Construction method of large-span reinforced concrete horizontal members

Abstract

The invention relates to the technical field of construction engineering, and is a method for constructing large-span reinforced concrete horizontal components. The method comprises the following steps: setting up an early-dismantling support frame system and a late-dismantling support frame system according to drawings of a design support system, wherein both the early-dismantling support frame system and the late-dismantling support frame system adopt a disc-type scaffold; supporting and casting wall column casting formwork, beam casting formwork and floor slab casting formwork in sequence; removing the wall column formwork when the concrete strength of the wall column structure reaches 50% of the design strength; removing the early-dismantling support frame system and the formwork on the early-dismantling support frame system when the concrete strength reaches 75% of the design strength; and removing the late-dismantling support frame system and the formwork on the late-dismantling support frame system when the concrete strength reaches 100% of the design strength. The construction method artificially reduces the structural span during the construction stage to reduce its internal force, so that the formwork can be removed early without affecting the safety of the structure, thereby accelerating material turnover, reducing costs, improving work efficiency and shortening construction period.

Description

Technical Field

[0001] The present invention relates to the technical field of construction engineering, in particular to a construction method of a large-span reinforced concrete horizontal member. Background Art

[0002] With the development of the construction industry, after the concrete pouring of reinforced concrete horizontal components in buildings is completed, the requirements for the concrete strength when removing the formwork are directly related to the span size. Among them, according to the national standard "Concrete Structure Engineering Construction and Acceptance Code" GB50204-2002, the concrete strength of the formwork and support of the cast-in-place concrete structure when it is removed should meet the design requirements. If there are no design requirements, the following regulations should be met: 1. When the span of the bottom formwork and formwork is ≤2.0m, the formwork can be removed only when the concrete strength reaches 50% of the design strength; 2. When the span of the slab bottom formwork and formwork is between 2.0m and 8.0m, the formwork can be removed only when the concrete strength reaches 75% of the design strength; 3. For beams and arch shells, when the span is ≤8.0m, the concrete strength can be removed only when it reaches 75% of the design strength; when the span is greater than 8.0m, the concrete strength can be removed only when it reaches 100% of the design strength; that is, the larger the span of the concrete horizontal member, the higher the demolding strength requirement. At the same time, the concrete strength growth characteristic is that the early strength grows quickly and the later strength grows slowly; currently, steel pipe scaffolding is usually used for support. After the large-span reinforced concrete horizontal member is poured, the formwork cannot be removed until the strength reaches 100%. The demolding cycle is relatively long, which affects the construction progress and reduces the utilization rate of turnover materials such as formwork supports, resulting in waste of resources and increased construction costs. Summary of the Invention

[0003] The present invention aims to solve the above problems, thereby providing a method for constructing large-span reinforced concrete horizontal members that can shorten the turnover period of formwork and support brackets, improve construction efficiency, and reduce construction costs.

[0004] The present invention solves the above problem by adopting a method for constructing a large-span reinforced concrete horizontal member, comprising the following steps:

[0005] S1: Divide the early demolition area into the late demolition area according to the span of the horizontal components, and design the support systems for the early demolition area and the late demolition area accordingly. The support systems are divided into the early demolition support frame system and the late demolition support frame system. The spacing between the late demolition support frame system's late demolition poles and the adjacent late demolition poles or wall columns is 2m to 8m. The early demolition support frame system is installed between the late demolition support frame systems. The spacing between the early demolition poles of the early demolition support frame system and the adjacent early demolition poles, adjacent late demolition poles or wall columns is 0.6m, 0.9m, and 1.2m.

[0006] S2: Erect the early-dismantling support frame system and the late-dismantling support frame system according to the design support system drawings. At the same time, support the wall column casting formwork. Both the early-dismantling support frame system and the late-dismantling support frame system use disc-type scaffolding. When erecting, first erect the standard quadrilateral support lattice, and then support the remaining support lattices in a mutually perpendicular or straight manner.

