Low-damage self-resetting concrete column foot connecting joint structure and construction method

Abstract

The invention discloses a low-damage self-resetting concrete column foot connecting joint structure and a construction method, the low-damage self-resetting concrete column foot connecting joint structure comprises a concrete foundation, a low-damage prefabricated concrete frame column, a prestressed steel strand and a low-yield-point energy-consuming reinforcing steel bar, the prestressed steel strand penetrates through the concrete foundation and the low-damage prefabricated concrete frame column and is tensioned and anchored; the concrete foundation and the low-damage prefabricated concrete frame columns are connected; the low-yield-point energy-consuming steel bars are pre-buried at the bottoms of the low-damage prefabricated concrete frame columns; the problems that in an existing multi-layer self-resetting concrete bottom layer column foot connecting joint, column bottom concrete is seriously damaged by pressure under the action of a high axial compression ratio and in a large deformation state, and resetting after an earthquake is affected are solved, meanwhile, the energy dissipation capacity of a component is improved by combining the energy dissipation steel bars, damage and residual deformation of the concrete at the end of the component under the action of the earthquake are reduced, and the energy dissipation performance is improved. And the repairable performance of the structure is improved.

Description

Technical Field

[0001] The invention relates to the technical field of civil engineering, and in particular to a low-damage self-resetting concrete column foot connection node structure and a construction method. Background Art

[0002] Reinforced concrete frames are currently an important form of structural load-bearing and lateral force resistance. However, actual earthquakes have shown that although traditional concrete frame structures designed according to specifications have basically ensured the safety of people's lives after the earthquake, a large number of the bottom columns of the structure still suffered unexpected damage. They were difficult to repair after the earthquake and had to be demolished and rebuilt, which not only caused huge economic losses, but also seriously affected the stability and development of the city after the earthquake.

[0003] The bottom column of the concrete frame is the position that is prone to damage in an actual earthquake. The deformation is concentrated at the bottom of the column and the open part of the beam-column node by prestressing the precast column and the foundation, and the precast beam-column node, and an additional damper is set here to dissipate the seismic energy. This is the working principle of the self-resetting structure. At present, the anti-damage measures adopted by the self-resetting concrete frame node are mainly the following: First, spiral stirrups or steel mesh are set at the end of the precast component, and a fiber concrete cushion is set between the contact interface to increase the local pressure capacity of the concrete; second, steel plates or top and bottom angle steels are set at the end of the precast component to form a steel-steel contact surface, and the longitudinal reinforcement of the component is welded to the steel plate to bear the pressure together; third, the stirrups are increased at the end of the precast component or steel boots are used to form constrained concrete, or the top and bottom friction devices are used to constrain the concrete to improve its deformation capacity; fourth, the damper and the component are connected by special steel plates at the end of the precast component, which can protect the contact surface and dissipate energy.

[0004] For multi-story frames, the bottom column foot bears the self-weight of the entire structure, and the axial compression ratio is often large. Under the action of an earthquake, the depth of the column foot compression zone is large, the nonlinear compressive strain of the edge concrete is large, and the column foot concrete is severely crushed, which often loses its repair value after an earthquake and even threatens life safety. Therefore, the concrete at the bottom of the bottom column of the existing multi-story concrete frame is severely damaged under the action of an earthquake, which affects post-earthquake repair and even causes structural collapse. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a low-damage self-resetting concrete column foot connection node structure and construction method, which solves the technical problem that the bottom columns in the current traditional multi-story concrete frame are subjected to large axial pressure, and the concrete at the bottom of the column is easily compressed and damaged seriously under the action of an earthquake, which is difficult to repair after an earthquake and may even cause the structure to collapse. The proposed connection node structure has the advantages of low damage under earthquake action, simple construction, and easy post-earthquake reset and repair. It can further promote the development and application of self-resetting concrete frame structures and reduce the occurrence of serious damage to the bottom columns of traditional frames, which are difficult to repair or even collapse after an earthquake.

