions at the positions corresponding to the upper and lower flanges of the folded column base plate and the top longitudinal reinforcement of the concrete foundation, and a concrete pouring hole is opened in the center of the horizontal inner partition.

[0011] When the steel column is an H-shaped steel column, a horizontal partition is provided at the position corresponding to the top longitudinal reinforcement of the concrete foundation; and the zigzag column base plates located on both sides of the web of the H-shaped steel column extend into the interior of the H-shaped steel column and are fixedly connected to the side wall of the web of the H-shaped steel column.

[0012] When the steel column is a circular tube column, an outer ring plate is fitted and fixed on the outer side of the circular tube column at the position corresponding to the top longitudinal reinforcement of the concrete foundation.

[0013] In some embodiments, the top longitudinal reinforcement is connected to the steel column by a steel sleeve fixed to the outside of the steel column, and the top longitudinal reinforcement is arranged parallel to the top surface of the concrete foundation.

[0014] In some embodiments, a plurality of studs are welded to the upper surface of the upper flange, the lower surface of the lower flange, and both sides of the web of the zigzag column base plate.

[0015] In some embodiments, the length of the polygonal column base plate extending beyond the steel column is not less than twice the cross-sectional height of the steel column in the same direction, the width of the polygonal column base plate is not less than 0.7 times the cross-sectional width of the steel column in the same direction, and the thickness of the upper and lower flanges of the polygonal column base plate is not less than the wall thickness of the steel column.

[0016] In some embodiments, the distance between the zigzag column base plate and the top and bottom of the concrete foundation is not less than 200mm, and the distance between the zigzag column base plate and the side of the concrete foundation is not less than 150mm.

[0017] Furthermore, this invention also discloses a design method for the above-mentioned zigzag anchored steel column base node structure. The steel column base node structure includes four zigzag-shaped column base plates arranged in pairs opposite each other. Two of the four zigzag-shaped column base plates perpendicular to the main bending moment direction of the steel column are designated as first zigzag-shaped column base plates, and the other two are designated as second zigzag-shaped column base plates. The method includes the following steps:

[0018] The cross-sectional dimensions and length L1 of the first polygonal column base plate are determined based on the dimensions of the cross-section of the steel column.

[0019] The bending angle of the first polygonal column base plate is determined based on the included angle between the top and bottom surfaces of the concrete foundation and the steel column.

[0020] Determine the thickness of the top surface concrete of the first polygonal column base plate;

[0021] According to the bidirectional constraint requirements, the cross-sectional dimensions and length L2, bending angle, and thickness of the top concrete of the second folded column base plate are determined based on the cross-sectional dimensions and length L1, bending angle, and thickness of the top concrete of the first folded column base plate; wherein, when the included angle between the second folded column base plate and the first folded column base plate is α, the length L2 of the second folded column base plate is determined according to the following formula;

[0022]

[0023] Using the center of the node of the broken column foot of the steel column as the rotation center, the required shear stud bearing capacity at the top and bottom of each broken column foot plate and the required stirrup bearing capacity of each broken column foot plate are calculated according to the plane section assumption.

[0024] Compared with the prior art, the above invention has at least one of the following advantages or beneficial effects:

[0025] I. Technological Advancement: By connecting zigzag-shaped column base plates to all four sides of the steel column base and embedding them within the concrete foundation, the internal forces of the steel column can be effectively transferred to the concrete foundation. This allows for refined design of the strong joint requirements of the steel column base, ensuring that the column base joints do not fail before the column body under moderate to severe earthquakes. Simultaneously, it increases the contact area between the column base and the concrete foundation, effectively reducing the risk of punching shear failure of the foundation and also reducing the thickness of the base plate required for punching shear, thus saving on project costs.

[0026] II. Construction Convenience: In this invention, the zigzag column base plate is only pre-embedded within a short section of the concrete foundation, thereby reducing construction difficulty and facilitating quality control. Furthermore, the zigzag column base plate is very lightweight, which is advantageous for transportation and hoisting.

[0027] III. Engineering Economy: The rigid connection node of the steel column base in this invention reduces the foundation depth and lowers the project cost compared to the embedded column base. Compared to the externally enclosed column base and the exposed column base, it avoids the column base protruding from the ground and affecting the building function.

