A concrete filled steel tube-steel tube vertical hybrid structural system

Abstract

The application discloses a kind of steel pipe concrete-steel pipe vertical mixed structure system, and relates to the field of building structure, especially to the field of steel structure and steel-concrete composite structure.The structure system includes lower floor steel pipe concrete column, upper floor steel pipe column, steel pipe concrete-steel pipe conversion column and steel pipe concrete-steel pipe transition section corner shear connector.The structure system includes intermediate transition method and whole layer transition method, and intermediate transition method has interlayer steel pipe concrete-steel pipe conversion column.The application is applied to building structure, which can effectively improve the bearing capacity of steel frame, reduce the setting of support or shear wall, and optimize the system.It can be used in buildings with lower layer height greater than upper layer height, and the lower layer filled with concrete enhances the stiffness, strength, deformation capacity and impact resistance of the column, so that the cross-sectional size of the lower floor steel pipe concrete column and the upper floor steel pipe column remains consistent, without the need to increase the steel pipe cross section to meet the structural requirements, reducing the cross-sectional transition process, reducing construction cost, speeding up the construction progress, increasing the building usable area, and improving the economic value of the building.The lower steel pipe concrete column increases the structure's blast resistance, impact resistance and flood resistance.The application can be used in new steel structure optimization design, old steel structure house reinforcement and reconstruction, and post-earthquake structure repair.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of building structure, especially to the field of steel structure and steel-concrete composite structure. BACKGROUND

[0002] In building structure, the lower column bears large axial force and shear force, and the height of the first floor or the lower floors is often greater than the upper part due to the functional requirements of the building. Therefore, the cross section of the lower frame column and frame beam needs to be increased in the structural design to enhance its carrying capacity and stiffness. In steel frame structure, the large cross section of the lower steel column and the small cross section of the upper part will lead to steel pipe variable cross section joint, resulting in the increase of construction cost. At the same time, the increase of the column section reduces the building usable area, which is not good for economic benefit. In addition, due to the increase of the lower floor height, the structure often needs to be set with support or shear wall, which will greatly increase the structure cost.

[0003] The steel pipe concrete column is composed of outer steel pipe and inner filled concrete. The outer steel pipe changes its buckling mode due to the lateral support provided by the internal concrete, and its carrying capacity is improved. The inner filled concrete is constrained by the steel pipe, and has better carrying capacity and deformation capacity than ordinary concrete. The outer steel pipe can serve as the formwork of the inner filled concrete, reducing the construction cost. Therefore, the combination of steel pipe concrete structure and steel structure will bring a series of beneficial effects. SUMMARY

[0004] Technical problem: In the current steel structure building, the large cross section of the lower column leads to uneconomical and reduced building usable area, and the column variable cross section joint setting leads to complex construction.

[0005] Technical solution: The purpose of the present application can be achieved by the following technical solution: a steel pipe concrete-steel pipe vertical hybrid structure system, comprising a lower floor steel pipe concrete column (1), an upper floor steel pipe column (2), a steel pipe concrete-steel pipe conversion column (3), and a steel pipe concrete-steel pipe transition section corner shear connector (4).

[0006] Further, in the above steel pipe concrete-steel pipe vertical hybrid structure system, the length of the lower floor steel pipe concrete column (1) is determined by the building and structural requirements.

[0007] Further, in the above steel pipe concrete-steel pipe vertical hybrid structure system, the steel pipe concrete-steel pipe conversion column (3) is divided into two conversion modes, i.e. intermediate transition method and whole layer transition method, according to its position.

[0008] Further, in the above steel pipe concrete-steel pipe vertical hybrid structure system, the steel pipe concrete-steel pipe conversion column has a certain length of transition section, and a certain number of steel pipe concrete-steel pipe transition section corner shear connectors (4) are arranged to enhance the combination of the steel pipe and the concrete (8) of the steel pipe concrete-steel pipe conversion column (3).

