Construction method of high-rise large-span cantilever structure

Abstract

The application provides a high-layer large-span cantilever structure construction method, which comprises the steps of pre-embedded layer steel bar, elastic line composite pre-embedded part position, U-shaped pre-embedded bar installation, pre-embedded layer concrete pouring, cantilever I-shaped steel installation, full-tent module template support erection and cantilever structure construction. The application can effectively shorten the construction period, improve the construction efficiency, reduce the construction cost and has good popularization and application value.

Description

Technical Field

[0001] This invention relates to the field of cantilever structure construction technology, specifically a construction method for high-rise, large-span cantilever structures. Background Technology

[0002] With the acceleration of urbanization, the available land area in cities is decreasing significantly. To utilize urban land more efficiently, high-rise buildings are increasingly used in residential construction, and a large number of high-rise buildings will emerge in future urbanization. In high-end residential projects, large-span cantilever structures are often used on the roofs for aesthetic and structural purposes. In actual construction, since the lower part of the large-span cantilever structure lacks the support of the main structure, cantilevered I-beams are required as bottom supports. The embedded fasteners of the bottom I-beams often experience misalignment due to rebar tying, formwork erection, and concrete pouring and vibration. At the same time, traditional wire tying methods are not strong enough, and welding fixing methods can damage the main reinforcement bars, reducing the quality of the main reinforced concrete structure. Summary of the Invention

[0003] In view of the above-mentioned prior art, the present invention proposes a construction method for high-rise large-span cantilever structures, thereby improving the construction quality and ensuring construction safety under the working conditions of high-rise large-span cantilever structures.

[0004] This invention provides a construction method for a high-rise, large-span cantilever structure, comprising the following steps:

[0005] S1. Construction of embedded layer steel reinforcement: Select steel reinforcement of the corresponding specifications according to the design drawings and connect them according to the standards to ensure the overall stability of the steel reinforcement;

[0006] S2. Mark the location of the composite embedded parts: According to the detailed drawings of the cantilever beam of the high-rise roof, use an ink line to mark the center point of the embedded parts to facilitate the installation and correction of the embedded parts;

[0007] S3. Installation of U-shaped embedded bars: Two lower positioning short bars are placed horizontally on the upper side of the bottom reinforcement of the floor slab. The lower positioning short bars are fixed to the bottom reinforcement of the floor slab using fasteners. The U-shaped embedded bars are passed through the lower positioning short bars and fixed to the lower positioning short bars using fasteners. Two upper positioning short bars are placed vertically on the lower side of the top reinforcement of the floor slab. The upper positioning short bars are fixed to the top reinforcement of the floor slab using fasteners and to the U-shaped embedded bars using fasteners, thereby stabilizing the U-shaped embedded bars.

[0008] S4. Concrete pouring for embedded layer: Pouring floor slab concrete;

[0009] S5. Installation of cantilevered I-beams: The cantilevered I-beams are anchored using the U-shaped pre-embedded reinforcement bars;

[0010] S6. Erection of full-span formwork support: Erect a full-span formwork support on the upper side of the cantilevered I-beam;

[0011] S7. Construction of cantilever structure: Lay square timber neatly according to the design spacing requirements, then lay the bottom formwork of the cantilever structure, and pour the concrete of the cantilever structure after the bottom formwork is laid.

[0012] Preferably, in S3, a set of U-shaped embedded bars are pre-embedded both inside and outside the floor slab where the cantilevered I-beams are installed.

[0013] Preferably, in S3, the fastener includes a left semicircular ring and a right semicircular ring. One end of the left semicircular ring and the right semicircular ring are connected by a rotating shaft, and the other ends of the left semicircular ring and the right semicircular ring are fastened together. The other end of the left semicircular ring is provided with multiple slots, and the other end of the right semicircular ring is provided with a fastener. The fastener and the slots are engaged to fix steel bars of different diameters.

[0014] Preferably, in S4, the straight section of the U-shaped pre-embedded bar embedded in the floor slab concrete is not less than 20cm.

[0015] Preferably, in S5, the outer end of the cantilevered I-beam is obliquely suspended from the upper floor beam by steel wire rope, and round steel lifting rings are pre-embedded in the upper floor beam, with each steel wire rope end being secured by no less than 3 clamps.

