Prefabricated concrete-filled steel tubular column component capable of applying prestress and construction method of prefabricated concrete-filled steel tubular column component

Abstract

The invention provides a prefabricated concrete-filled steel tube column component capable of applying prestress and a construction method thereof.The prefabricated concrete-filled steel tube column component comprises a base, a concrete-filled steel tube component and prestress reinforcing ribs, the base comprises a bottom plate, a connecting steel tube and a lower end plate which are fixedly connected with one another from bottom to top, and the concrete-filled steel tube component is columnar; comprising an external steel pipe and a corrugated pipe, a prestress reinforcing rib penetrates through an upper end plate and a lower end plate, and the ratio eta of the prestress P applied by the prestress reinforcing rib to the compression bearing capacity N0 of the prefabricated concrete filled steel tubular column component is equal to P / N0, 0.1 lt; eta < = 0.2, N0 = Ascfsc, fsc is the design value of the compressive strength of the concrete-filled steel tube with the unit of MPa, and Asc is the cross-sectional area of the concrete-filled steel tube with the unit of mm < 2 >. According to the prefabricated concrete-filled steel tubular column component, under the same section size, the self weight of the component can be reduced while the impact resistance of the component is improved, the rigidity of the component is improved by applying the prestress ratio within a certain range, and therefore the overall stability, the impact resistance and the energy dissipation capacity of the component are improved.

Description

Technical Field

[0001] The invention relates to a pile-column structure with special purpose, in particular to a prefabricated steel tube concrete column component capable of applying prestress and a construction method thereof. Background Art

[0002] Prestressed steel tube concrete components are a new type of composite component formed by filling concrete in steel tubes and applying prestress through specific technical means. This component makes full use of the respective advantages of steel tubes and concrete, such as the tensile properties of steel tubes and the compressive properties of concrete, thereby optimizing the structural performance. In addition, through prestressing technology, the stiffness and bearing capacity of the structure can be significantly improved, and it is widely used in different fields such as bridge engineering, construction engineering and water conservancy engineering. In particular, for the support columns and impacted bridge piers in debris flow protection structures, the application of prestress can significantly improve the impact resistance of such structures.

[0003] At present, domestic and foreign scholars' research on the impact resistance of steel tube concrete components mainly focuses on improving the cross-sectional form and increasing the strength of the filled concrete. The existing research has the following technical problems: (1) Improvement of steel tube concrete's ability to resist horizontal impact: At present, the ability to resist horizontal impact is improved by increasing the cross-sectional area of ​​the component, increasing the wall thickness of the steel tube, or adding internal round steel tubes. The disadvantage of such methods is that they significantly increase the weight of the component, thereby increasing the deformation of the structure during the stress process. This deformation not only affects the aesthetics of the structure, but also may pose a threat to the stability and safety of the structure. First, excessive self-weight of the component will increase the stress level of the structure during the stress process, thereby accelerating the fatigue and damage of the structure. Increased self-weight may also cause the generation and expansion of structural cracks, reducing the durability and service life of the structure. Second, increased self-weight of the component also has an adverse effect on the seismic performance of the structure. A heavy structure will be subjected to greater inertial force under the action of an earthquake, thereby increasing the seismic response and damage risk of the structure. Therefore, the impact of the self-weight of the component on the seismic performance of the structure needs to be specially considered in seismic design. In addition, increasing the cross-sectional area of ​​the component not only reduces the actual usable area, but also increases the difficulty and cost of construction.

[0004] (2) Problems of applying prestress to steel tube concrete columns: Under static loads, the method of applying prestress can not only reduce the cross-sectional dimensions of components and significantly reduce the proportion of structural weight in the total design load, but also reduce cracks and limit crack development. At the same time, the application of prestress can reduce the deflection of structures or components, improve the structural stiffness and durability of structural components, and the shear and fatigue resistance under repeated loads. In addition, under impact loads, the application of prestress can significantly improve the impact resistance of components. However, the quantitative relationship between the prestress ratio and the stiffness increase has not been determined. At the same time, under impact loads, higher stiffness may lead to lower energy dissipation capacity. In addition, the current prestressing methods are all for beam components, and there is a lack of a new column foot structure that considers the column bottom connection problem and can apply prestress to steel tube concrete columns.

[0005] (3) Problems with traditional construction methods: First, on-site construction limits the quality of the project and increases the potential for safety accidents in open-air and high-altitude operations. Second, it is greatly affected by natural environmental conditions and various factors, and the construction period is long. In addition, on-site wet operations have low production efficiency. In short, traditional construction methods have many problems and defects in environmental pollution, safety, quality, management, etc.

