A construction method for connecting an existing foundation with a newly built core tube after a design change

Abstract

The present invention is a construction method for connecting an existing foundation with a newly built core tube after a design change, and the steps are as follows: connect the embedded parts area to form a ring belt, excavate as a whole, divide the ring belt into several cutting blocks according to the parameters of the lifting equipment, and perform cutting operations by using a water drill to wash holes and a lock saw to cut in sequence; arrange interface rebar holes and column foot pre-embedded holes at equal intervals horizontally and vertically along the interface between the new and old concrete; put rebars in the interface rebar holes, and bury column foot pre-embedded keys at the column foot pre-embedded holes; hoist the steel column in place, connect the rebars to the lifting ears of the steel column through cables, and connect the steel column to the column foot pre-embedded keys through bolts; use a layered concrete pouring method, which is divided into bottom layer concrete pouring, middle layer concrete pouring, and surface layer concrete pouring. The present invention improves the efficiency of pre-embedded grooving, ensures the construction accuracy of steel column hoisting, gives full play to the coordination of existing structures for temporary measures, and reduces costs.

Description

Technical Field

[0001] The present invention relates to the technical field of existing structure reconstruction, and in particular to a construction method for connecting an existing foundation with a newly built core tube after a design change. Background Art

[0002] The super high-rise core tube is the main load-bearing component of super high-rise buildings. All the loads of the building are transmitted from top to bottom through the core tube to the foundation. Therefore, the construction of the connection between the core tube and the foundation is particularly critical. Under normal circumstances, the connection between the core tube and the foundation should be cast in place. However, when the foundation has been cast and hardened, the design will be changed, and the connection construction between the new core tube and the existing foundation will face huge challenges.

[0003] The core tube and the existing foundation are generally connected by embedded steel columns, which require drilling holes in the existing foundation for embedding. However, when the core tube is higher, the depth of the embedded steel columns will also increase. If ultra-deep holes are drilled, how to ensure the accuracy of the embedded steel columns and how to improve the efficiency of the embedded construction are issues that need to be urgently addressed in this field. Summary of the invention

[0004] The present invention aims to solve the deficiencies of the prior art and provides a construction method for connecting an existing foundation with a newly built core tube after a design change.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A construction method for connecting an existing foundation with a newly built core tube after a design change, the specific steps are:

[0007] S1. Excavation of the connection area between the existing foundation and the core tube:

[0008] S11. Cutting area design:

[0009] Connect the embedded parts area to form a ring belt, which is excavated as a whole. The groove width of the ring belt is b and the groove depth is h;

[0010] S12, cutting plan design:

[0011] According to the parameters of the lifting equipment, the ring belt is divided into several cutting blocks, and the length of the cutting block is l;

[0012] S13, cutting operation:

[0013] The process is carried out in a sequential manner of water drilling, hole washing and lock saw cutting, specifically:

[0014] First, construct the first cutting block D1, and use a water drill to vertically punch the edges B1, B2, and L1 to the depth , at depth Use a water drill to punch horizontally and insert the lock saw along the three sides of B1, B2, and L1 to the depth Cut horizontally at the position, lift the lock through the bottom to lift out the upper half of the concrete block of section D1; then use a water drill to vertically punch edges B1, B2, and L1 to the depth , at depth Use a water drill to punch horizontally and insert the lock saw along the three sides of B1, B2, and L1 to the depth The position is horizontally cut, and the lifting lock passes through the bottom to lift out the lower half of the concrete block of section D1; repeat the above operation to cut the subsequent blocks until all the concrete blocks are cut;

[0015] After the cutting is completed, the exposed surface behind the cutting surface is roughened to form the interface between the new and old concrete, and the exposed steel bars are cleaned to expose the original foundation reinforcement at the interface between the new and old concrete;

[0016] S2. Pre-buried construction:

[0017] Arrange the interface reinforcement holes and column foot pre-embedded holes at equal intervals horizontally and vertically along the interface between the new and old concrete; put reinforcement into the interface reinforcement holes, and bury the column foot pre-embedded keys in the column foot pre-embedded holes;

[0018] S3, hoisting steel column:

[0019] The steel column is hoisted in place, the anchor bar is connected to the lifting lug of the steel column through cables, and the steel column is connected to the embedded key at the column foot through bolts;

[0020] S4. Concrete pouring:

[0021] The concrete is poured in layers, which is divided into bottom layer concrete pouring, middle layer concrete pouring and surface layer concrete pouring.

