A high-strength and high-ductility steel pipe concrete column

Abstract

The application provides a high-strength and high-ductility steel pipe concrete column, which comprises a rectangular outer steel pipe and arc-shaped inner steel plates connected to each steel pipe surface on the inner side of the rectangular outer steel pipe, the arc-shaped inner steel plates and the steel pipe surfaces on the inner side of the rectangular outer steel pipe form four closed and non-intersecting cavities, the core area is outside the cavities in the rectangular outer steel pipe, and the core area is filled with concrete; the arc-shaped inner steel plates provide a constraint similar to a round steel pipe on the core of the concrete column, so that the concrete in all areas inside the outer steel pipe can be well constrained, meanwhile, the arc-shaped inner steel plates provide a supporting action for the outer steel pipe, effectively delay the local buckling deformation of the rectangular outer steel pipe, and the steel pipe concrete column component has high strength and good ductility.

Description

Technical Field

[0001] This invention belongs to the field of building construction, and in particular relates to a high-strength and high-ductility steel-concrete composite column. Background Technology

[0002] Steel-concrete composite structural systems are widely used in modern engineering construction. Among them, concrete-tube steel columns (CFSTs) are widely used due to their superior structural performance. They eliminate the need for temporary formwork during concrete pouring, thereby shortening the construction period and saving labor costs. The outer steel tube in a CFST column delays the lateral expansion and failure of the concrete core, while the concrete core effectively prevents the inward buckling of the outer steel tube.

[0003] Circular steel tube concrete and square steel tube concrete are currently the two most common cross-sectional forms. Circular steel tubes provide good confinement for the concrete column core, but due to their external curved surfaces, external ring plates are usually required when connecting beams and columns. In contrast, square steel tubes allow for easier component connections due to their flat external surfaces, making square steel tube concrete columns more widely used in structures. However, square steel tubes offer less confinement for the concrete column core than circular steel tubes and are more prone to local buckling failure. When using high-strength steel and high-strength concrete, the poor confinement effect and local buckling problems of square steel tubes become even more pronounced, significantly reducing the ductility of composite columns and hindering the application of high-strength square steel tube concrete columns.

[0004] To improve the structural performance of square steel tube concrete columns, various design methods exist in current applications, such as welding stiffening ribs inside the steel tube, using stirrups to confine the concrete column core, and inserting a round steel tube inside the square steel tube. However, these methods cannot simultaneously solve the problems of local buckling deformation and improve the restraint effect, and they also increase the amount of construction work and prolong the construction period. Therefore, developing a new type of high-strength and high-ductility square steel tube concrete column has significant engineering practical significance and socio-economic value. Summary of the Invention

[0005] Based on this, the present invention provides a high-strength and high-ductility steel-concrete composite column to overcome various defects of existing steel-concrete composite column components.

[0006] The present invention discloses a high-strength and high-ductility steel-concrete composite column, comprising a rectangular outer steel pipe and an arc-shaped inner steel plate connected to each steel pipe surface inside the rectangular outer steel pipe. The arc-shaped inner steel plate and the steel pipe surface inside the rectangular outer steel pipe form four closed and non-intersecting cavities. The area outside the internal cavity of the rectangular outer steel pipe is the core area, which is filled with concrete.

[0007] Optionally, the arc-shaped inner steel plate is a semi-circular inner steel plate.

[0008] Optionally, the inner steel plate of the arc shape is a semi-elliptical inner steel plate.

[0009] Optionally, the arc-shaped surface of the inner arc-shaped steel plate coincides with the interface between the invalid constraint region and the effective constraint region of the outer rectangular steel pipe.

[0010] Optionally, the cavity formed inside the rectangular outer steel tube is filled with concrete.

[0011] Optionally, the cavity may be filled with concrete of the same strength as the core area.

[0012] Optionally, the cavity and the core area can be filled with concrete of different strengths.

[0013] Optionally, the cavity is filled with high-strength concrete, and the core area is filled with ordinary-strength concrete.

[0014] Optionally, the rectangular outer steel pipe and the arc-shaped inner steel plate are made of high-strength steel.