[0006] How to design a component that can effectively improve the component's ability to resist horizontal impact without significantly increasing its own weight, and how to determine the amount of prestress to be applied so that it can increase stiffness while also improving energy dissipation capacity have become technical problems that need to be solved urgently in this field. Of course, while completing the above technical tasks, we also have to consider a package of details such as how to achieve the application of prestress to the component, how to achieve friendly processing and convenient use. Summary of the invention

[0007] In response to the above technical problems, the present invention provides a prefabricated steel tube concrete column component that can be prestressed and has stronger impact resistance under the same cross-sectional area, and a construction method thereof. The component clearly defines the amount of prestress to be applied, so that the component can increase its stiffness while improving its energy consumption capacity.

[0008] The technical solution of the present invention is: a prefabricated steel tube concrete column component capable of applying prestress, comprising a base, a steel tube concrete component and prestressed reinforcement ribs, wherein the base comprises a bottom plate, a connecting steel tube and a lower end plate fixedly connected to each other from bottom to top, and a first mounting hole is opened at the center of the plate surface of the lower end plate; The steel tube concrete component is columnar, including an external steel tube and a corrugated tube, an upper end plate is fixedly arranged at the top end of the external steel tube, and the corrugated tube is arranged between the upper end plate and the lower end plate; the bottom end of the external steel tube is fixedly connected to the lower end plate, a grouting hole communicating with the inner cavity of the corrugated tube is also opened on the plate surface of the lower end plate, and a second mounting hole and a grouting hole communicating with the inner cavity of the corrugated tube are opened on the plate surface of the upper end plate; The prestressed reinforcement ribs penetrate the upper end plate and the lower end plate, and the upper and lower ends of the prestressed reinforcement ribs are respectively fixed to the upper end plate and the lower end plate anchors; Grouting material is poured into the cavity of the corrugated pipe through the grouting holes, and concrete is filled between the corrugated pipe and the external steel pipe; The prestress applied by the prestressed reinforcement P Compressive bearing capacity of precast concrete-filled steel tube columns N 0 Ratio η = P / N 0 , the 0.1< η ≤0.20, where N 0 = A sc f sc , f sc is the design value of compressive strength of concrete-filled steel tube, unit: MPa, A sc is the cross-sectional area of ​​the steel tube concrete member, unit: mm 2 .

[0009] Preferably, the prestressed reinforcement bars are steel strands or steel bars.

[0010] Preferably, anchor mounting holes are provided on the bottom plate, and the upper and lower ends of the prestressed reinforcement ribs are fixed by upper end anchors and lower end anchors respectively.

[0011] Preferably, a plurality of stiffening ribs are connected between the lower end plate and the bottom plate.

[0012] Preferably, the grouting material is a cement-based grouting material or a non-shrinkage cement-based grouting material, and the 28-day compressive strength is not less than 50 MPa.

[0013] Preferably, a plurality of fixing holes are provided on the bottom plate.

[0014] A construction method for a prefabricated steel tube concrete column member is also provided, comprising the following steps: Step 1: weld the external steel pipe to the lower end plate, weld the lower end plate to the connecting steel pipe, weld the connecting steel pipe to the bottom plate, and weld the stiffening rib to the external steel pipe, the lower end plate, the connecting steel pipe and the bottom plate respectively; Step 2: Fix the corrugated pipe to the center of the external steel pipe, then fill the space between the external steel pipe and the corrugated pipe with concrete, vibrate it, and let it stand. After the concrete strength reaches the requirement, weld the upper end plate to the external steel pipe. Step 3: The prestressed reinforcement bar passes through the second mounting hole and the first mounting hole, the lower end anchor is fixed to the first mounting hole on the lower surface of the lower end plate through the anchor mounting hole, the lower end of the prestressed reinforcement bar is fixed to the lower end anchor, and then the upper end of the prestressed reinforcement bar is tensioned by the tensioning equipment to apply prestress to the component, and the upper end anchor is fixed to the second mounting hole on the upper surface of the upper end plate; Step 4: After tensioning is completed, pour the grouting material from the grouting hole to fill the gap between the corrugated pipe and the prestressed reinforcement until the grouting material flows out from the grouting hole. The grouting is completed and the component is manufactured; Step 5: Install the manufactured components on site and connect them with the embedded parts on site.

