Method for accurately controlling thickness of bottom steel bar protective layer of concrete beam and slab structure

Abstract

The invention discloses a method for accurately controlling the thickness of a steel bar protection layer at the bottom of a concrete beam and slab structure. The method comprises the following steps that S1, a plurality of sets of cushion blocks A and tire ribs are placed above a beam and slab formwork at intervals; s2, positioning and placing stirrups above the tire ribs, wherein the stirrups are annular; s3, a plurality of cushion blocks B are installed at the bottoms of the stirrups, the cushion blocks B are fixedly connected with the stirrups, and the cushion blocks B are arranged at equal intervals; and S4, the cushion block A is chiseled away, the tire ribs are dismantled, the stirrups integrally fall on the cushion block B, the cushion block B falls on the beam and plate formwork, and cushion block conversion is completed. The method for accurately controlling the thickness of the bottom steel bar protection layer of the concrete beam and plate structure is provided. The method is suitable for reinforced concrete beam and plate structures, construction operation is simple, the bottom reinforcement cushion blocks are chiseled away and replaced, so that reinforcement tire ribs are removed, the problem that the thickness of a tire rib protection layer is insufficient is solved, and the purpose of accurately controlling the thickness of the concrete structure reinforcement protection layer is achieved.

Description

Technical Field

[0001] The present invention relates to the field of controlling the thickness of a steel bar protective layer at the bottom of a concrete beam-slab structure, and more specifically, to a method for accurately controlling the thickness of a steel bar protective layer at the bottom of a concrete beam-slab structure. Background Art

[0002] In the construction of reinforced concrete structures such as cast-in-place beams and slabs, the most important inspection and control indicator is the thickness of the steel bar protective layer. The thickness of the reinforced concrete protective layer is the distance from the outer edge of the outermost steel bar (including stirrups, structural steel bars or distribution bars, etc.) to the concrete surface. Too large a protective layer thickness will cause economic waste, and the width of the cracks generated after the component is stressed will be too large; too small a protective layer thickness will not provide ideal anti-corrosion protection for the internal steel bars, and the effective anchoring performance of the stressed steel bars will not meet the requirements. Therefore, in the construction of cast-in-place reinforced concrete structures, the thickness of the steel bar protective layer must be strictly controlled to meet the design requirements, and the error cannot be too large.

[0003] The construction of cast-in-place reinforced concrete structures such as beams and slabs is to tie the steel bars first and then pour the concrete. When tying the steel bars, the stirrups are usually positioned and tied first, and then the main bars and structural bars are positioned and tied with the stirrups. The stirrups are at the outermost layer, and controlling the thickness of the steel bar protection layer of the beam and slab structure is mainly to control the thickness of the steel bar protection layer at the bottom of the stirrups to meet the design requirements.

[0004] At present, the following method is generally used to control the thickness of the bottom protective layer of the stirrups of beams and slabs: place a circular or long strip concrete pad on the existing foundation or formwork at the bottom, and then place the positioning steel bars (rebars) of the stirrups on the pad. The rebars and pads are connected by binding tape or wire, and the stirrups and rebars are fixed by electric welding or wire. The thickness of the pad plus the straight bar of the rebar should be equal to the thickness of the stirrup protective layer. For beam-slab structures with existing geotechnical foundations at the bottom, steel bar saddles or finished steel saddles can be used instead of concrete pads.

[0005] This method is simple to operate, and the concrete pads, horse stools and tire bars can be poured into the concrete structure together. However, this method does not consider the influence of tire bars on the thickness of the protective layer. Especially as the size of beams and slabs increases, the number of tire bars increases. In complex natural environments, the thickness of the tire bar protective layer is insufficient, which makes it more likely for the bottom concrete to crack and / or tire bar to rust, thereby causing the corrosion of the overall structural steel bars, reducing the service life of the concrete structure and endangering the structural safety.