[0009] Furthermore, in the aforementioned steel-concrete composite-steel-pipe vertical hybrid structural system, the corner shear connector (4) of the steel-concrete composite-steel-pipe transition section is composed of four oblique rectangular plates (5). This is achieved by pre-cutting eight sections of height h into the wall of the square steel pipe (7) at the location where the corner shear connector (4) of the steel-concrete composite-steel-pipe transition section needs to be installed. s +2mm, width is The vertical elongated hole (6), h s t1 is the height of the oblique rectangular plate (5), t2 is the thickness of the oblique rectangular plate (5), and t2 is the wall thickness of the square steel pipe (7). The length of the oblique rectangular plate (5) matches the opening position of the vertical elongated hole (6). The oblique rectangular plate (5) is inserted into the pre-drilled vertical elongated hole (6) of the square steel pipe (7) and extends out from the vertical elongated hole (6) closest to the wall of the adjacent square steel pipe (7). Finally, the oblique rectangular plate (5) and the square steel pipe (7) are connected as a whole by welding to form a steel-concrete composite-steel pipe transition section shear connector (4).

[0010] Furthermore, in the above-mentioned steel-concrete composite-steel-pipe vertical hybrid structure system, the oblique rectangular plate (5) can be pre-drilled with a certain diameter circular hole (9) according to the bearing capacity requirements.

[0011] Furthermore, in the aforementioned steel-concrete composite-steel-pipe vertical hybrid structural system, the square steel pipe (7) can be pre-cut to a height of h. s A slanted elongated hole (10) with a width of t1+2mm is added to reduce the weakening of the steel pipe cross section.

[0012] Beneficial effects: The present invention has the following advantages over the prior art:

[0013] (1) The steel-concrete composite-steel-pipe vertical hybrid structure system disclosed in this invention will effectively improve the stiffness, bearing capacity, deformation capacity and impact resistance of the steel frame, reduce or even eliminate the need for supports or shear walls, and optimize the structural system.

[0014] (2) The steel-concrete composite-steel-pipe vertical hybrid structure system disclosed in this invention can be used in buildings where the lower floor height is greater than the upper floor height. The lower floor is filled with concrete to enhance the stiffness, strength, deformation capacity and impact resistance of the column. This ensures that the cross-sectional dimensions of the steel-concrete composite columns in the lower floors are consistent with those of the steel-pipe columns in the upper floors. The structural requirements can be met without increasing the cross-section of the steel pipe, reducing the process of cross-section transition, lowering construction costs, accelerating the construction progress, increasing the usable area of ​​the building, and improving the economic value of the building.

[0015] (3) The steel-concrete composite-steel-pipe vertical hybrid structure system disclosed in this invention increases the structure’s resistance to explosion, impact and flood by the lower steel-concrete composite column.

[0016] (4) The disclosed steel pipe concrete-steel pipe vertical mixed structure system can reinforce the steel frame, and can be used for new steel structure optimization design, old steel frame reinforcement reconstruction and post-earthquake repair. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a schematic diagram of the intermediate transition method in the application;

[0018] Figure 2 It is a schematic diagram of the whole layer transition method in the application;

[0019] Figure 3 , Figure 4 , Figure 5 It is a calculation diagram of the inflection point of the steel pipe concrete-steel pipe conversion column (3) in the intermediate transition method in the application.

[0020] Figure 6 , Figure 7 , Figure 8 , Figure 9 , Figure 10 , Figure 11 It is a schematic diagram of the corner shear connector (4) of the steel pipe concrete-steel pipe transition section in the application;

[0021] Figure 12 , Figure 13 It is a construction process of the corner shear connector (4) of the steel pipe concrete-steel pipe transition section in the application;

[0022] Figure 14 , Figure 15 , Figure 16 It is a calculation diagram of the interface shear requirement of the steel pipe concrete-steel pipe conversion column (3) transition section in the application.

[0023] In the figure: 1 is a lower floor steel pipe concrete column, 2 is an upper floor steel pipe column, 3 is a steel pipe concrete-steel pipe conversion column, 4 is a steel pipe concrete-steel pipe transition section shear connector, 5 is an oblique rectangular plate, 6 is a vertical long hole, 7 is a square steel pipe, 8 is concrete, 9 is a round hole, 10 is an oblique long hole DETAILED DESCRIPTION

[0024] The application will be further described below in combination with the drawings.

