Construction method for superposed cantilever concrete structure of high-rise building

Abstract

The invention discloses a construction method for a superposed cantilever concrete structure of a high-rise building. The construction method comprises the following steps of construction preparation, processing and manufacturing of supporting system components, construction of a lower small triangular supporting system, installation of upper trapezoidal supporting system components, erection of a full-space supporting frame, construction of a superposed cantilever layer structure, formwork removal, and inspection and acceptance of a cast-in-place structure. Wherein construction of the lower small triangular supporting system and installation of components of the upper trapezoidal supporting system jointly form a stable triangular supporting system, the stress and transmission mode of the structural system is optimized twice, a cantilever is changed into a simple support, and the unloading mode is simplified from a complex mode. And collapse accidents caused by the fact that the overhanging I-shaped steel cannot bear upper loads are avoided. And the problems of positions, lengths and the like of inner and outer anchoring points of the I-shaped steel are not limited any more. And the used materials can be recycled, so that resources are saved, and the cost is greatly reduced. The construction technology is mature, operation is easy, convenient and fast, and high applicability and generalizability are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of construction, in particular to a high-rise building superimposed cantilever concrete structure construction method. BACKGROUND

[0002] With the development of construction engineering, the application scenarios of unique and beautiful house shapes are more and more, in order to realize the demand of the owner, the designer often makes some special treatment on the structure. In the construction of high-rise building, the building outer structure is protruding cantilever on the basis of the cantilever, so that the superimposed cantilever structure appears.

[0003] For the construction of the above superimposed cantilever structure, it is found through research that the main construction difficulty is the construction of the formwork support system, which makes it difficult to realize the superimposed cantilever structure, as follows: Firstly, the traditional formwork support system adopts the method of manufacturing steel platform, which is complex, large in steel quantity, high in manufacturing cost, and after use, the steel can only be recycled as waste, causing resource waste; Secondly, the cantilever I-beam is used as the formwork support system. First of all, the outer anchoring point of the conventional cantilever I-beam is generally set at the end of the lower structure, and the end of the lower structure is a cantilever structure, so that the remaining load of the upper cantilever steel beam after compensation is all borne by the lower cantilever structure. Since the load bearing capacity of the lower cantilever structure is limited, it is difficult to achieve; Thirdly, change the outer anchoring point of the cantilever I-beam to the root of the lower cantilever structure. Due to the limitation of the size of the I-beam (generally 9m), the anchoring length is insufficient (less than 3m), so the cantilever I-beam system cannot bear the remaining load of the upper part; Fourthly, the size of the I-beam is increased, but when arranged in plane, there will be a problem of crossing and not being able to arrange, so it is also impossible to achieve. SUMMARY

[0004] The present application proposes a high-rise building superimposed cantilever concrete structure construction method, which can effectively solve the problems mentioned in the background art; In order to achieve the above purpose, the present application adopts the following technical scheme.

[0005] A high-rise building superimposed cantilever concrete structure construction method, comprising the following steps: S1, construction preparation: S11, personnel allocation, engineering materials, mechanical equipment and tools and equipment; S12, special construction scheme and expert demonstration, bearing capacity calculation of lower cantilever concrete structure.

[0006] When the lower cantilever concrete structure cannot bear the load transmitted from the upper part, structural reinforcement measures should be developed and implemented in advance; or continuous multi-layered underbrace I-beams are provided until the load effect is completely eliminated.

[0007] S13, scheme disclosure, before construction, the construction unit should make special disclosure according to the relevant provisions on the special construction scheme which has been demonstrated and passed.

[0008] S2, support system component support system component processing, manufacturing The support system component includes cantilever I-beam, coupling beam I-beam, underbrace I-beam, tie I-beam, cantilever I-beam anchor ring, underbrace end connection embedded part, and underbrace bottom connection embedded part.

[0009] S21, I-beam blanking (i.e. cantilever I-beam, coupling beam I-beam, underbrace I-beam, tie I-beam blanking) includes the following steps: S211, selecting I-beam; S212, cutting I-beam, and numbering and marking the cut blanking I-beam.

[0010] S213, I-beam notch end face treatment (i.e. the end face should be flat); polishing the I-beam notch end face to be smooth.

[0011] S22, cantilever I-beam anchor ring processing, manufacturing S221, the anchor ring is made of round steel. The round steel is bent into a "U" shape.

[0012] The length of the bent anchor of the anchor ring should meet the specification requirements and reach the lower position of the structural steel bar. The round steel used is ≥φ16 round steel.

[0013] S222, anchor ring thread making, The anchor ring thread should be continuous and smooth, and the thread length should meet the requirements of double nuts and exposed thread length.

[0014] S23, underbrace connection embedded part processing, manufacturing S231, determining the type of underbrace connection embedded part, the underbrace connection embedded part includes: underbrace I-beam end embedded part, underbrace I-beam root embedded part, and tie I-beam connection embedded part.

[0015] S232, the underbrace connection embedded part is formed by steel plate panel and anchor bolt welding.

[0016] The steel plate panel has a length and width cross-sectional dimension greater than the end face size of the connection I-beam, and the thickness is preferably ≥10mm thick; The anchor bolt is made of 4 ≥φ12 steel bars bent into anchors; The length of the bent anchor can meet the requirements of the end and tie beam plate structure position, root and vertical structure connection, respectively.