[0028] IV. The design method of the steel column base node structure with broken line anchorage in this invention has the advantages of reducing foundation depth, reducing foundation thickness, and saving project costs. Attached Figure Description

[0029] The invention, its features, shape, and advantages will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings. Like reference numerals denote like parts throughout the drawings. The drawings are not drawn to scale; their focus is on illustrating the gist of the invention.

[0030] Figure 1 This is a top view of the steel column base node structure with zigzag anchorage in Embodiment 1 of the present invention;

[0031] Figure 2 for Figure 1 Sectional view at point AA;

[0032] Figure 3 for Figure 2 Sectional view at point BB;

[0033] Figure 4 This is a three-dimensional structural diagram of the box-shaped steel column and the folded-line column base plate in Embodiment 1 of the present invention.

[0034] Figure 5 This is a top view of the steel column base node structure with zigzag anchorage in Embodiment 2 of the present invention;

[0035] Figure 6 for Figure 3 Sectional view at CC;

[0036] Figure 7 for Figure 6 Sectional view at point DD;

[0037] Figure 8 This is a top view of the steel column base node structure with zigzag anchorage in Embodiment 3 of the present invention;

[0038] 1 is a box-shaped steel column; 2 is a zigzag column base plate; 3 is a concrete foundation; 4 is a horizontal inner diaphragm; 41 is a concrete pouring hole; 5 is a stud; 6 is a bottom longitudinal reinforcement; 7 is a top longitudinal reinforcement; 8 is a steel sleeve; 9 is a stirrup; 10 is an H-shaped steel column; 11 is a horizontal diaphragm; 12 is a circular tube column; 13 is an outer ring plate. Detailed Implementation

[0039] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but these are not intended to limit the scope of the invention.

[0040] Example 1:

[0041] like Figures 1-4As shown, this embodiment discloses a steel column base node structure with zigzag anchorage, including a concrete foundation 3, a box-shaped steel column 1, and a zigzag column base plate 2; that is, the steel column in this embodiment is a box-shaped steel column 1, and the zigzag column base plate 2 is welded and fixedly connected to the four sides of the column base of the box-shaped steel column 1 to form a zigzag column base at the bottom of the steel column; the zigzag column base plate 2 is an H-beam, and the bottom of the steel column and the zigzag column base plate 2 are both embedded in the concrete foundation 3, and the surface of the zigzag column base plate 2 is provided with studs 5; the concrete foundation 3 is provided with top longitudinal reinforcement 7 and bottom longitudinal reinforcement 6, and stirrups 9 are sleeved between the top longitudinal reinforcement 7 and the bottom longitudinal reinforcement 6. The inner cavity of the box-shaped steel column 1 is provided with horizontal inner partitions 4 at positions corresponding to the upper and lower flanges of the folded column base plate 2 and the top longitudinal reinforcement 7 of the concrete foundation 3. A concrete pouring hole 41 is opened in the center of the horizontal inner partitions 4 at positions corresponding to the upper flange of the folded column base plate 2 and the upper longitudinal reinforcement of the concrete foundation 3 for pouring concrete to the bottom of the box-shaped steel column 1. In this embodiment, by fixing the folded column base plate 2 to the four sides of the column base of the box-shaped steel column 1, the contact area between the column base and the concrete foundation 3 is increased, effectively reducing the risk of punching and breaking of the foundation under the column. On the other hand, since the H-beam is very light, it is relatively advantageous for transportation and hoisting.

[0042] Specifically, multiple studs 5 are welded to the upper surface of the upper flange, the lower surface of the lower flange, and both sides of the web of the zigzag column base plate 2. These studs 5 are evenly arranged along the length of the zigzag column base plate 2 to strengthen the connection between the zigzag column base plate 2 and the concrete foundation 3, thereby further improving the stability of the column base node of the box-shaped steel column 1.

