Standardized fabricated concrete square tube composite column with tie rods and connecting joint

Abstract

The application discloses a standardized assembly type concrete square tube composite column with a constraint pull rod and a connecting joint, which comprises a prefabricated square tube, connecting steel bars, a constraint pull rod and concrete. The connecting steel bars are arranged on the upper part and the lower part of the prefabricated square tube in a vertical direction along a pouring core area of the prefabricated square tube or are arranged along the whole length of the prefabricated square tube. The end of the connecting steel bars extends out of the prefabricated square tube. The constraint pull rod is arranged in a plastic hinge area of the column body. The constraint pull rod is fixed on the side wall of the pouring core area of the prefabricated square tube at both ends. The concrete is poured in the pouring core area of the prefabricated square tube. The constraint pull rod is arranged in the plastic hinge area, and the constraint pull rod can effectively constrain the pouring core area concrete and the connecting steel bars, which is helpful to improve the bearing capacity, plastic deformation capacity and ductility and other stress performance of the square tube composite column. The standardized assembly type concrete square tube composite column with the constraint pull rod is formed by pouring the concrete on site. By adjusting the grade of the connecting steel bars and the pouring core concrete, the concrete square tube composite column can be applied to different axial forces and bending moments, and the standard prefabricated column can be selected.

Description

Technical Field

[0001] This invention belongs to the field of prefabricated concrete building structure technology, specifically involving a standardized prefabricated concrete square tube composite column with restraint tie rods and its connection nodes. Background Technology

[0002] Article 3.0.3 of the current national standard "Evaluation Standard for Prefabricated Buildings" (GB / T51129-2017) stipulates that prefabricated buildings should meet the requirement that the evaluation score of the main structure should not be less than 20 points. In the prefabricated building scoring table, the main structure has a full score of 50 points. Vertical components such as columns, supports, load-bearing walls, and ductile wall panels should account for 35%–80% of the total structure, earning 20–30 points. Components such as beams, slabs, stairs, balconies, and air conditioning panels should account for 70%–80%, earning 10–20 points. If vertical components are not prefabricated, the proportion of beams, slabs, stairs, balconies, and air conditioning panels must reach 80%. Due to the complexity of the project, this would pose significant difficulties in disassembling the components. Therefore, prefabricating vertical components is an effective method to solve the difficulty of disassembling prefabricated components.

[0003] Over the years, the development of prefabricated buildings, from steel structures to prefabricated concrete structures, has been slow. The market size is still insufficient, and factors such as low standardization, weak integration between design and production, and immature construction team technology have hindered the realization of the cost advantages of prefabricated buildings. Costs are generally 200-500 yuan / m² higher than traditional construction methods. 2 Currently, precast columns are the main vertical components used in prefabricated buildings. The design of precast components should adhere to the principles of standardization and modularization, minimizing the number of component types, increasing standardization, and reducing costs. However, in actual engineering projects, due to the complexity and uncertainty of the projects, the selection of precast column specifications cannot currently be standardized. Each column must be custom-made for a specific project, leading to excessively high costs. Furthermore, the heavy weight of precast columns makes hoisting difficult. Therefore, there is an urgent need to explore a new approach to develop universal, standardized precast column products that can reduce costs and increase standardization while employing prefabricated technology. Summary of the Invention

[0004] The first objective of this invention is to provide a standardized prefabricated concrete square tube composite column with restraint rods, which features simple production process, convenient transportation and construction, high installation error tolerance, high construction efficiency, reduced construction costs, improved standardization, energy saving and environmental protection, and good seismic performance.

[0005] The first objective of this invention is achieved through the following technical solution: a standardized prefabricated concrete square tube composite column with restraining tie rods, characterized in that it comprises prefabricated square tubes, connecting steel bars, restraining tie rods, and concrete. The connecting steel bars are vertically arranged along the core-filling area of ​​the prefabricated square tube at its upper and lower parts or along its entire length, and the connecting steel bars extend out of the end of the prefabricated square tube. The restraining tie rods are arranged in the plastic hinge area of ​​the column, and the two ends of the restraining tie rods are fixed to the side wall of the core-filling area of ​​the prefabricated square tube. The concrete is poured into the core-filling area of ​​the prefabricated square tube.