[0017] S3, lower small triangular support system construction According to the construction sequence of the engineering structure, the construction sequence of the support system is: lower support I-beam root part pre-embedded part pre-embedding → lower support I-beam end part pre-embedded part pre-embedding → lower small triangular support system lower support I-beam installation.

[0018] S31, lower support I-beam root part pre-embedded part pre-embedding S311, the lower support I-beam root part pre-embedded part is buried synchronously with the construction of the lower structure; when there is a structural column, it is buried outside the column root part; when there is no structural column, it is buried in the center line position of the column beam.

[0019] S312, the burial is strictly carried out in accordance with the requirements of “Concrete Structure Engineering Construction Specification” GB50666 and “Concrete Structure Engineering Construction Quality Acceptance Specification” GB50204.

[0020] S313, BIM technology should be used to assist accurate positioning, and after pre-embedding, all are checked before pouring the structure concrete, and cannot be missed.

[0021] S314, the bent anchor steel bar of the lower support I-beam root part pre-embedded part is welded with the additional steel bar and then connected with the main reinforcement by binding; the additional steel bar L is greater than or equal to 1000mm; the elevation of the panel steel plate is consistent with the elevation of the cast-in-place concrete surface layer after completion; the film protection treatment is taken on the panel before pouring the concrete.

[0022] S32, lower support I-beam end part pre-embedded part pre-embedding The lower support I-beam end part pre-embedded part is buried synchronously with the construction of the lower structure, and is buried in the center position of the lower cantilever structure end beam. Its construction process and operation requirements are the same as those of the lower support I-beam root part pre-embedded part pre-embedding.

[0023] S33, lower support I-beam installation S331, before installing the lower support I-beam, the lower support connection pre-embedded part (lower support I-beam end part and lower support I-beam root part pre-embedded part) is checked and cleaned.

[0024] S332, the lower support I-beam is hoisted to the installation position, and the end part and the root part of the lower support I-beam are aligned with the steel plate panel of the lower support connection pre-embedded part.

[0025] S333, after the lower support I-beam is in place, two welders simultaneously perform welding operations at the end part and the root part. First, spot welding is performed for temporary support, and then overall welding is performed. After welding is completed, the lifting cable is removed.

[0026] S334, after welding is completed, the welding quality is checked.

[0027] S4, upper trapezoidal support system component installation According to the construction sequence of the engineering structure, the support system construction sequence is: tie I-beam connecting embedded part installation → cantilever I-beam anchor ring embedding → cantilever and beam I-beam installation → lower support I-beam installation of the upper trapezoidal support system → tie I-beam installation.

[0028] S41, tie I-beam connecting embedded part embedding The tie I-beam connecting embedded part is embedded in the lower cantilever structure root beam synchronously with the construction of the lower structure.

[0029] S42, cantilever I-beam anchor ring installation S421, the anchor ring is embedded synchronously when installing the reinforced steel of the superimposed cantilever lower structure.

[0030] S422, at least 2 anchor rings are embedded for each I-beam, the outer anchor ring is arranged at the center position of the cantilever structure beam (or beam), and the inner anchor ring is arranged at a distance of ≥20 cm from the tail end of the I-beam.

[0031] S423, the anchor ring is firmly welded with the main reinforcement through additional reinforcement; Two additional reinforcements are added on each side of the anchor ring, and the additional reinforcements are all φ10 or more reinforcements, and the additional reinforcement L is ≥1500 mm.

[0032] S424, after the embedding is completed, all are checked before the structure concrete pouring, and no omission is allowed.

[0033] S43, cantilever I-beam installation S431, after the lower structure concrete pouring is completed, the cantilever I-beam is hoisted to the structure floor of the lower layer.

[0034] S432, the cantilever I-beam is first inserted into the anchor ring, and then the resting position is adjusted accurately.

[0035] S433, a steel plate pressing plate is arranged on the upper part of the anchor ring, the end part is initially screwed, the wooden wedge is laterally wedged on both sides, the end part nut is finally screwed, and the cantilever I-beam installation is sequentially completed.

[0036] S44, beam I-beam installation After the cantilever I-beam installation is completed, the beam I-beam is hoisted to the cantilever I-beam, and the resting position is adjusted. The bottom of the beam I-beam is connected by welding with the cantilever I-beam.

[0037] S45, lower support I-beam installation The lower support I-beam installation in this process is implemented after the cantilever and beam I-beam installation is completed. The construction process and operation points are the same as the lower support I-beam installation (S3, lower support I-beam installation in S33, lower support I-beam installation in the construction of the lower small triangular support system) in the lower small triangular support system of the present method.

[0038] S46, installation of tie I-beam S461, before installation of tie I-beam, check and clean the end part embedded part of lower support I-beam and the connecting embedded part of tie I-beam.

[0039] S462, place the lower support I-beam to the installation position, align the end part of tie I-beam with the steel plate panel of connecting embedded part of tie I-beam, and vertically set the tie I-beam on the lower support I-beam to complete the installation.

[0040] S463, after installation of tie I-beam, simultaneously perform welding operation at the end part and the root part. First, spot welding is performed for temporary support, and then overall welding is performed.

[0041] S464, after welding is completed, check the welding quality.

