CN102409808B - Steel tube concrete superposed column with mild steel casing outer packed concrete at bottom and preparation method thereof - Google Patents

Abstract

The invention relates to a concrete-filled steel tube composite column with soft steel casing at the bottom and concrete outsourcing and its method, comprising an inner steel tube (1), inner concrete of the steel tube (2), outer concrete of the steel tube (4), longitudinal reinforcement (5), hoops Rib (6) and mild steel casing (3). The present invention is a combination of steel pipe and concrete, a combination of internal steel pipe concrete and external reinforced concrete, a combination of bottom mild steel casing and internal steel pipe, and is a composite column of multiple combination restraint steel pipe concrete; the bottom soft steel casing of the present invention (3) It is beneficial to improve the horizontal and vertical bearing capacity, ductility and energy dissipation capacity of the composite column; since the damage of the composite column generally occurs at the root of the column, the strengthening of the root can effectively reduce its cross-sectional area and increase With a large use area, the amount of concrete will be reduced, the structure's self-weight will be reduced, and the energy consumption of construction will be reduced. Under the condition of the same steel consumption, it can bring greater economic benefits.

Description

Concrete-filled Steel Tube Composite Column with Soft Steel Casing at the Bottom and Outsourcing Concrete and Its Practice

technical field

The invention relates to a novel steel pipe concrete composite column, in particular to a steel pipe concrete composite column with a soft steel casing at the bottom and a concrete outsourcing method, and a method thereof.

Background technique

With the development of production technology and the improvement of people's living standards, people's requirements for various types of buildings are also increasing, and they have certain requirements for the safety and comfort of structures. Reinforced concrete columns and concrete filled steel tubes are used more and more in various high-rise and super high-rise buildings, and each has its own advantages. Reinforced concrete columns give full play to the respective advantages of steel bars and concrete, and have good seismic performance and fire-proof and anti-corrosion properties; steel tube concrete columns overcome the shortcomings of steel tubes that are prone to local buckling, and at the same time play a restraining role in concrete, giving full play to steel tubes and concrete. Advantages of concrete.

While reinforced concrete columns and steel tube concrete columns are widely used, their shortcomings are also increasingly apparent. The cross-sectional size of reinforced concrete columns is large, occupying the use space, and the deformation capacity is limited; the fire performance of steel tube concrete columns is poor; the emergence of steel tube concrete composite columns has solved this problem for us to a certain extent, but in super In high-rise structures, the cross-sectional size of ordinary concrete-filled steel tube composite columns is still very large, and the damage of the structure is mostly concentrated at the bottom of the composite steel tube concrete composite columns. This requires us to strengthen the design of the bottom of the composite column, give full play to the seismic performance of the material, and ensure the safety of the structure.

Contents of the invention

The technical problem to be solved by the invention is to increase the anti-seismic defense line of the concrete-filled steel tube composite column and improve its anti-seismic performance. In order to solve this problem, the present invention proposes a concrete-filled steel tube composite column with a soft steel casing at the bottom and concrete outsourcing and a method thereof.

The technical scheme adopted in the present invention is:

Concrete-filled steel tube composite column with mild steel casing at the bottom to outsource concrete, characterized in that: the composite column includes inner steel pipe, inner concrete of steel pipe, outer concrete of steel pipe, longitudinal bars, stirrups and soft steel casing; The inner concrete of the steel pipe is poured, the outer concrete of the inner steel pipe is poured with the outer concrete of the steel pipe, and the longitudinal bars and stirrups are pre-embedded in the outer concrete of the steel pipe; The ground or the top surface of the foundation and anchored to it. Its anchorage length should meet the design requirements.

The concrete-filled steel tube composite column has a rectangular or circular cross-section.

The inner steel pipe is a rectangular steel pipe or a round steel pipe.

The height of the mild steel casing above the ground or the top surface of the foundation is 1.0h, where h is the diameter of the circular section of the inner steel pipe or the long side dimension of the rectangular section. That is to strengthen the plastic hinge domain at the bottom of the concrete-filled steel tube composite column, delay or avoid the damage of the bottom of the concrete-filled steel tube composite column, give full play to its seismic bearing capacity and energy dissipation capacity, and make it show better performance under earthquake .