[0006] Compared to ordinary precast columns, this invention eliminates the need for specialized precast columns designed for different axial forces and bending moments. Standardized precast square tubes can be directly selected, and connecting steel bars of equal or unequal diameter, quantity, and length are configured in the core-filling area according to the column's stress calculations. Typically, the internal forces are greatest at the column top and bottom, while the bending moments near or close to the column center are smaller. In this case, the inflection point is at or near the column center. Therefore, connecting steel bars are configured within a certain range at the column top and bottom according to stress requirements, forming a connecting area. Areas without connecting steel bars are unconnected areas. If calculations require connection in this area, the connecting steel bars should extend into the unconnected area, forming a connected steel bar area. Under stress, the precast square tube's own steel bars and the connecting steel bars jointly bear the load under compressive stress. Tensile forces or bending moments generated at the column ends are borne by the connecting steel bars. Furthermore, according to the stress principle, the bending moment in areas without connecting steel bars is usually smaller and can therefore be borne by the precast square tube's own steel bars. This invention incorporates restraint rods in the plastic hinge zone. The number and spacing of these restraint rods are determined by calculation. These restraint rods effectively constrain the concrete in the core-filling zone and the connecting reinforcing bars, thus improving the load-bearing capacity, plastic deformation capacity, and ductility of the square tube composite column. Standardized prefabricated concrete square tube composite columns with restraint rods are constructed by casting concrete on-site. By adjusting the connecting reinforcing bars and the grade of the core-filling concrete, the concrete square tube composite columns can be adapted to different axial forces and bending moments, enabling the selection of standard precast columns.

[0007] The prefabricated square tube of the present invention is produced in a factory using concrete and steel reinforcement.

[0008] The constraint tie rods described in this invention are several horizontal tie rods and / or longitudinal tie rods arranged horizontally.

[0009] The connecting reinforcement bars of this invention are steel cages made of stirrups and longitudinal bars, and the restraining tie rods pass through the steel cages. The configuration of the connecting reinforcement bars can be calculated and determined according to the actual stress of the project, with equal or unequal diameters, quantities, and lengths, so that the precast concrete square tube composite columns can be used to standardize the precast column cross-section under different axial forces and bending moments.

[0010] In this invention, the stirrups in the plastic hinge zone of the connecting steel bars are densified, and the spacing of the stirrups near the column end in the plastic hinge zone is smaller than the spacing of the stirrups farther from the column end. The area where the plastic hinge is formed is the connecting plastic hinge zone, where the stirrups are densified and restraint rods are provided. The remaining connecting area is the connecting steel bar extension zone, where the stirrups are not densified, and the longitudinal reinforcement should meet the anchorage requirements.

[0011] The precast square tube of this invention has several pairs of through T-shaped connecting holes on its side wall. Two T-shaped connecting holes in each pair are positioned opposite each other. Both ends of each restraint rod are inserted into a pair of T-shaped connecting holes. The length of the restraint rod is 5mm to 10mm smaller than the width of the precast square tube. The T-shaped connecting holes are filled with concrete, and the grooves are sealed and smoothed. After the connecting steel bars are installed, the restraint rods are installed at the grooved connecting holes. The restraint rods are not exposed outside the column. After the restraint rods are assembled, the grooves are sealed with concrete and smoothed.

[0012] The precast square tube of this invention has a groove on its outer wall, and the T-shaped connecting hole extends into the groove. A steel plate is embedded in the groove, and the steel plate is connected to the end of the restraining tie rod. Mortar is applied to the outer surface of the steel plate and smoothed out. This invention uses a steel plate as a hoop around the column base to strengthen the plastic hinge area of ​​the square tube composite column, which can improve the compressive deformation resistance of the concrete.