[0042] S5, erection of full-support frame The erection of full-support frame is strictly in accordance with the design drawing of special construction scheme, the current "Safety Technical Standard for Steel Tubular Scaffolding with Couplers for Building Construction" JGJ130, and "Safety Technical Standard for Steel Tubular Scaffolding with Disc Locks for Building Construction" JGJ / T231. The following matters should also be well done: The erection of full-support frame is performed after the completion and acceptance of all cantilever I-beams, coupling I-beams, and tie I-beams.

[0043] Before erection, first, complete the erection of outside protection frame according to the design drawing of scheme, so as to form a safe and closed operation platform at the cantilever part.

[0044] Before erection, according to the design drawing, weld positioning steel bars at the upper part of all coupling I-beams according to the position of formwork support frame vertical rod.

[0045] S6, construction of superimposed cantilever layer structure S61, vertical structure construction The vertical structure construction includes steel bar binding of column and wall, installation of formwork, concrete pouring and curing.

[0046] The construction can be performed in strict accordance with the design drawing, the current "Concrete Structure Engineering Construction Quality Acceptance Standard" GB50204, and "Concrete Structure Engineering Construction Standard" GB50666.

[0047] S62, construction of structural beam and slab The construction of structural beam and slab includes installation of formwork, steel bar binding, concrete pouring and curing. The construction is strictly in accordance with the design drawing, the current "Concrete Structure Engineering Construction Quality Acceptance Standard" GB50204, and "Concrete Structure Engineering Construction Standard" GB50666. The following matters should also be well done: (1) Must be in the vertical structure of concrete pouring is completed, and the concrete strength reaches more than 75% after.

[0048] (2) Concrete pouring must meet the following requirements: ① The concrete pouring of overhanging parts should be poured uniformly from inside to outside, first pouring the non-overhanging parts, and then pouring the overhanging parts.

[0049] ② Strictly prohibit personnel to concentrate in the same position of the overhanging part during pouring.

[0050] ③ The concrete pile height of the overhanging part is strictly prohibited to protrude 100mm from the board surface.

[0051] S7, form removal Strictly according to the current relevant standards and specifications of "Concrete Structure Engineering Construction Specification" GB50666, the following matters should also be paid attention to: 1. Demolition time requirement Strictly control the demolition time, the form removal of the overhanging part must meet the following conditions at the same time.

[0052] (1) The concrete strength reaches 100%.

[0053] (2) The concrete of the upper structure layer has been poured.

[0054] (3) When the static and dynamic load combination of the upper structure layer is large, it should be reviewed to meet the load requirements of the upper structure layer concrete.

[0055] 2. Demolition sequence requirement (1) According to the design provisions of the form. When there is no design, the principle of "first support and then remove, then support and then remove, first remove non-bearing form, then remove bearing form, from top to bottom" can be adopted.

[0056] (2) First remove the upper trapezoidal support system, and then remove the lower small triangular support system.

[0057] S8, inspection and acceptance of cast-in-place structure After the structure layer construction is completed, and after the formwork and support system are all removed, according to the requirements of the current standards and specifications of "Concrete Structure Engineering Construction Quality Acceptance Specification" GB50204, "Building Engineering Construction Quality Unified Acceptance Standard" GB50300, "Concrete Structure Site Detection Technical Standard" GB / T50784, the cast-in-place structure is inspected and accepted, including: beam slab column concrete strength, floor thickness, reinforcement protection layer, axis, column perpendicularity, geometric size.

[0058] The beneficial effects of the prior art are: Firstly, the load transfer and stress path of the present application is clear, safe and reliable. Most of the upper load is borne by the vertical stiffness of the lower support I-beam of the upper "ladder-shaped formwork support system" and the overall strength of the poured concrete, and the remaining load is transferred downward. The lower "small triangle formwork support system" bears the load transferred downward from the upper part and transfers it to the lower non-cantilever structure, ensuring the stiffness and stability of the entire formwork support system.

[0059] Secondly, the present application forms a stable "triangular support system" by the joint action of the "upper ladder" and "lower small triangle" support systems, and optimizes the structure system stress and transfer form twice, changing from cantilever to simple support and from complex to simple unloading mode.

[0060] Thirdly, the present application uses the "upper ladder" support system to change the stress form of the cantilever I-beam. The cantilever I-beam mainly serves as the platform and force transmission component of the upper full-support frame, and partially bears the upper load. The remaining load is transferred to the lower non-cantilever component through the "lower small triangle" support system. The upper and lower layers work together and will not collapse due to the cantilever I-beam unable to bear the upper load. Moreover, the inner and outer anchoring points of the cantilever I-beam only serve as fixing points, and the position and length of the inner and outer anchoring points of the I-beam are no longer restricted.

[0061] Fourthly, the materials used in the present application are common, easy to obtain, and can be recycled and leased for use, saving resources and significantly reducing costs.