[0006] The technical solution of the present invention is as follows:

[0007] In a first aspect of the present invention, a low-damage self-resetting concrete column base connection node structure is provided, comprising a concrete foundation, a low-damage precast concrete frame column, a prestressed steel strand and a low-yield point energy-absorbing steel bar, wherein the prestressed steel strand passes through the concrete foundation and the low-damage precast concrete frame column and is tensioned and anchored to connect the concrete foundation and the low-damage precast concrete frame column; the low-yield point energy-absorbing steel bar is pre-buried at the bottom of the low-damage precast concrete frame column, and the low-yield point energy-absorbing steel bar connects the bottom of the low-damage precast concrete frame column to the top of the concrete foundation by means of embedded reinforcement; the bottom of the low-damage precast concrete frame column adopts steel fiber concrete.

[0008] In some embodiments of the present invention, steel fiber concrete is used in the range of 2 times the cross-section height at the bottom of the low-damage precast concrete frame column, and ordinary concrete of equal strength is used in the remaining parts.

[0009] In some embodiments of the present invention, the steel fiber concrete uses end hook type steel fibers, and the volume content of the steel fibers is 1.0%-2.0%.

[0010] In some embodiments of the present invention, prestressed tendon holes are reserved in the centers of the concrete foundation and the low-damage precast concrete frame columns to allow the prestressed steel strands to pass through the concrete foundation and the low-damage precast concrete frame columns.

[0011] In some embodiments of the present invention, the prestressed steel strands are provided in a non-bonded manner, the prestressed tendon ducts are not grouted, and the number of steel strands and the tensioning control stress are obtained by calculation.

[0012] In some embodiments of the present invention, a reserved channel for energy-absorbing steel bars is reserved at the top of the concrete foundation at a position corresponding to the low-yield point energy-absorbing steel bars, and the low-yield point energy-absorbing steel bars and the reserved channel for energy-absorbing steel bars are connected by anchor glue.

[0013] In some embodiments of the present invention, the bottom of the low-damage precast concrete frame column is treated with a steel fiber concrete mortar of a set thickness to form a steel fiber concrete mortar contact surface.

[0014] In some embodiments of the present invention, the low yield point energy-absorbing steel bars of the low-damage precast concrete frame column are ordinary hot-rolled steel bars with low yield point, and a non-bonded section is formed within 200 mm of the column bottom by wrapping with plastic cloth.

[0015] In some embodiments of the present invention, longitudinal bars and stirrups are arranged in the low-damage precast concrete frame column, and the longitudinal bars and stirrups are tied to form a steel cage.

[0016] In a second aspect of the present invention, a construction method of a low-damage self-resetting concrete column foot connection node structure is provided, comprising:

[0017] Prefabricated or cast-in-place concrete foundation, with reserved holes for prestressed tendons and energy-absorbing steel bars on the concrete foundation;

[0018] Low-damage precast concrete frame columns, in which prestressed reinforcement holes are reserved and low-yield point energy-absorbing steel bars are embedded;

[0019] A steel fiber concrete mortar treatment of a set thickness is performed at the bottom of the low-damage precast concrete frame column, and the low-damage precast concrete frame column is hoisted on the concrete foundation;

[0020] The prestressed steel strands pass through the concrete foundation and the low-damage precast concrete frame columns and are tensioned and anchored to connect the concrete foundation and the low-damage precast concrete frame columns.

[0021] One or more technical solutions of the present invention have the following beneficial effects:

[0022] (1) The low-damage self-resetting concrete column base connection node structure provided by the present invention has a prefabricated bottom column, which is connected to the foundation by a prestressed steel strand, and energy-absorbing steel bars with a low yield point are arranged between the column base and the foundation to dissipate the energy generated by the earthquake. In order to prevent the column base from being seriously damaged under the action of its own weight, prestress and reciprocating earthquake, steel fibers are added to the area of ​​the column base that is twice the cross-sectional height (≥ the nonlinear stress diffusion area of ​​the column base) to inhibit the development and accumulation of microcracks in the concrete and improve the compressive toughness, thereby reducing the degree of damage to the concrete at the column base and improving the self-resetting ability and repairability of the column base.