[0007] S3: Supporting the beam casting formwork and the floor slab casting formwork on the early-removal support frame system and the late-removal support frame system in sequence; then, concrete pouring of the wall column structure, beam structure, and floor slab structure is carried out in sequence;

[0008] S4: When the concrete strength of the wall column structure reaches 50% of the design strength, the wall column formwork is removed and transported out of the working surface;

[0009] S5: When the concrete strength of the beam structure and floor slab structure reaches 75% of the design strength, the early dismantling support frame system and the beam casting formwork and floor slab casting formwork supported by the early dismantling support frame system are removed and transported out of the working surface;

[0010] S6: When the concrete strength of the beam structure and floor slab structure reaches 100% of the design strength, the late-removal support frame system and the beam casting formwork and floor slab casting formwork supported by the late-removal support frame system are removed and transported out of the working surface.

[0011] Furthermore, in step S3, the beam casting formwork and the floor slab casting formwork as well as the main purlin and the secondary purlin are completely disconnected at the boundary between the early demolition area and the late demolition area, and the early demolition support frame system and the late demolition support frame system can be used and dismantled independently.

[0012] Furthermore, the early dismantling support frame system is provided with two layers, namely an upper layer of disc-type scaffolding and a lower layer of disc-type scaffolding, and step S5 specifically includes:

[0013] S501: When the concrete strength of the beam structure and floor slab structure reaches 75% of the design strength, the upper scaffolding should be dismantled and transported out of the working surface;

[0014] S502: Then, a springboard is set up on the lower-level disc-type scaffolding, and the beam casting formwork and floor slab casting formwork are removed and transported out of the working surface;

[0015] S503: Remove the lower-level disc-type scaffolding and transport it out of the working surface.

[0016] Furthermore, when removing the crossbar in the early removal support frame system or the late removal support frame system, use a hammer to evenly hit both ends of the crossbar so that both ends of the crossbar are lifted out at the same time.

[0017] Compared with the prior art, the present invention adopting the above technical solution has the following outstanding features:

[0018] The present invention is applicable to buildings with a larger span, such as floor slabs and beams of residential buildings, public buildings and industrial plants; formwork support systems of bridges, culverts and other projects; formwork support systems of multi-story, high-rise and super-high-rise buildings with a large number of standard floors or standard rooms; and floor slab support systems of buildings with a large single-story area and difficult turnover of formwork support systems. This construction method artificially reduces the span of the structure during the construction phase to reduce its internal force, so that the formwork can be dismantled early without affecting the safety of the structure, thereby accelerating material turnover, reducing investment, lowering costs, improving work efficiency, accelerating construction progress and shortening the construction period. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the plane design of the early demolition area and the late demolition area in an embodiment of the present invention;

[0020] Figure 2 This is a schematic plan view of the spacing between vertical poles in an embodiment of the present invention;

[0021] Figure 3 for Figure 2 Schematic diagram of the facade design of the support system at AA in the middle;

[0022] Figure 4 Schematic diagram of the support system structure after the scissors brace and sweeping rod are removed in an embodiment of the present invention;

[0023] Figure 5 for Figure 4 Schematic diagram of the dismantled scissor brace;

[0024] Figure 6 Schematic diagram of the support system structure after the upper layer of the disc-type scaffolding is removed in an embodiment of the present invention;

[0025] Figure 7 for Figure 6 Schematic diagram of the upper level disc-type scaffolding being dismantled;

[0026] Figure 8 Schematic diagram of the rear support system structure for removing the corresponding beam casting formwork and floor slab casting formwork in the early demolition area according to an embodiment of the present invention;

[0027] Figure 9 for Figure 8 Schematic diagram of the dismantled beam casting formwork and floor slab casting formwork;

[0028] Figure 10 Schematic diagram of the support system structure after the lower layer of the disc-type scaffolding is removed in an embodiment of the present invention;

[0029] Figure 11 for Figure 9 Schematic diagram of the lower level of the disc-type scaffolding being dismantled;

[0030] Figure 12 This is a schematic diagram of the main structure after the late demolition support frame system and the corresponding beam casting formwork and floor slab casting formwork in the late demolition area are removed in an embodiment of the present invention;

[0031] Figure 13 for Figure 12 Schematic diagram of the late demolition support frame system and the corresponding beam casting formwork and floor slab casting formwork in the late demolition area.