[0062] Fifthly, the present application improves the traditional construction technology, and the construction technology is mature, simple, convenient and fast, and has strong applicability and generalizability. BRIEF DESCRIPTION OF DRAWINGS

[0063] Figure 1 It is a system schematic diagram of the process principle of the large triangular support system of the present application. Figure 2 It is a schematic diagram of the upper ladder-shaped support system of the present application. Figure 3 It is a schematic diagram of the lower small triangle support system of the present application. Figure 4 It is a process flow chart of the present application. Figure 5 It is a schematic diagram of the inboard anchor ring (left) and beam inner anchor ring (right) of the present application. Figure 6 It is a schematic diagram of the finished product of the connecting embedded part from the front view (left), side view (middle) and top view (right) of the present application. Figure 7 It is a schematic diagram of the beam inner embedded part (left) and column inner embedded part (right) of the present application. Figure 8Fig. 1 is a schematic diagram of the pre-buried in-slab anchor ring (left) and the pre-buried in-beam anchor ring (right) of the present application; Figure 9 Fig. 2 is a schematic diagram of the installation of the cantilevered I-beam of the present application; Figure 10 Fig. 3 is a schematic diagram of the positioning of the vertical support pole of the cantilevered I-beam formwork of the present application; In the figure: 101. Non-cantilevered part, 102. First cantilevered part, 103. Second cantilevered part, 104. Superimposed cantilevered layer, 105. Lower layer, 106. Lower layer, 107. Upper trapezoidal support system, 108. Lower small triangular support system, 109. Large triangular support system, 201. Cantilevered I-beam, 202. Coupling I-beam, 203. Lower support I-beam, 204. Tied I-beam, 205. Anchor ring, 206. Lower support I-beam end pre-buried part, 207. Lower support I-beam root pre-buried part, 208. Tied I-beam connecting pre-buried part, 209. Additional steel bars, 210. Wooden wedge, 301. External frame, 302. Safety cantilevered net, 303. Positioning steel bars. DETAILED DESCRIPTION

[0064] Example 1, refer to the attached Figures 1-10 A construction method for superimposed cantilevered concrete structure of high-rise building, comprising the following steps: I. Construction preparation of support system components In addition to personnel allocation, engineering materials, mechanical equipment and tools and equipment entering the site according to the conventional reinforced concrete structure construction, the following preparations need to be focused on: 1. Special construction scheme and expert demonstration Before construction, the construction unit shall prepare a special construction scheme in accordance with the requirements (Ministry of Housing and Urban-Rural Development Order No. 37, Construction Quality Management Office Document No. 31, Construction Quality Management Office Document No. 48, etc.), and organize expert demonstration. After passing, the construction can be organized.

[0065] When preparing the special construction scheme, the bearing capacity of the lower layer 104 cantilevered concrete structure shall be calculated. When the calculation determines that the lower layer 104 cantilevered concrete structure cannot bear the load transmitted from the upper part, structural reinforcement measures shall be developed and implemented in advance, or a lower support I-beam 203 is provided for continuous multiple layers until the load influence is completely eliminated. The reinforcement measures shall be reviewed and confirmed by the design unit.

[0066] 2. Scheme briefing Before construction, the construction unit shall conduct special briefing on the special construction scheme that has been demonstrated and passed in accordance with relevant regulations.

[0067] II. Processing and manufacturing of support system components Support system components include cantilever I-beam 201, beam I-beam 202, lower support I-beam 203, tie I-beam 204, cantilever I-beam anchor ring 205, lower support connection embedded parts. All components should be processed and manufactured in the factory, cutting, welding, threading should be carried out by special equipment.

[0068] 1. I-beam blanking (i.e. cantilever I-beam 201, beam I-beam 202, lower support I-beam 203, tie I-beam 204 blanking) (1) The material of the I-beam should be qualified, its specifications, models, etc. should meet the design requirements, the I-beam should be straight, without bending and twisting, without damage, corrosion, etc. on the surface. The welding quality of the I-beam extended by welding should meet the current "Steel Structure Welding Specification" GB50661.

[0069] (2) The length of the I-beam blanking should meet the design drawing requirements. The I-beam after blanking should be numbered and marked with the position of connection and welding for easy installation.

[0070] (3) The cut end face should be smooth, and the burr generated during cutting should be polished round by an angle grinder.

[0071] 2. Cantilever I-beam anchor ring 205 processing and manufacturing (1) The anchor ring 205 is preferably made of round steel ≥φ16, and the round steel quality should be qualified, its specifications, models, etc. should meet the design requirements, without serious corrosion, damage, etc. on the surface. The round steel is bent into "U" type, and the bending length of the anchor should meet the specification requirements and reach the lower layer 104 position of the structure reinforcement. It is recommended to collect short reinforcement on site to save cost.

[0072] (2) The thread of the anchor ring 205 should be continuous and smooth, without damage to the thread, and the length of the thread should meet the requirements of double nuts and exposed thread length according to the structure position of the anchor ring 205. The exposed thread is not less than 3 threads.

[0073] 3. Lower support connection embedded part processing and manufacturing (1) The lower support connection embedded part of this method includes: lower support I-beam end embedded part 206, lower support I-beam root embedded part 207, tie I-beam connection embedded part 208.

[0074] (2) The embedded part is formed by welding of steel plate panel and anchor bolt. The panel steel plate panel length and width section size should be larger than the end face size of the connecting I-beam, and the thickness is preferably ≥10mm thick; the anchor bolt is preferably made of 4≥φ12 steel bars, and the bending length should meet the requirements of the end and tie beam plate structure position, root and vertical structure connection respectively. The bending steel bar and the panel should be connected by plug welding.

