A prefabricated ecc shell steel pipe recycled concrete column and a construction method thereof

Abstract

The application discloses a prefabricated ECC shell steel pipe recycled concrete column and a construction method thereof, and belongs to the technical field of building engineering assembly. The prefabricated ECC shell steel pipe recycled concrete column comprises a prefabricated ECC shell, a steel pipe, recycled concrete, stirrups and longitudinal reinforcement. The cross-sectional shape of the prefabricated ECC shell and the steel pipe can be circular or square respectively. The prefabricated ECC shell steel pipe recycled concrete column has the advantages that the ECC material with strong ultimate deformation capacity is used to replace the outer concrete of the steel pipe concrete laminated column, recycled concrete is filled in the steel pipe in the case of greatly improving the seismic capacity, the shortage of natural aggregates and the piling problem of urban waste are solved, and the sustainable development demand is met. Furthermore, the prefabricated construction technology is adopted, so that the formwork is not needed on the construction site, the on-site construction operation is greatly reduced, and the construction efficiency is improved.

Description

Technical Field

[0001] This invention relates to a prefabricated ECC-shell steel pipe recycled concrete column and its construction method, belonging to the field of prefabricated building construction technology. Background Technology

[0002] With the rapid development of the construction industry, the demand for concrete is increasing daily, leading to a greater use of natural aggregates such as crushed stone. This overexploitation of natural resources like sand and gravel has resulted in a series of environmental pollution and ecological imbalance problems. Furthermore, the demolition of old concrete buildings and damage from natural disasters have created a serious land occupation problem for cities due to the large amounts of construction waste. Therefore, to improve the reuse rate of construction waste and reduce the exploitation of natural resources, recycled concrete, which replaces natural aggregates by crushing and washing waste concrete blocks, has broad application prospects.

[0003] Concrete-filled steel tubular (CFST) has been widely used and developed in the past decade or so, but it still has drawbacks such as susceptibility to local buckling and poor fire resistance. Therefore, the concept of CFST composite columns has been proposed and developed to some extent. Based on this, some scholars have proposed using ECC (extracorporeal concrete) material to replace the ordinary concrete outside the steel tubing to improve the seismic performance and durability of the structure. ECC material can also effectively improve the load-bearing capacity and fire resistance of CFST composite columns.

[0004] In recent years, with the transformation and upgrading of the construction industry structure, issues such as how to reduce on-site construction workload, improve construction efficiency, enhance building quality, and meet sustainable development requirements have received increasing attention. Prefabricated construction has become the main direction for the future development of the construction industry. This invention combines the advantages of recycled concrete, ECC, and prefabricated assembly, making full use of the characteristics of ECC—high ultimate tensile strain but compressive strength similar to ordinary concrete—and has numerous advantages such as significantly reducing on-site construction workload, compensating for the mechanical defects of recycled aggregates through composite structures, and environmental protection and sustainable development. Summary of the Invention

[0005] The purpose of this invention is to propose a prefabricated ECC shell steel pipe recycled concrete column and its construction method, which has the characteristics of convenient on-site construction, good seismic performance and meeting the requirements of sustainable development.

[0006] To achieve the above objectives, the present invention provides a prefabricated ECC shell steel tube recycled concrete column, comprising a prefabricated ECC shell, a steel tube, recycled concrete, stirrups and longitudinal reinforcement; the prefabricated ECC shell uses an engineering cement-based composite material with an ultimate tensile strain far exceeding that of ordinary concrete; the stirrups and longitudinal reinforcement are connected and tied into a steel cage and placed inside the ECC shell; the recycled concrete is filled inside the steel tube.

[0007] Furthermore, the thickness of the prefabricated ECC shell is not less than 60 mm.

[0008] Furthermore, the thickness of the inner protective layer of the prefabricated ECC shell is not less than 20mm, and the thickness of the outer protective layer of the steel bars is not less than 20mm.

[0009] Furthermore, the thickness of the inner protective layer of the reinforcing bars of the ECC shell is the minimum distance between the inner side of the longitudinal reinforcement and the outer wall of the steel pipe, and the thickness of the outer protective layer of the reinforcing bars is the minimum distance between the outer side of the stirrup and the edge of the prefabricated ECC shell.

[0010] Furthermore, the prefabricated ECC shell is manufactured in the factory, cured, and then transported as a whole to the construction site.

[0011] Furthermore, the steel pipe serves as the inner template during the prefabrication of the ECC shell.

[0012] Furthermore, the prefabricated ECC shell has a circular or square cross-sectional shape.

[0013] Furthermore, the cross-sectional shape of the steel pipe is circular or square.