[0006] In view of the above problems, it is urgent to develop a new method for controlling the thickness of the steel bar protective layer at the bottom of reinforced concrete structures such as cast-in-place beams and slabs, so that the thickness of all steel bar protective layers meets the design requirements. Summary of the invention

[0007] In order to achieve these purposes and other advantages according to the present invention, a preferred embodiment of the present invention provides a method for accurately controlling the thickness of the steel bar protective layer at the bottom of a concrete beam-slab structure, comprising the following steps: S1. Place a plurality of groups of pads A and reinforcing bars at intervals above the beam and slab formwork, wherein each group of reinforcing bars is located above the pads A; S2. Positioning and placing stirrups above the tire reinforcement, wherein the stirrups are annular and fixedly connected to the tire reinforcement; S3, installing a plurality of pads B at the bottom of the stirrups, wherein the pads B are fixedly connected to the stirrups, and the plurality of pads B are arranged at equal intervals; S4. Chisel off pad A, remove the reinforcing bars, make the stirrups fall onto pad B as a whole, and pad B falls onto the beam and slab formwork to complete the pad conversion.

[0008] According to a preferred embodiment of the present invention, the following steps are also included: S5. Tie the main reinforcement, structural reinforcement and stirrups together.

[0009] According to a preferred embodiment of the present invention, the cushion block A and the cushion block B are staggered.

[0010] According to a preferred embodiment of the present invention, the distance between two adjacent pads A is 2-3 times the distance between two adjacent pads B.

[0011] According to a preferred embodiment of the present invention, the main reinforcement is attached to the inner side of the stirrup, and the structural reinforcement is annular and is distributed in the stirrup in the transverse and longitudinal directions.

[0012] According to a preferred embodiment of the present invention, the diameter of the tire bar is not less than 20 mm.

[0013] The present invention has at least the following beneficial effects: The present invention provides a method for accurately controlling the thickness of the steel bar protective layer at the bottom of a concrete beam or slab structure. The method is applicable to reinforced concrete beams and slab structures, and the construction operation is simple. The steel bar tire is removed by chiseling and replacing the bottom steel bar pad, thereby avoiding the problem of insufficient thickness of the tire bar protective layer, and achieving the purpose of accurately controlling the thickness of the steel bar protective layer of the concrete structure.

[0014] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the installation of step S1 in the present invention; Figure 2 This is a schematic diagram of the installation of step S2 in the present invention; Figure 3 This is a schematic diagram of the installation of step S3 in the present invention; Figure 4 This is a schematic diagram of the installation of step S4 in the present invention; Figure 5 It is a schematic diagram of the installation of step S5 in the present invention. DETAILED DESCRIPTION

[0016] The present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0017] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art can think of other obvious variations. The basic principles of the present invention defined in the following description can be applied to other embodiments, variations, improvements, equivalents, and other technical solutions that do not deviate from the spirit and scope of the present invention.

[0018] Those skilled in the art should understand that, in the disclosure of the present invention, the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0019] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0020] like Figure 1-5 As shown, a preferred embodiment of the present invention provides a method for accurately controlling the thickness of the steel bar protective layer at the bottom of a concrete beam-slab structure, comprising the following steps: S1, placing a plurality of groups of pads A1 and reinforcing bars 2 at intervals above the beam and slab formwork 5, wherein each group of reinforcing bars 2 is located above the pads A1; S2, positioning and placing stirrups 3 above the tire reinforcement 2, wherein the stirrups 3 are annular and are fixedly connected to the tire reinforcement 2; S3, installing a plurality of pads B4 at the bottom of the stirrup 3, wherein the pads B4 are fixedly connected to the stirrup 3, and the plurality of pads B4 are arranged at equal intervals; S4, chisel off the pad A1, remove the tire reinforcement 2, make the stirrup 3 fall on the pad B4 as a whole, and the pad B4 falls on the beam and slab formwork to complete the pad conversion.