[0043] In this embodiment, the length of the aforementioned polygonal column base plate 2 (which can also be considered as the length of the polygonal column base plate 2 extending out of the steel column) is not less than twice the cross-sectional height of the steel column in the same direction (i.e., the length of the polygonal column base plate 2 is not less than twice the height of the cross-section of the box-shaped steel column 1 along the length direction of the polygonal column base plate 2, the cross-section of the box-shaped steel column 1 after being cut along the length direction of the polygonal column base plate 2 is square, the horizontal dimension of the square is the width, and the vertical dimension is the height). The height of the section along the length of plate 2 can also be described as the distance between the polygonal column base plate 2 and the polygonal column base plate 2 on the opposite side of the polygonal column base plate 2. The width of the polygonal column base plate 2 is not less than 0.7 times the width of the section along the same direction of the box-shaped steel column 1 (i.e., the width of the polygonal column base plate 2 is not less than 0.7 times the width of the section along the length of the polygonal column base plate 2 of the box-shaped steel column 1). The thickness of the upper and lower flanges of the polygonal column base plate 2 is not less than the thickness of the wall panel of the box-shaped steel column 1. The distance between the polygonal column base plate 2 and the top and bottom of the concrete foundation 3 is not less than 200 mm; the distance between the polygonal column base plate 2 and the side of the concrete foundation 3 is not less than 150 mm.

[0044] In this embodiment, the top longitudinal reinforcement 7 is connected to the box-shaped steel column 1 by a steel sleeve 8 fixed to the outside of the box-shaped steel column 1, and the top longitudinal reinforcement 7 is set parallel to the top surface of the concrete foundation 3. The broken column base plate 2 is also set parallel to the top surface of the concrete foundation 3.

[0045] Based on theoretical analysis and full-scale test verification, this embodiment shows that the length and cross-sectional parameters of the above-mentioned polygonal column base plate 2 can meet the requirements of reliable column base embedment stiffness and bearing capacity for the upper box-shaped steel column 1, and can effectively transfer the internal force of the box-shaped steel column 1 to the concrete foundation 3.

[0046] Example 2:

[0047] like Figures 5-7 As shown, this embodiment discloses a steel column base node structure with zigzag anchorage. This embodiment is largely the same as the first embodiment described above, except that the zigzag anchorage steel column base node structure in this embodiment includes a concrete foundation 3, an H-shaped steel column 10, and a zigzag column base plate 2. That is, the steel column in this embodiment is an H-shaped steel column 10, and the zigzag column base plates 2 are fixedly connected to the front, back, left, and right sides of the base of the H-shaped steel column 10. The zigzag column base plates 2 located on both sides of the web of the H-shaped steel column 10 extend into the interior of the H-shaped steel column 10 and are fixedly connected to the side walls of the web of the H-shaped steel column 10. Horizontal partitions 11 are provided on both sides of the web of the H-shaped steel column 10 at positions corresponding to the top longitudinal reinforcement 7 of the concrete foundation 3. Specifically, the zigzag column base plates 2 connected to both sides of the web of the H-shaped steel column 10 extend into the interior of the zigzag column base plates 2 and are fixedly connected to the web of the zigzag column base plates 2 (the dimension of one end of the zigzag column base plate 2 connected to the web of the H-shaped steel column 10 is smaller than the dimensions of other positions of the zigzag column base plate 2 so that it can extend into the interior of the zigzag column base plate 2 and be fixedly connected to the web of the zigzag column base plate 2), thereby making the connection between the zigzag column base plates 2 and the H-shaped steel column 10 more secure; wherein, the length of the zigzag column base plates 2 connected to both sides of the web of the H-shaped steel column 10 extending out of the H-shaped steel column 10 is not less than twice the cross-sectional height of the H-shaped steel column 10 in the same direction.

[0048] Example 3:

[0049] like Figure 8 As shown, this embodiment discloses a steel column base node structure with zigzag anchorage. This embodiment is largely the same as the first embodiment described above. The difference is that the zigzag anchorage steel column base node structure in this embodiment includes a concrete foundation 3, a steel pipe column, and a zigzag column base plate 2. That is, the steel column in this embodiment is a steel pipe column, and the outer side of the circular pipe column 12 is fitted and fixed with an outer ring plate 13 at the position corresponding to the top longitudinal reinforcement 7 of the concrete foundation 3 (no need to set a horizontal inner partition 4 or a horizontal partition 11).

