Small-to-large node bottom-support-free construction method for ultrahigh variable-cross-section stand column

Abstract

The invention discloses a bottom-support-free construction method for a small-to-large joint of an ultrahigh variable-cross-section stand column. The bottom-support-free construction method comprises the following steps that S1, a formwork is selected; s2, reinforcing the template; s3, steel bars are installed; s4, concrete pouring; and S5, binding and reinforcing the formwork and the reinforcing steel bars, in the step S1, after the procedures of binding the reinforcing steel bars of the lower section stand column of the ultrahigh independent column and reinforcing the formwork are completed, a bridging piece formwork is installed, the plane size of a bridging piece is equal to the section size of the upper section stand column, the height of the bridging piece is 200-400 mm, in the step S2, batten back ridges are installed at the bottom of the bridging piece formwork, the distance between the batten back ridges and the upper section stand column is 100-300 mm, and the height of the batten back ridges is 100-300 mm. In the implementation process, the problem that when small-to-large joint segment construction is conducted on a large-section constraint edge column of a core tube structure, a bottom formwork support in an upper section stand column section increasing area is difficult to arrange is effectively solved, the working procedure of bottom supporting at the position is omitted, operation is convenient, the working procedure is simplified, and the construction efficiency and the construction reliability are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of construction methods for the bottom support of independent columns, and particularly to a construction method for avoiding the bottom support at the "small-to-large" node of a super-high variable-section column. Background Art

[0002] During the construction of a super-high-rise scientific research office building, the structural type is a core tube-steel frame structure. Among them, the core tube wall columns are independently constructed first using the climbing formwork process. The wall columns are reinforced with integral large steel formwork and scattered wooden formwork. There are "small-to-large" wall column nodes in the local structural design.

[0003] The traditional method for segmental construction of independent columns is to set the side formwork for the upper column segment, with the root being on the already cast concrete column of the lower segment. However, the key to constructing the "small-to-large" node of a super-high independent column lies in: the stable support of the bottom formwork for the enlarged cross-section part of the upper column segment, and it is necessary to ensure that the column bottom formwork can bear the self-weight and impact force of the concrete during the concrete pouring process of the upper column segment;

[0004] However, in the prior art, the variable-section node position of the super-high independent column is relatively high from the lower ground foundation. It is difficult to set the vertical support for the bottom formwork in the enlarged cross-section area of the column. At the same time, the side formwork of the lower column segment uses standardized steel formwork, and the process of setting the diagonal support on the side of the lower column segment is also relatively complex. This greatly increases the construction difficulty of the upper column segment at the "small-to-large" node of the variable-section wall column. Therefore, the present invention proposes a construction method for avoiding the bottom support at the "small-to-large" node of a super-high variable-section column to solve the above problems. Summary of the Invention

[0005] Based on the technical problem that in the background art, the variable-section node position of the super-high independent column is relatively high from the lower ground foundation, it is difficult to set the vertical support for the bottom formwork in the enlarged cross-section area of the column. At the same time, the side formwork of the lower column segment uses standardized steel formwork, and the process of setting the diagonal support on the side of the lower column segment is also relatively complex. This greatly increases the construction difficulty of the upper column segment at the "small-to-large" node of the variable-section wall column, the present invention proposes a construction method for avoiding the bottom support at the "small-to-large" node of a super-high variable-section column.

[0006] A construction method for avoiding the bottom support at the "small-to-large" node of a super-high variable-section column proposed by the present invention includes the following steps:

[0007] S1: Formwork selection;

[0008] S2: Formwork strengthening;

[0009] S3: Steel bar installation;

[0010] S4: Concrete pouring;

[0011] S5: Formwork and steel bar binding and reinforcement;

[0012] Preferably, in the step S1, after the steel bar binding and formwork reinforcement processes of the lower column of the ultra-high independent column are completed, the formwork installation of the cantilever slab is carried out. The plane size of the cantilever slab is the same as the cross-sectional size of the upper column, and the height is 200 - 400 mm.