[0015] Preferably, in step 2, after concrete is filled between the outer steel pipe and the corrugated pipe and vibrated, the steel pipe needs to be left standing for at least 7 days.

[0016] The prefabricated steel tube concrete column component structure capable of applying prestress of the present invention enables the grouting material to fill the gap between the corrugated pipe and the steel strand through the design of the grouting holes and the grouting holes, which not only ensures the fixed position of the steel strand, but also enhances the adhesion between the steel strand and the concrete. The present invention innovatively transfers the prestress to the concrete effectively through the tightly bonded grouting material, thereby improving the bearing capacity and stability of the overall structure. By enhancing the adhesion between the steel strand and the concrete, the grouting material can improve the stress performance of the structure. Under the condition of the same cross-sectional area, the impact resistance is stronger, the rigidity of the overall component is higher, making it more solid and durable, and at the same time reducing the deadweight of the component. The structural grouting material can tightly wrap the steel strand to form a protective layer to prevent the steel strand from being eroded by the external environment, thereby extending the service life of the structure.

[0017] The present invention increases the prestress ratio η The value is designed to be 0.1< η ≤0.2, which not only meets the requirement of slowing down the plastic deformation of the component, but also enables the component to have a larger bearing capacity; this prestressing force can increase the stiffness of the component while improving its energy consumption capacity.

[0018] The components provided by the present invention can be prefabricated in a factory and then installed on site without the need for outdoor on-site production, which can better overcome the problems of steel tube concrete component construction in an on-site construction environment, such as high-altitude welding problems and concrete pouring problems. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0020] Figure 1 is a three-dimensional schematic diagram of the present invention, Figure 2 is a three-dimensional exploded view of the present invention, Figure 3 is a transverse cross-sectional view of the steel tube concrete member of the present invention, Figure 4 is a vertical cross-sectional view of the steel tube concrete member in the present invention, Figure 5 is a three-dimensional schematic diagram of the upper end plate in the present invention, Figure 6 is a schematic diagram of the structure of the top of the column of the present invention, Figure 7 Schematic diagram of the structure of the bottom of the column of the present invention, Figure 8 is a three-dimensional schematic diagram of the lower end plate in the present invention, Fig. 9 is a three-dimensional schematic diagram of the bottom plate of the present invention, Fig.10 is a three-dimensional schematic diagram of the rib plate in the present invention, Fig.11 The bending moment time history curve of the fixed end of the steel tube concrete cantilever column with different prestress under impact load is shown in the figure. Fig.12 Lateral displacement of cantilever column under impact load w d and peak bending moment M max The graph of the change of prestress ratio, Fig.13 It is a schematic diagram of the stiffness ratio when different prestresses are applied to the components. Fig.14 It is a schematic diagram of the maximum value of internal energy absorbed by the component under different prestress ratios. In the figure, 1 is a steel tube concrete component, 1-1 is an external steel tube, 1-2 is concrete, 1-3 is a corrugated pipe, 1-4 is a grouting material, 2 is a prestressed reinforcement bar, 3 is an upper end anchor, 4 is an upper end plate, 4-1 is a second mounting hole, 4-2 is a slurry outlet hole, 5 is a lower end plate, 5-1 is a notch, 5-2 is a first mounting hole, 5-3 is a grouting hole, 6 is a reinforcing rib, 6-1 is a right-angle cut, 6-2 is an inner chamfer, 6-3 is an outer chamfer, 7 is a connecting steel tube, 8 is a bottom plate, 8-1 is a bolt hole, 8-2 is an anchor mounting hole, 9 is a high-strength bolt, and 10 is a lower end anchor. DETAILED DESCRIPTION