[0016] Preferably, in S6, when erecting a full-span formwork support with a height not exceeding 8m, vertical diagonal braces are installed on each layer of the first span facing inward from the outer facade of the support, and vertical diagonal braces are installed on the bottom and top layers of the support. In the internal area of ​​the support, vertical diagonal braces are installed longitudinally and laterally from bottom to top every 5 spans, or large scissor braces are erected using steel pipes with fasteners. When erecting a full-span formwork support with a height exceeding 8m, diagonal braces are fully installed, continuous scissor braces are installed, and a horizontal safety net is installed in the middle of the support. When the height of the support does not exceed 4 steps, no horizontal diagonal brace is installed on the top layer. When the height of the support exceeds 4 steps, a horizontal diagonal brace or a horizontal scissor brace with steel pipes with fasteners is installed on the top layer.

[0017] Compared to existing technologies, the advantages of this invention are as follows: In the construction of high-rise, large-span cantilever structures, this invention achieves accurate one-time installation of pre-embedded fasteners, avoiding damage to the main reinforcement bars of the original structure and eliminating the need for secondary adjustments due to misalignment caused by concrete pouring. In the original construction process, pre-embedded fasteners often damage the main reinforcement bars and cause misalignment during subsequent construction. Correcting and adjusting these issues during the installation of the cantilevered I-beams wastes manpower and affects the construction period. Furthermore, the misalignment of formwork supports caused by pre-embedded fastener misalignment is improved, avoiding secondary reinforcement of the formwork supports, shortening the construction period, saving materials, and ensuring construction safety. The high-rise, large-span cantilever structure construction method of this invention can effectively shorten the construction period, improve construction efficiency, and reduce construction costs, making it highly valuable for widespread application. Attached Figure Description

[0018] Figure 1 This is a front view construction drawing of the U-shaped pre-embedded reinforcement in an embodiment of the present invention.

[0019] Figure 2 This is a side view construction drawing of the U-shaped pre-embedded reinforcement in an embodiment of the present invention.

[0020] Figure 3 This is a schematic diagram of the structure of the fastener in an embodiment of the present invention.

[0021] Figure 4 This is a construction schematic diagram of the cantilevered I-beams and full-span formwork support in an embodiment of the present invention.

[0022] Figure 5 This is a schematic diagram of the steel wire rope structure in an embodiment of the present invention.

[0023] In the diagram, 1. Bottom reinforcement of floor slab; 2. Lower positioning short reinforcement; 3. U-shaped embedded reinforcement; 4. Top reinforcement of floor slab; 5. Upper positioning short reinforcement; 6. Left semi-circular ring; 7. Right semi-circular ring; 8. Rotation shaft; 9. Slot; 10. Clip; 11. Cantilevered I-beam; 12. Wire rope; 13. Clamp; 14. Full-span formwork support. Detailed Implementation

[0024] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to specific illustrations. Example

[0025] A construction method for a high-rise, long-span cantilever structure includes the following steps:

[0026] S1. Construction of embedded layer reinforcement: Select reinforcement of the corresponding specifications according to the design drawings and connect them according to the standards to ensure the overall stability of the reinforcement. The reinforcement grade, lap splice method and anchorage length need to be checked carefully to ensure accuracy.

[0027] S2. Mark the location of the composite embedded parts: According to the detailed drawings of the cantilever beam of the high-rise roof, use an ink line to mark the center point of the embedded parts to facilitate the installation and correction of the embedded parts;

[0028] S3, U-shaped embedded reinforcement installation: Refer to Figure 1 , 2Two lower positioning short bars 2 are placed horizontally on the upper side of the bottom reinforcement bar 1 of the floor slab. The lower positioning short bars 2 are fixed to the bottom reinforcement bar 1 of the floor slab using fasteners. The U-shaped embedded bar 3 passes through the lower positioning short bars 2 from the bottom side and is fixed to the lower positioning short bars 2 using fasteners. Two upper positioning short bars 5 are placed longitudinally on the lower side of the top reinforcement bar 4 of the floor slab. The upper positioning short bars 5 are fixed to the top reinforcement bar 4 of the floor slab using fasteners and are also fixed to the U-shaped embedded bar 3 using fasteners, thereby stabilizing the U-shaped embedded bar 3. (Refer to...) Figure 4 On the floor slab where the cantilevered I-beam 11 is installed, a set of U-shaped embedded bars are pre-embedded inside and outside the floor. The inner set is pre-embedded 20mm from the tail of the cantilevered I-beam, and the outer set is 20cm from the inner set.

