A truncated cone connection structure of a pile-column structure passing through a structural bottom plate and its construction method

Abstract

The present invention belongs to the field of building structures, and relates to a truncated cone connection structure of a pile-column structure that passes through a structural bottom plate, and a construction method thereof. The technical solution is as follows: the pile-column structure is divided into a lower pile section, an upper column section, and a connecting portion therebetween by a newly built basement structural bottom plate; the connecting portion is a truncated cone connection section; the truncated cone connection section is a variable diameter section that is smaller at the top and larger at the bottom; the top section of the truncated cone connection section is smaller than the section of the pile section; the newly built basement structural bottom plate and the truncated cone connection section are cast as a whole, and the steel cage of the pile-column structure adopts a split type, and the longitudinal main bars of the steel cage are divided into column section main bars and pile section main bars; the column section main bars are anchored into the pile section and welded to the pile section main bars; the pile section main bars are anchored upward into the basement structural bottom plate; the shape of the steel cage in the truncated cone connection section is smaller at the top and larger at the bottom. The problem of low reliability of the connection node between the existing pile-column structure and the structural bottom plate is solved.

Description

Technical Field

[0001] The invention belongs to the field of building structures, and in particular relates to a connection structure of a support pile column and a structural bottom plate in an underground space development project of an existing structure. Background Art

[0002] With the continuous advancement and deepening of urbanization in my country, the development of large cities is becoming increasingly saturated, and land resources are becoming increasingly scarce. The transformation and upgrading of existing land is imminent, and the renewal and renovation of existing buildings has become a new hot spot and new trend. In the renovation of existing buildings, adding basements or adding basement floors is a relatively common situation. Usually, the newly built underground structure engineering piles can be used as underpinning piles. During the underpinning stage, the underpinning piles support the upper existing structure, and the soil below is excavated and the basement structure is constructed. After the new basement is completed, the load of the upper existing structure is borne by the structural columns, the underpinning pile column sections are retired and chiseled out, and the underpinning pile column sections are connected to the new basement structure bottom plate as the main structure engineering piles to share the upper load. Since the pile column structure directly passes through the new structure bottom plate, it is required that the pile column structure and the structure bottom plate have a good connection to ensure that the two can reliably complete the force transmission. The traditional pile column structure and the structure bottom plate connection node only rely on the concrete interface friction to complete the force transmission, which has low reliability and is difficult to meet the pressure and pull-out requirements of the engineering pile. Summary of the invention

[0003] To solve the above technical problems, the present invention provides a pile-column structure truncated cone connection structure passing through a structural bottom plate and a construction method thereof, which solves the problem of low reliability of the connection node between the existing pile-column structure and the structural bottom plate.

[0004] The technical solution of the present invention is: a truncated cone connection structure of a pile-column structure passing through a structural bottom plate, wherein the pile-column structure is divided into a lower pile section, an upper column section and a connection part therebetween by a newly built basement structure bottom plate; the connection part is a truncated cone connection section; the truncated cone connection section is a variable diameter section that is smaller at the top and larger at the bottom; the top section of the truncated cone connection section is smaller than the section of the pile section; the newly built basement structure bottom plate and the truncated cone connection section are cast as a whole, the steel cage of the pile-column structure adopts a split type, and the longitudinal main bars of the steel cage are divided into column section main bars and pile section main bars; the column section main bars are anchored into the pile section and welded to the pile section main bars; the pile section main bars are anchored upward into the basement structure bottom plate; the shape of the steel cage in the truncated cone connection section is smaller at the top and larger at the bottom.

[0005] Based on the above technical features: a reinforced ring beam is set at the connection between the new basement structure floor and the truncated cone type connecting section.

[0006] Based on the above technical features: shear keys or water-stop steel plates are added to the outer surface of the frustum-type connecting section.

[0007] Based on the above technical features: the outer surface of the frustum-type connecting section is a rough surface.

[0008] Based on the above technical features: a construction method of a pile column structure truncated cone connection structure passing through a structural bottom plate includes:

[0009] Step 1: Integrally cast the pile section, connecting part and column section; including the construction of the steel cage, the steel cage of the connecting part gradually transitions according to the cross-section of the upper column section and the lower pile section.

[0010] Step 2: Before pouring the new basement structure slab and new structure columns, remove the protective layer of concrete reinforcement at the connection part to form a frustum-shaped connection section.

[0011] Step 3: Pour the new basement structure floor and structural columns; pull out the main reinforcement of the pile section and anchor it into the new basement structure floor.

[0012] Step 4: Chisel out the column section.

[0013] Based on the above technical features: In step three, the construction of a reinforced ring beam is added, and a reinforced ring beam is set between the new basement structure floor and the conical connecting section.