[0013] The concrete used for the precast square tubes described in this invention is ordinary concrete, high-strength concrete, or high-performance concrete.

[0014] The cross-section of the core-filling area of ​​the prefabricated square tube described in this invention is rectangular or circular.

[0015] The second objective of this invention is to provide a connection node for the aforementioned standardized prefabricated concrete square tube composite column with constraint tie rods.

[0016] The second objective of this invention is achieved through the following technical solution: a connection node for the aforementioned standardized prefabricated concrete square tube composite column with restraint rods, characterized in that it comprises an upper standardized prefabricated concrete square tube composite column with restraint rods, a lower standardized prefabricated concrete square tube composite column with restraint rods, and a structural beam / slab. The area between the upper and lower standardized prefabricated concrete square tube composite columns with restraint rods and the structural beam / slab is a node area. The connecting steel bars of the upper standardized prefabricated concrete square tube composite column with restraint rods pass downward through the node area and extend into the lower standardized prefabricated concrete square tube composite column with restraint rods to become connecting steel bars therein. The concrete of the upper and lower standardized prefabricated concrete square tube composite columns with restraint rods and the concrete of the node area are poured in one go.

[0017] On the one hand, this invention eliminates the need for grouting sleeve connections during construction, solving the grouting quality problem. The connection structure is simple, requiring less technical expertise, and the construction process is straightforward and convenient, accelerating construction progress, saving formwork, and reducing construction costs. On the other hand, the precast square tubes are lightweight, solving the problem of component weight and facilitating hoisting. This invention can use precast square tubes with a uniform cross-section according to actual needs, achieving standardization by adjusting the configuration of connecting steel bars. Furthermore, it allows for the selection of grouting materials or concrete of any strength for pouring as needed. Therefore, this invention has a wide range of applications and is suitable for widespread promotion and use.

[0018] The structural beam described in this invention is a precast beam, a cast-in-place beam, or a composite beam.

[0019] The cross-sectional shape of the node area described in this invention can be rectangular, rhomboid, or circular, or other shapes can be adopted according to actual engineering needs, making it flexible and convenient for actual installation and operation.

[0020] The standardized prefabricated concrete square tube composite column with upper restraint tie rod described in this invention has a grouting layer between the lower end and the node area, and the grouting layer is filled with C60 grouting material or injection grout.

[0021] The cross-section of the node region in this invention is larger than the cross-section of the standardized prefabricated concrete square tube composite column with restraint rods, and the cross-sectional shape of the node region is rectangular, rhomboid, or circular; or the cross-section of the node region is the same size as the cross-section of the standardized prefabricated concrete square tube composite column with restraint rods.

[0022] The connection node described in this invention forms a connection structure with the frame, diagonal brace, or shear wall.

[0023] Compared with the prior art, the present invention has the following significant effects:

[0024] (1) The node connection method of the present invention is simple to operate, does not require the use of grouting sleeve connection, solves the grouting quality problem, has low requirements for construction technology, simple construction procedures, and is convenient to construct, which can speed up the construction progress, save formwork, save energy and protect the environment, and reduce construction costs. On the other hand, the prefabricated square tube is lightweight, which solves the problem of the component's self-weight and makes hoisting more convenient.

[0025] (2) The upper end of the concrete square tube composite column of the present invention is rigidly connected to the structural beam, and the lower end is rigidly connected to the structural beam. The precast square tube itself has a certain vertical bearing capacity and bending resistance. The force of the entire column is borne by the precast square tube and the connecting steel bars in the core area. In the column with a small bending moment, when the force is satisfied, the connecting steel bars do not extend into it, and the precast square tube itself resists the bending moment. In the range of large internal forces at the top and bottom of the column, the connecting steel bars are configured to resist the bending moment together.

[0026] (3) The constraint tie rod of the present invention can effectively constrain the concrete and connecting steel bars in the core grouting area, which helps to improve the load-bearing capacity, plastic deformation capacity and ductility of the square tube composite column.