[0022] In step S11, the groove width b of the ring belt is 1-2 m on both sides of the cross-sectional width of the steel column, and the groove depth h of the ring belt is 0.2-0.5 m more than the designed buried depth of the steel column.

[0023] In step S12, according to the lifting height and working radius of the lifting equipment, the corresponding rated lifting capacity M0 is obtained by referring to the manual of the lifting equipment, and the maximum weight M of the cut blocks is calculated according to M0 ≥ 1.3M, where 1.3 is the safety factor to avoid the influence of the lifting dynamic load, and then the bulk density of the concrete is obtained by looking up the table. , calculate the volume of a single cut block , and according to the designed slot width b and slot depth h, the length of a single cutting block is calculated .

[0024] In step S13, the interface between the new and old concrete is roughened, and the difference in concave and convex is not less than 6 mm.

[0025] In step S3, the steel column is hoisted by an external lifting machine, and the hoisting machine does not come off during the installation process.

[0026] In step S3, the lifting lugs are separately manufactured and welded to the flanges of the steel columns or modified from the friction shear studs of the steel columns.

[0027] The specific steps of step S4 are:

[0028] S41, bottom layer concrete pouring:

[0029] In the pouring area of ​​the bottom concrete, set up the stand-up steel bars and tie them to the embedded steel bars, connecting them vertically and horizontally to form a stable spatial structure; set up the wooden formwork, pass the stand-up steel bars through the wooden formwork and fix them in the area to be poured, and then pour the bottom concrete;

[0030] S42, middle layer concrete pouring:

[0031] After the bottom layer concrete hardens, set up the steel bars in the pouring area of ​​the middle layer concrete and tie them to the embedded steel bars, connecting them vertically and horizontally to form a stable spatial structure; set up the wooden formwork, pass the steel bars through the wooden formwork and fix them in the area to be poured, and then pour the middle layer concrete;

[0032] S43, surface concrete pouring:

[0033] After the middle layer of concrete hardens, connect the newly poured foundation reinforcement with the original foundation reinforcement, place the bottom U-shaped clamp, fix the steel formwork, set a tie point on the upper part of the steel formwork and connect it to the lug of the steel column through a cable, and pour the surface concrete;

[0034] Finally, the finished surface of the newly poured foundation is formed.

[0035] The beneficial effects of the present invention are as follows: the present invention not only improves the efficiency of pre-embedded grooving and ensures the construction accuracy of steel column hoisting, but also the arrangement of construction steps gives full play to the coordination of the existing structure with temporary measures, reduces the cost of temporary construction measures, and ensures the safety, efficiency and economy of the new core tube built on the existing foundation. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram of the newly built core tube and the existing foundation position of the present invention;

[0037] Figure 2 This is a schematic diagram of the connection between the traditional partially slotted core tube and the foundation;

[0038] Figure 3 To improve the schematic diagram of the connection between the integral slotted core tube and the foundation;

[0039] Figure 4To improve the overall slotted stage division plan;

[0040] Figure 5 To improve the integral slotting stage, the elevations are divided;

[0041] Figure 6 It is the layout diagram of embedded openings;

[0042] Figure 7 It is the layout drawing of embedded installation;

[0043] Figure 8 This is a schematic diagram of steel column installation;

[0044] Fig. 9 This is a schematic diagram of the concrete pouring for the bottom floor;

[0045] Fig.10 This is a schematic diagram of the middle layer concrete pouring;

[0046] Fig.11 This is a schematic diagram of pouring surface concrete;

[0047] Fig.12 Complete the schematic diagram for connecting the new core tube with the existing foundation;

[0048] In the figure: 1-existing foundation; 2-core tube; 3-interface between new and old concrete; 4-original foundation reinforcement; 5-interface reinforcement hole; 6-pre-embedded hole at column foot; 7-embedded reinforcement; 8-pre-embedded key at column foot; 9-steel column; 10-hanging ear; 11-cable; 12-bottom concrete layer; 13-middle concrete layer; 14-surface concrete layer; 15-erection reinforcement; 16-wooden formwork; 17-new foundation reinforcement; 18-bottom U-shaped clamp; 19-steel formwork; 20-new foundation finished surface;

[0049] The following is a detailed description of the embodiments of the present invention with reference to the accompanying drawings. DETAILED DESCRIPTION

[0050] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The embodiments are only used to explain the present invention and are not used to limit the scope of the present invention. The present invention is described in more detail by way of example with reference to the accompanying drawings in the following paragraphs. The advantages and features of the present invention will become clearer according to the following description. It should be noted that the accompanying drawings are all in a very simplified form and are not in precise proportions, and are only used to facilitate and clearly assist in explaining the purpose of the embodiments of the present invention.