[0021] S5. Tie the main reinforcement 6 and the structural reinforcement 7 in the stirrup together. The two sides and the bottom of the stirrup can be reinforced by welding part of the main reinforcement in advance.

[0022] In the above technical solution, the pad A made of concrete is mainly used to fix the stirrups. The pad A is placed horizontally. The thickness of the pad A and the pad B are the same, which is equal to the thickness of the stirrup protective layer.

[0023] The above technical scheme removes the stirrups to position the tire bars through the conversion of the pads, thereby avoiding the influence of insufficient thickness of the tire bar protective layer, and at the same time accurately controls the thickness of the stirrup protective layer to meet the design requirements. In the above technical scheme, the tire bars are removed and pulled out through the conversion of the pads, thereby avoiding the influence of the tire bars on the thickness of the protective layer. As long as the thickness of the pad B is accurately controlled, the thickness of the protective layer can be accurately controlled.

[0024] Since pad A only needs to bear the stirrup load in the early stage, the pad spacing can be arranged larger, the pad material requirements are lower, the entire construction process is simple to operate, the project volume is small, and the cost is low.

[0025] Compared with the existing method of removing the tire reinforcement by lifting the entire steel structure, it avoids the use of large lifting equipment and has higher construction safety performance.

[0026] According to a preferred embodiment of the present invention, pad A and pad B are staggered. A is a temporary support position, which will be removed later. In order not to hinder the later arrangement of B, A and pad B are staggered.

[0027] According to a preferred embodiment of the present invention, the distance between two adjacent pads A is 2-3 times the distance between two adjacent pads B. Because pads A only need to bear the stirrup load in the early stage, the pad spacing can be arranged larger and the pad material requirements are lower.

[0028] According to a preferred embodiment of the present invention, the main reinforcement is attached to the inner side of the stirrup, and the structural reinforcement is annular and distributed in the stirrup transversely and longitudinally to increase the overall strength of the stirrup.

[0029] According to a preferred embodiment of the present invention, the diameter of the tire bar is not less than 20 mm, which can better ensure the strength of the entire protective layer.

[0030] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A method for accurately controlling the thickness of the steel bar protective layer at the bottom of a concrete beam-slab structure, characterized in that: The following steps are involved: S1. Place a plurality of groups of pads A and reinforcing bars at intervals above the beam and slab formwork, wherein each group of reinforcing bars is located above the pads A; S2. Positioning and placing stirrups above the tire reinforcement, wherein the stirrups are annular and fixedly connected to the tire reinforcement; S3, installing a plurality of pads B at the bottom of the stirrups, wherein the pads B are fixedly connected to the stirrups, and the plurality of pads B are arranged at equal intervals; S4. Chisel off pad A, remove the reinforcing bars, make the stirrups fall onto pad B as a whole, and pad B falls onto the beam and slab formwork to complete the pad conversion.

2. The method for accurately controlling the thickness of the steel bar protective layer at the bottom of a concrete beam-slab structure according to claim 1 is characterized in that: The following steps are also included: S5. Tie the main reinforcement, structural reinforcement and stirrups together.

3. The method for accurately controlling the thickness of the steel bar protective layer at the bottom of a concrete beam-slab structure according to claim 1 is characterized in that: Pad A and pad B are staggered.

4. The method for accurately controlling the thickness of the steel bar protective layer at the bottom of a concrete beam-slab structure according to claim 1 is characterized in that: The distance between two adjacent pad blocks A is 2-3 times the distance between two adjacent pad blocks B.

5. The method for accurately controlling the thickness of the steel bar protective layer at the bottom of a concrete beam-slab structure according to claim 2 is characterized in that: The main reinforcement is attached to the inner side of the stirrup, and the structural reinforcement is annular and is distributed in the stirrup transversely and longitudinally.

6. The method for accurately controlling the thickness of the steel bar protective layer at the bottom of a concrete beam-slab structure according to claim 1 is characterized in that: The tire reinforcement diameter is not less than 20 mm.

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