[0032] In the figure: 1. Early demolition area; 101. Upper-level disc-type scaffolding; 102. Lower-level disc-type scaffolding; 2. Late demolition area; 201. Late demolition support frame system; 3. Column structure; 4. Beam structure; 401. First beam; 402. Second beam; 5. Scissors brace; 6. Main purlin; 7. Secondary purlin; 8. Floor slab casting formwork; 9. Floor slab structure; 10. Pad; 11. Springboard. DETAILED DESCRIPTION

[0033] The present invention will be further described below with reference to the embodiments, the purpose of which is only to provide a better understanding of the content of the present invention. Therefore, the examples given do not limit the scope of protection of the present invention.

[0034] This embodiment combines the technical characteristics of the independent dismantling of each span of the disc-type scaffolding and the law of rapid early strength growth of concrete to design a construction method for large-span reinforced concrete horizontal members. This method can achieve the goal of early removal of most formwork by reducing the span of structural beams and slabs under the conditions specified in the "Concrete Structure Engineering Construction and Acceptance Code" GB50204-2002, thereby ultimately achieving the goals of energy saving and efficiency improvement. Figures 1 to 13 , specifically including the following steps:

[0035] S1: If Figure 1 、 Figure 2 , divide the early demolition area 1 and the late demolition area 2 according to the span of the horizontal components, and set up corresponding support systems. The support system under the early demolition area 1 is the early demolition support frame system, and the support system under the late demolition area 2 is the late demolition support frame system 201; the spacing between the late demolition poles of the late demolition support frame system 201 and the adjacent late demolition poles or wall columns is 2m~8m; the early demolition support frame systems are arranged between the late demolition support frame systems 201, and the spacing between the early demolition poles of the early demolition support frame system and the adjacent early demolition poles, adjacent late demolition poles or wall columns is 0.6m~1.2m;

[0036] Both the early dismantling support frame system and the late dismantling support frame system 201 use disc-type scaffolding. The disc-type scaffolding uprights are made of Q345 low-carbon alloy steel. The disc-type scaffolding is hot-dip galvanized inside and outside, with a silver appearance, and has a beautiful appearance after erection. The disc-type scaffolding is relatively flexible in disassembly between frames, and each span can be dismantled independently without being restricted by materials.

[0037] S2: If Figure 3 According to the drawings of the design support system, the point position lines of the rods in the support system are placed, and the early-dismantling support frame system and the late-dismantling support frame system 201 are set up. At the same time, the wall column casting formwork is supported; when setting up the early-dismantling support frame system and the late-dismantling support frame system 201, first set up the standard quadrilateral support lattice, and then support the remaining support lattices according to the principle of mutual perpendicularity or straightness; 250mm×50mm×4000mm wooden boards need to be laid under the vertical poles of the disc-type scaffolding as pads 10, and the vertical poles of the upper and lower scaffoldings need to be aligned to ensure effective load transfer.

[0038] S3: First, the beam casting formwork and the floor slab casting formwork 8 are supported on the early dismantling support frame system and the late dismantling support frame system 201 in sequence; the formwork process includes: installation of the main keel 6 and the secondary keel 7 → elevation adjustment → laying of the casting formwork (beam casting formwork and floor slab casting formwork 8) → acceptance by the quality inspector; then, the reinforcement binding and concrete pouring of the wall column structure, beam structure 4 and floor slab structure 9 are carried out in sequence; in this embodiment, as Figure 2 The beam structure 4 includes a first beam body 401 of 400 mm×800 mm and a second beam body 402 of 300 mm×600 mm.