[0023] (2) The low-damage self-resetting concrete column base connection node structure provided by the present invention adopts steel fiber concrete at the bottom of the prefabricated column. By improving the compressive toughness of concrete, the crushing damage of the column base contact interface caused by the high axial pressure caused by the deadweight of the structure and prestress and the earthquake action is reduced, the reset ability of the structure is improved, and it is convenient for rapid post-earthquake repair. The construction is simple and fast. At the same time, energy-absorbing steel bars are used as additional dampers in combination with the steel fiber concrete column base. Only holes need to be reserved during foundation construction. The connection is made by planting steel bars. The node form is simple and the construction is easy to operate, which avoids large-scale steel structure operations and has lower costs.

[0024] (3) The low-damage self-resetting concrete column base connection node structure provided by the present invention adopts steel fiber mortar as the mortar at the bottom of the column to enhance the bonding force between the foundation concrete and the fiber concrete at the bottom of the column, thereby transmitting the shear force at the bottom of the column and avoiding the need to set up additional shear-resistant connectors.

[0025] (4) The low-damage self-resetting concrete column base connection node structure provided by the present invention uses steel fiber concrete at the bottom of the column to reduce contact interface damage, sets energy-absorbing steel bars to dissipate seismic energy, and lays fiber mortar to transmit shear force, which greatly simplifies the form of the self-resetting column base node and is more convenient for engineering construction and application.

[0026] (5) The present invention solves the problem that in the existing multi-layer self-resetting concrete bottom column foot connection nodes, the concrete at the bottom of the column is severely damaged under high axial compression ratio (caused by prestress, structural deadweight and horizontal earthquake action) and large deformation state (caused by earthquake action), which affects the post-earthquake reset. At the same time, the present invention combines energy-absorbing steel bars to improve the energy absorption capacity of the components, reduce the damage and residual deformation of the concrete at the ends of the components under earthquake action, and improve the structural repairability.

[0027] (6) The present invention is applicable to the connection between the column foot and the foundation when the building has many floors and the axial pressure of the bottom column is relatively large due to gravity; the bottom column foot connection method can be applied to a self-resetting frame in which both the beam column and the foundation adopt a self-resetting connection form, and can also be used for a bottom self-resetting frame in which only the bottom column adopts a self-resetting form and the other floors adopt a traditional beam-column rigid connection form. When used for the bottom self-resetting frame, the self-resetting force can be provided only by the deadweight according to calculation, without setting prestressed tendons. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the low-damage self-resetting concrete column foot connection node structure of the present invention;

[0029] Figure 2 for Figure 1 Sectional view at AA in the middle;

[0030] Figure 3 for Figure 1 Cross-section at the middle BB;

[0031] Figure 4 for Figure 1 Sectional view at CC;

[0032] Figure 5 The position of the low-damage self-resetting concrete column foot connection node structure of the present invention in the multi-layer self-resetting frame;

[0033] Figure 6 It is the position of the low-damage self-resetting concrete column foot connection node structure of the present invention in the bottom self-resetting frame.

[0034] In the figure: Ⅰ. Concrete foundation; Ⅱ. Low-damage precast concrete frame column; 1. Steel fiber concrete area; 2. Ordinary concrete area; 3. Prestressed steel strand; 4. Low yield point energy-absorbing steel bars; 5. Prestressed tendon anchor; 6. Steel fiber concrete mortar contact surface; 7. Longitudinal bars; 8. Stirrups; 9. Prestressed tendon channels; 10. Reserved channels for energy-absorbing steel bars. DETAILED DESCRIPTION

[0035] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0036] Example 1

[0037] In a typical embodiment of the present invention, a low-damage self-centering concrete column foot connection node structure is proposed, which is applied to a multi-story self-centering concrete frame, such as Figure 1-Figure 5 As shown, it includes a concrete foundation I, a low-damage precast concrete frame column II, a prestressed steel strand 3 and a low-yield point energy-absorbing steel bar 4. The prestressed steel strand 3 passes through the concrete foundation I and the low-damage precast concrete frame column II and is tensioned and anchored to connect the concrete foundation I and the low-damage precast concrete frame column II; the low-yield point energy-absorbing steel bar 4 is pre-buried at the bottom of the low-damage precast concrete frame column II, and beard bars are reserved. The low-yield point energy-absorbing steel bar 4 connects the bottom of the low-damage precast concrete frame column II with the top of the concrete foundation I by means of embedded bars; the bottom of the low-damage precast concrete frame column II adopts steel fiber concrete.