[0075] Three, lower small triangular support system 108 construction According to the construction sequence of the engineering structure, the construction sequence of the support system is: pre-burying of lower support I-beam root pre-burying part 207 → pre-burying of lower support I-beam end pre-burying part 206 → installation of lower support I-beam 203.

[0076] 1. Pre-burying of lower support I-beam root pre-burying part 207 (1) The lower support I-beam root pre-burying part 207 is buried simultaneously with the construction of the lower layer 106 structure. When there is a structural column, it is buried outside the column root part. When there is no structural column, it is buried at the center line position of the column beam.

[0077] (2) The burying should be strictly in accordance with the requirements of "Code for Construction of Concrete Structures" GB50666 and "Code for Construction Quality Acceptance of Concrete Structures" GB50204.

[0078] (3) BIM technology should be used to assist accurate positioning. After pre-burying is completed, all should be checked before pouring of the structural concrete, and nothing should be missed.

[0079] (4) The bent anchor steel bars of the pre-burying part should be welded with the additional steel bars 209 and then connected with the main reinforcement. The L of the additional steel bars 209 is greater than or equal to 1000mm. The elevation of the face plate steel plate should be consistent with the elevation of the concrete surface after pouring. The face plate should be protected by film before pouring of the concrete. 2. Pre-burying of lower support I-beam end pre-burying part 206 The pre-burying of the lower support I-beam end pre-burying part 206 is buried simultaneously with the construction of the lower layer structure, and is buried at the center position of the end beam of the lower layer 104 cantilever structure. Its construction process and operation requirements are the same as those of the pre-burying of the lower support I-beam root pre-burying part 207.

[0080] 3. Installation of lower support I-beam 203 (1) Before installation of the lower support I-beam 203, the end and root of the lower support I-beam 203 and the pre-burying part 207 should be checked and cleaned to ensure that the welding surface is free of contamination.

[0081] (2) The lower support I-beam 203 is hoisted to the installation position by using a tower crane, and the end and root of the lower support I-beam 203 are aligned with the pre-burying part steel plate face plate with the help of manual assistance to complete the positioning.

[0082] (3) After the lower support I-beam 203 is positioned, two welders simultaneously perform welding operations at the end and root. Temporary support is provided by spot welding first, and then overall welding is performed. The sling can only be removed after welding is completed, and it is strictly prohibited to remove it in advance.

[0083] (4) After welding is completed, the welding quality should be checked in full. The weld should be uniform and full, and should not have phenomena such as missed welding, spot welding, and false welding.

[0084] Four, Installation of upper trapezoidal support system 107 components According to the construction sequence of the engineering structure, the construction sequence of the support system is: installation of tie I-beam connecting embedded part 208 → embedding of cantilever I-beam anchor ring 205 → installation of cantilever and beam I-beam 202 → installation of lower support I-beam 203 → installation of tie I-beam 204.

[0085] 1. Tie I-beam connecting embedded part 208 is embedded The tie I-beam connecting embedded part 208 is embedded in the lower cantilever structure root beam simultaneously with the construction of the lower structure.

[0086] 2. Installation of cantilever I-beam anchor ring 205 (1) The anchor ring 205 is embedded simultaneously with the installation of the reinforcement of the superimposed cantilever lower structure.

[0087] (2) At least 2 anchor rings 205 are embedded for each I-beam, and the outer anchor ring 205 is arranged at the center of the cantilever structure beam (or beam), and the inner anchor ring 205 is arranged at a distance of ≥20 cm from the tail end of the I-beam.

[0088] (3) The anchor ring 205 is firmly welded with the main reinforcement by additional reinforcement 209; Two additional reinforcements 209 are added on each side of the anchor ring 205, and the additional reinforcement 209 is φ10 or more reinforcement, and the additional reinforcement 209L is ≥1500 mm.

[0089] (4) After the embedding is completed, all are checked before the structure concrete pouring, and no omission is allowed.

[0090] 3. Installation of cantilever I-beam 201 (1) After the lower structure concrete pouring is completed, the cantilever I-beam 201 is hoisted to the lower structure floor.

[0091] (2) First, the cantilever I-beam 201 is inserted into the anchor ring 205, and then the resting position is adjusted accurately.

[0092] (3) Steel plate pressing plate is arranged on the upper part of the anchor ring 205, the end fixed nut is initially screwed, the wooden wedge 210 is used for lateral wedging on both sides, the end nut is finally screwed, and the installation of the cantilever I-beam 201 is completed in sequence.

[0093] 4. Installation of beam I-beam 202 After the installation of the cantilever I-beam 201 is completed, the beam I-beam 202 is hoisted to the cantilever I-beam 201, and the resting position is adjusted. The bottom of the beam I-beam 202 is connected by welding with the cantilever I-beam 201.

[0094] 5. Installation of lower support I-beam 203 The lower bracing I-beam 203 is installed after the cantilever I-beam 201 and the coupling beam I-beam 202 are installed. The construction process and operation points are the same as those of the lower bracing I-beam 203 installation in the "lower triangular support system 108" of the present construction method (i.e., 3, lower bracing I-beam 203 installation in the construction of the "lower triangular support system 108").

[0095] 6. Pulling I-beam 204 installation (1) Before the pulling I-beam 204 is installed, the end part embedded part 206 of the lower bracing I-beam and the pulling I-beam connecting embedded part 208 are inspected and cleaned.