[0014] Based on the above technical features: in step 2, the outer surface of the frustum-shaped connecting section is roughened.

[0015] Based on the above technical features: In step 2, shear keys or water-stop steel plates are added to the outer interface of the frustum-type connecting section.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The present invention provides a truncated cone connection structure of a pile-column structure that passes through the structural bottom plate and a construction method thereof, which effectively transmits the upper vertical load through the truncated cone connection section of variable diameter. Compared with the existing structure, the vertical load can not only be transmitted by the interface friction between the pile-column structure and the new basement structure bottom plate, but also partially converted into interface pressure. At the same time, the interface pressure can further increase the interface friction, so that the shear bearing capacity of the connection node is greatly improved. A reinforcing ring beam is set in the connection area between the new basement structure bottom plate and the pile-column structure to avoid node failure caused by damage to the connection surface. In addition, the steel cage of the pile-column structure adopts a split type, and the main reinforcement of the column segment is anchored into the pile segment and welded to the main reinforcement of the pile segment. The main reinforcement of the pile segment is pulled out and anchored into the structural bottom plate during the construction of the new basement structure bottom plate, which meets the connection structure requirements between the pile body and the structural bottom plate, so as to achieve the purpose of giving full play to the pull-out bearing capacity of the pile body. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a plan view of the frustum-type connection structure of the pile-column structure that passes through the structural base plate.

[0019] Figure 21-1 is a schematic cross-sectional view of the cone-shaped connection structure of the pile-column structure passing through the structural base plate.

[0020] Figure 3 Schematic diagram of the split steel cage for pile-column structure.

[0021] Figure 4 A schematic diagram of step 1 of the construction method flow of a pile-column structure cone-type connection structure that passes through a structural base plate.

[0022] Figure 5 A schematic diagram of step two of the construction method flow for a pile-column structure cone-type connection structure that passes through a structural base plate.

[0023] Figure 6 Schematic diagram of step three of the construction method flow for a pile-column structure cone-type connection structure that passes through a structural base plate.

[0024] Figure 7 Schematic diagram of step 4 of the construction method flow of the pile-column structure cone connection structure passing through the structural base plate.

[0025] Reference numerals:

[0026] 1-pile segment; 2-column segment; 3-conical connecting segment; 4-new basement structure floor; 5-new structural column; 6-reinforced ring beam; 7-pile segment main reinforcement; 8-column segment main reinforcement. DETAILED DESCRIPTION

[0027] The specific embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. These embodiments are only used to illustrate the present invention, but not to limit the present invention.

[0028] In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0029] like Figure 1 and Figure 2As shown, the pile-column structure passes through the new basement structure bottom plate 4, and the pile-column structure is divided into a lower pile section 1, an upper column section 2 and a connecting portion therebetween by the new basement structure bottom plate 4; the connecting portion is a truncated cone-shaped connecting section 3; the truncated cone-shaped connecting section 3 is a variable diameter section with a small top and a large bottom; the top section of the truncated cone-shaped connecting section 3 is smaller than the section of the pile section 1; the new basement structure bottom plate 4 and the truncated cone-shaped connecting section 3 are cast as a whole. A reinforcing ring beam 6 is provided at the connecting portion between the new basement structure bottom plate 4 and the pile-column structure to improve the node strength. Figure 1 and Figure 2 It is shown in the figure that four pile-column structures pass through the new basement structure floor 4, and the new structure column 5 is located on the new basement structure floor 4 within the enclosed range of the four pile-column structures. The layout of the new structure column 5 and the pile-column structure here is only a schematic diagram.

[0030] like Figure 3 As shown, the steel cage of the pile-column structure adopts a split type, and the longitudinal main reinforcement of the steel cage is divided into column segment main reinforcement 8 and pile segment main reinforcement 7; the column segment main reinforcement 8 is anchored into the pile segment 1 and welded with the pile segment main reinforcement 7; the pile segment main reinforcement 7 is pulled out and anchored into the newly built basement structure bottom plate 4 during the construction of the new basement structure bottom plate 4 to enhance the pull-out bearing capacity of the connection node and achieve the purpose of giving full play to the pull-out bearing capacity of the pile body. The steel cage at the connection between the pile-column structure and the basement structure bottom plate 4 is small at the top and large at the bottom. Before the pouring of the basement structure bottom plate 4, the concrete steel protection layer of the connection section is stripped to form a truncated cone structure with a variable diameter, and the external interface is roughened to enhance the shear bearing capacity of the connection node. Or a shear key or a water-stop steel plate is added to the external interface to further improve the shear resistance or water-stop performance of the interface.

[0031] like Figures 4 to 7 Shown is a specific construction method of the present invention.