[0013] Furthermore, the integral pouring of the cantilever slab and the lower column can be realized at one time.

[0014] Preferably, in the step S2, wooden square back ribs are installed at the bottom of the cantilever slab formwork, with a spacing of 100 - 300 mm.

[0015] Furthermore, the wooden square back ribs and the bottom formwork form an integral body, enhancing the overall stiffness of the wooden formwork and ensuring the stability during the pouring of the cantilever slab concrete without vertical supports for the plane formwork.

[0016] Preferably, in the step S3, the cantilever slab steel bars, additional steel bars and the hidden beam steel bars are installed successively in the cantilever slab formwork, and the additional steel bars are anchored into the lower column by at least 400 - 600 mm.

[0017] Furthermore, the integrity between the cantilever slab and the lower column is strengthened, and more loads can be borne on the cantilever slab.

[0018] Preferably, in the step S4, the concrete of the lower column and the cantilever slab is integrally poured.

[0019] Furthermore, the bottom (cantilever slab) of the upper column is pre-formed, providing a stable bottom formwork for the concrete pouring of the remaining height section of the upper column and eliminating the need for additional support settings.

[0020] Preferably, in the step S5, the steel bar binding and side formwork reinforcement of the remaining height section of the upper column are carried out, and finally the concrete is poured, and the hidden beam with a height of 700 - 900 mm at the column bottom is set synchronously.

[0021] Furthermore, additional steel bar construction measures are added at the "small to large" cross-section position of the independent column, and finally the segmented construction of the ultra-high variable cross-section independent column is completed.

[0022] Preferably, it includes a lower column and an upper column. The lower column is installed at the bottom of the upper column. A cantilever slab formwork is installed on the upper column. Wooden square back ribs are installed on the cantilever slab formwork. Cantilever slab steel bars and additional steel bars are installed inside the cantilever slab formwork. A pile bottom hidden beam is installed on the right side of the bottom of the upper column, and a cantilever slab is arranged at the bottom of the pile bottom hidden beam.

[0023] Preferably, hidden beam steel bars are arranged on the pile bottom hidden beam.

[0024] The beneficial effects of the present invention:

[0025] In the process of implementation, the present invention effectively solves the problem that it is difficult to set the bottom formwork support for the enlarged area at the bottom of the upper column during the segmented construction of the "small-to-large" joint of the large-section boundary column in the core tube structure, omits the process of bottom support at this position, is convenient to operate, simplifies the process, and significantly improves the construction efficiency and reliability of construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The front view of the independent column proposed by the present invention

[0027] Figure 2 The working flow chart proposed by the present invention.

[0028] In the figure: 1, lower column; 2, upper column; 3, cantilever slab; 4, cantilever slab formwork; 5, cantilever slab steel bars; 6, additional steel bars; 7, wooden square back ribs; 8, pile bottom concealed beam; 9, concealed beam steel bars. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The present invention will be further described below in conjunction with specific embodiments.

[0030] Refer to Figure 1 , Embodiment 1

[0031] A construction method for the "small-to-large" joint of a super-high variable-section column without bottom support is proposed in this embodiment, including the following steps:

[0032] S1: Formwork selection. After the steel bar binding and formwork reinforcement processes of the lower column 1 of the super-high independent column are completed, the cantilever slab formwork 4 is installed. The plane size of the cantilever slab 3 is the same as the cross-sectional size of the upper column 2, and the height is 300 mm, which can realize the one-time integral pouring of the cantilever slab 3 and the lower column 1;

[0033] S2: Formwork strengthening. The wooden square back ribs 7 are installed at the bottom of the cantilever slab formwork 4 with a spacing of 200 mm. The wooden square back ribs 7 form an integral body with the bottom formwork, enhancing the overall stiffness of the wooden formwork and ensuring the stability during the concrete pouring of the cantilever slab 3 without vertical support for the plane formwork;