[0014] This invention also provides a construction method for a precast ECC-clad steel pipe recycled concrete column, comprising the following steps: Step 1, prefabrication of the component in the factory: first, tying stirrups and longitudinal bars to the outside of the steel pipe; then, setting up formwork outside the stirrups; and pouring ECC concrete between the outer formwork and the steel pipe. After the ECC shell has cured, the outer formwork is removed. Step 2, on-site construction: hoisting the precast ECC shell to the appropriate position; without setting up formwork again, directly pouring recycled concrete inside the steel pipe; and waiting for the internal recycled concrete to cure before proceeding with subsequent construction.

[0015] Compared with the prior art, the present invention has the following advantages: (1) This invention uses ECC material with an ultimate tensile strain far exceeding that of ordinary concrete as the outer shell, which solves the problem that the outer side of the column is most susceptible to tensile failure under large eccentric pressure, and fully utilizes the good tensile properties of ECC. (2) Recycled concrete is used inside the steel pipe. Waste concrete is crushed and processed to form recycled aggregate, which replaces natural aggregate, reduces the mining of natural sand and gravel resources, protects the ecological environment of aggregate production areas, and meets the needs of sustainable development. (3) The mechanical properties of the recycled concrete inside the steel pipe are improved by the constraint effect of the steel pipe, which effectively makes up for the mechanical defects of recycled concrete aggregate compared with natural aggregate, reduces the adverse effects of recycled aggregate, and organically combines the ecological requirements of green development and sustainable development with the mechanical performance requirements of improving the load-bearing capacity of buildings. (4) Factories can provide more convenient pouring equipment and more suitable curing conditions compared to construction sites. Prefabricating ECC shells in factories can ensure the quality of component construction while facilitating mass production, reducing a significant amount of manpower, material resources, and energy. The prefabricated shell form also eliminates the need for on-site formwork, greatly reducing the workload on the construction site. This not only improves construction efficiency and shortens the construction period but also reduces on-site construction noise, which is beneficial to environmental protection. Attached Figure Description

[0016] Figure 1 Cross-sectional view of a square steel tube column for a square ECC casing.

[0017] Figure 2 Cross-sectional view of a square ECC outer shell with a circular steel tube column.

[0018] Figure 3 Cross-sectional view of a square steel tube column with a circular ECC outer shell.

[0019] Figure 4 Cross-sectional view of a circular steel tube column housing a circular ECC.

[0020] In the diagram: 1-Precast ECC shell; 2-Longitudinal reinforcement; 3-Stirrups; 4-Steel pipe; 5-Recycled concrete Detailed Implementation

[0021] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the invention.

[0022] Example 1: The prefabricated ECC outer shell steel pipe recycled concrete column in this embodiment is as follows: Figure 1 As shown: Step 1: Factory Prefabrication. Square steel pipes (4) are used. Square stirrups (3) and longitudinal bars (2) are tied together to form a reinforcing cage on the outside of the steel pipes (4). The outer edge of the stirrups (3) is at least 20mm away from the edge of the prefabricated ECC shell (1), and the minimum distance between the inner edge of the longitudinal bars (2) and the outer wall of the steel pipe (4) is at least 20mm. Then, an outer formwork for the square ECC shell is erected outside the stirrups, and the steel pipes (4) are used as the inner formwork. The ECC shell is poured, and after curing, the outer formwork is removed. The steel pipes (4) do not need to be removed. Step 2: On-site Construction. The prefabricated ECC shell (1) and steel pipes (4) are transported to the construction site as a whole, hoisted into the appropriate position, and recycled concrete (5) is poured inside the steel pipes (4). After curing, subsequent construction is carried out.

[0023] Example 2: The prefabricated ECC outer shell steel pipe recycled concrete column in this embodiment is as follows: Figure 2 As shown: Step 1: Factory Prefabrication. The steel pipe 4 is a circular steel pipe. Square stirrups 3 and longitudinal bars 2 are tied together to form a reinforcing cage on the outside of the steel pipe 4. The outer edge of the stirrups 3 is at least 20mm away from the edge of the prefabricated ECC shell 1, and the minimum distance between the inner edge of the longitudinal bars 2 and the outer wall of the steel pipe 4 is at least 20mm. Then, an outer formwork for the square ECC shell is erected outside the stirrups, and the steel pipe 4 is used as its inner formwork. The ECC shell is poured, and after curing, the outer formwork is removed. The steel pipe 4 does not need to be removed. Step 2: On-site Construction. The prefabricated ECC shell 1 and steel pipe 4 are transported to the construction site as a whole, hoisted into the appropriate position, and recycled concrete 5 is poured inside the steel pipe 4. After curing, subsequent construction is carried out.