[0050] Example 4:

[0051] This invention discloses a design method for a steel column base joint structure with zigzag anchorage. Based on the zigzag anchorage steel column base joint structures in Embodiments 1 to 3 above, this design method determines the relevant parameter suggestions and structural design methods for the zigzag anchorage rigid joint structure through full-scale tests combined with theoretical analysis. The steel column base joint structure includes four zigzag-shaped column base plates arranged in pairs opposite each other. These zigzag-shaped column base plates are vertically bent and anchored into the foundation. The cross-section of the zigzag-shaped column base plates is H-shaped, and the cross-section of the steel column can be box-shaped, H-shaped, or circular. The steel column base joint structure includes four zigzag-shaped column base plates arranged in pairs opposite each other. Two of the four zigzag-shaped column base plates perpendicular to the main bending moment direction of the steel column are designated as the first zigzag-shaped column base plates, and the remaining two zigzag-shaped column base plates are designated as the second zigzag-shaped column base plates. Specifically, this design method includes the following steps:

[0052] Step S1: Determine the cross-sectional dimensions and length L1 of the first zigzag column base plate according to the dimensions of the cross-section of the steel column and the stress conditions. The thickness of the flange and web of the first zigzag column base plate is the same as the wall thickness of the steel column.

[0053] Specifically, the formula for determining the cross-sectional dimensions and length L1 of the first polygonal column base plate based on the cross-sectional dimensions of the steel column is as follows:

[0054] H zj =k1h z Formula (1)

[0055] B zj =k2b z Formula (2)

[0056] L1=k3h z Formula (3)

[0057] Among them, H zj B represents the cross-sectional height of the first polygonal column base plate; zj h represents the cross-sectional width of the first polygonal column base plate. z b represents the section height of the steel column perpendicular to the direction of the principal bending moment. z k1 represents the cross-sectional width of the steel column perpendicular to the principal bending moment direction; k2 represents the height ratio coefficient of the first polygonal column base plate, and the value of k1 can be from 0.7 to 1.0; k3 represents the width ratio coefficient of the first polygonal column base plate, and the value of k1 can be from 0.7 to 1.0; L1 represents the length of the first polygonal column base plate; k3 represents the length ratio coefficient of the first polygonal column base plate, and the value of k3 can be from 2.0 to 3.0.

[0058] Step S2: Determine the bending angle of the first zigzag column base plate based on the included angle between the top and bottom surfaces of the concrete foundation and the steel column. Generally, after bending, the zigzag column base plate is parallel to the top surface of the concrete foundation or parallel to the bottom surface of the concrete foundation.

[0059] Step S3: Determine the thickness of the top concrete of the first zigzag column base plate. To meet punching shear requirements, the zigzag column base plate should be placed as high as possible in the foundation.

[0060] Step S4: According to the bidirectional constraint requirements, determine the cross-sectional dimensions and length L2, bending angle, and top surface concrete thickness of the second folded column base plate based on the cross-sectional dimensions and length L1, bending angle, and top surface concrete thickness of the first folded column base plate; wherein, when the included angle between the second folded column base plate and the first folded column base plate is α, determine the length L2 of the second folded column base plate according to formula (1);

[0061]

[0062] Step S5: Using the node center of the broken column foot of the steel column as the rotation center, calculate the required shear stud bearing capacity at the top and bottom of each broken column foot plate and the required stirrup bearing capacity of each broken column foot plate according to the plane section assumption.

[0063] Specifically, calculate the required shear stud bearing capacity at the top and bottom of each polygonal column base plate and the required stirrup bearing capacity of each polygonal column base plate according to the following formulas.

[0064] M1+M2+M3+M4≥M u,base Formula (5)

[0065]

[0066]

[0067]

[0068] N As =f y A S Formula (9)

[0069]