[0027] (4) The present invention uses steel plates as hoops around the column base to strengthen the plastic hinge area of ​​the square tube composite column, which can improve the compressive deformation resistance of concrete.

[0028] (5) According to different seismic resistance levels and reinforcement ratio requirements, the same building or the same floor can select standard precast square tubes. The stress can be met by adjusting the diameter, quantity, length of the connecting steel bars and the strength grade of the core grouting area. Compared with ordinary precast columns, it is not necessary to produce precast columns according to different axial forces and bending moments, and it is impossible to select precast columns of uniform specifications to form a standardized precast column. Therefore, the present invention can achieve standardization, thereby reducing the cost.

[0029] (6) According to the different bearing capacities of the nodes in this invention, the area is appropriately enlarged to enhance the bearing capacity of the nodes, reduce the possibility of node failure, and realize strong nodes and weak components; the concrete strength grades of the node area, structural beams and upper and lower precast concrete square tube composite column core grouting areas can be the same or different, and can be poured in the same batch or in batches depending on whether they are the same or different.

[0030] (7) The precast square tube part of the present invention forms a standard product. The precast square tube can be formed into a series of standard products such as 500×500×80mm, 600×600×80mm, 700×700×100mm, 800×800×100mm, and 1000×1000×100mm of C60 concrete or other grades of concrete according to the reinforcement ratio required by the seismic grade. Attached Figure Description

[0031] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0032] Figure 1 This is an axial cross-sectional view of the connection node in Embodiment 1 of the present invention;

[0033] Figure 2 This is a cross-sectional schematic diagram of the connection node in Embodiment 1 of the present invention;

[0034] Figure 3 This is an axial cross-sectional view of the prefabricated concrete square tube composite column of Embodiment 1 of the present invention;

[0035] Figure 4 This is a schematic cross-sectional view of the prefabricated concrete square tube composite column according to Embodiment 1 of the present invention;

[0036] Figure 5This is a schematic cross-sectional view of the prefabricated concrete square tube composite column according to Embodiment 2 of the present invention;

[0037] Figure 6 This is an axial cross-sectional view of the prefabricated concrete square tube composite column of Embodiment 3 of the present invention;

[0038] Figure 7 This is a schematic cross-sectional view of the prefabricated concrete square tube composite column according to Embodiment 3 of the present invention;

[0039] Figure 8 This is a schematic cross-sectional view of the prefabricated concrete square tube composite column of Embodiment 4 of the present invention. Detailed Implementation

[0040] Example 1

[0041] like Figure 3 , 4 The diagram illustrates a standardized prefabricated concrete square tube composite column with restraining tie rods according to the present invention. It includes a prefabricated square tube 2, connecting reinforcing bars, restraining tie rods 7, and concrete. In this embodiment, the connecting reinforcing bars are vertically arranged along the core-filling area of ​​the prefabricated square tube 2 at its upper and lower parts, with no connecting reinforcing bars in the middle of the column. In other embodiments, the connecting reinforcing bars can be arranged along the entire length of the core-filling area of ​​the prefabricated square tube. The connecting reinforcing bars extend beyond the end of the prefabricated square tube 2. The restraining tie rods 7 are located in the plastic hinge area of ​​the column, with both ends fixed to the sidewalls of the core-filling area of ​​the prefabricated square tube 2. Concrete is poured into the core-filling area of ​​the prefabricated square tube 2. The cross-section of the core-filling area can be rectangular or circular. The type of concrete poured is determined according to the stress and can be of the same or different grade as the beam / slab.

[0042] In this embodiment, the standardized prefabricated concrete square tube composite column with restraint rods has a rectangular cross-section. The prefabricated square tube 2 is rectangular, and the core-filling area has a rectangular cross-section. The prefabricated square tube 2 is manufactured in a prefabrication plant by pouring concrete using stirrups 4 and longitudinal reinforcement 3. The concrete used for the prefabricated square tube can be ordinary concrete, high-strength concrete, or high-performance concrete. Standardized prefabricated square tubes can be mass-produced. The prefabricated square tube 2 can be formed into a series of products such as 500×500×80mm, 600×600×80mm, 700×700×80mm, 800×800×100mm, and 1000×1000×100mm of C60 concrete according to the reinforcement ratio required by the seismic grade. As market demand increases, it can be gradually expanded to a series of products with different grades (C30, C40, C50) and different wall thicknesses. The uniformly sized prefabricated square tubes have a certain vertical load-bearing capacity and bending resistance, and can be mass-produced.