[0024] Example 3: The prefabricated ECC outer shell steel pipe recycled concrete column in this embodiment is as follows: Figure 3 As shown: Step 1: Factory Prefabrication. Square steel pipes (4) are used. Circular stirrups (3) and longitudinal reinforcement bars (2) are tied together to form a reinforcing cage around the steel pipes (4). The outer edge of the stirrups (3) is at least 20mm from the edge of the prefabricated ECC shell (1), and the inner edge of the longitudinal reinforcement bars (3) is at least 20mm from the outer wall of the steel pipe (4). Then, an outer formwork for the circular ECC shell is erected outside the stirrups, and the steel pipes (4) are used as the inner formwork. The ECC shell is poured, and after curing, the outer formwork is removed. The steel pipes (4) do not need to be removed. Step 2: On-site Construction. The prefabricated ECC shell (1) and steel pipes (4) are transported to the construction site as a whole, hoisted into the appropriate position, and recycled concrete (5) is poured inside the steel pipes (4). After curing, subsequent construction is carried out.

[0025] Example 4: The prefabricated ECC outer shell steel pipe recycled concrete column in this embodiment is as follows: Figure 4 As shown: Step 1: Factory Prefabrication. The steel pipe 4 is a circular steel pipe. Circular stirrups 3 and longitudinal reinforcement 2 are tied together to form a reinforcing cage on the outside of the steel pipe 4. The outer edge of the stirrups 3 is at least 20mm away from the edge of the prefabricated ECC shell 1, and the minimum distance between the inner edge of the longitudinal reinforcement 2 and the outer wall of the steel pipe 4 is at least 20mm. Then, an outer formwork for the circular ECC shell is erected outside the stirrups, and the steel pipe 4 is used as its inner formwork. The ECC shell is poured, and after curing, the outer formwork is removed. The steel pipe 4 does not need to be removed. Step 2: On-site Construction. The prefabricated ECC shell 1 and steel pipe 4 are transported to the construction site as a whole, hoisted into the appropriate position, and recycled concrete 5 is poured inside the steel pipe 4. After curing, subsequent construction proceeds.

[0026] The above-described specific embodiments are merely illustrative of the examples of the present invention and are not intended to limit the scope of the invention. Those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, and any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A prefabricated ECC-coated steel tube recycled concrete column, characterized in that, It includes a precast ECC shell (1), a steel pipe (4), recycled concrete (5), stirrups (3) and longitudinal reinforcement (2); the material used for the precast ECC shell (1) is an engineering cement-based composite material (ECC) with an ultimate tensile strain far exceeding that of ordinary concrete; the stirrups (3) and longitudinal reinforcement (2) are linked and tied into a steel cage and placed inside the ECC shell; the recycled concrete (5) is filled inside the steel pipe.

2. A prefabricated ECC-shell steel pipe recycled concrete column according to claim 1, characterized in that, The thickness of the prefabricated ECC shell (1) is not less than 60 mm.

3. A prefabricated ECC-shell steel tube recycled concrete column according to claim 1, characterized in that, The thickness of the inner protective layer of the prefabricated ECC shell (1) is not less than 20 mm, and the thickness of the outer protective layer of the steel bars is not less than 20 mm.

4. A prefabricated ECC-shell steel tube recycled concrete column according to claim 3, characterized in that, The thickness of the inner protective layer of the reinforcing bars of the ECC shell (1) is the minimum distance between the inner side of the longitudinal reinforcement (2) and the outer wall of the steel pipe, and the thickness of the outer protective layer of the reinforcing bars is the minimum distance between the outer side of the stirrup (3) and the edge of the prefabricated ECC shell (1).

5. A prefabricated ECC-shell steel pipe recycled concrete column according to claim 1, characterized in that, The prefabricated ECC shell (1) is manufactured in the factory and transported to the construction site after curing.

6. A prefabricated ECC-shell steel tube recycled concrete column according to claim 1, characterized in that, The steel pipe (4) serves as the inner template during the prefabrication of the ECC shell.

7. A prefabricated ECC-shell steel tube recycled concrete column according to claim 1, characterized in that, The prefabricated ECC shell (1) has a circular or square cross-sectional shape.

8. A prefabricated ECC-shell steel tube recycled concrete column according to claim 1, characterized in that, The steel pipe (4) has a circular or square cross-section.

9. A construction method for a precast ECC-shell steel pipe recycled concrete column, characterized in that, Includes the following steps: Step 1: Factory prefabrication of components. First, tie the stirrups (3) and longitudinal bars (2) to the outside of the steel pipe (4). Then, set up the formwork outside the stirrups and use ECC to pour concrete between the outer formwork and the steel pipe. After the ECC shell is cured, remove the outer formwork. Step 2: On-site construction. Hoist the prefabricated ECC shell (1) to the corresponding position. There is no need to set up the formwork again. Pour recycled concrete (5) directly into the steel pipe (4). After the internal recycled concrete is cured, the subsequent construction can be carried out.

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