[0025] As Figure 1 And Figure 2As shown, a vertical hybrid structure system of steel-concrete composite steel tube and steel tube is disclosed, relating to the field of building structures, particularly to the field of steel structures and steel-concrete composite structures. This hybrid structure system includes lower-floor steel-concrete composite columns (1), upper-floor steel tube columns (2), steel-concrete composite steel tube transition columns (3), and corner shear connectors (4) for the steel-concrete composite steel tube transition section. In the figure, h1 > h2, corresponding to a building with a commercial area at the bottom and a residential apartment at the top with a lower floor height, or a residential building with a basement floor height greater than the upper floor height. The vertical hybrid structure system of steel-concrete composite steel tube and steel tube includes a full-floor transition method and an intermediate transition method based on the location of the steel-concrete composite steel tube transition column (3). The full-floor transition method involves the steel-concrete composite steel tube transition position being located at the beam-column node, while the intermediate transition method involves the steel-concrete composite steel tube transition position being located between frame columns. The location of the steel-concrete composite steel tube transition is determined by structural and architectural requirements and is not limited to the location shown in the figure.

[0026] For the intermediate transition method, the location of the inter-story inflection point can be calculated using the displacement method. The specific calculation process is as follows:

[0027] Taking a single-story, single-span steel-concrete composite partially infilled frame as an example, such as Figure 3 As shown, h3 is the filling height of concrete (8). It is a symmetrical structure, therefore it can be simplified as follows: Figure 4 As shown, the displacement method yields the following... Figure 5 The four basic unknowns of the rigid frame shown can be used to list the equilibrium equations to obtain the internal forces of the rigid frame, and then the location of the inflection point of the intermediate transition steel-concrete-steel-pipe conversion column (3) can be obtained.

[0028] like Figure 6 As shown, this is the shear-resistant connector (4) at the corner of the steel-concrete composite-steel-pipe transition section of the vertical hybrid structural system. The shear-resistant connector (4) at the corner of the steel-concrete composite-steel-pipe transition section includes four oblique rectangular plates (5). The oblique rectangular plates (5) extend into the steel pipe through pre-drilled vertical elongated holes (6) in the square steel pipe (7) and protrude from the pre-drilled vertical elongated holes (6) in the adjacent square steel pipe (7). Finally, the four oblique rectangular plates (5) and the square steel pipe (7) are welded together to form a whole.

[0029] like Figure 7 As shown, the square steel pipe (7) has two pre-cut openings on each of its four sides, each with a height of h. s +2, Width is The vertical elongated hole (6), t1 is the thickness of the oblique rectangular plate (5), and t2 is the wall thickness of the square steel pipe (7).

[0030] like Figure 8 As shown, this is a cross-sectional view of the corner shear connector (4)1-1 of the steel-concrete composite-steel-pipe transition section. Figure 9As shown, under certain usage conditions, in order to avoid excessive weakening of the steel pipe cross-section by the vertical elongated hole (6), the square steel pipe (7) can also have two holes with a height of h pre-drilled on each of its four sides. s +2, an oblique elongated hole (10) with a width of t1+2, where t1 is the thickness of the oblique rectangular plate (5).

[0031] like Figure 11 As shown, the oblique rectangular plate (5) has pre-processed circular holes (9) to meet the structural bearing capacity requirements. The corner shear connector (4) with circular holes (9) has a bearing capacity of... F l2 For the local compressive bearing capacity of the concrete (8) at the contact surface of the oblique rectangular plate (5), A cs3 The contact area between the opening of the oblique rectangular plate (5) and the concrete (8).

[0032] like Figure 12 , Figure 13 As shown, the construction process of the corner shear connector (4) of the steel-concrete-steel-pipe transition section is as follows: pre-process 4 oblique rectangular plates (5), and process 8 joints with a height of h on the 4 sides of the outer wall of the square steel pipe. s +2, Width is Vertical elongated holes (6) or 8 holes with a height of h s +2, Width is The oblique elongated hole (10) is t1, which is the thickness of the oblique rectangular plate (5), and t2 is the wall thickness of the square steel pipe (7). The length of the oblique rectangular plate (5) is matched with the opening position of the vertical elongated hole (6) or the oblique elongated hole (10). The oblique rectangular plate (5) is inserted into the pre-drilled vertical elongated hole (6) or the oblique elongated hole (10-1) of the square steel pipe (7) and extends out from the vertical elongated hole (6) or the oblique elongated hole (10) closest to the wall of the adjacent square steel pipe (7). Finally, the oblique stiffening rib (5) is connected to the square steel pipe (7) by welding to form a whole steel pipe concrete-steel pipe transition section shear connection (4).