[0032] Step 1: If Figure 4 As shown, firstly, the pile-column structure is constructed, and the pile segment 1, the connecting part and the column segment 2 are integrally cast; including the construction of the steel cage, the steel cage of the connecting part gradually transitions according to the cross-sections of the upper column segment 2 and the lower pile segment 1; the pile-column structure is used to support the upper structure load A of the existing building.

[0033] Step 2: If Figure 5 As shown, excavation is then carried out downwards, and the structural beams and slabs of each basement floor are constructed. Before the new basement structural bottom slab 4 and the new structural columns 5 are cast, the concrete reinforcement protective layer of the connecting section is stripped off to form a variable diameter frustum-type connecting section 3, and the external interface is roughened. Other treatments may also be performed on the external interface, such as adding shear keys or water-stopping steel plates, etc., to further improve the shear resistance or water-stopping performance of the interface.

[0034] Step 3: If Figure 6As shown, a new basement structure floor 4 and new structure columns 5 are cast, a reinforcing ring beam 6 is arranged between the new basement structure floor 4 and the truncated cone type connecting section 3, and the main reinforcement 7 of the pile segment is pulled out and anchored into the new basement structure floor 4.

[0035] Step 4: If Figure 7 As shown, the column section 2 is retired and removed, and the upper structure load A is borne by the newly built structure column 5. The pile section 1 is connected to the newly built basement structure floor 4 and serves as a main structure engineering pile to share the upper load borne by the newly built structure column 5.

[0036] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A truncated cone connection structure of a pile column structure passing through a structural bottom plate, characterized in that: The pile-column structure is divided into a lower pile section (1), an upper column section (2) and a connecting portion therebetween by a newly built basement structure bottom plate (4); the connecting portion is a truncated cone-shaped connecting section (3); the truncated cone-shaped connecting section (3) is a variable diameter section with a smaller upper portion and a larger lower portion; the top section of the truncated cone-shaped connecting section (3) is smaller than the section of the pile section (1); the newly built basement structure bottom plate (4) and the truncated cone-shaped connecting section (3) are cast as a whole; the steel cage of the pile-column structure is split-type; the longitudinal main reinforcement of the steel cage is divided into column section main reinforcement (8) and pile section main reinforcement (7); the column section main reinforcement (8) is anchored into the pile section (1) and welded to the pile section main reinforcement (7); the pile section main reinforcement (7) is anchored upward into the newly built basement structure bottom plate (4); the shape of the steel cage in the truncated cone-shaped connecting section (3) is small at the top and large at the bottom.

2. The truncated cone connection structure of a pile column structure passing through a structural bottom plate according to claim 1, characterized in that: A reinforcing ring beam (6) is provided at the connection between the new basement structure bottom plate (4) and the truncated cone-shaped connecting section (3).

3. The truncated cone connection structure of a pile column structure passing through a structural bottom plate according to claim 1, characterized in that: The outer surface of the truncated cone-shaped connecting section (3) is additionally provided with a shear key or a water-stopping steel plate.

4. The truncated cone connection structure of a pile column structure passing through a structural bottom plate according to claim 1, characterized in that: The outer surface of the frustum-shaped connecting section (3) is a rough surface.

5. The construction method of the truncated cone connection structure of a pile column structure passing through a structural bottom plate according to claim 1, characterized in that: Step 1: integrally casting the pile segment (1), the connecting portion and the column segment (2); including the construction of the steel cage, wherein the steel cage of the connecting portion gradually transitions according to the cross-sections of the upper column segment (2) and the lower pile segment (1); Step 2: before pouring the newly built basement structure floor (4) and the newly built structure column (5), the concrete reinforcement protective layer of the connection part is stripped off to form the frustum-shaped connection section (3); Step 3: pouring the newly built basement structure floor (4) and newly built structure columns (5); pulling out the main reinforcement of the pile segment (7) and anchoring it into the newly built basement structure floor (4); Step 4: Chisel out the column section (2).

6. The construction method of the truncated cone connection structure of a pile column structure passing through a structural bottom plate according to claim 5, characterized in that: In the step three, the construction of a reinforced ring beam (6) is added, and the reinforced ring beam (6) is arranged between the new basement structure floor (4) and the truncated cone connecting section (3).

7. The construction method of a truncated cone connection structure of a pile column structure passing through a structural bottom plate according to claim 5 or 6, characterized in that: In the second step, the outer surface of the frustum-shaped connecting section (3) is roughened.

8. The construction method of a truncated cone connection structure of a pile column structure passing through a structural bottom plate according to claim 5 or 6, characterized in that: In the second step, a shear key or a water-stop steel plate is added to the outer surface of the truncated cone connecting section (3).

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