[0015] On the other hand, the present invention also provides a construction method for the above-mentioned steel-concrete composite column, comprising:

[0016] Weld the inner arc-shaped steel plate to the steel sheet with the arc-shaped end;

[0017] A steel sheet with an arc-shaped inner steel plate welded on it is welded through the arc-shaped end to form a rectangular outer steel pipe. The arc-shaped inner steel plate is located inside the rectangular outer steel pipe. The arc-shaped inner steel plate and the inner steel pipe surface of the rectangular outer steel pipe form four closed and non-intersecting cavities. The area outside the inner cavity of the rectangular outer steel pipe is the core area.

[0018] Fill the core area with concrete.

[0019] Optionally, the cavity can be filled with concrete.

[0020] The high-strength, high-ductility steel-concrete composite column provided by this invention has the following beneficial effects:

[0021] The curved inner steel plate forms a cavity with the inner surface of the rectangular steel tube, providing a novel cross-sectional form for steel-concrete composite columns. The curved inner steel plate acts as a stiffener, providing excellent support for the outer steel tube, reducing the width-to-thickness ratio of the steel tube, and effectively delaying local buckling deformation of the rectangular outer steel tube. Simultaneously, the curved inner steel plate provides a constraint effect on the concrete similar to that of a circular steel tube, compensating for the deficiency of ineffective constraint areas within traditional rectangular steel tubes. Furthermore, as a form of internal stiffener embedded between the concrete column cores, the curved inner steel plate maintains a lower temperature than the outer steel tube in a fire environment, resulting in better fire resistance. This novel steel-concrete composite column, when using high-strength steel and a mixture of concretes of varying strengths, can improve the load-bearing capacity of the composite column while ensuring good ductility. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0023] Figure 1 This diagram illustrates the ineffective and effective constraint regions of steel pipes with different cross-sectional shapes.

[0024] Figure 2 A perspective view of a square steel tube concrete column provided in an embodiment of the present invention;

[0025] Figure 3 A longitudinal cross-sectional view of a square steel tube concrete column provided in an embodiment of the present invention;

[0026] Figure 4 This is the cross-section of a square steel tube concrete column provided in an embodiment of the present invention;

[0027] Figure 5 The cross-section of a square steel tube concrete column is provided in another embodiment of the present invention;

[0028] Figure 6 A cross-section of a rectangular steel tube concrete column provided in another embodiment of the present invention;

[0029] Figure 7 Load-strain curves of concrete-filled steel tube columns under different concrete filling methods;

[0030] Figure 8 A cross-section of a rectangular steel tube concrete column provided in another embodiment of the present invention;

[0031] Figure 9 A flowchart illustrating the processing method of the steel pipe portion in a square steel-concrete composite column provided in an embodiment of the present invention. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] According to calculations and proofs from relevant studies, such as Figure 1As shown, commonly used rectangular and polygonal steel tube concrete columns contain ineffective restraint regions, while circular steel tube concrete columns consist entirely of effective restraint regions. The ineffective restraint regions are located near the inner surface of the steel tube. In a cross-section, the interface between the ineffective and effective restraint regions in a rectangular steel tube concrete column is formed by a quadratic parabola with an initial tangent slope of 45 degrees. The existence of these ineffective restraint regions results in poor restraint of the concrete column core by the rectangular and polygonal steel tubes. Compared to circular steel tubes, rectangular and polygonal steel tubes are more prone to local buckling in their planes, leading to the failure of the composite column. When high-strength steel and high-strength concrete are used to improve load-bearing capacity, the aforementioned problems of poor restraint and local buckling become more pronounced, increasing the brittleness of the composite column and further reducing its ductility.

[0034] Based on the shortcomings of existing designs, this invention provides a new cross-sectional form of steel-concrete composite column, which is illustrated by the following embodiments.

[0035] like Figures 2-4 As shown, taking a square steel tube as an example, the high-strength and high-ductility steel tube concrete column provided by the present invention includes a rectangular outer steel tube 1 and an arc-shaped inner steel plate 2 connected to each steel tube surface inside the rectangular outer steel tube. The arc-shaped inner steel plate 2 and the steel tube surface inside the rectangular outer steel tube 1 form four closed and non-intersecting cavities 3. The area outside the inner cavity 3 of the rectangular outer steel tube 1 is the core area 4. The cavities 3 and the core area 4 are filled with concrete.