[0021] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0022] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on this patent; in order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0023] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "inner", "outer", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as a limitation on this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0024] In the description of the present invention, unless otherwise clearly specified and limited, if the term "connection" or the like appears to indicate the connection relationship between components, the term should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two components or the interaction relationship between two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] Figures 1 to 10 It is a prefabricated steel tube concrete column member that can be prestressed. Figure 1 and Figure 2 It includes a base, a steel tube concrete component 1 and a prestressed reinforcement rib 2. The base comprises a bottom plate 8, a connecting steel pipe 7 and a lower end plate 5 which are fixedly connected to each other from bottom to top, and a first mounting hole 5-2 is opened at the center of the plate surface of the lower end plate 5; See also Figure 3 and Figure 4 The steel tube concrete component 1 is columnar, including an external steel tube 1-1 and a corrugated tube 1-3. An upper end plate 4 is fixedly arranged at the top of the external steel tube 1-1, and the corrugated tube 1-3 is arranged between the upper end plate 4 and the lower end plate 5; the bottom end of the external steel tube 1-1 is fixedly connected to the lower end plate 5, and a grouting hole 5-3 communicating with the inner cavity of the corrugated tube 1-3 is also opened on the plate surface of the lower end plate 5, see Figure 5 A second mounting hole 4-1 and a slurry outlet hole 4-2 communicating with the inner cavity of the bellows 1-3 are provided on the surface of the upper end plate 4. See also Figure 6 and Figure 7 The prestressed reinforcement rib 2 passes through the upper end plate 4 and the lower end plate 5, the upper and lower ends of the prestressed reinforcement rib 2 are respectively fixed to the upper end anchor 3 and the lower end anchor 10, and a notch 5-1 is correspondingly provided on the lower end plate 5; Grouting material 1-4 is poured into the cavity of the corrugated pipe 1-3 through the grouting hole 5-3, and concrete 1-2 is filled between the corrugated pipe 1-3 and the external steel pipe 1-1; The prestress P applied by the prestressed reinforcement 2 and the compressive bearing capacity of the precast steel tube concrete column N 0 Ratio η = P / N 0 , 0.1< η ≤0.20. Among them, N 0 = A sc f sc , f sc is the design value of compressive strength of concrete-filled steel tube, unit: MPa, A sc is the cross-sectional area of ​​the steel tube concrete member, unit: mm 2 .

[0026] In this embodiment, the prestressed reinforcing bar 2 is a steel strand. Those skilled in the art may also use other high-strength materials with toughness.

[0027] In this embodiment, the bottom plate 8 is provided with an anchor mounting hole 8-2 for mounting the lower anchor 10, and the upper and lower ends of the prestressed reinforcement rib 2 are respectively fixed by the upper anchor 3 and the lower anchor 10. The use of anchors for fixing is a conventional technique in the art, and the specific structure will not be described in detail.

[0028] See also Figures 8 to 10 In this embodiment, a plurality of stiffening ribs 6 are connected between the lower end plate 5 and the bottom plate 8. The stiffening ribs 6 are provided with right-angle cutouts 6-1, inner chamfers 6-2, and outer chamfers 6-3 for easy installation, and the lower end plate 5 is provided with corresponding notches 5-1 for installing the stiffening ribs 6.

[0029] Grouting material 4-1 type is cement-based grouting material or non-shrinkage cement-based grouting material, usually with a 28-day compressive strength ≥50MPa.

[0030] In this embodiment, bolt holes 8-1 are respectively provided at the four corners of the bottom plate 8, and the steel tube concrete component 1 is fixed to the on-site embedded parts by high-strength bolts 9; In this embodiment, the construction method of the prefabricated steel tube concrete column component includes the following steps: Step 1: Weld the external steel pipe 1-1 to the lower end plate 5, weld the lower end plate 5 to the connecting steel pipe 7, weld the connecting steel pipe 7 to the bottom plate 8, and weld the stiffening rib 6 to the external steel pipe 1-1, the lower end plate 5, the connecting steel pipe 7 and the bottom plate 8 respectively; Step 2: fix the corrugated pipe 1-3 to the center of the external steel pipe 1-1, then fill the concrete 1-2 between the external steel pipe 1-1 and the corrugated pipe 1-3, and vibrate, and then let it stand for at least 7 days. After the strength of the concrete 1-2 reaches the requirements, the specific strength requirements are set by technicians in this field according to the actual performance indicators required. This is a conventional technology and will not be described in detail. Weld the upper end plate 4 to the external steel pipe 1-1; Step 3: Pass the prestressed reinforcement rib 2 through the second mounting hole 4-1 and the first mounting hole 5-2, fix the lower end anchor 10 to the first mounting hole 5-2 on the lower surface of the lower end plate 5 through the anchor mounting hole 8-2, fix the lower end of the prestressed reinforcement rib 2 to the lower end anchor 10, then tension the upper end of the prestressed reinforcement rib 2 through the tensioning equipment to apply prestress to the component, and fix the upper end anchor 3 to the second mounting hole 4-1 on the upper surface of the upper end plate 4, and fix the upper end of the prestressed reinforcement rib 2 to the upper end anchor 3; Step 4: After tensioning is completed, the grouting material 1-4 is poured in from the grouting hole 5-3 to fill the gap between the corrugated pipe 1-3 and the prestressed reinforcement 2, until the grouting material 1-4 flows out from the grouting hole 4-2, the grouting is completed, and the component is manufactured in the factory; Step 5: Install the manufactured components on site, and connect the high-strength bolts 9 with the embedded parts on site to complete the installation.