[0051] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may also be a component centered. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may also be a component centered. When a component is considered to be "set on" another component, it may be directly set on the other component or there may also be a component centered. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0053] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0054] A construction method for connecting an existing foundation with a newly built core tube after a design change, the specific steps are:

[0055] S1. Excavation of the connection area between the existing foundation 1 and the core tube 2:

[0056] S11. Cutting area design:

[0057] The position relationship between the new core tube 2 and the existing foundation 1 is as follows Figure 1 , the core tube 2 needs to go deep into the existing foundation 1 to ensure a stable connection.

[0058] Traditional connection methods such as Figure 2 , the integral connection between the newly built core tube 2 and the existing foundation 1 is ensured by partially grooving and embedding the steel column 9. However, due to the deep embedding depth of the steel column 9, it is difficult to place the embedded parts after partial grooving, and the verticality and positioning accuracy of the steel column 9 are also difficult to ensure, which greatly reduces the efficiency of grooving.

[0059] Therefore, the embedded parts area is finally connected to form a ring belt, which is excavated as a whole, avoiding the difficulty of three-way positioning of a single embedded hole and improving the construction efficiency. Figure 3 .

[0060] The width b of the ring belt groove is 1-2m on both sides of the cross-sectional width of the steel column 9, and the depth h of the ring belt groove is 0.2-0.5m higher than the designed buried depth of the steel column 9.

[0061] S12, cutting plan design:

[0062] Design the cutting block size according to the lifting equipment.

[0063] According to the lifting height and working radius of the lifting equipment, refer to the manual of the lifting equipment to obtain the corresponding rated lifting capacity M0, and calculate the maximum weight M of the cut blocks according to M0 ≥ 1.3M, where 1.3 is the safety factor to avoid the influence of the lifting dynamic load, and then look up the table to obtain the bulk density of the concrete , calculate the volume of a single cut block , and according to the designed slot width b and slot depth h, the single cutting block length is calculated .

[0064] S13, cutting operation:

[0065] In order to improve efficiency, a sequential operation method of water drilling hole washing and lock saw cutting is adopted.

[0066] like Figure 4 First, construct the D1 section: use a water drill to vertically punch the edges B1, B2, and L1 to a depth of ,like Figure 5 At position ① in the middle; then at depth Use a water drill to punch horizontally, such as Figure 5 Insert the lock saw along the three sides of B1, B2 and L1 to the depth of The horizontal cutting is carried out at the position of the D1 section, and the lifting lock passes through the bottom to lift out the upper half of the concrete block of the D1 section. Figure 5 At position ⑤ in the middle; use a water drill to vertically punch edges B1, B2, and L1 to a depth of ,like Figure 5 At the ③ position in the middle; at the depth Use a water drill to punch horizontally, such as Figure 5 At position ④ in the middle; insert the lock saw along the three sides of B1, B2, and L1 to the depth The position of the horizontal cutting is carried out, and the lifting lock passes through the bottom to lift out the lower half of the concrete block of section D1. Figure 5 At the ⑥ position in the middle.

[0067] Next, construct section D2: Use a water drill to vertically punch edges B3 and L2 to a depth of ,like Figure 5 At position ① in the figure; then use a water drill to drill horizontally at a certain depth, such as Figure 5 At position ② in the middle; insert the lock saw along the three sides of B2, B3, and L2 to the depth The position of the horizontal cutting is carried out, and the lifting lock passes through the bottom to lift out the upper half of the concrete block of section D2. Figure 5 Use a water drill to vertically punch edges B3 and L2 to a depth of h. Figure 5At position ③ in the figure; use a water drill to chisel horizontally at depth, such as Figure 5 At position ④ in the figure, insert the lock saw along the three sides of B2, B3, and L2, and make horizontal cuts at the depth h. The lifting lock passes through the bottom to lift out the lower half of the concrete block of section D2, as shown in the figure. Figure 5 At the ⑥ position in the middle.