[0036] The curved inner steel plate provides constraint similar to that of a circular steel tube, effectively restraining the concrete filling the cavity and transforming the previously ineffective restraint areas in the rectangular steel-concrete composite column into effective restraint areas. Simultaneously, the core area remains an effective restraint area within the original rectangular steel-concrete composite column. Therefore, all concrete filling areas within the cross-section of this novel steel-concrete composite column are in a well-restrained state. Furthermore, the curved inner steel plate can also be considered as an internal longitudinal stiffener for the outer steel tube, providing support and reducing its width-to-thickness ratio, effectively delaying local buckling deformation of the outer steel tube. In fire conditions, the curved inner steel plate embedded in the concrete heats up slowly due to its protection, improving the fire resistance of the composite column. The new steel-concrete composite column uses high-strength steel for both the outer steel tube and the curved inner steel plate, while the cavity and core area are filled with high-strength concrete and ordinary-strength concrete respectively. This increases the load-bearing capacity of the composite column while enhancing its deformation capacity and ductility, achieving the design of a high-strength, high-ductility steel-concrete composite column.

[0037] by Figure 4 For example, the inner arc-shaped steel plate can be a semi-circular steel plate, or in possible designs it can be as follows: Figure 5 As will be understood by those skilled in the art, the diameter or major and minor axes of the inner arc-shaped steel plate can be adjusted according to the width-to-thickness ratio of the outer steel pipe to obtain a better overall restraint effect and an anti-local buckling effect.

[0038] In possible designs, the curved edge of the inner steel plate can also coincide with the interface between the ineffective and effective constraint regions in a traditional rectangular steel tube, such as... Figure 1 (a) and Figure 1 (b) means that, from the perspective of cross-sectional shape, the projected edge of the arc-shaped inner steel plate coincides with the interface between the two regions. This design makes the original ineffective constraint area inside the rectangular steel tube subject to a constraint similar to that of the circular steel tube. The concrete column core on the entire cross-section is effectively constrained, resulting in better compressive performance than traditional rectangular steel tube concrete columns.

[0039] In possible designs, for rectangular steel-concrete composite columns with unequal lengths and widths, the inner curved steel plate can be partly semi-circular and partly semi-elliptical, such as... Figure 6 As shown, all inner steel plates may use the same arc shape, but the present invention does not further limit this.

[0040] Those skilled in the art should understand that the rectangular steel pipe referred to in this invention is not limited to square steel pipes, but also includes steel pipes with rectangular cross-sections. Furthermore, based on the technical concept of this invention, in further designs, such a design can also be applied to other polygonal steel pipes, such as pentagons, hexagons, octagons, etc., as long as the inner arc-shaped steel plate and the inner surface of the polygonal steel pipe form a closed and non-intersecting cavity, they all fall within the scope of this invention. Similarly, when applied to other polygonal steel pipes, the design of the inner arc-shaped steel plate can be semi-circular or semi-elliptical, or it can be the interface between the invalid constraint region and the effective constraint region of the polygon, such as... Figure 1 (c) and Figure 1 (d)

[0041] The concrete filling the core area inside the rectangular outer steel tube can be of the same or different strength as the concrete filling the cavity. For example, the cavity can be filled with ultra-high strength concrete (e.g., C90 / 105), while the core area can be filled with ordinary strength concrete (e.g., C50 / 60). Mixing concrete of different strengths can overcome the problem of poor ductility caused by the high brittleness of ultra-high strength concrete, and can also improve the load-bearing capacity of the concrete-filled steel tube column. Figure 7 The load-strain curves of steel-concrete composite columns with different cores are shown. Traditional steel-concrete composite columns filled with only ordinary strength concrete have poor load-bearing capacity. Traditional steel-concrete composite columns filled with only ultra-high strength concrete show a significant decrease in load-bearing capacity after brittle failure. However, the novel steel-concrete composite column provided in this embodiment of the invention has a separated cavity and core area, which can realize the mixed use of concrete of different strengths. In this case, the novel steel-concrete composite column has both good load-bearing capacity and ductility, and the composite column has better toughness.

[0042] In some designs, the cavity may not be filled with concrete to reduce the overall weight of the component. The hollow cavity can be used to lay electrical wires or drainage pipes, or it can be partially filled with... Figure 8 As shown.