[0070] Where M1 represents the moment of the resultant force of concrete compressive stress about the center of the joint; M2 represents the moment of the shear force of the stud about the center of the joint; M3 represents the moment of the resultant force of the tensile force of the reinforcing bars connecting the top of the polygonal column base plate to the bottom of the steel column about the center of rotation; M4 represents the moment of the resultant force of the stirrups about the center of rotation; M u,base V represents the ultimate bending capacity at the base of the steel column. b1V represents the resultant shear force of the studs on the top surface of the polygonal column base plate; b2 This represents the resultant shear force of the studs on the bottom surface of the polygonal column base plate; f c h1 represents the design value of the concrete compressive strength; h1 represents the thickness of the concrete at the top of the polygonal column base plate, with a minimum thickness of 200mm; α s N represents the vertical distance from the resultant point of the reinforcing bars connecting the top of the polygonal column base plate to the bottom of the steel column to the outer edge of the foundation concrete; As This indicates the design value of the tensile force of the reinforcing steel connecting the top of the polygonal column base plate to the bottom of the steel column; f y This indicates the design strength of the longitudinal reinforcement connecting the top of the polygonal column base plate to the bottom of the steel column; f yv Indicates the tensile strength of the stirrups; A sv The area of ​​a single stirrup is represented; η1 represents the reduction factor for uneven stirrup stress, and the value of η1 ranges from 0.6 to 0.9; n represents the number of stirrup legs, which can generally be taken as 2.0 times the number of stirrup legs in the length range of the broken-line column base plate.

[0071] Calculate the required stirrup bearing capacity for each polygonal column base plate using the following formula;

[0072] V s2 ≥V s1 Formula (11)

[0073] V s1 =f v t w h w Formula (12)

[0074] V s2 =η1nf yv A sv +0.7f t bh0 formula (13)

[0075] b = B zj +2h1+H zj Formula (14)

[0076] h0 = H zj +h1 formula(15)

[0077] Among them, V s1 V represents the shear capacity of the web of a polygonal column base; s2 This indicates the shear capacity of the concrete and stirrups in the polygonal column base plate; f v Indicates the shear strength of steel; t w Indicates the thickness of the web of the polygonal column base plate; h w Indicates the height of the web of the polygonal column base; f trepresents the design value of the tensile strength of concrete; b represents the width of the shear concrete; h0 represents the depth of the shear concrete.

[0078] In addition, when the steel column is a box-shaped steel column, the design method also includes the step of arranging the concrete pouring holes and ventilation holes of the inner diaphragm according to the cross-section of the steel column.

[0079] Those skilled in the art should understand that variations can be implemented by combining existing technology with the above embodiments, which will not be elaborated here. Such variations do not affect the essence of the present invention, and will not be elaborated here either.

[0080] The preferred embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and the devices and structures not described in detail should be understood as being implemented in a conventional manner in the art. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the scope of the present invention. This does not affect the essential content of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the present invention's technical solutions still fall within the protection scope of the present invention.