[0043] In this embodiment, the constraint tie rods are several horizontally arranged longitudinal tie rods. In other embodiments, the constraint tie rods can also be transverse tie rods. Several pairs of through T-shaped connecting holes 13 are provided on the side wall of the precast square tube 2. Two T-shaped connecting holes 13 in each pair are arranged opposite each other. Both ends of each constraint tie rod 7 are inserted into a pair of T-shaped connecting holes 13. The length of the constraint tie rod is 5mm to 10mm smaller than the width of the precast square tube. The T-shaped connecting holes 13 are filled with concrete, and the grooves are sealed and smoothed. Depending on the stress requirements, the T-shaped connecting holes can be arranged in both the longitudinal and transverse directions of the column, or they can be arranged in one direction, with several holes spaced at certain intervals.

[0044] The connecting reinforcement is a steel cage made of stirrups 6 and longitudinal bars 5, and the restraint rod 7 passes through the steel cage.

[0045] In the plastic hinge zone, the stirrups of the connecting reinforcement are densified, and within the plastic hinge zone, the spacing of the stirrups near the column end is smaller than that of the stirrups farther from the column end. Specifically, the reinforcement (connecting reinforcement and restraint rods) is set in four zones: Zone 1 is the area near the column end of the plastic hinge zone where the stirrups are densified and restraint rods are installed, forming a densified zone; Zone 2 is the area far from the column end of the plastic hinge zone where the stirrup spacing can be appropriately widened, forming a stirrup decreasing zone; Zone 3 is the area where the length of the connecting reinforcement exceeds the plastic hinge zone, forming a connecting reinforcement extension zone, where the stirrups are not densified; Zone 4 is the area in the middle of the precast concrete square tube composite column where the bending moment is small, and according to calculations, the connecting reinforcement does not need to extend into the middle, forming a zone without connecting reinforcement. If calculations require it, it is a zone with connecting reinforcement.

[0046] like Figure 1 , 2As shown, a connection node for a standardized prefabricated concrete square tube composite column with restraint rods includes an upper standardized prefabricated concrete square tube composite column 8 with restraint rods, a lower standardized prefabricated concrete square tube composite column 9 with restraint rods, and a structural beam 12. Both the upper and lower standardized prefabricated concrete square tube composite columns 8 and 9 are constructed by setting connecting steel bars and restraint rods 7 within the core-filling area of ​​the precast square tube 2 and then pouring concrete 10. The node area 11 is between column 9 and structural beam 12. The connecting steel bars of the upper-layer standardized prefabricated concrete square tube composite column 8 with restraint rods pass downward through the node area 11 and extend into the lower-layer standardized prefabricated concrete square tube composite column 9 with restraint rods to become the connecting steel bars therein. T-shaped connection holes 13 are reserved on the wall of the prefabricated square tube 2. The restraint rods 7 are installed in the T-shaped connection holes 13 and concrete is poured to seal the groove of the T-shaped connection holes 13 near the outer wall of the tube. The concrete of the upper-layer standardized prefabricated concrete square tube composite column 8 with restraint rods, the lower-layer standardized prefabricated concrete square tube composite column 9 with restraint rods, and the concrete of the node area 11 are poured at one time.

[0047] The concrete in the core grouting area can be selected with different strength grades by controlling the axial compression ratio. By adjusting the strength grades of the connecting steel bars and the core grouting concrete, the standardized precast concrete square tube composite column with restraint rods can be adapted to different axial forces and bending moments to standardize the precast column section.