A certain number of ventilation holes are reserved at corresponding positions of the inner steel pipe. The concrete can be poured densely, and at the same time, the inner and outer concrete of the steel pipe are connected as a whole.

The mild steel casing and the inner steel pipe are fixed by bolt connection.

The thickness of the mild steel casing is not less than the thickness of the inner steel pipe.

The fabrication sequence of the concrete-filled steel tube composite column with mild steel casing at the bottom and concrete outsourcing is as follows:

1) Make the inner steel pipe and the mild steel casing at the bottom according to the requirements, reserve a certain number of air holes within the full height range of the inner steel pipe, so that the inner concrete of the steel pipe and the outer concrete of the steel pipe can be connected as a whole through the air holes;

2) Two-way bolt holes are reserved in the positions corresponding to the inner steel pipe and the soft steel casing at the bottom according to actual needs;

3) Weld the corresponding nuts on the outer surface of the bolt holes reserved in the inner steel pipe;

4) Put the mild steel casing on the outer side of the bottom wall of the inner steel pipe, and correctly position the inner steel pipe and the soft steel casing at the bottom, penetrate the bolts, and tighten the bolts through the nuts on the outer side of the inner steel pipe;

5) Binding the outer longitudinal bars and stirrups to form a reinforcement mesh;

6) Reserve a certain protective layer thickness on the outside of the steel mesh to support the formwork;

7) Concrete is poured into the formwork, and after forming, it becomes a concrete-filled steel tube composite column with a soft steel casing at the bottom and outsourcing concrete. Since the inner steel pipe and mild steel casing are wrapped by outer concrete, it can act as a hoop.

The concrete-filled steel tube composite column with soft steel casing at the bottom and the concrete outsourcing method of the present invention, under the action of frequent earthquakes, the concrete-filled steel tube composite column is less stressed, and at this time, the soft steel casing and the inner steel pipe are squeezed by the concrete. Frictional energy consumption under pressure; the extrusion of concrete not only improves its frictional energy dissipation capacity, but also connects the mild steel casing and the inner steel pipe as a whole, and its overall working performance is good, with high rigidity and strength; Under earthquake action, due to the increased deformation of the CFST composite column, the connection between the soft steel casing and the internal steel pipe weakens, and their joint performance degrades. They begin to give full play to their ductility and energy dissipation, and the overall stiffness decreases. The structure period becomes longer and the earthquake action decreases, which is equivalent to adding an anti-seismic defense line and improving the safety of the structure.

After pouring concrete, only for the soft steel casing and the inner steel pipe, the rigidity of the joint between the soft steel casing and the inner steel pipe is weaker than the stiffness of the concrete inside the steel pipe, forming an internal rigidity and an external Flexible structure, and the exterior of the soft steel casing is also wrapped by reinforced concrete. This structure is conducive to the energy dissipation capacity under the action of earthquakes, and can give full play to the energy dissipation capacity of the external soft steel casing and the steel tube concrete composite column; Compared with ordinary concrete-filled steel tube columns with the same cross-section and the same load, the concrete-filled steel tube composite column with soft steel casing at the bottom and outsourcing concrete improves the shear resistance of the member, and it is easy to realize strong shear and weak bending; it has good ductility, Under the action of dynamic load, especially earthquake load, it can dissipate energy through its own deformation, and block or delay the damage of the structure.

Beneficial effect

Compared with ordinary concrete-filled steel tube composite columns, the present invention has the following advantages:

The present invention is a combination of steel pipe and concrete, a combination of internal steel pipe concrete and external reinforced concrete, a combination of bottom soft steel casing and internal steel pipe, and a composite steel pipe concrete column constrained by multiple combinations; the bottom soft steel composite column of the present invention The steel casing is beneficial to improve the horizontal and vertical bearing capacity, ductility and energy dissipation capacity of the composite column; since the damage of the composite column generally occurs at the root of the column, the strengthening of the root can effectively reduce its cross-sectional area and increase With a large use area, the amount of concrete will be reduced, the structure's self-weight will be reduced, and the energy consumption of construction will be reduced. Under the condition of the same steel consumption, it can bring greater economic benefits.