[0029] Reference Figure 3 The fastener includes a left semicircular ring 6 and a right semicircular ring 7. One end of the left semicircular ring 6 and the right semicircular ring 7 are rotatably connected by a rotating shaft 8. The other ends of the left semicircular ring 6 and the right semicircular ring 7 are fastened together. The other end of the left semicircular ring 6 is provided with multiple slots 9, and the other end of the right semicircular ring 7 is provided with a fastener 10. The fastener 10 is engaged with the slots 9 to fix steel bars of different diameters.

[0030] S4. Concrete pouring of embedded layer: Pour floor slab concrete. The straight section of the U-shaped embedded bar 3 embedded in the floor slab concrete shall not be less than 20cm. During the pouring process, control the uniformity and density of the concrete. When vibrating, the vibrator shall not touch the reinforcing bars, formwork and embedded bars to avoid the embedded parts from being misaligned due to vibration. After pouring, leveling, finishing and roughening work shall be carried out.

[0031] S5. Installation of Cantilevered I-beams: The cantilevered I-beams for this floor can only be erected when the concrete strength of the floor slab reaches 75%, as per [reference needed]. Figure 4 The cantilevered I-beam 11 is anchored using U-shaped embedded reinforcing bars 3 on the inner and outer sides; the anchoring points of the cantilevered I-beam 11 on the floor slab are wedged tightly with wooden wedges as a safety reserve; the outer end of the cantilevered I-beam 11 is obliquely suspended from the upper floor beam by steel wire rope 12, and round steel lifting rings are pre-embedded in the upper floor beam, referring to... Figure 5 Each wire rope 12 has at least 3 clamps 13 at its end, with each clamp 13 spaced 9cm apart, and the clamp 13 at the end is 12cm away from the end of the rope. The inner anchor point of the cantilever I-beam 11 is welded to the U-shaped embedded reinforcement 3 on both sides, with a weld length of 5d, to bear the horizontal thrust of the inclined wire rope 12 on the cantilever I-beam 11. The wire rope 12 needs to be taut so that the outer end of the cantilever I-beam 11 arches by 30mm.

[0032] S6. Erection of full-span formwork scaffolding: Refer to... Figure 4A full-span formwork scaffold 14 is erected on the upper side of the cantilevered I-beam 11. All column extensions of the full-span formwork scaffold 14 are connected using connecting sleeves; overlapping is strictly prohibited. The cantilever length of the adjustable support extending beyond the top horizontal bar should not exceed 650mm, and the exposed length of the threaded rod should not exceed 400mm. The adjustable support should be inserted into the upright for at least 150mm. Each longitudinal and transverse horizontal bar is connected and stretched through a disc-lock joint. For disc-lock modules that do not meet the requirements, ordinary steel pipes can be used for fastener connections. When the full-span formwork scaffold 14 has a height not exceeding 8m, the scaffold... Vertical diagonal bracing is installed on each floor of the first span facing inward from the outer facade. Vertical diagonal bracing is also installed on the bottom and top floors of the support. In the internal area of ​​the support, vertical diagonal bracing is installed longitudinally and laterally from bottom to top every 5 spans, or large scissor bracing is erected using steel pipes with couplers. When the full-span formwork support 14 with an erection height exceeding 8m, diagonal bracing is fully installed and continuous scissor bracing is installed. A horizontal safety net is installed in the middle of the support. When the height of the support does not exceed 4 steps, no horizontal diagonal bracing is installed on the top floor. When the height of the support exceeds 4 steps, horizontal diagonal bracing or horizontal scissor bracing with steel pipes with couplers is installed on the top floor.

[0033] S7. Construction of Cantilever Structure: Lay 40mm×90mm×2000mm square timber neatly according to the design spacing requirements, then lay the bottom formwork of the cantilever structure. After the bottom formwork is laid, pour the concrete for the cantilever structure. When laying the bottom formwork, first align it with the column head and nail it securely. Use 40mm×90mm timber strips as supports and uprights. Use 30mm wide, 18mm thick formwork as press feet to tighten the bottom of the side formwork. Then, straighten the side formwork. Depending on the cross-sectional area of ​​the cantilever structure, add φ14 through-wall bolts in the middle of the cantilever structure. Additionally, when the cantilever structure... When the span of the structure is greater than 4 meters, the bottom of the cantilever structure should be arched according to the design requirements. When pouring concrete for the cantilever structure, control the pouring speed and pouring time to avoid premature setting or segregation due to excessive pouring time. The vibration time should be until the concrete surface shows a layer of slurry and no longer sinks, which should be about 20 seconds. The vibrator should not touch the formwork, reinforcing bars, or embedded pipes. During pouring, a dedicated person should be assigned to watch the formwork and reinforcing bars for displacement or deformation. Any problems should be dealt with promptly. Construction workers should be equipped with safety protection devices, and a dedicated person should be assigned to supervise the construction to ensure construction quality and safety.