[0048] The concrete strength grades of the joint area, structural beams, and the core grouting areas of the standardized prefabricated concrete square tube composite columns with restraint rods in the upper and lower layers can be the same or different, and can be poured in the same batch or in batches depending on whether they are the same or different.

[0049] The connecting steel bars of the upper-layer standardized prefabricated concrete square tube composite column 8 with restraint rods and the lower-layer standardized prefabricated concrete square tube composite column 9 with restraint rods are located at the upper and lower parts of their column bodies. The connecting steel bars of the upper part extend upward to the top of the column, and the connecting steel bars of the lower part extend downward to the bottom of the column. However, there are no connecting steel bars in the middle of the column body. That is, the connecting steel bars of the upper and lower-layer standardized prefabricated concrete square tube composite columns with restraint rods are not set along the entire length. There is no connecting steel bar in a certain range in the middle of the column body of the standardized prefabricated concrete square tube composite column with restraint rods. This makes the lower end of the upper-layer standardized prefabricated concrete square tube composite column 8 with restraint rods semi-rigidly connected or hinged to the structural beam 12, and the upper end of the lower-layer standardized prefabricated concrete square tube composite column 9 with restraint rods rigidly connected to the structural beam 12.

[0050] The connecting reinforcement is a steel cage made of stirrups 6 and longitudinal bars 5. The configuration of the connecting reinforcement can be calculated and determined according to the actual stress of the project, and the diameter, quantity and length can be equal or different, so that the precast concrete square tube composite column can be used to control different axial forces and bending moments and standardize the precast column section.

[0051] The cross-section of the node area is larger than the cross-section of the standardized prefabricated concrete square tube composite column with restraint rods, and the cross-sectional shape of the node area is rectangular, rhomboid, or circular; or the cross-section of the node area is the same size as the cross-section of the standardized prefabricated concrete square tube composite column with restraint rods.

[0052] In this embodiment, the structural beam is a precast beam, a cast-in-place beam, or a composite beam. When the structural beam is a cast-in-place beam or a composite beam, a grouting layer 14 is provided between the lower end of the upper-layer standardized prefabricated concrete square tube composite column 8 with restraint tie rod and the node area 11. The grouting layer is filled with C60 grouting material or injection grout.

[0053] Example 2

[0054] like Figure 5 As shown, the difference between this embodiment and embodiment 1 is that the constraint rod 7 consists of several horizontal and vertical tie rods arranged horizontally and intersecting each other perpendicularly.

[0055] Example 3

[0056] like Figure 6 , 7 As shown, the difference between this embodiment and embodiment 1 is that: when producing precast square tubes, a groove with a depth of 5mm is reserved on the opposite sides of the outer wall of the plastic hinge area of ​​the precast square tube 2, and the T-shaped connecting hole extends into the groove. A steel plate 15 is embedded in the groove, and the constraint tie rod 7 passes through the core filling area and is connected and fixed to the steel plate 15 through the connecting hole. After assembly and fixing, mortar 16 is applied to the outer plate surface of the steel plate 15 and smoothed.

[0057] Example 4

[0058] like Figure 8 As shown, the difference between this embodiment and embodiment 3 is that a groove with a depth of 5mm is reserved around the outer and inner walls of the plastic hinge area of ​​the prefabricated square tube, and the T-shaped connecting hole extends into the groove. A steel plate 15 is embedded in the groove, and the constraint tie rod 7 passes through the core filling area and is connected and fixed to the steel plate 15 through the connecting hole. After assembly and fixing, mortar 16 is applied to the outer plate surface of the steel plate 15 and smoothed.

[0059] The constraint rod 7 consists of several horizontal and longitudinal tie rods arranged horizontally and perpendicularly to each other.

[0060] The connection node of this invention can form a connection structure with other ordinary frames, diagonal braces, and shear walls.

[0061] In other embodiments, the core filling area of ​​the prefabricated square tube has a circular cross-section.