Description of drawings

Fig. 1 is a schematic plan view when the inner steel pipe of a circular cross-section concrete-filled steel pipe composite column with soft steel casing and outsourcing concrete is a rectangle;

Fig. 2 is a schematic plan view when the inner steel pipe of a circular cross-section concrete-filled steel pipe composite column with a soft steel casing outsourcing concrete is circular;

Fig. 3 is a schematic plan view when the internal steel pipe of the rectangular section concrete filled steel pipe composite column with soft steel casing outsourcing concrete at the bottom is circular;

Fig. 4 is a schematic plan view when the internal steel pipe of a rectangular section concrete filled steel tube composite column with soft steel casing outsourcing concrete at the bottom is a rectangle;

Fig. 5 is A-A sectional view among Fig. 1, Fig. 2, Fig. 3 and Fig. 4;

Among them: 1-inner steel pipe, 2-concrete inside steel pipe, 3-mild steel casing, 4-outer concrete steel pipe, 5-longitudinal reinforcement, 6-stirrup, 7-bolt, 8-tension reinforcement, 9-ground or Foundation top.

Detailed ways

Example 1

A structural form of the concrete-filled steel tube composite column with soft steel sleeves at the bottom and outsourcing concrete is shown in Figure 1, and its section is shown in Figure 5, including the inner steel tube 1, the inner concrete 2 of the steel tube, and the outer concrete 4 of the steel tube , longitudinal bars 5, stirrups 6 and mild steel sleeves 3; the inner steel pipe 1 is poured with the inner concrete 2 of the steel pipe, the outer part of the inner steel pipe 1 is poured with the outer concrete 4 of the steel pipe, and the outer concrete 4 of the steel pipe is pre-embedded with longitudinal bars 5 and hoops Rib 6; the outer side of the bottom wall of the inner steel pipe 1 is wrapped with a mild steel sleeve 3, and the mild steel sleeve 3 extends into the lower ground or the top surface 9 of the foundation and is anchored to it. The concrete-filled steel tube composite column has a circular cross-section. The inner steel pipe 1 is a rectangular steel pipe. The height of the mild steel casing 3 above the ground or foundation top surface 9 is 1.0h, where h is the long side dimension of the rectangular section of the inner steel pipe 1 . A certain number of ventilation holes are reserved at corresponding positions of the inner steel pipe 1 . The concrete can be poured densely, and at the same time, the inner and outer concrete of the steel pipe are connected as a whole. The soft steel casing 3 and the inner steel pipe 1 are connected and fixed by bolts 7 . The thickness of the mild steel casing 3 is not less than the thickness of the inner steel pipe 1 .

The method of the concrete-filled steel tube composite column with soft steel casing at the bottom and outsourcing concrete is as follows:

1) Make the inner steel pipe 1 and the mild steel casing 3 at the bottom according to the requirements, reserve a certain number of air holes within the full height of the inner steel pipe 1, so that the inner concrete 2 of the steel pipe and the outer concrete 4 of the steel pipe can pass through the air holes join together;

2) Two-way bolt holes are reserved in the positions corresponding to the inner steel pipe 1 and the soft steel casing 3 at the bottom according to actual needs;

3) Weld corresponding nuts (not shown in the figure) on the outer surface of the bolt holes reserved in the inner steel pipe 1;

4) Set the mild steel casing 3 on the outer side of the bottom wall of the inner steel pipe 1, and correctly position the inner steel pipe 1 and the soft steel casing 3 at the bottom, penetrate the bolt 7, and pass the nut on the outer surface of the inner steel pipe 1 Tighten the bolt 7;

5) binding the outer longitudinal bars 5 and stirrups 6 to form a reinforcement mesh;

6) Reserve a certain protective layer thickness on the outside of the steel mesh to support the formwork;

7) Concrete is poured into the formwork, and after forming, it becomes a concrete-filled steel tube composite column with a soft steel casing at the bottom and outsourcing concrete.

Example 2

Another structural form of the concrete-filled steel tube composite column with a soft steel casing at the bottom and outsourcing concrete is shown in Figure 2, and its section is shown in Figure 5. The outer shape of the composite column is circular, and the inner steel pipe 1 is also circular, and the other structural forms are the same as in Embodiment 1.