[0043] In possible designs, the cross-sectional form of the cavity formed by the arc-shaped inner steel plate and the rectangular outer steel tube proposed in this invention can also be used as a beam member. When used as a beam member, the core area inside the steel tube is filled with ordinary strength concrete, the upper part of the steel tube is under compression, so the upper cavity is filled with ultra-high strength concrete, and the lower part of the steel tube is under tension, so the lower cavity can remain hollow. Figure 8 As shown.

[0044] In possible designs, both the rectangular outer steel tube and the curved inner steel plate are made of high-strength steel to provide better column strength.

[0045] like Figure 9 As shown in the embodiments of the present invention, a construction method for the steel-concrete composite column shown in the above embodiments is also provided. Similar to the traditional construction method, the outer steel pipe and the arc-shaped inner steel plate are completed by cold forming and welding processes.

[0046] Specifically, since the arc-shaped inner steel plate needs to be located inside the rectangular outer steel pipe, the cold-formed arc-shaped inner steel plate is first welded to the steel sheet with arc-shaped ends. Then, the steel sheet with the arc-shaped inner steel plate is welded through the arc-shaped ends to form a rectangular steel pipe. The arc-shaped inner steel plate is located inside the rectangular steel pipe. The arc-shaped inner steel plate and the inner steel pipe surface of the rectangular steel pipe form four closed and non-intersecting cavities. The area outside the cavities inside the rectangular outer steel pipe is the core area. Concrete is poured in the cavity area and the core area.

[0047] To prevent premature fracture due to stress concentration, welding should be avoided at the corners when splicing rectangular outer steel pipes.

[0048] To simplify the pouring process and improve construction efficiency, the concrete inside the cavity can be filled in the factory first, and then the concrete in other areas inside the outer steel pipe can be filled on the construction site.

[0049] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-strength, high-ductility steel-concrete composite column, characterized in that, It includes a rectangular outer steel pipe and an arc-shaped inner steel plate welded to each steel pipe surface inside the rectangular outer steel pipe. The arc-shaped inner steel plate and the steel pipe surface inside the rectangular outer steel pipe are welded to form four closed and non-intersecting cavities. The arc-shaped surface of the arc-shaped inner steel plate coincides with the interface between the ineffective constraint region and the effective constraint region of the rectangular outer steel pipe. The area outside the inner cavity of the rectangular outer steel pipe is the core area, which is filled with concrete.

2. The high-strength, high-ductility steel-concrete composite column according to claim 1, characterized in that, The arc-shaped inner steel plate is a semi-circular inner steel plate.

3. The high-strength, high-ductility steel-concrete composite column according to claim 1, characterized in that, The arc-shaped inner steel plate is a semi-elliptical inner steel plate.

4. The high-strength, high-ductility steel-concrete composite column according to claim 1, characterized in that, The cavity is filled with concrete.

5. The high-strength, high-ductility steel-concrete composite column according to claim 4, characterized in that, The cavity is filled with concrete of the same strength as the core area.

6. The high-strength, high-ductility steel-concrete composite column according to claim 4, characterized in that, The cavity is filled with concrete of different strengths than the core area.

7. The high-strength, high-ductility steel-concrete composite column according to claim 4 or 6, characterized in that, The cavity is filled with high-strength concrete, while the core area is filled with ordinary-strength concrete.

8. The high-strength, high-ductility steel-concrete composite column according to claim 1, characterized in that, The rectangular outer steel pipe and the arc-shaped inner steel plate are made of high-strength steel.

9. A construction method for a high-strength, high-ductility steel-concrete composite column as described in any one of claims 1 to 8, characterized in that, include: The inner arc-shaped steel plate is welded to a steel sheet with an arc-shaped end; A steel sheet with an arc-shaped inner steel plate welded on it is welded through the arc-shaped end to form a rectangular outer steel pipe. The arc-shaped inner steel plate is located inside the rectangular outer steel pipe. The arc-shaped inner steel plate and the inner steel pipe surface of the rectangular outer steel pipe form four closed and non-intersecting cavities. The area outside the inner cavity of the rectangular outer steel pipe is the core area. Concrete was poured in the core area.

10. The construction method according to claim 9, characterized in that, The construction method also includes: The cavity is filled with concrete.

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