[0038] In this embodiment, steel fiber concrete is used within a range of 2 times the cross-sectional height at the bottom of the low-damage precast concrete frame column II, and ordinary concrete of equal strength is used in the remaining parts. Therefore, the low-damage precast concrete frame column II includes a steel fiber concrete area 1 and an ordinary concrete area 2. The length of the steel fiber concrete area 1 is 2 times the corresponding cross-sectional height (equivalent to the plastic hinge height of the column bottom). The strength of the fiber concrete is the same as that of the ordinary concrete. The fiber concrete uses end hook-type steel fibers with a volume content of 1.0%-2.0%, so that the compressive toughness of the concrete is significantly improved, and the fibers are not easy to clump during construction.

[0039] In this embodiment, a prestressed tendon channel 9 is reserved in the center of the concrete foundation I and the low-damage precast concrete frame column II to allow the prestressed steel strand 3 to pass through the concrete foundation I and the low-damage precast concrete frame column II.

[0040] In this embodiment, the prestressed steel strand 3 is arranged at the center position of the concrete foundation I and the low-damage precast concrete frame column II to provide a stable and effective self-restoring force after deformation, and will not cause the prestressed steel strand 3 to deform too much and yield when the opening angle at the bottom of the column is large; when one bundle of steel strands cannot meet the design requirements, two bundles can be set, arranged symmetrically along the center of the cross-section, with a spacing of not less than 50 mm, to ensure smooth tensioning of the prestressed steel strands.

[0041] In this embodiment, the low yield point energy-absorbing steel bars 4 are symmetrically arranged on both sides of the prestressed steel strands 3, so that when the column base is opened, the energy-absorbing steel bars produce a large deformation, thereby providing reliable energy dissipation, and the net distance between the low yield point energy-absorbing steel bars 4 and the reserved holes of the prestressed tendons and the edges of the components is not less than 30 mm, so as to ensure sufficient bonding strength between the energy-absorbing steel bars 4 and the surrounding steel fiber concrete.

[0042] In this embodiment, the prestressed steel strand 3 is non-bonded, and the prestressed tendon duct 9 is not grouted, so that the deformation is concentrated at the bottom of the column, and the column II maintains an elastic state without cracking. The number of steel strands and the tension control stress are obtained by calculation. For details, please refer to Chapter 2 of the book "Recoverable Functional Earthquake-Proof Structures - Basic Concepts and Design Methods" by Lu Xilin et al.: Self-resetting reinforced concrete frame structure system, to ensure that the prestress is sufficient to provide complete self-resetting capability and the steel strands do not yield under the action of a large earthquake.

[0043] In this embodiment, a reserved channel 10 for energy-absorbing steel bars is reserved at the top of the concrete foundation I and at the position corresponding to the low-yield-point energy-absorbing steel bars 4. The reserved beard bars of the low-yield-point energy-absorbing steel bars 4 and the reserved channel 10 for energy-absorbing steel bars are connected by anchoring glue, and the low-yield-point energy-absorbing steel bars 4 provide additional energy-absorbing capacity. Furthermore, the low-yield-point energy-absorbing steel bars 4 of the low-damage precast concrete frame column II are ordinary hot-rolled steel bars HRB400 with low yield points. The unbonded section is formed by wrapping plastic cloth within 200mm of the column bottom. During an earthquake, the column bottom opens, and the deformation is concentrated on the unbonded section of the energy-absorbing steel bars, which becomes the main additional energy-absorbing component.

[0044] In this embodiment, the bottom of the low-damage precast concrete frame column II is treated with a set thickness of steel fiber concrete mortar, the thickness of which is 20 mm, to form a steel fiber concrete mortar contact surface 6, and the strength grade of the steel fiber mortar used is one level higher than the strength grade of the steel fiber concrete at the bottom of the column, so as to form a reliable bond between the components and transfer shear force.