Example 3

Another structural form of the concrete-filled steel pipe composite column with a soft steel casing at the bottom and outsourcing concrete is shown in Figure 3, and its cross-sectional view is shown in Figure 5. The outer shape of the composite column is rectangular, and the inner steel pipe 1 is circular, and other structural forms are the same as in Embodiment 1.

Example 4

Another structural form of the concrete-filled steel tube composite column with a soft steel casing at the bottom and outsourcing concrete is shown in Figure 4, and its section is shown in Figure 5. The outer shape of the composite column is rectangular, and the inner steel pipe is also rectangular, and other structural forms are the same as in Embodiment 1.

The above are typical embodiments of the present invention, and the practice of the present invention is not limited thereto.

Claims (8)

1. A steel pipe concrete composite column with a soft steel casing at the bottom and outsourced concrete, characterized in that: the composite column includes an inner steel pipe (1), inner concrete of the steel pipe (2), outer concrete of the steel pipe (4), longitudinal reinforcement ( 5), stirrup (6) and mild steel casing (3); the inner steel pipe (1) is poured with steel pipe inner concrete (2), the inner steel pipe (1) is poured with steel pipe outer concrete (4), and the outer steel pipe concrete (4) are pre-embedded with longitudinal reinforcement (5) and stirrup (6); the outer side of the bottom pipe wall of the inner steel pipe (1) is wrapped with a mild steel sleeve (3), and the mild steel sleeve (3) extends into the lower part ground or foundation top surface (9) and anchored thereto. 2. The concrete-filled steel tube composite column with soft steel casing at the bottom and concrete outsourcing as claimed in claim 1, characterized in that: the concrete-filled steel tube composite column has a rectangular or circular cross-section. 3. The concrete-filled steel pipe composite column with soft steel casing at the bottom and concrete outsourcing as claimed in claim 1, characterized in that: the inner steel pipe (1) is a rectangular steel pipe or a circular steel pipe. 4. The concrete-filled steel tube composite column with a mild steel sleeve at the bottom as claimed in claim 3, characterized in that: the height of the mild steel sleeve (3) above the ground or the top surface of the foundation (9) is 1.0h, where h is the diameter of the circular section of the inner steel pipe (1) or the long side dimension of the rectangular section. 5. The concrete-filled steel pipe composite column with mild steel casing at the bottom and concrete outsourcing as claimed in claim 1, characterized in that: a certain number of ventilation holes are reserved at corresponding positions of the inner steel pipe (1). 6. The concrete-filled steel tube composite column with mild steel casing at the bottom and outsourcing concrete as claimed in claim 1, characterized in that: the mild steel casing (3) and the inner steel pipe (1) are connected and fixed by bolts (7) . 7. The concrete-filled steel tube composite column with mild steel casing at the bottom and outsourcing concrete as claimed in claim 1, characterized in that: the thickness of the mild steel casing (3) is not less than the thickness of the inner steel pipe (1). 8. The method of the concrete-filled steel tube composite column with a mild steel casing at the bottom and outsourcing concrete as claimed in any one of claims 1-7, wherein the manufacturing sequence is as follows: 1) Make the inner steel pipe (1) and the mild steel casing (3) at the bottom according to the requirements, and reserve a certain number of ventilation holes within the full height range of the inner steel pipe (1) so that the concrete (2) inside the steel pipe and the steel pipe The external concrete (4) can be connected as a whole through the vent hole; 2) Two-way bolt holes are reserved in the positions corresponding to the inner steel pipe (1) and the mild steel casing (3) at the bottom according to actual needs; 3) Weld corresponding nuts on the outer surface of the bolt holes reserved in the inner steel pipe (1); 4) Put the mild steel casing (3) on the outer side of the bottom wall of the inner steel pipe (1), and correctly position the inner steel pipe (1) and the soft steel casing (3) at the bottom, and penetrate the bolt (7) , and tighten the bolt (7) through the nut on the outer surface of the inner steel pipe (1); 5) Binding the outer longitudinal bars (5) and stirrups (6) to form a reinforcement mesh; 6) Reserve a certain protective layer thickness on the outside of the steel mesh to support the formwork; 7) Concrete is poured into the formwork, and after forming, it becomes a concrete-filled steel tube composite column with a soft steel casing at the bottom and outsourcing concrete.

Images