[0031] The present invention adopts the design of the grouting hole 5-3 and the grouting hole 4-2 so that the grouting material 1-4 can fill the gap between the corrugated pipe 1-3 and the prestressed reinforcement bar 2, which not only ensures the fixed position of the prestressed reinforcement bar 2, but also enhances the adhesion between the prestressed reinforcement bar 2 and the concrete 1-2. Through tight adhesion, the grouting material 1-4 can effectively transfer the prestress to the concrete 1-2, thereby improving the bearing capacity and stability of the overall structure.

[0032] By enhancing the bonding force between the prestressed reinforcement bar 2 and the concrete 1-2, the grouting material 1-4 can improve the stress-bearing performance of the structure, making it stronger and more durable. In addition, the structural grouting material 1-4 can tightly wrap the prestressed reinforcement bar 2 to form a protective layer to prevent the prestressed reinforcement bar 2 from being eroded by the external environment, thereby extending the service life of the structure.

[0033] When prestressing is applied to the steel tube concrete column, the overall stiffness of the component can be improved. However, higher stiffness may lead to lower energy dissipation capacity. It is necessary to determine the amount of prestressing under impact load so that it can increase the energy dissipation capacity while increasing the stiffness of the component. Through experiments, it was found that under impact load, the plastic deformation of the prestressed component was significantly reduced compared with the non-prestressed component.

[0034] Depend on Fig.11 It can be seen that the bending moment borne by the component vibrates multiple times, and compared with the component without prestress, the vibration law of the bending moment time history diagram has changed significantly. The vibration frequency of the prestressed component is faster, and it has reciprocated multiple times around the equilibrium position. This shows that the ends of the prestressed component are mostly in the elastic stage and have not yet developed to the plastic stage. The component consumes energy through multiple elastic vibration deformations. In addition, with the increase of prestress, the bending moment borne by the component also increases (i.e., the ordinate). This increased bending moment is caused by the application of prestress, that is, the additional bending moment caused by the axial load.

[0035] Depend on Fig.12 It can be seen that the lateral displacement of the component does not change much with the increase of the prestress ratio; the peak moment of the component increases with the increase of the prestress ratio. This is because the application of prestress changes the deformation law of the component. Although it cannot effectively reduce the lateral limit displacement of the component, it can effectively reduce the plastic deformation of the component, so that the cantilever component only undergoes elastic deformation, which reduces the damage of the component. η When the prestress ratio is less than 0.20, the bending moment of the member is smaller than that of the member without prestress. η When ≥0.20, the bending moment borne by the member is greater than that of the member without prestressing, which is not conducive to further bearing of the member.

[0036] Depend on Fig.13It can be seen that the stiffness of the prestressed component is significantly improved. The stiffness of the component is the largest when the prestress ratio is 0.2. Considering the effect of impact load, the instantaneous stiffness of the component can reach 192 times that of the component without prestress. k / k 0 It is the ratio of the stiffness with prestress to the stiffness without prestress.

[0037] Depend on Fig.14 It is known that when η When >0.1, the energy absorption capacity of the prestressed component is greater than that of the non-prestressed component.

[0038] In summary, the prestress ratio is 0.1< η When ≤0.2, the stiffness and energy dissipation capacity of the component can be improved, and the requirements for slowing down the plastic deformation of the component can be met.

[0039] The prefabricated steel tube concrete column components of the present invention can reduce the self-weight of components while improving the impact resistance of components under the same cross-sectional size. By applying a certain range of prestress ratios, the stiffness of the components is improved, thereby improving the overall stability, impact resistance and energy consumption capacity of the components. The construction convenience, adaptability and flexibility are improved, and the construction efficiency and quality are improved. The force-bearing performance of the structure is improved, and the durability of the structure is improved, thereby extending the service life of the structure. This design can effectively apply prestress to the column components, improve the impact resistance of the components, and reduce the self-weight of the components. Overall, it improves the comprehensive performance of existing steel tube concrete column components, prefabricated components in the factory, improves the construction convenience, and extends the service life of the components.