[0045] In this embodiment, longitudinal reinforcement 7 and stirrups 8 are arranged in the low-damage precast concrete frame column II. The longitudinal reinforcement 8 and stirrups 8 are tied to form a steel cage. The longitudinal reinforcement 7 and stirrups 8 are designed in accordance with the current national "Concrete Structure Design Standard", but the longitudinal reinforcement is cut off at the end of the component and does not extend into the foundation.

[0046] In this embodiment, both ends of the prestressed steel strand 3 are anchored by prestressed tendon anchors 5. In order to prevent the excessive local pressure generated by the prestress on the anchorage area at the end of the component from causing local pressure damage, the anchorage area at the bottom of the foundation and the top of the component needs to be configured with indirect steel bars in accordance with the current national "Concrete Structure Design Standard".

[0047] The main working principle of the connection method in the low-damage self-resetting concrete column base connection node structure provided in this embodiment is: the prestressed steel strand 3 provides a reset force, steel fibers are added to the column bottom concrete of the low-damage precast concrete frame column II to improve its compressive toughness and reduce local crushing in the contact area with the foundation, and the energy-absorbing steel bars with unbonded sections provide additional energy absorption capacity to reduce the horizontal displacement of the structure.

[0048] Example 2

[0049] In another typical embodiment of the present invention, a low-damage self-resetting concrete column foot connection node structure is proposed, which is applied to the bottom self-resetting concrete frame, such as Figure 1-Figure 4 and Figure 6 As shown, it also includes a concrete foundation I, a low-damage precast concrete frame column II and a low-yield point energy-absorbing steel bar 4. The prestressed steel strand 3 passes through the concrete foundation I and the low-damage precast concrete frame column II and is tensioned and anchored to connect the concrete foundation I and the low-damage precast concrete frame column II; the low-yield point energy-absorbing steel bar 4 is respectively embedded in the top and bottom of the low-damage precast concrete frame column II, and the bottom low-yield point energy-absorbing steel bar 4 connects the bottom of the low-damage precast concrete frame column II with the top of the concrete foundation I by means of embedded reinforcement, and the top low-yield point energy-absorbing steel bar has reserved beard bars cast into the upper structure; the top and bottom of the low-damage precast concrete frame column II are both made of steel fiber concrete.

[0050] In this embodiment, low-damage self-resetting concrete columns are only used for the bottom layer of the frame. After the construction of the low-damage precast concrete columns of the bottom layer is completed, the construction method above the second layer is the same as the construction method of the ordinary cast-in-place concrete frame structure.

[0051] The construction method of the low-damage self-resetting concrete column base connection node structure of this embodiment is similar to that of Embodiment 1, except that: in this embodiment, steel fiber concrete is used in the range of 2 times the cross-sectional height of the top and bottom of the low-damage precast concrete frame column II, and ordinary concrete of equal strength is used in the remaining parts. Because the bottom and top of the bottom column of the structure will open under the action of an earthquake to form a concentrated deformation area, the top and bottom of the column will be subject to a large contact pressure, resulting in crushing and damage of the concrete. Therefore, steel fiber concrete is used in the top and bottom of the low-damage precast concrete frame column II of this embodiment.

[0052] In this embodiment, it is necessary to embed low-yield point energy-absorbing steel bars 4 at the top and bottom of the low-damage precast concrete frame column II respectively. Because the bottom and top of the columns of the bottom layer of the structure will open under the action of an earthquake to form a concentrated deformation area, low-yield point energy-absorbing steel bars are required to be set at the top and bottom of the column to dissipate the earthquake capacity. The low-yield point energy-absorbing steel bars 4 at the bottom of the column are also connected to the precast or cast-in-place foundation I by embedding reinforcement. After the low-yield point energy-absorbing steel bars 4 at the top of the column are reserved with beard bars, the beard bars are cast into the upper structure and connected to the upper structure.

[0053] In this embodiment, since contact surfaces are formed between the top of the low-damage precast concrete frame column II and the upper structure, and between the bottom and the cast-in-place or precast foundation I, the top and bottom need to be treated with steel fiber concrete mortar of a set thickness to form a steel fiber concrete mortar contact surface 6 to form reliable bonding between the components and transfer shear force.