[0096] (2) The lower bracing I-beam 203 is moved to the installation position, the end part of the pulling I-beam 204 is manually aligned with the steel plate panel of the pulling I-beam connecting embedded part 208, and the pulling I-beam 204 is vertically arranged on the lower bracing I-beam 203 to complete the positioning.

[0097] (3) After the pulling I-beam 204 is positioned, two welders simultaneously perform welding operations at the end part and the root part. Temporary support is first performed by spot welding, and then overall welding is performed.

[0098] (4) After welding is completed, the welding quality is checked.

[0099] Five, full support frame erection The erection of the full support frame is strictly in accordance with the design drawings of the special construction scheme, the current "Safety Technical Standard for Building Construction Fastener Type Steel Pipe Scaffold" JGJ130, "Safety Technical Standard for Building Construction Socket Type Disc Type Steel Pipe Scaffold" JGJ / T231, etc. The following matters should also be done well: 1. The erection of the full support frame should be carried out after the cantilever I-beam 201, the coupling beam I-beam 202, the pulling I-beam 204, etc. are all completed and pass the acceptance.

[0100] 2. Before erection, the erection of the outer protection frame (including the outer frame 301 and the safety cantilever net 302) should be completed according to the design drawings of the scheme, so as to form a safe and closed operation platform at the cantilever part.

[0101] 3. Before erection, according to the design drawings, a positioning steel bar 303 with a diameter of φ25 or more is welded on the upper part of all the coupling beam I-beams 202 according to the position of the formwork support frame vertical rod, with a height of ≥15 cm, to prevent the support vertical rod from slipping.

[0102] Six, superimposed cantilever layer 103 structure construction 1. Vertical structure construction Vertical structure construction includes steel bar binding, formwork installation, concrete pouring and curing of column and wall. The construction can be carried out according to the design drawing, the current "Concrete Structure Engineering Construction Quality Acceptance Specification" GB50204, "Concrete Structure Engineering Construction Specification" GB50666 and other requirements.

[0103] 2. Structural beam and slab construction The construction of structural beam and slab includes formwork installation, steel bar binding, concrete pouring and curing. In addition to strictly following the design drawing, the current "Concrete Structure Engineering Construction Quality Acceptance Specification" GB50204, "Concrete Structure Engineering Construction Specification" GB50666 and other construction, the following matters should also be done well: (1) After the vertical structure concrete pouring is completed and the concrete strength reaches more than 75%, the vertical structure and the formwork support system should be effectively connected to enhance the stability of the formwork support system.

[0104] (2) The concrete pouring must meet the following requirements: ① The concrete pouring of overhanging part should be uniformly poured from inside to outside, pouring the non-overhanging part first and then the overhanging part.

[0105] ② During pouring, personnel are strictly prohibited from gathering at the same position of the overhanging part.

[0106] ③ The concrete pile height of the overhanging part is strictly prohibited to protrude the board surface by 100mm.

[0107] Seven, formwork removal In addition to strictly following the current relevant standards and specifications such as "Concrete Structure Engineering Construction Specification" GB50666, the following matters should be paid attention to: 1. Demolition time requirement The demolition time is strictly controlled. The formwork of the overhanging part must meet the following conditions at the same time, otherwise it is strictly prohibited to remove in advance.

[0108] (1) The concrete strength reaches 100%.

[0109] (2) The concrete of the upper structure layer has been poured.

[0110] (3) When the static and dynamic load combination of the upper structure layer is large, it should be reviewed to meet the load requirements of the upper structure layer concrete before removal.

[0111] 2. Demolition sequence requirement (1) It should be carried out according to the design specification of formwork. When there is no design specification, the principle of "first support and then remove, later support and then remove, remove non-bearing formwork first and then remove bearing formwork, from top to bottom" can be adopted.

[0112] (2) First remove the upper trapezoidal support system 107, then remove the lower small triangular support system 108.

[0113] Eight, cast-in-place structure inspection and acceptance After the construction of the structural layer is completed and after the formwork and support system are all removed, the cast-in-place structure should be inspected and accepted according to the requirements of the current standards and specifications such as the “Concrete Structure Engineering Construction Quality Acceptance Specification” GB50204, the “Building Engineering Construction Quality Unified Acceptance Standard” GB50300, and the “Concrete Structure On-site Detection Technical Standard” GB / T50784, including: beam and slab concrete strength, floor thickness, reinforcement cover, axis, column perpendicularity, geometric size, and other items.

[0114] Working principle and method of use: In the construction of the overhanging concrete structure component of the high-rise building, the overhanging I-beam 201 and the double-layered downbrace I-beam 203 are combined with the lower concrete structure that has been poured to form a “large triangular support system 109” that can bear the load of the upper overhanging structure as a whole.

[0115] The bottom end of the large triangular support system 109 is located at the non-overhanging part 101, and the horizontal side of the large triangular support system 109 is located at the first overhanging part 102 and the second overhanging part 103, i.e., used to support the overhanging layer 104; The “large triangular support system 109” is divided into: the upper trapezoidal support system 107 and the lower small triangular support system 108.

[0116] The upper trapezoidal support system 107 is located at the lower layer 105 of the overhanging layer 104, and the lower small triangular support system 108 is located at the lower layer 106 of the overhanging layer 104.