[0033] The shear force transfer capacity of the steel-concrete composite-steel-pipe transition section shear connector (4) is calculated using the following formula:

[0034]

[0035] In the formula, F l1 For the local compressive bearing capacity of the concrete (8) at the bottom contact surface of the oblique rectangular plate (5), A cs1 f is the contact area between the bottom surface of the oblique rectangular plate (5) and the concrete (8). yd f is the yield strength of the steel in the oblique rectangular plate (5). ce A represents the interfacial bond strength between the oblique rectangular plate (5) and the concrete (8). cs2 The contact area between the oblique rectangular plate (5) and the concrete (8) on the side.

[0036] When considering the oblique rectangular plate (5) pre-opening bearing capacity requirements of the circular hole (9), the shear transfer bearing capacity calculation formula is as follows:

[0037]

[0038] In the formula, F l1 is the local compressive bearing capacity of the oblique rectangular plate (5) bottom contact surface concrete (8), A cs1 is the contact area between the bottom surface of the oblique rectangular plate (5) and the concrete (8), f yd is the yield strength of the steel material of the oblique rectangular plate (5), f ce is the interfacial adhesion between the oblique rectangular plate (5) and the concrete (8), A cs2 is the contact area between the oblique rectangular plate (5) and the concrete (8), F l2 is the local compressive bearing capacity of the oblique rectangular plate (5) contact surface concrete (8), A cs3 is the contact area between the oblique rectangular plate (5) and the concrete (8).

[0039] The shear bearing capacity requirement of the steel pipe concrete-steel pipe transition section of the steel pipe concrete-steel pipe vertical hybrid structure system can be obtained according to the following component level calculation, respectively calculating the interface shear force generated by the steel pipe concrete-steel pipe transition section under the action of axial force, bending moment and shear force without steel pipe concrete-steel pipe transition section shear connector (4).

[0040] As Figure 14 shown, in the steel pipe concrete-steel pipe transition section of the steel pipe concrete-steel pipe transition section, the stress σ s of the steel pipe decreases to σ s , the stress of the filled concrete (8) increases from 0 to σ c , and the end boundary of the steel pipe concrete-steel pipe transition section is: in the elastic stage, the strains of the two are equal, at this time:

[0041]

[0042] Under the action of axial force, the transmission area of the internal force from the steel pipe to the concrete (8) through the bonding surface is A, and the transmitted internal force value is:

[0043] N1=Af ce =l1l2f ce

[0044] Where f ce is the design value of the bonding strength between the steel pipe and the concrete (8); l1 is the length of the steel pipe concrete-steel pipe transition section under the action of axial force; l2 is the inner wall circumference of the steel pipe cross section.

[0045] From the strain compatibility equation, we have:

[0046]

[0047] N1 = N c

[0048] Then

[0049] In the formula, N is the axial force at the top of the concrete-filled steel tube-steel tube transfer column (3), N c is the axial force transmitted to the internal filling concrete (8).

[0050] Under the action of bending moment:

[0051]

[0052] M1 = F1 · y1 F1 = l1 'l2 'f ce

[0053]

[0054] Substitute the above formula into the strain compatibility equation in the preceding text, and then we have:

[0055]

[0056] Where: M1 is the bending moment acting on the internal concrete (8), which is provided by the bonding force F1 between the steel tube and the concrete (8), as shown in Figure 15 ; M is the external moment acting on the concrete-filled steel tube-steel tube transfer column (3) column; l1'is the length of the transition section of the concrete-filled steel tube-steel tube transfer column (3) under the action of bending moment; l2'is the contact perimeter of the steel tube wall and the concrete (8) in the compression zone of the cross section, as shown in Figure 16 ; I is the moment of inertia of the concrete-filled steel tube cross section.