[0068] Repeat the above steps until all concrete blocks are cut.

[0069] After the cutting is completed, the exposed surface behind the cutting surface is roughened to form the interface 3 between the new and old concrete. The interface 3 between the new and old concrete should be roughened with a concave-convex difference of not less than 6mm. The exposed steel bars are cleaned to expose the original foundation reinforcement 4 at the interface 3 between the new and old concrete.

[0070] S2. Pre-buried construction:

[0071] Although the integral grooving improves the efficiency of grooving, it also weakens the connection strength between the new and old concrete, especially the connection strength of the vertical section, which has a great impact on the overall bending and shear bearing capacity.

[0072] Therefore, the interface reinforcement holes 5 and the column foot pre-embedded holes 6 are arranged at equal intervals horizontally and longitudinally along the interface 3 between the new and old concrete. Figure 5 Next, the embedded steel bar 7 is put in later to improve the tensile performance of the concrete at the interface between the new and old concrete 3, such as Figure 6 , and bury the column foot embedded key 8 to facilitate the subsequent installation of the steel column 9.

[0073] S3, hoisting steel column 9:

[0074] The steel column 9 is hoisted by an external lifting machine. The hoisting machine does not unhook during the installation process. The embedded steel bar 7 is connected to the lifting ear 10 of the steel column 9 through a cable 11, and the steel column 9 is connected to the embedded key 8 at the column foot through bolts. Figure 8 .

[0075] The lifting lug 10 can be manufactured separately and welded to the flange of the steel column 9 , or it can be modified from the friction shear nail of the steel column 9 .

[0076] S4. Concrete pouring:

[0077] The concrete is poured in layers, which includes pouring of a bottom layer of concrete 12 , pouring of an intermediate layer of concrete 13 , and pouring of a surface layer of concrete 14 .

[0078] S41, bottom layer concrete pouring:

[0079] like Fig. 9As shown, in the pouring area of ​​the bottom concrete 12, upright steel bars 15 are arranged and tied to the embedded bars 7, connected vertically and horizontally to form a stable spatial structure; a wooden formwork 16 is set up, and the upright steel bars 15 are passed through the wooden formwork 16 and fixed in the area to be poured, and then the bottom concrete 12 is poured.

[0080] S42, middle layer concrete pouring

[0081] like Fig.10 As shown, after the bottom layer concrete 12 hardens, the vertical reinforcement bars 15 are arranged in the pouring area of ​​the middle layer concrete 13 and tied to the embedded reinforcement bars 7, and connected vertically and horizontally to form a stable spatial structure; the wooden formwork 16 is set up, and the vertical reinforcement bars 15 are passed through the wooden formwork 16 and fixed in the area to be poured, and then the middle layer concrete 13 is poured.

[0082] S43, surface concrete pouring

[0083] like Fig.11 As shown, after the middle layer of concrete 13 hardens, the newly poured foundation reinforcement 17 is connected to the original foundation reinforcement 4, the bottom U-shaped clamp 18 is placed, the steel formwork 19 is fixed, and a tie point is set on the upper part of the steel formwork 19 to connect it to the ear 10 of the steel column 9 through the cable 11, and the surface concrete 14 is poured.

[0084] Finally, the newly poured foundation finished surface 20 is formed, such as Fig.12 .

[0085] The present invention not only improves the efficiency of pre-embedded grooving and ensures the construction accuracy of the hoisting of the steel column 9, but also the arrangement of the construction steps gives full play to the coordination of the existing structure with temporary measures, reduces the cost of temporary construction measures, and ensures the safety, efficiency and economy of the new core tube 2 on the existing foundation 1.