[0040] It should be noted that the above specific implementations are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art should understand that various modifications, equivalent substitutions, changes, etc. can be made to the present invention based on the technical content disclosed in this application document. However, as long as these changes do not deviate from the spirit of the present invention, they should be within the scope of protection of the present invention. In addition, some terms used in the specification and claims of this application are not restrictive, but are only for the convenience of description.

Claims

1. A prefabricated steel tube concrete column member capable of applying prestress, comprising a base, a steel tube concrete member and prestressed reinforcement ribs, characterized in that: The base comprises a bottom plate, a connecting steel pipe and a lower end plate which are fixedly connected to each other from bottom to top, and a first mounting hole is opened at the center of the plate surface of the lower end plate; The steel tube concrete component is columnar, including an external steel tube and a corrugated tube, an upper end plate is fixedly arranged at the top end of the external steel tube, and the corrugated tube is arranged between the upper end plate and the lower end plate; the bottom end of the external steel tube is fixedly connected to the lower end plate, a grouting hole communicating with the inner cavity of the corrugated tube is also opened on the plate surface of the lower end plate, and a second mounting hole and a grouting hole communicating with the inner cavity of the corrugated tube are opened on the plate surface of the upper end plate; The prestressed reinforcement ribs penetrate the upper end plate and the lower end plate, and the upper and lower ends of the prestressed reinforcement ribs are respectively fixed to the upper end plate and the lower end plate anchors; Grouting material is poured into the cavity of the corrugated pipe through the grouting holes, and concrete is filled between the corrugated pipe and the external steel pipe; The prestress applied by the prestressed reinforcement P Compressive bearing capacity of precast concrete-filled steel tube columns N Ratio of 0 η = P / N 0, 0.1< η ≤0.2, where N 0= A sc f sc , f sc is the design value of compressive strength of concrete-filled steel tube, unit: MPa, A sc is the cross-sectional area of ​​the steel tube concrete member, unit: mm 2 .

2. The prefabricated steel tube concrete column member capable of applying prestress according to claim 1, characterized in that: The prestressed reinforcement bars are steel strands or steel bars.

3. The prefabricated steel tube concrete column member capable of applying prestress according to claim 1, characterized in that: Anchor mounting holes are provided on the bottom plate, and the upper and lower ends of the prestressed reinforcement bars are fixed by upper end anchors and lower end anchors respectively.

4. The prefabricated steel tube concrete column member capable of applying prestress according to claim 1, characterized in that: A plurality of stiffening ribs are connected between the lower end plate and the bottom plate.

5. The prefabricated steel tube concrete column member capable of applying prestress according to claim 1, characterized in that: The grouting material type is cement-based grouting material or non-shrinkage cement-based grouting material, and the 28-day compressive strength is not less than 50MPa.

6. The prefabricated steel tube concrete column member capable of applying prestress according to claim 1, characterized in that: The bottom plate is provided with a plurality of fixing holes.

7. A construction method for prefabricated steel tube concrete column components, characterized in that: The following steps are involved: Step 1: weld the external steel pipe to the lower end plate, weld the lower end plate to the connecting steel pipe, weld the connecting steel pipe to the bottom plate, and weld the stiffening rib to the external steel pipe, the lower end plate, the connecting steel pipe and the bottom plate respectively; Step 2: Fix the corrugated pipe to the center of the external steel pipe, then fill the space between the external steel pipe and the corrugated pipe with concrete, vibrate it, and let it stand. After the concrete strength reaches the requirement, weld the upper end plate to the external steel pipe. Step 3: The prestressed reinforcement bar passes through the second mounting hole and the first mounting hole, the lower end anchor is fixed to the first mounting hole on the lower surface of the lower end plate through the anchor mounting hole, the lower end of the prestressed reinforcement bar is fixed to the lower end anchor, and then the upper end of the prestressed reinforcement bar is tensioned by the tensioning equipment to apply prestress to the component, and the upper end anchor is fixed to the second mounting hole on the upper surface of the upper end plate; Step 4: After tensioning is completed, pour the grouting material from the grouting hole to fill the gap between the corrugated pipe and the prestressed reinforcement until the grouting material flows out from the grouting hole. The grouting is completed and the component is manufactured; Step 5: Install the manufactured components on site and connect them with the embedded parts on site.

8. The construction method of a prefabricated steel tube concrete column member according to claim 7, characterized in that: In step 2, after filling the space between the outer steel pipe and the corrugated pipe with concrete and vibrating it, the steel pipe needs to be left standing for at least 7 days.

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