[0034] S3: Steel bar installation. The cantilever slab steel bars 5, additional steel bars 6, and concealed beam steel bars 9 are installed successively in the cantilever slab formwork 4. Among them, the additional steel bars 6 are anchored into the lower column by at least 500 mm, strengthening the integrity of the cantilever slab 3 and the lower column and enabling the cantilever slab 3 to bear more loads;

[0035] S4: Concrete pouring. The concrete of the lower column 1 and the cantilever slab 3 is integrally poured. The cantilever slab 3 at the bottom of the upper column 2 is pre-formed, providing a stable bottom formwork for the concrete pouring of the remaining height section of the upper column 2 and eliminating the need for additional support setting;

[0036] S5: Template and steel bar binding and reinforcement. Carry out the binding of steel bars for the remaining height section of the upper column 2 and the reinforcement of the side formwork. Finally, pour concrete, and simultaneously complete the setting of the concealed beam with a height of 800 mm at the column bottom. Additional steel bar construction measures are added at the "small to large" cross-section position of the independent column, and finally complete the segmented construction of the super-high variable cross-section independent column;

[0037] The lower column 1 and the upper column 2. The lower column 1 is installed at the bottom of the upper column 2. A cantilever slab formwork 4 is installed on the upper column 2. A wooden square backing 7 is installed on the cantilever slab formwork 4. Cantilever slab steel bars 5 and additional steel bars 6 are installed inside the cantilever slab formwork 4. A pile bottom concealed beam 8 is installed on the right side at the bottom of the upper column 2. A cantilever slab 3 is arranged at the bottom of the pile bottom concealed beam 8. Concealed beam steel bars 9 are arranged on the pile bottom concealed beam 8.

[0038] Refer to Figure 1 , Embodiment 2

[0039] In this embodiment, a construction method for the "small to large" node of a super-high variable cross-section column without bottom support is proposed, including the following steps:

[0040] S1: Template selection. After the binding of steel bars and the reinforcement of the formwork for the lower column 1 of the super-high independent column are completed, install the cantilever slab formwork 4. The plane size of the cantilever slab 3 is the same as the cross-section size of the upper column 2, and the height is 290 mm, which can realize the one-time integral pouring of the cantilever slab 3 and the lower column 1;

[0041] S2: Template strengthening. Install a wooden square backing 7 at the bottom of the cantilever slab formwork 4, with a spacing of 210 mm. The wooden square backing 7 forms an integral body with the bottom formwork, enhancing the overall stiffness of the wooden formwork and ensuring the stability during the pouring of the concrete of the cantilever slab 3 without vertical support for the plane formwork;

[0042] S3: Steel bar installation. Install the cantilever slab steel bars 5, additional steel bars 6 and concealed beam steel bars 9 inside the cantilever slab formwork 4 in sequence. Among them, the additional steel bars 6 are anchored into the lower column by at least 310 mm, strengthening the integrity of the cantilever slab 3 and the lower column, and enabling the cantilever slab 3 to bear more loads;

[0043] S4: Concrete pouring. Pour the concrete of the lower column 1 and the cantilever slab 3 integrally. The cantilever slab 3 at the bottom of the upper column 2 is pre-formed, providing a stable bottom formwork for the pouring of the concrete of the remaining height section of the upper column 2, eliminating the need for additional support settings;

[0044] S5: Template and steel bar binding and reinforcement. Carry out the binding of steel bars for the remaining height section of the upper column 2 and the reinforcement of the side formwork. Finally, pour concrete, and simultaneously complete the setting of the concealed beam with a height of 790 mm at the column bottom. Additional steel bar construction measures are added at the "small to large" cross-section position of the independent column, and finally complete the segmented construction of the super-high variable cross-section independent column;

[0045] The lower column 1 and the upper column 2, the lower column 1 is installed at the bottom of the upper column 2, a cantilever slab formwork 4 is installed on the upper column 2, a square timber backing 7 is installed on the cantilever slab formwork 4, cantilever slab steel bars 5 and additional steel bars 6 are installed inside the cantilever slab formwork 4, a pile bottom concealed beam 8 is installed on the right side at the bottom of the upper column 2, a cantilever slab 3 is arranged at the bottom of the pile bottom concealed beam 8, and concealed beam steel bars 9 are arranged on the pile bottom concealed beam 8.