[0086] The present invention is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as various improvements are made using the method concept and technical solution of the present invention, or are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A construction method for connecting an existing foundation with a newly built core tube after a design change, characterized in that: The specific steps are: S1. Excavation of the connection area between the existing foundation (1) and the core tube (2): S11. Cutting area design: Connect the embedded parts area to form a ring belt, which is excavated as a whole. The groove width of the ring belt is b and the groove depth is h; The groove width b of the ring belt is 1-2 m on both sides of the cross-sectional width of the steel column (9), and the groove depth h of the ring belt is 0.2-0.5 m more than the designed buried depth of the steel column (9); S12, cutting plan design: According to the parameters of the lifting equipment, the ring belt is divided into several cutting blocks, and the length of the cutting block is l; According to the lifting height and working radius of the lifting equipment, refer to the manual of the lifting equipment to obtain the corresponding rated lifting capacity M0, and calculate the maximum weight M of the cut blocks according to M0 ≥ 1.3M, where 1.3 is the safety factor to avoid the influence of the lifting dynamic load, and then look up the table to obtain the bulk density of the concrete , calculate the volume of a single cut block , and according to the designed slot width b and slot depth h, the length of a single cutting block is calculated ; S13, cutting operation: The process is carried out in a sequential manner of water drilling, hole washing and lock saw cutting, specifically: First, construct the first cutting block D1, and use a water drill to vertically punch the edges B1, B2, and L1 to the depth , at depth Use a water drill to punch horizontally and insert the lock saw along the three sides of B1, B2, and L1 to the depth Cut horizontally at the position, lift the lock through the bottom to lift out the upper half of the concrete block of section D1; then use a water drill to vertically punch edges B1, B2, and L1 to the depth , at depth Use a water drill to punch horizontally and insert the lock saw along the three sides of B1, B2, and L1 to the depth The position is horizontally cut, and the lifting lock passes through the bottom to lift out the lower half of the concrete block of section D1; repeat the above operation to cut the subsequent blocks until all the concrete blocks are cut; After the cutting is completed, the exposed surface behind the cutting surface is roughened to form a new and old concrete interface (3), and the exposed steel bars are cleaned to expose the original foundation steel bars (4) at the new and old concrete interface (3); S2. Pre-buried construction: Arrange interface reinforcement holes (5) and column foot pre-embedded holes (6) at equal intervals in the horizontal and longitudinal directions along the interface between the new and old concrete (3); place reinforcement bars (7) in the interface reinforcement holes (5), and embed column foot pre-embedded keys (8) in the column foot pre-embedded holes (6); S3, hoisting steel column (9): The steel column (9) is hoisted into place, the embedded steel bar (7) is connected to the lifting lug (10) of the steel column (9) via a cable (11), and the steel column (9) is connected to the embedded key (8) at the column foot via bolts; S4. Concrete pouring: The concrete is poured in layers, which are divided into pouring of bottom layer concrete (12), pouring of middle layer concrete (13), and pouring of surface layer concrete (14).

2. A construction method for connecting an existing foundation with a newly built core tube after a design change according to claim 1, characterized in that: In step S13, the interface (3) between the new and old concrete is roughened, with the difference in height being no less than 6 mm.

3. A construction method for connecting an existing foundation with a newly built core tube after a design change according to claim 2, characterized in that: In step S3, the steel column (9) is hoisted using an external lifting machine, and the hoisting machine does not become unhooked during the installation process.

4. A construction method for connecting an existing foundation with a newly built core tube after a design change according to claim 3, characterized in that: In step S3, the lifting lug (10) is manufactured separately and welded to the flange of the steel column or is modified from the friction shear stud of the steel column.

5. A construction method for connecting an existing foundation with a newly built core tube after a design change according to claim 4, characterized in that: The specific steps of step S4 are: S41. Pouring of bottom concrete (12): In the pouring area of ​​the bottom concrete (12), erecting steel bars (15) are arranged and tied to the embedded steel bars (7) to form a stable spatial structure in a vertical and horizontal manner; erecting a wooden formwork (16), passing the erecting steel bars (15) through the wooden formwork (16) and fixing them in the area to be poured, and then pouring the bottom concrete (12); S42, pouring of intermediate layer concrete (13): After the bottom layer concrete (12) hardens, a frame steel bar (15) is arranged in the pouring area of ​​the middle layer concrete (13) and is tied to the embedded steel bar (7) to form a stable spatial structure by connecting them vertically and horizontally; a wooden formwork (16) is set up, and the frame steel bar (15) is passed through the wooden formwork (16) and fixed in the area to be poured, and then the middle layer concrete (13) is poured; S43, pouring of surface concrete (14): After the middle layer concrete (13) hardens, the newly poured foundation reinforcement (17) is connected to the original foundation reinforcement (4), the bottom U-shaped clamp (18) is placed, the steel formwork (19) is fixed, and a tie point is set on the upper part of the steel formwork (19) and connected to the ear (10) of the steel column (9) through a cable (11), and the surface layer concrete (14) is poured; Finally, a newly poured foundation finished surface (20) is formed.

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