[0057] Under the action of shear force:

[0058] According to the shear stress mutual equality theorem, the shear force generated at the interface between the steel tube and the concrete (8) perpendicular to the direction of the shear force under the action of shear force can be ignored due to the thinness of the steel tube wall; the interface between the steel tube and the concrete (8) parallel to the direction of the shear force does not generate shear force. Therefore, the interface shear force generated by the transition section of the concrete-filled steel tube-steel tube transfer column (3) under the action of shear force can be ignored.

[0059] Therefore, the interface shear force generated in the compression zone of the transition section of the concrete-filled steel tube-steel tube transfer column (3) under the action of compression and bending is obtained by adding the interface shear force generated under the action of axial force and bending moment:

[0060]

[0061] According to the shear demand, the size and strength of the shear connector (4) of the concrete-filled steel tube-steel tube transition section are determined.

[0062] The above-mentioned only is the preferred embodiment of the present application, but the present application is not limited to the specific embodiments described above. Those of ordinary skill in the art can also make several modifications, supplements or use similar ways instead without departing from the principles of the present application, which should also be considered as the protection scope of the present application.

[0063] Although the terms such as 1-concrete-filled steel tube column of lower floor, 2-steel tube column of upper floor, 3-concrete-filled steel tube-steel tube transition column, 4-concrete-filled steel tube-steel tube transition section corner shear connector, 5-inclined rectangular plate, 6-vertical long hole, 7-square steel tube, 8-concrete, 9-round hole, 10-inclined long hole are used more frequently herein, the possibility of using other terms is not excluded. The use of these terms is only for more convenient description and explanation of the essence of the present application, and it is against the spirit of the present application to interpret them as any kind of additional limitation.

Claims

1. A steel tube concrete-steel tube vertical hybrid structure system, comprising a lower floor steel tube concrete column (1), an upper floor steel tube column (2), a steel tube concrete-steel tube conversion column (3) and a steel tube concrete-steel tube transition section corner shear connector (4), characterized in that: The steel tube concrete-steel tube conversion column (3) uses the steel tube concrete-steel tube transition section corner shear connector (4) to enhance the combined effect of the square steel tube (7) and the inner filled concrete (8); The steel pipe concrete-steel pipe transition section corner shear connector (4) is composed of four oblique rectangular plates (5), eight vertical long holes (6) with a height of h s +2mm and a width of are pre-opened on the wall of the square steel pipe (7) at the position where the steel pipe concrete-steel pipe transition section corner shear connector (4) is needed to be arranged, h s is the height of the oblique rectangular plate (5), t1 is the thickness of the oblique rectangular plate (5), and t2 is the wall thickness of the square steel pipe (7). The length of the oblique rectangular plate (5) matches the opening position of the vertical long hole (6). The oblique rectangular plate (5) is inserted into the nearest vertical long hole (6) of the adjacent square steel pipe (7) wall from the vertical long hole (6) pre-opened on the square steel pipe (7), and finally the oblique rectangular plate (5) is connected with the square steel pipe (7) as a whole by welding. The four oblique rectangular plates are the steel pipe concrete-steel pipe transition section shear connector (4).

2. The CFST-SSVS system according to claim 1, wherein: According to the position of the steel tube concrete-steel tube conversion column (3), it is divided into two conversion methods of intermediate transition method and whole layer transition method.

3. The CFST-SSVS system according to claim 1, wherein: The shear capacity calculation formula of the steel tube concrete-steel tube transition section corner shear connector (4) is: In the formula, F l1 is the partial compression bearing capacity of the oblique rectangular plate bottom surface contacting the concrete (8), A cs1 is the contact area between the oblique rectangular plate (5) bottom surface and the concrete (8), f yd is the yield strength of the steel material of the oblique rectangular plate (5), f ce is the interfacial adhesion between the oblique rectangular plate (5) and the concrete (8), A cs2 is the contact area between the oblique rectangular plate (5) side and the concrete (8).