[0046] Refer to Figure 1 , Embodiment 3

[0047] In this embodiment, a construction method for the "small to large" node of a super-high variable cross-section column without bottom support is proposed, including the following steps:

[0048] S1: Formwork selection. After the steel bar binding and formwork reinforcement procedures of the lower column 1 of the super-high independent column are completed, the cantilever slab formwork 4 is installed. The plane size of the cantilever slab 3 is the same as the cross-section size of the upper column 2, and the height is 310 mm, which can realize the one-time integral pouring of the cantilever slab 3 and the lower column 1;

[0049] S2: Formwork strengthening. Square timber backings 7 are installed at the bottom of the cantilever slab formwork 4 with a spacing of 220 mm. The square timber backings 7 form an integral body with the bottom formwork, enhancing the overall stiffness of the wooden formwork and ensuring the stability during the concrete pouring of the cantilever slab 3 without vertical support for the plane formwork;

[0050] S3: Steel bar installation. The cantilever slab steel bars 5, additional steel bars 6 and concealed beam steel bars 9 are successively installed inside the cantilever slab formwork 4. Among them, the additional steel bars 6 are anchored into the lower column by at least 490 mm, strengthening the integrity of the cantilever slab 3 and the lower column, and enabling the cantilever slab 3 to bear more loads;

[0051] S4: Concrete pouring. The concrete of the lower column 1 and the cantilever slab 3 is integrally poured. The cantilever slab 3 at the bottom of the upper column 2 is pre-formed, providing a stable bottom formwork for the concrete pouring of the remaining height section of the upper column 2 and eliminating the need for additional support settings;

[0052] S5: Formwork and steel bar binding and reinforcement. The steel bar binding and side formwork reinforcement of the remaining height section of the upper column 2 are carried out, and finally the concrete is poured. The 810 mm high concealed beam at the column bottom is set synchronously, and additional steel bar construction measures are added at the "small to large" cross-section position of the independent column, and finally the sectional construction of the super-high variable cross-section independent column is completed;

[0053] The lower column 1 and the upper column 2, the lower column 1 is installed at the bottom of the upper column 2, a cantilever slab formwork 4 is installed on the upper column 2, a square timber backing 7 is installed on the cantilever slab formwork 4, cantilever slab steel bars 5 and additional steel bars 6 are installed inside the cantilever slab formwork 4, a pile bottom concealed beam 8 is installed on the right side at the bottom of the upper column 2, a cantilever slab 3 is arranged at the bottom of the pile bottom concealed beam 8, and concealed beam steel bars 9 are arranged on the pile bottom concealed beam 8.

[0054] Reference Figure 1 , Example 4

[0055] In this embodiment, a construction method for the bottom - support - free "small - to - large" node of a super - high variable - section column is proposed, including the following steps:

[0056] S1: Template selection. After the steel bar binding and formwork reinforcement processes of the lower column 1 of the super - high independent column are completed, the formwork 4 of the cantilever slab is installed. The plane size of the cantilever slab 3 is the same as the cross - section size of the upper column 2, and the height is 300 mm, which enables the integral pouring of the cantilever slab 3 and the lower column 1 at one time;

[0057] S2: Formwork strengthening. Install the wooden square back - brace 7 at the bottom of the formwork 4 of the cantilever slab, with a spacing of 190 mm. The wooden square back - brace 7 forms an integral body with the bottom formwork, enhancing the overall stiffness of the wooden formwork and ensuring the stability during the concrete pouring of the cantilever slab 3 without vertical support for the plane formwork;

[0058] S3: Steel bar installation. Install the steel bars 5 of the cantilever slab, additional steel bars 6, and the steel bars 9 of the concealed beam in the formwork 4 of the cantilever slab in sequence. Among them, the additional steel bars 6 are anchored into the lower column by at least 500 mm, strengthening the integrity between the cantilever slab 3 and the lower column and enabling the cantilever slab 3 to bear more loads;