[0054] In this embodiment, the prestressed steel strands 3 need to be tensioned and anchored after the second-layer cast-in-place beams are cast.

[0055] The main working principle of the connection method in the low-damage self-resetting concrete column foot connection node structure provided in this embodiment is: the self-weight of the structure and the prestressed steel strand 3 provide the reset force, steel fibers are added to the concrete at the top and bottom of the low-damage precast concrete frame column II to improve its compressive toughness and reduce local crushing in the contact area with the upper structure and foundation, and the energy-absorbing steel bars with unbonded sections provide additional energy absorption capacity to reduce the horizontal displacement of the structure.

[0056] The expected effects achieved by the low-damage self-resetting concrete column foot connection node structure of the present invention are as follows: under the action of frequent earthquakes, the structure is in an elastic state, and the interface at the bottom of the column does not open; under the action of a fortified earthquake, the interface at the bottom of the column opens, but does not exceed a certain limit, so that the steel fiber concrete at the edge of the column bottom section remains intact, and the energy-consuming steel bars do not yield, and no repair is required after the earthquake; under the action of a rare earthquake, the structural deformation is mainly concentrated between the contact surface between the column bottom and the foundation, and the column itself only produces a small amount of elastic deformation. After the structure has undergone a large deformation, the prestress in the prefabricated column and the deadweight of the structure provide the column with a reset force to return to its original position; the steel fiber concrete at the bottom of the column is in a high axial pressure (precast Under the combined action of prestressed steel bars (caused by stress and structural deadweight) and horizontal earthquakes, only the protective layer may be crushed, the core area constrained fiber concrete remains intact (has not reached the peak compressive strain), the energy-absorbing steel bars yield and dissipate the seismic energy input into the structure to reduce the horizontal displacement of the structure, and the residual deformation of the structure after the earthquake is controlled within a certain range. The main components only need to be slightly repaired before they can be put into use; under the action of extremely rare earthquakes, the prestressed steel bars do not yield, the fiber concrete protective layer at the bottom of the column peels off, the fiber concrete in the core area is not crushed (has not reached the ultimate compressive strain), the energy-absorbing steel bars may be broken, the residual deformation of the structure is large, and the difficulty of post-earthquake repair is greater, but the structure as a whole does not collapse. The overall effect of adding steel fibers to the bottom of the column is that the damage to the bottom of the column is reduced under the action of earthquakes of all intensities, and the column does not need to be repaired after the earthquake or the difficulty of repair is reduced.

[0057] The present invention is expected to be feasible in that it adds fiber to the concrete in the nonlinear stress diffusion zone at the bottom of the column to enhance the compressive toughness of the concrete, thereby reducing the compressive damage at the bottom of the column and improving the recoverable performance of the structure. When used in combination with energy-absorbing steel bars, its construction is simple and fast compared with other types of damage prevention measures, and it is worthy of strong promotion and application, especially for multi-story self-righting concrete frame structures and bottom-level self-righting frame structures where the axial pressure at the bottom of the column is relatively large due to self-weight.

[0058] Example 3

[0059] This embodiment provides a construction method for a low-damage self-resetting concrete column foot connection node structure, comprising:

[0060] Prefabricated or cast-in-place concrete foundation, with reserved holes for prestressed tendons and energy-absorbing steel bars on the concrete foundation;

[0061] Low-damage precast concrete frame columns, in which prestressed reinforcement holes are reserved and low-yield point energy-absorbing steel bars are embedded;

[0062] A steel fiber concrete mortar treatment of a set thickness is performed at the bottom of the low-damage precast concrete frame column, and the low-damage precast concrete frame column is hoisted on the concrete foundation;

[0063] The prestressed steel strands pass through the concrete foundation and the low-damage precast concrete frame columns and are tensioned and anchored to connect the concrete foundation and the low-damage precast concrete frame columns.