[0117] The upper trapezoidal support system 107: the obliquely arranged downbrace I-beam 203 is combined with the overhanging I-beam 201 and the lower poured concrete structure to form an optimized load bearing and transmission route for the overhanging I-beam 201, making the overhanging I-beam 201 mainly serve as a platform and force transmission component for the upper full-support frame, and the upper main load is borne by the downbrace I-beam 203 and the lower poured concrete structure, while effectively solving the problems of insufficient anchoring length and position of the inner and outer anchoring points of the overhanging I-beam 201.

[0118] The lower small triangular support system 108: the obliquely arranged downbrace I-beam 203 is connected to the end of the lower overhanging structure and the root of the lower layer 106 overhanging structure (column root or beam top) to form an optimized load transmission path for the lower overhanging structure, with the frame system bearing the remaining upper load, while changing the stress mode of the lower overhanging structure from cantilever to simply supported, thereby increasing the load-bearing capacity of the lower overhanging structure.

Claims

1. A construction method for a superimposed cantilevered concrete structure of a high-rise building, characterized in that: The following steps are involved: S1. Construction preparation; S2. Processing and production of support system components: The supporting system components include cantilever I-steel (201), connecting beam I-steel (202), lower support I-steel (203), tie I-steel (204), cantilever I-steel anchor ring (205), and lower support connection embedded parts; The lower support connection embedded parts include: lower support I-beam end embedded parts (206), lower support I-beam root embedded parts (207), and tie I-beam connection embedded parts (208); S3. Construction of the lower small triangle support system (108): The construction sequence is: embedding the embedded parts (207) at the root of the lower supporting I-beam → embedding the embedded parts (206) at the end of the supporting I-beam → installing the lower supporting I-beam (203) of the lower small triangle supporting system (108); S4. Installation of upper trapezoidal support system (107) components: The construction sequence is: installation of the tie I-beam connection embedded parts (208) → embedding of the cantilever I-beam anchor ring (205) → installation of the cantilever and connecting beam I-beam (202) → installation of the lower support I-beam (203) of the upper trapezoidal support system (107) → installation of the tie I-beam (204); S5. Erection of full-hall support frame; S6, superimposed cantilever layer (103) structural construction; S7, template removal; S8. Inspection and acceptance of cast-in-place structures.

2. The construction method of a high-rise building superimposed cantilever concrete structure according to claim 1, characterized in that: Step S1: Construction preparation, including the following steps: S11. Personnel deployment, construction materials, machinery and equipment, and tools entering the site; S12, special construction plan and expert demonstration, calculation of bearing capacity of lower cantilever concrete structure; S13. Plan briefing: Before construction, the construction unit should conduct a special briefing on the special construction plan that has been verified and approved in accordance with relevant regulations.

3. The construction method of a high-rise building superimposed cantilever concrete structure according to claim 1, characterized in that: Step S2 supports the processing and production of system components, including the following steps: S21, I-beam cutting: S22, cantilever I-beam anchor ring (205) processing, production: S221, anchor ring (205) is made of round steel; the round steel is bent into a "U" shape; S222, anchor ring (205) thread production; The thread of the anchor ring (205) should be continuous and smooth, and the thread length should meet the requirements of the double nut and the thread length; S23. Processing and production of embedded parts for lower support connection: S231. Determine the model of the embedded parts for the lower support connection; S232, the lower support connection embedded parts are formed by welding steel plate panels and anchor bolts; The anchor bolts are made of bent steel bars; The length of the bent anchor can meet the requirements of the end and the tie beam-slab structure position, and the connection between the root and the vertical structure.

4. The construction method of a high-rise building superimposed cantilever concrete structure according to claim 1, characterized in that: Step S3: Construction of the lower small triangle support system (108), including the following steps: S31, embedded parts (207) at the root of the lower support I-beam: S311, the embedded parts (207) at the root of the lower support I-beam are embedded synchronously with the construction of the lower layer (106) structure; when there are structural columns, they are embedded outside the column root position; when there are no structural columns, they are embedded in the center line position of the column beam; S312, burial is carried out as required; S313, accurate positioning, after pre-embedding is completed, full inspection before pouring structural concrete; S314, the bent anchor reinforcement of the embedded part at the root of the lower support I-beam is welded to the additional reinforcement (209) and then tied to the main reinforcement; S32, embedded parts (206) at the end of the lower support I-beam: The embedded part (206) at the end of the lower support I-beam is embedded synchronously with the construction of the lower structure and is embedded in the center of the end beam of the lower cantilever structure; S33, installation of lower support I-beam (203): S331. Before installing the lower support I-beam (203), check and clean the lower support connection embedded parts; S332, hoisting the lower support I-beam (203) to the installation position, aligning the end and the root of the lower support I-beam (203) with the steel plate panel of the lower support connection embedded part; S333, after the lower support I-beam (203) is in place, welding is performed simultaneously at the end and the root; first spot welding is performed for temporary support, and then full welding is performed; after welding is completed, the sling is removed; S334. After welding is completed, check the welding quality.