Claims

1. A design method for a steel column base node structure with polygonal anchorage, characterized in that, The steel column base node structure with zigzag anchoring includes a concrete foundation, a steel column, and four zigzag-shaped column base plates arranged in pairs opposite to each other. The bottom four sides of the steel column are fixedly connected with the zigzag column base plate to form a zigzag column base at the bottom of the steel column; the zigzag column base plate is H-beam, the bottom of the steel column and the zigzag column base plate are both embedded in the concrete foundation, and the surface of the zigzag column base plate is provided with studs. The concrete foundation is provided with top longitudinal bars and bottom longitudinal bars, and stirrups are sleeved between the top longitudinal bars and the bottom longitudinal bars; the top longitudinal bars are connected to the steel column through steel sleeves fixed to the outside of the steel column, and the top longitudinal bars are set parallel to the top surface of the concrete foundation. The length of the zigzag column base plate extending beyond the steel column is not less than twice the cross-sectional height of the steel column in the same direction, the width of the zigzag column base plate is not less than 0.7 times the cross-sectional width of the steel column in the same direction, and the thickness of the upper and lower flanges of the zigzag column base plate is not less than the wall thickness of the steel column. The distance between the zigzag column base plate and the top and bottom of the concrete foundation is not less than 200 mm, and the distance between the zigzag column base plate and the side of the concrete foundation is not less than 150 mm. The steel column is a box-type steel column, an H-type steel column, or a round tube column; When the steel column is a box-shaped steel column, the inner cavity of the box-shaped steel column is provided with horizontal inner partitions at the positions corresponding to the upper and lower flanges of the folded column base plate and the top longitudinal reinforcement of the concrete foundation, and a concrete pouring hole is opened in the center of the horizontal inner partition. When the steel column is an H-shaped steel column, a horizontal partition is provided at the position corresponding to the top longitudinal reinforcement of the concrete foundation; and the zigzag column base plates located on both sides of the web of the H-shaped steel column extend into the interior of the H-shaped steel column and are fixedly connected to the side wall of the web of the H-shaped steel column. Of the four polygonal column base plates, two polygonal column base plates perpendicular to the main bending moment direction of the steel column are designated as first polygonal column base plates, and the other two polygonal column base plates are designated as second polygonal column base plates; the method includes the following steps: The cross-sectional dimensions and length of the first polygonal column base plate are determined based on the cross-sectional dimensions of the steel column. ; Specifically, the cross-sectional dimensions and length of the first polygonal column base plate are determined based on the cross-sectional dimensions of the steel column. The formula is as follows: ； in, This indicates the cross-sectional height of the first polygonal column base plate; This indicates the cross-sectional width of the first polygonal column base plate; This represents the section height of the steel column perpendicular to the direction of the principal bending moment. This indicates the width of the section of the steel column perpendicular to the direction of the principal bending moment; This represents the height ratio coefficient of the first polygonal column base plate. This represents the width ratio coefficient of the first polygonal column base plate; Indicates the length of the first polygonal column base plate; This represents the length ratio coefficient of the first polygonal column base plate; The bending angle of the first polygonal column base plate is determined based on the included angle between the top and bottom surfaces of the concrete foundation and the steel column. Determine the thickness of the top surface concrete of the first polygonal column base plate; According to the bidirectional constraint requirements, based on the cross-sectional dimensions and length of the first polygonal column base plate... The bending angle and the thickness of the top concrete determine the cross-sectional dimensions and length of the second polygonal column base plate. The bending angle and the thickness of the top concrete surface; wherein, when the included angle between the second zigzag column base plate and the first zigzag column base plate is α, the length of the second zigzag column base plate is determined according to the following formula. ; Taking the center of the node of the broken column foot of the steel column as the rotation center, the required shear stud bearing capacity at the top and bottom of each broken column foot plate and the required stirrup bearing capacity of each broken column foot plate are calculated according to the plane section assumption. Specifically, calculate the required shear stud bearing capacity at the top and bottom of each polygonal column base plate and the required stirrup bearing capacity of each polygonal column base plate according to the following formulas; Where M1 represents the moment of the resultant force of concrete compressive stress about the center of the joint; M2 represents the moment of the shear force of the stud about the center of the joint; M3 represents the moment of the resultant force of the tensile force of the reinforcing bars connecting the top of the polygonal column base plate to the bottom of the steel column about the center of rotation; M4 represents the moment of the resultant force of the stirrups about the center of rotation; M u,base V represents the ultimate bending capacity at the base of the steel column. b1 V represents the resultant shear force of the studs on the top surface of the polygonal column base plate; b2 This represents the resultant shear force of the studs on the bottom surface of the polygonal column base plate; f c h1 represents the design value of the concrete compressive strength; h1 represents the thickness of the concrete at the top of the polygonal column base plate. This represents the vertical distance from the point where the resultant force of the reinforcing bars connecting the top of the polygonal column base plate to the bottom of the steel column to the outer edge of the foundation concrete; N As This indicates the design value of the tensile force of the reinforcing steel connecting the top of the polygonal column base plate to the bottom of the steel column; f y This indicates the design strength of the longitudinal reinforcement connecting the top of the polygonal column base plate to the bottom of the steel column; f yv Indicates the tensile strength of the stirrups; A sv η1 represents the area of ​​a single stirrup; n represents the reduction factor for uneven stress in the stirrup; n represents the number of stirrup legs. Calculate the required stirrup bearing capacity for each polygonal column base plate using the following formula; Among them, V s1 V represents the shear capacity of the web of a polygonal column base; s2 This indicates the shear capacity of the concrete and stirrups in the polygonal column base plate; f v Indicates the shear strength of steel; t w Indicates the thickness of the web of the polygonal column base plate; h w Indicates the height of the web of the polygonal column base plate; f t represents the design value of the tensile strength of concrete; b represents the width of the shear concrete; h0 represents the depth of the shear concrete.

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