[0039] S4: When the concrete strength of the wall-column structure (in this embodiment, column structure 3 is used as an example) reaches 50% of the design strength (test block pressure test), the column casting formwork is removed and transported out of the working surface;

[0040] S5: When the concrete strength of the beam structure 4 and the floor structure 9 reaches 75% of the design strength, the early dismantling support frame system and the beam casting formwork and floor casting formwork 8 supported by the early dismantling support frame system are dismantled and transported out of the working surface; wherein the early dismantling support frame system is provided with two layers, namely, the upper layer disc-type scaffolding 101 and the lower layer disc-type scaffolding 102. Step S5 specifically includes:

[0041] S501: When the concrete strength of the beam structure 4 and the floor structure 9 reaches 75% of the design strength, first remove the scissor brace 5 and the sweeping rod (such as Figure 4 、 Figure 5 ), and then remove the upper layer of the buckle type scaffolding 101 (such as Figure 6 、 Figure 7 ), transport the demolished parts out of the working surface in batches;

[0042] S502: Then, a springboard 11 (such as Figure 8 ), remove the early demolition area 1 and the main keel 6, secondary keel 7, beam casting formwork and floor slab casting formwork 8 (such as Figure 9 ), transport out of the working face;

[0043] S503: Remove the lower layer of the buckle type scaffolding 102 (such as Figure 10、 Figure 11 ), and transported out of the working face.

[0044] S6: When the concrete strength of the beam structure 4 and the floor structure 9 reaches 100% of the design strength, remove the late demolition support frame system 201 and the late demolition area 2 beam casting formwork and floor casting formwork 8 (such as Figure 12 、 Figure 13 ) and transported out of the working surface.

[0045] During construction, it should be noted that the wall column casting formwork, beam casting formwork and floor slab casting formwork 8 as well as the main purlin 6 and secondary purlin 7 must be completely disconnected at the boundary between the early demolition area 1 and the late demolition area 2, and the support systems (disc-type scaffolding support frames) corresponding to the early demolition area 1 and the late demolition area 2 can be used and dismantled independently; when the demolition conditions are met, the cross bars of one span between the early demolition area 1 and the late demolition area 2 can be completely dismantled without being affected; after dismantling the early demolition support frame system and the beam casting formwork and floor slab casting formwork 8 supported on the early demolition support frame system, the remaining late demolition support frame system 201 and the main structure wall columns together form a structural span of ≤8m, thereby achieving the purpose of early dismantling of large-span formwork; in addition, it should be noted that when dismantling the cross bars in the early demolition support frame system or the late demolition support frame system 201, use a hammer to evenly hit both ends of the cross bar so that both ends of the cross bar are lifted out at the same time.

[0046] The scope of application of this construction method includes: 1. Applicable to the formwork support system of floor slabs and beams of residential, public buildings and industrial plants; bridges, culverts and other projects; 2. Applicable to the formwork support system of multi-story, high-rise and super high-rise buildings with more standard floors or standard rooms; 3. Applicable to the floor support system of buildings with large single-story area and difficult turnover of formwork support system; 4. Applicable to the floor support system of various types of buildings such as frame structure, shear wall structure, frame shear wall structure, especially buildings with larger spans.

[0047] The technical features of this construction method include: 1. Standardization of the construction process, standardization of the structural dimensions of the support system and the node connection method, which reduces the arbitrariness during erection and avoids the possibility of unstable structures and variable states of nodes; 2. Fast material turnover, low investment, quick results, and significant economic benefits; 3. Quick installation and disassembly, high work efficiency, and shortened construction period; 4. It is conducive to civilized construction and on-site management, and the support system is neat and standardized, which is conducive to civilized construction and on-site management; 5. Due to the fast turnover of the casting formwork, the amount of formwork material used is reduced, which reduces the felling of trees and bamboo forests, is beneficial to environmental protection, and has good social benefits.