5. The construction method of a high-rise building superimposed cantilever concrete structure according to claim 1, characterized in that: Step S4: installing the upper trapezoidal support system (107) components, including the following steps: S41, pre-embedded parts (208) for connecting I-beams: The tie I-beam connection embedded parts (208) are embedded in the root beam of the lower cantilever structure synchronously with the construction of the lower structure; S42, installation of cantilevered I-beam anchor ring (205): S421, the anchor ring (205) is embedded in advance and is carried out simultaneously with the installation of the structural reinforcement of the next layer of the superimposed cantilever; S422, at least two anchor rings (205) are embedded in each I-beam, with the outer anchor ring (205) being located at the center of the cantilevered structural beam and the inner anchor ring (205) being located at a distance of ≥20 cm from the tail end of the I-beam; S423, the anchor ring (205) is firmly welded to the main reinforcement of the structure through the additional reinforcement (209); Two additional steel bars (209) are added on each side of the anchor ring (205); S424. After pre-embedding is completed, a full inspection shall be carried out before pouring the structural concrete; S43, cantilever I-beam (201) installation: S431, after the concrete pouring of the lower structure is completed, the cantilevered I-beam (201) is hoisted to the lower structural floor; S432, first insert the cantilever I-beam (201) into the anchor ring (205), and then adjust the shelf position accurately; S433, a steel plate pressure plate is set on the upper part of the anchor ring (205), the end fixing nut is initially tightened, the two sides are laterally wedged with wooden wedges (210), and the end nut is finally tightened, and the installation of the cantilever I-beam (201) is completed in sequence; S44, Connecting beam I-beam (202) installation: After the cantilever I-beam (201) is installed, the connecting beam I-beam (202) is hoisted onto the cantilever I-beam (201) and the placement position is adjusted; the bottom of the connecting beam I-beam (202) is connected to the cantilever I-beam (201) by welding; S45, installation of lower support I-beam (203): This process is implemented after the installation of the lower support I-beam (203) and the cantilever and connecting beam I-beam (202) is completed. S46, tie I-beam (204) installation: S461, before installing the tie I-beam (204), inspect and clean the lower support I-beam end embedded parts (206) and the tie I-beam connection embedded parts (208); S462, move the lower support I-beam (203) to the installation position, align the end of the tie I-beam (204) with the steel plate panel of the tie I-beam connection embedded part (208), and vertically install the tie I-beam (204) on the lower support I-beam (203), completing the installation; S463, after the tie I-beam (204) is in place, welding is performed simultaneously at the end and the root; first spot welding is performed for temporary support, and then full welding is performed; S464. After welding is completed, check the welding quality.

6. The construction method of a high-rise building superimposed cantilever concrete structure according to claim 1, characterized in that: Step S5: When setting up the full-floor support frame, the following matters should be done: The full-height support frame is erected after the cantilever I-beam (201), the connecting beam I-beam (202), and the tie I-beam (204) are all completed and accepted; Before erection, first complete the erection of the outer protective frame according to the design drawings to form a safe and closed operating platform at the cantilevered part; Before erection, according to the design drawings, positioning steel bars (303) are welded on the upper part of all the connecting beam I-beams (202) according to the position of the formwork support frame uprights.

7. The construction method of a high-rise building superimposed cantilever concrete structure according to claim 1, characterized in that: Step S6 is to construct the structure of the superimposed cantilever layer (103), including the following steps: S61. Vertical structure construction: Vertical structure construction includes reinforcement binding of columns and walls; formwork installation; concrete pouring and curing; S62, Structural beam and slab construction: The construction of structural beams and slabs includes formwork installation, steel bar binding, concrete pouring and maintenance. The following matters should be done well: (1) The vertical structure must be poured after the concrete is poured and the concrete strength reaches 75% or above; (2) Concrete pouring must meet the following requirements: ① Concrete pouring of cantilevered parts should be evenly poured from the inside to the outside, pouring the non-cantilevered parts (101) first and then pouring the cantilevered parts; ②During pouring, it is strictly forbidden for people to stand at the same position on the cantilever part; ③ The concrete pile in the cantilevered part is strictly prohibited from protruding 100mm from the slab surface.

8. The construction method of a superimposed cantilevered concrete structure of a high-rise building according to claim 1, characterized in that: In step S7, when removing the template, pay attention to the following matters: The demoulding time must be strictly controlled. The demoulding time of the cantilevered parts must meet the following conditions at the same time: (1) Concrete strength reaches 100%; (2) The concrete of the upper structural layer has been poured; (3) When the combination of static and dynamic loads on the upper structure is large, it should be reviewed to ensure that it can meet the load requirements of the upper structure concrete; Demolding sequence requirements: (1) Follow the design requirements of the template; (2) First remove the upper trapezoidal support system (107), and then remove the lower small triangle support system (108).

9. The construction method of a high-rise building superimposed cantilever concrete structure according to claim 1, characterized in that: Step S8: Inspection and acceptance of cast-in-place structure. After the structural layer construction is completed and the formwork and support system are completely removed, the cast-in-place structure is inspected and accepted, including: concrete strength of beams, slabs and columns, floor slab thickness, steel bar protection layer, axis, column verticality, and geometric dimensions.

10. The construction method of a high-rise building superimposed cantilever concrete structure according to claim 3, characterized in that: Step S21 of blanking the I-beam includes the following steps: S211, select I-beam; S212, cutting the I-beams, and numbering and marking the cut I-beams; The cutting length of I-beams should comply with the requirements of the design drawings; number the I-beams after cutting and mark the connection and welding positions; S213, I-beam cut end face treatment.

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