[0034] The above are merely embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structures made using the contents of the present invention specification and drawings, whether directly or indirectly applied to other related technical fields, are similarly within the patent protection scope of the present invention.

Claims

1. A construction method of a high-rise large-span cantilever structure, characterized in that, It comprises the following steps: S1, pre-embedded layer of reinforcement construction: according to the design drawing to select the corresponding specification of reinforcement, according to the standard for connection, to ensure the overall stability of the reinforcement; S2, the position of the elastic line composite embedded part: according to the high-rise roof cantilever beam development drawing, the center point position of the embedded part is popped out with ink line, so as to facilitate the installation and correction of the embedded part; S3, U type pre-embedded reinforcement installation: two lower positioning short reinforcement are placed on the upper side of the floor bottom reinforcement along the transverse direction, the lower positioning short reinforcement is fixed with the floor bottom reinforcement by using the buckle, the U type pre-embedded reinforcement is passed through the lower side of the lower positioning short reinforcement, and is fixed with the lower positioning short reinforcement by using the buckle, two upper positioning short reinforcement are placed on the lower side of the floor top reinforcement along the longitudinal direction, the upper positioning short reinforcement is fixed with the floor top reinforcement by using the buckle, and is fixed with the U type pre-embedded reinforcement by using the buckle, so that the U type pre-embedded reinforcement is stable; the buckle comprises a left half ring and a right half ring, one end of the left half ring and the right half ring is connected through a rotating shaft, the other end of the left half ring and the right half ring is buckled, the other end of the left half ring is provided with a plurality of clamping grooves, the other end of the right half ring is provided with a buckle, and the buckle is connected with the clamping groove in a matched mode, so as to fix the reinforcement with different diameters; S4, pre-embedded layer of concrete pouring: pouring floor concrete; S5, cantilevered I-beam installation: anchoring the cantilevered I-beam through the U type pre-embedded reinforcement; S6, full-form template support erection: erecting full-form template support on the upper side of the cantilevered I-beam; when the erection height of the full-form template support is less than 8m, vertical inclined rods are arranged on the first span of the outer vertical surface of the support, vertical inclined rods are arranged on the bottom layer and the top layer of the support, and vertical inclined rods or large scissors supports formed by the fastener steel pipes are arranged in the internal area of the support every 5 spans from the bottom to the top in the longitudinal and transverse directions; when the erection height of the full-form template support is more than 8m, the inclined rods are densely arranged, continuous scissors supports are arranged, and horizontal safety nets are arranged in the middle part of the support; when the height of the support is less than 4 steps, the top layer horizontal inclined rod is not arranged; when the height of the support is more than 4 steps, the top layer horizontal inclined rod or the horizontal scissors support formed by the fastener steel pipe is arranged; S7, cantilever structure construction: laying the square wood neatly according to the design interval requirement, then laying the bottom mold of the cantilever structure, and then pouring the cantilever structure concrete after the bottom mold is laid.

2. The construction method of a high-rise large-span cantilever structure according to claim 1, wherein In S3, a group of U type pre-embedded reinforcement is embedded in the floor on the inside and outside of the cantilevered I-beam.

3. The construction method of a high-rise large-span cantilever structure according to claim 1 or 2, characterized in that, In S4, the U type pre-embedded reinforcement is embedded in the straight section of the floor concrete by not less than 20cm.

4. The construction method of a high-rise large-span cantilever structure according to claim 1 or 2, characterized in that, In S5, the outer end of the cantilevered I-beam is obliquely pulled and hung on the upper floor beam by using the steel wire rope, the round steel ring is pre-embedded in the upper floor beam, and the rope head of each steel wire rope is clamped and fastened by not less than 3 clamping buckles.

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