[0059] S4: Concrete pouring. Pour the concrete of the lower column 1 and the cantilever slab 3 integrally. The cantilever slab 3 at the bottom of the upper column 2 is pre - formed, providing a stable bottom formwork for the concrete pouring of the remaining height section of the upper column 2 and eliminating the need for additional support settings;

[0060] S5: Formwork and steel bar binding and reinforcement. Bind the steel bars of the remaining height section of the upper column 2 and reinforce the side formwork. Finally, pour the concrete, and synchronously complete the setting of the concealed beam with a height of 795 mm at the column bottom. Additional steel bar construction measures are added at the "small - to - large" cross - section position of the independent column, and finally complete the segmented construction of the super - high variable - section independent column;

[0061] The lower column 1 and the upper column 2, the lower column 1 is installed at the bottom of the upper column 2. There is a formwork 4 of the cantilever slab installed on the upper column 2, a wooden square back - brace 7 installed on the formwork 4 of the cantilever slab, steel bars 5 of the cantilever slab and additional steel bars 6 installed inside the formwork 4 of the cantilever slab. There is a concealed beam 8 at the bottom of the right side of the upper column 2, a cantilever slab 3 is arranged at the bottom of the concealed beam 8 at the pile bottom, and steel bars 9 of the concealed beam are arranged on the concealed beam 8 at the pile bottom.

[0062] Reference Figure 1 , Example 5

[0063] In this embodiment, a construction method for the bottom - support - free "small - to - large" node of a super - high variable - section column is proposed, including the following steps:

[0064] S1: Template Selection. After the steel bar binding and formwork reinforcement of the lower column 1 of the ultra-high independent column are completed, the cantilever slab formwork 4 is installed. The plane size of the cantilever slab 3 is the same as the cross-sectional size of the upper column 2, and the height is 305 mm, enabling the integral casting of the cantilever slab 3 and the lower column 1 at one time.

[0065] S2: Formwork Strengthening. Install the wooden square back ribs 7 at the bottom of the cantilever slab formwork 4 with a spacing of 200 mm. The wooden square back ribs 7 and the bottom formwork form a whole, enhancing the overall stiffness of the wooden formwork and ensuring the stability during the concrete pouring of the cantilever slab 3 without vertical supports for the plane formwork.

[0066] S3: Steel Bar Installation. Install the cantilever slab steel bars 5, additional steel bars 6, and the hidden beam steel bars 9 in the cantilever slab formwork 4 in sequence. Among them, the additional steel bars 6 are anchored into the lower column by at least 510 mm, strengthening the integrity between the cantilever slab 3 and the lower column and enabling the cantilever slab 3 to bear more loads.

[0067] S4: Concrete Pouring. Pour the concrete of the lower column 1 and the cantilever slab 3 integrally. The cantilever slab 3 at the bottom of the upper column 2 is pre-formed, providing a stable bottom formwork for the concrete pouring of the remaining height section of the upper column 2 and eliminating the need for additional support settings.

[0068] S5: Formwork and Steel Bar Binding and Reinforcement. Carry out the steel bar binding and side formwork reinforcement of the remaining height section of the upper column 2, and finally pour the concrete, synchronously completing the setting of the hidden beam with a height of 800 mm at the column bottom. Additional steel bar construction measures are added at the position where the cross-section of the independent column "changes from small to large", and finally the segmented construction of the ultra-high variable cross-section independent column is completed.

[0069] The lower column 1 and the upper column 2. The lower column 1 is installed at the bottom of the upper column 2. The cantilever slab formwork 4 is installed on the upper column 2. The wooden square back ribs 7 are installed on the cantilever slab formwork 4. The cantilever slab steel bars 5 and the additional steel bars 6 are installed inside the cantilever slab formwork 4. The pile bottom hidden beam 8 is installed on the right side at the bottom of the upper column 2. The cantilever slab 3 is arranged at the bottom of the pile bottom hidden beam 8. The hidden beam steel bars 9 are arranged on the pile bottom hidden beam 8.