[0064] In this embodiment, the precast or cast-in-place concrete foundation I and the low-damage precast concrete frame column II are manufactured separately, and the bottom of the low-damage precast concrete frame column II forms a steel fiber concrete mortar contact surface 6 with the top of the concrete foundation I. Prestressed tendon holes 9 are reserved at corresponding positions of the concrete foundation I and the low-damage precast concrete frame column II. The prestressed steel strand 3 passes through the concrete foundation I and the low-damage precast concrete frame column II, is tensioned and anchored at the end by a prestressed tendon anchor 5, thereby connecting the precast or cast-in-place concrete foundation I and the low-damage precast concrete frame column II together.

[0065] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. A low-damage self-resetting concrete column foot connection node structure, characterized in that: It includes a concrete foundation, a low-damage precast concrete frame column, a prestressed steel strand and a low-yield point energy-absorbing steel bar. The prestressed steel strand passes through the concrete foundation and the low-damage precast concrete frame column and is tensioned and anchored to connect the concrete foundation and the low-damage precast concrete frame column. The low-yield point energy-absorbing steel bar is embedded in the bottom of the low-damage precast concrete frame column. The low-yield point energy-absorbing steel bar connects the bottom of the low-damage precast concrete frame column with the top of the concrete foundation by means of embedded reinforcement. The bottom of the low-damage precast concrete frame column adopts steel fiber concrete.

2. The low-damage self-resetting concrete column foot connection node structure according to claim 1, characterized in that: The low-damage precast concrete frame column uses steel fiber concrete in the range of 2 times the cross-section height at the bottom, and uses ordinary concrete of equal strength in the remaining parts.

3. The low-damage self-resetting concrete column foot connection node structure according to claim 2, characterized in that: Steel fiber concrete uses end hook type steel fiber, and the volume content of steel fiber is 1.0%-2.0%.

4. The low-damage self-resetting concrete column foot connection node structure according to claim 1, characterized in that: Prestressed tendon holes are reserved in the center of the concrete foundation and the low-damage precast concrete frame column to allow the prestressed steel strands to pass through the concrete foundation and the low-damage precast concrete frame column.

5. The low-damage self-resetting concrete column foot connection node structure according to claim 4, characterized in that: The prestressed steel strands are prepared in a non-bonding manner, the prestressed tendon ducts are not grouted, and the number of steel strands and the tensioning control stress are obtained by calculation.

6. The low-damage self-resetting concrete column foot connection node structure according to claim 1, characterized in that: A reserved channel for energy-absorbing steel bars is reserved at the top of the concrete foundation at a position corresponding to the low-yield point energy-absorbing steel bars, and the low-yield point energy-absorbing steel bars and the reserved channel for the energy-absorbing steel bars are connected by embedding glue.

7. The low-damage self-resetting concrete column foot connection node structure according to claim 1, characterized in that: The bottom of the low-damage precast concrete frame column is treated with steel fiber concrete mortar of a set thickness to form a steel fiber concrete mortar contact surface.

8. The low-damage self-resetting concrete column foot connection node structure according to claim 1, characterized in that: The low-yield point energy-absorbing steel bars of the low-damage precast concrete frame column are ordinary hot-rolled steel bars with low yield points, and a non-bonded section is formed within 200 mm of the column bottom by wrapping with plastic cloth.

9. The low-damage self-resetting concrete column foot connection node structure according to claim 1, characterized in that: Longitudinal bars and stirrups are arranged in the low-damage precast concrete frame column, and the longitudinal bars and stirrups are tied to form a steel cage.

10. A construction method for a low-damage self-resetting concrete column foot connection node structure as claimed in any one of claims 1 to 9, characterized in that: include: Prefabricated or cast-in-place concrete foundation, with reserved holes for prestressed tendons and energy-absorbing steel bars on the concrete foundation; Low-damage precast concrete frame columns, in which prestressed reinforcement holes are reserved and low-yield point energy-absorbing steel bars are embedded; A steel fiber concrete mortar treatment of a set thickness is performed at the bottom of the low-damage precast concrete frame column, and the low-damage precast concrete frame column is hoisted on the concrete foundation; The prestressed steel strands pass through the concrete foundation and the low-damage precast concrete frame columns and are tensioned and anchored to connect the concrete foundation and the low-damage precast concrete frame columns.

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