4. The CFST-SSVS system according to claim 1, wherein: The oblique rectangular plate (5) can be pre-opened a circular hole (9) of a certain diameter according to the bearing capacity requirement; the shear capacity calculation formula of the steel tube concrete-steel tube transition section corner shear connector (4) composed of four oblique rectangular plates (5) with circular holes (9) is: Wherein, F l1 The partial compression bearing capacity of the contact surface between the oblique rectangular plate (5) and the concrete (8), A cs1 The contact area between the oblique rectangular plate (5) and the concrete (8), f yd The yield strength of the steel material of the oblique rectangular plate (5), f ce The interfacial adhesion between the oblique rectangular plate (5) and the concrete (8), A cs2 The contact area between the side of the oblique rectangular plate (5) and the concrete (8), F l2 The partial compression bearing capacity of the contact surface between the oblique rectangular plate (5) and the concrete (8), A cs3 The contact area between the oblique rectangular plate (5) and the concrete (8), f 5. The CFST-SSVS system according to claim 1, wherein: The steel pipe concrete-steel pipe transition section corner shear connector (4) is composed of four inclined rectangular plates (5). In order to avoid that the vertical long hole (6) excessively weakens the steel pipe section under certain use conditions, eight inclined long holes (10) with a height of h s +2mm and a width of t1+2mm are pre-opened on the wall of the square steel pipe (7) at the position where the steel pipe concrete-steel pipe transition section corner shear connector (4) is arranged. s h is the height of the inclined rectangular plate (5), t1 is the thickness of the inclined rectangular plate (5), and the length of the inclined rectangular plate (5) is matched with the opening position of the inclined long hole (10). The inclined rectangular plate (5) is inserted into the nearest inclined long hole (10) on the wall of the adjacent square steel pipe (7) from the inclined long hole (10) pre-opened on the square steel pipe (7), and finally the inclined rectangular plate (5) is connected with the square steel pipe (7) as a whole by welding to form the steel pipe concrete-steel pipe transition section shear connector (4).

6. The CFST-SSVS system according to claim 2, wherein: The shear capacity requirement of the interface of the transition section of the concrete-filled steel tube-steel tube vertical hybrid structure system concrete-filled steel tube-steel tube transition column (3) can be obtained by component level calculation. The interface shear force generated by the axial force, bending moment and shear force of the concrete-filled steel tube-steel tube transition column (3) transition section without the concrete-filled steel tube-steel tube transition section shear connector (4) is calculated respectively: in the concrete-filled steel tube-steel tube transition column (3) transition section, the stress σ' of the steel tube s is reduced to σ s , the stress of the filled concrete (8) is increased from 0 to σ c , and the end boundary of the concrete-filled steel tube-steel tube transition section: in the elastic stage, the strains of the two are equal, at this time: Under the action of the axial force, the transmission area of the internal force from the steel tube to the concrete (8) through the bonding surface is A, and the transmitted internal force value is N1=Af ce = l1l2f ce , where f ce is the design value of the bonding strength between the steel tube and the concrete (8), l1 is the length of the concrete-filled steel tube-steel tube transition column (3) transition section under the action of the axial force, and l2 is the inner wall perimeter of the steel tube cross section; the strain equalization equation is obtained as follows: N1=N c , then In the formula, N is the axial force at the top of the concrete-filled steel tube-steel tube transition column (3), and N c is the axial force transmitted to the internal filled concrete (8); under the action of the bending moment: M1=F1·y1, F1=l'1l'2f ce , Substituting the above formula into the strain equalization equation in the foregoing, the following is obtained: In the formula, M1 is the bending moment acting on the internal concrete (8), which is generated by the bonding force F1 between the steel tube and the concrete (8), M is the external moment acting on the concrete-filled steel tube-steel tube transition column (3); l'1 is the length of the concrete-filled steel tube-steel tube transition column (3) transition section under the action of the bending moment, l'2 is the contact perimeter of the steel tube wall and the concrete (8) in the compression zone of the cross section, and I is the moment of inertia of the concrete-filled steel tube section; under the action of the shear force: according to the shear stress mutual equality theorem, the shear force generated by the interface between the steel tube and the concrete (8) in the direction perpendicular to the shear force under the action of the shear force can be obtained. Since the steel tube wall is thin, the shear force can be ignored; then the interface shear force generated in the compression zone of the concrete-filled steel tube-steel tube transition column (3) transition section under the action of the compression and bending is obtained by adding the interface shear forces generated under the action of the axial force and the bending moment:

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