[0070] Working Principle: When constructing the lower column 1, a cantilever slab 3 and a hidden beam are set at the upper part of the column head. The cross-sectional size of this cantilever slab 3 is the same as that of the upper column, which can be used as the foundation for the construction of the upper column. After the steel bar binding and formwork reinforcement of the lower column are completed, the cantilever slab formwork 4 is installed, and the plane range covers the area where the cross-section of the upper column increases. The wooden square back ribs 7 are installed on the cantilever slab formwork 4. The cantilever slab steel bars 5 and the additional steel bars 6 are arranged inside the cantilever slab formwork 4. The cantilever slab 3 and the lower column are integrally poured with concrete. The column bottom hidden beam is arranged at the bottom of the upper column 2. The cantilever slab 3 is arranged at the bottom of the column bottom hidden beam, and the cantilever slab 3 is used as the column bottom formwork for the concrete pouring of the remaining height section of the upper column 2.

[0071] Comparing the conventional construction method for the bottom support of columns with the construction methods for the bottom support of columns obtained in Embodiments 1 to 5, the construction methods obtained in Embodiments 1 to 5 are as follows in the table:

[0072]

[0073] As can be seen from the above table, the construction method for the "small-to-large" node of the ultra-high variable cross-section column without bottom support proposed by the present invention has been significantly improved, and Embodiment 1 is the best embodiment.

[0074] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A construction method for a "small to large" node of an ultra-high variable-section column without bottom support, characterized in that: The following steps are involved: S1: template selection; S2: template strengthening; S3: Steel bar installation; S4: Concrete pouring; S5: Formwork and steel bar binding reinforcement.

2. According to claim 1, a construction method for a "small to large" node of an ultra-high variable-section column without bottom support is characterized in that: In the step S1, after the steel bar binding and formwork reinforcement process of the lower column (1) of the super-high independent column is completed, the cantilever plate formwork (4) is installed. The plane size of the cantilever plate (3) is the same as the cross-sectional size of the upper column (2), and the height is 200-400 mm.

3. The construction method of a "small to large" node of an ultra-high variable-section column according to claim 1 is characterized in that: In the step S2, wooden back ribs (7) are installed at the bottom of the cantilever board template (4) with a spacing of 100-300 mm.

4. The construction method of a super-high variable-section column "small to large" node without bottom support according to claim 1 is characterized in that: In the step S3, the cantilever plate reinforcement (5), the additional reinforcement (6) and the hidden beam reinforcement (9) are installed in the cantilever plate formwork (4) in sequence, wherein the additional reinforcement (6) is anchored into the lower column by at least 400-600 mm.

5. The construction method of a "small to large" node of an ultra-high variable-section column according to claim 1 is characterized in that: In step S4, the lower column (1) and the cantilever plate (3) are integrally poured with concrete.

6. The construction method of a "small to large" node of an ultra-high variable cross-section column according to claim 1 is characterized in that: In step S5, the remaining height section of the upper column (2) is reinforced with steel bars and the side formwork is reinforced, and finally concrete is poured, and the 700-900 mm high hidden beam at the bottom of the column is simultaneously set.

7. According to claim 1, a construction method for a "small to large" node of an ultra-high variable-section column without bottom support comprises a lower column (1) and an upper column (2), characterized in that: The lower column (1) is mounted on the bottom of the upper column (2); a cantilever board template (4) is mounted on the upper column (2); a wooden back rib (7) is mounted on the cantilever board template (4); cantilever board reinforcement (5) and additional reinforcement (6) are mounted on the inner side of the cantilever board template (4); a pile bottom hidden beam (8) is mounted on the right side of the bottom of the upper column (2); and a cantilever board (3) is arranged at the bottom of the pile bottom hidden beam (8).

8. The construction method of the "small to large" node of the super-high variable-section column according to claim 7 is characterized in that: The pile bottom hidden beam (8) is provided with hidden beam steel bars (9).

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