[0048] When a large-span reinforced concrete horizontal member adopts an ordinary steel pipe fastener scaffolding system to support the casting formwork and the main purlin 6 and the secondary purlin 7, it is usually necessary to wait until the concrete strength reaches 100% before removing the casting formwork, the main purlin 6, the secondary purlin 7 and the supporting scaffolding. According to this method, part of the casting formwork, the main purlin 6, the secondary purlin 7 and the disc-type supporting scaffolding can be removed after the concrete strength reaches 75%. The removed casting formwork, the main purlin 6, the secondary purlin 7 and the disc-type supporting scaffolding can be immediately put into circulation and used, which greatly improves work efficiency and significantly reduces construction costs.

[0049] The above description is only a preferred embodiment of the present invention and does not limit the scope of the present invention. Any equivalent changes made using the contents of the present invention specification and its drawings are included in the scope of the present invention.

Claims

1. A method for constructing a large-span reinforced concrete horizontal member, characterized in that: The steps include: S1: Divide the early demolition area into the late demolition area according to the span of the horizontal components, and design the support frame system accordingly. The support system is divided into an early demolition support frame system and a late demolition support frame system. The spacing between the late demolition support frame system's late demolition poles and adjacent late demolition poles or wall columns is 2m to 8m. The early demolition support frame system is installed between the late demolition support frame systems. The spacing between the early demolition support frame system's early demolition poles and adjacent early demolition poles, adjacent late demolition poles or wall columns is 0.6m to 1.2m. S2: Erect the early-dismantling support frame system and the late-dismantling support frame system according to the design support system drawings. At the same time, support the wall column casting formwork. Both the early-dismantling support frame system and the late-dismantling support frame system use disc-type scaffolding. When erecting, first erect the standard quadrilateral support lattice, and then support the remaining support lattices in a mutually perpendicular or straight manner. S3: Supporting the beam casting formwork and the floor slab casting formwork on the early-removal support frame system and the late-removal support frame system in sequence; then, concrete pouring of the wall column structure, beam structure, and floor slab structure is carried out in sequence; S4: When the concrete strength of the wall column structure reaches 50% of the design strength, the wall column formwork is removed and transported out of the working surface; S5: When the concrete strength of the beam structure and floor slab structure reaches 75% of the design strength, the early dismantling support frame system and the beam casting formwork and floor slab casting formwork supported by the early dismantling support frame system are removed and transported out of the working surface; The early dismantling support frame system is provided with two layers, namely, an upper layer of disc-type scaffolding and a lower layer of disc-type scaffolding. Step S5 specifically includes: S501: When the concrete strength of the beam structure and floor slab structure reaches 75% of the design strength, the upper scaffolding should be dismantled and transported out of the working surface; S502: Then, a springboard is set up on the lower-level disc-type scaffolding, and the beam casting formwork and floor slab casting formwork are removed and transported out of the working surface; S503: Remove the lower layer of the scaffolding and transport it out of the working surface; S6: When the concrete strength of the beam structure and floor slab structure reaches 100% of the design strength, the late-removal support frame system and the beam casting formwork and floor slab casting formwork supported by the late-removal support frame system are removed and transported out of the working surface.

2. The method for constructing a large-span reinforced concrete horizontal member according to claim 1, characterized in that: In step S3, the beam casting formwork, the floor slab casting formwork, the main purlin and the secondary purlin are completely disconnected at the boundary between the early demolition area and the late demolition area, and the early demolition support frame system and the late demolition support frame system are used and dismantled independently.

3. The method for constructing a large-span reinforced concrete horizontal member according to claim 1, characterized in that: When removing the crossbar in the early removal support frame system or the late removal support frame system, use a hammer to evenly hit both ends of the crossbar so that both ends of the crossbar are lifted out at the same time.

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