[0062] In other embodiments, the construction method for the connection nodes of the upper-layer standardized prefabricated concrete square tube composite column with restraint rods, the lower-layer standardized prefabricated concrete square tube composite column with restraint rods, and the slab of the slab-column structure is similar to that for cast-in-place structural beams. The node areas are all cast in place, and the specific steps can be adjusted according to the actual site conditions and the different types of structural beams.

[0063] The embodiments of the present invention are not limited thereto. Based on the above description of the present invention, and in accordance with common technical knowledge and conventional means in the field, the present invention can be modified, replaced or altered in various other forms without departing from the basic technical concept of the present invention, and all such modifications or alterations fall within the scope of protection of the present invention.

Claims

1. A standardized prefabricated concrete square tube composite column with restraining tie rods, characterized in that: It comprises a precast square tube, connecting steel bars, restraining tie rods, and concrete. The precast square tube is fabricated by pouring concrete using stirrups and longitudinal reinforcement. The connecting steel bars are vertically arranged at the top and bottom or along the entire length of the grouting area of ​​the precast square tube, extending beyond the end of the tube. The restraining tie rods are located in the plastic hinge area of ​​the column, with both ends fixed to the sidewall of the grouting area of ​​the precast square tube. The concrete is poured into the grouting area of ​​the precast square tube. Several pairs of through T-shaped connecting holes are provided on the sidewall of the precast square tube, with two T-shaped connecting holes in each pair facing each other. A pair of T-shaped connecting holes are inserted into both ends of each restraining tie rod. In the T-shaped connection hole, the length of the restraining tie rod is 5mm to 10mm smaller than the width of the precast square tube. The T-shaped connection hole is filled with concrete and the groove is sealed and smoothed. The connecting reinforcement is a steel cage made of stirrups and longitudinal bars. The restraining tie rod passes through the steel cage. The stirrups of the connecting reinforcement in the plastic hinge zone are denser, and the spacing of the stirrups near the column end in the plastic hinge zone is smaller than the spacing of the stirrups away from the column end. A groove is opened on the outer wall of the precast square tube. The T-shaped connection hole extends into the groove. A steel plate is pre-embedded in the groove. The steel plate is connected to the end of the restraining tie rod, and mortar is applied to the outer surface of the steel plate and smoothed.

2. The standardized prefabricated concrete square tube composite column with restraining tie rod according to claim 1, characterized in that: The constraint tie rods are several horizontal tie rods and / or longitudinal tie rods arranged horizontally.

3. A connection node for a standardized prefabricated concrete square tube composite column with a restraining tie rod according to claim 1 or 2, characterized in that: It comprises an upper layer of standardized prefabricated concrete square tube composite columns with restraint rods, a lower layer of standardized prefabricated concrete square tube composite columns with restraint rods, and structural beams / slabs. The area between the upper and lower layers of standardized prefabricated concrete square tube composite columns with restraint rods and the structural beams / slabs is a node area. The connecting steel bars of the upper layer of standardized prefabricated concrete square tube composite columns with restraint rods pass downward through the node area and extend into the lower layer of standardized prefabricated concrete square tube composite columns with restraint rods to become connecting steel bars therein. The core concrete and node area concrete of the upper and lower layers of standardized prefabricated concrete square tube composite columns with restraint rods are poured in one go.

4. The connection node according to claim 3, characterized in that: The structural beams are precast beams, cast-in-place beams, or composite beams.

5. The connection node according to claim 4, characterized in that: The lower end of the standardized prefabricated concrete square tube composite column with restraint rods in the upper layer is provided with a grouting layer between the node area and the grouting layer, which is filled with C60 grouting material or injection grout.

6. The connection node according to claim 5, characterized in that: The cross-section of the node area is larger than the cross-section of the standardized prefabricated concrete square tube composite column with restraint rods, and the cross-sectional shape of the node area is rectangular, rhomboid, or circular; or the cross-section of the node area is the same size as the cross-section of the standardized prefabricated concrete square tube composite column with restraint rods.

7. The connection node according to claim 6, characterized in that: The connection nodes form a connection structure with the frame, diagonal bracing, or shear wall.

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