Structure and method for improving crack resistance of precast reinforced concrete beam-slab joint area

Abstract

The present invention discloses a structure and method for improving the crack resistance of precast reinforced concrete beam-slab node areas, the structure comprising a lower reinforced concrete column wall having a first steel bar; a precast reinforced concrete beam-slab hoisted on the lower reinforced concrete column wall, the precast reinforced concrete beam-slab having a second steel bar, the area where the precast reinforced concrete beam-slab intersects with the lower reinforced concrete column wall forming a node area, the second steel bars overlap each other in the node area, an isolation piece is provided on the outside of the second steel bar at the top adjacent to the node area; a post-cast section comprises high-performance concrete cast in the node area and the area adjacent to the node area. According to the structure for improving the crack resistance of precast reinforced concrete beam-slab node areas of the present invention, an isolation piece is provided on the outside of the second steel bar at the top adjacent to the node area, which can prevent adhesion between the second steel bar and the high-performance concrete, and cut off the force transmission between the second steel bar and the post-cast section concrete.

Description

Technical Field

[0001] The present invention relates to the field of structural engineering technology, and in particular to a structure for improving the crack resistance of a precast reinforced concrete beam-slab node area and a method for improving the crack resistance of a precast reinforced concrete beam-slab node area. Background Art

[0002] Among related technologies, my country's infrastructure construction is currently developing rapidly, and prefabricated buildings have been vigorously promoted. Prefabricated buildings primarily prefabricate structural components in processing plants, assemble them on-site, and ensure connections between the prefabricated components through various construction methods. In prefabricated buildings, the areas near the joints of precast reinforced concrete beams and slabs are mostly post-cast concrete. This shrinkage, coupled with the large bending moments applied to the concrete, can easily lead to cracking after construction. Once cracking occurs in reinforced concrete structures, it significantly impacts their durability and safety. Therefore, improving the crack resistance of these areas is crucial for the structure. Summary of the Invention

[0003] The present invention aims to address at least one of the technical problems existing in the prior art. To this end, one object of the present invention is to provide a structure for improving the crack resistance of precast reinforced concrete beam-slab joints. This structure helps prevent cracking in the negative bending moment zone near the joints of precast reinforced concrete beams and slabs, and is easy to construct.

[0004] Another object of the present invention is to provide a method for improving the crack resistance of precast reinforced concrete beam-slab node areas.

[0005] According to the first embodiment of the present invention, a structure for improving the crack resistance of precast reinforced concrete beam-slab node areas includes: a lower reinforced concrete column wall, the lower reinforced concrete column wall having a first steel bar extending in a vertical direction, and the lower reinforced concrete column wall is made of ordinary concrete; a precast reinforced concrete beam-slab, the precast reinforced concrete beam-slab being hoisted on the lower reinforced concrete column wall, the precast reinforced concrete beam-slab having a second steel bar extending in a horizontal direction, wherein the area where the precast reinforced concrete beam-slab intersects with the lower reinforced concrete column wall forms a node area, the second steel bars are overlapped with each other in the node area, and an isolation piece is provided on the outside of the second steel bar at the top adjacent to the node area; and a post-cast section, the post-cast section including high-performance concrete cast in the node area and the area adjacent to the node area.

[0006] According to the structure for improving the crack resistance of the node area of ​​the precast reinforced concrete beam and slab according to the embodiment of the present invention, an isolation piece is provided on the outer side of the position of the second steel bar adjacent to the node area, so that the second steel bar can be isolated from the high-performance concrete, thereby preventing the second steel bar and the high-performance concrete from bonding, and cutting off the force transmission between the second steel bar and the post-cast concrete, so that the second steel bar is evenly stressed and becomes the main part bearing the tensile force, while not transmitting the internal tensile force to the high-performance concrete, thereby greatly reducing the stress of the high-performance concrete.

[0007] In addition, the structure for improving the crack resistance of the precast reinforced concrete beam-slab node area according to the above embodiment of the present invention also has the following additional technical features:

[0008] According to some embodiments of the present invention, the isolation member is made of a material with a low elastic modulus, and the elastic modulus of the isolation member is lower than the elastic modulus of the ordinary concrete or the elastic modulus of the high performance concrete.

[0009] Furthermore, the isolation piece is a rubber piece or a polyethylene plastic piece.

[0010] Furthermore, the spacer is constructed in the shape of a sleeve, and an opening is formed on the sleeve, extending axially and penetrating the sleeve along the thickness direction of the sleeve, and the sleeve is suitable for being buckled on the outside of the second steel bar through the opening.

[0011] In some embodiments of the present invention, the spacer includes a first sub-spacer and a second sub-spacer, and the first sub-spacer and the second sub-spacer are respectively sleeved on the outside of the second steel bar and fixed by a strip component.

[0012] In some embodiments of the present invention, the isolation member is a rubber layer or a plastic layer wrapped around the outside of the second steel bar.

[0013] According to some embodiments of the present invention, the structure for improving the crack resistance of the node area of ​​precast reinforced concrete beams and slabs also includes: an upper reinforced concrete column wall, the upper reinforced concrete column wall is connected to the node area, and the upper reinforced concrete column wall is opposite to the lower reinforced concrete column wall in the upper and lower directions, and the upper reinforced concrete column wall is made of ordinary concrete; wherein the tensile strength of the high-performance concrete is higher than that of the ordinary concrete, and the high-performance concrete includes one of UHPC and ECC.

[0014] According to some embodiments of the present invention, a method for improving the crack resistance of a precast reinforced concrete beam-slab node area includes: step S1: constructing a lower layer of reinforced concrete column walls; step S2: hoisting the precast reinforced concrete beam-slab to a designated design position; step S3: overlapping a second steel bar in the node area; step S4: setting an isolation piece on the outside of the second steel bar located at the top adjacent to the node area; step S5: supporting the formwork and pouring a post-cast section using high-performance concrete; step S6: constructing an upper layer of reinforced concrete column walls; wherein the high-performance concrete has a higher tensile strength than ordinary concrete, and the high-performance concrete includes one of UHPC and ECC.

[0015] Furthermore, the isolation member is made of a material with a low elastic modulus, and the elastic modulus of the isolation member is lower than the elastic modulus of the ordinary concrete or the elastic modulus of the high performance concrete.

[0016] Furthermore, the isolator is a rubber part or a polyethylene plastic part, wherein the isolator is constructed in the shape of a sleeve, and an opening is formed on the sleeve, which extends axially and passes through the sleeve along the thickness direction of the sleeve, and the sleeve is suitable for being buckled on the outside of the second steel bar through the opening; or, the isolator includes a first sub-isolator and a second sub-isolator, and the first sub-isolator and the second sub-isolator are respectively sleeved on the outside of the second steel bar and fixed by a strip-shaped part; or, the isolator is a rubber part layer or a plastic part layer wrapped around the outside of the second steel bar.

[0017] The present invention has the following advantages over the prior art:

[0018] First, through the new idea of ​​"combining resistance and release" and "making full use of resources", the bond between the steel bars (such as the second steel bars, etc.) and the concrete (such as high-performance concrete, etc.) is partially destroyed, and the force transmission between the steel bars and the concrete is cut off, so that the steel bars are evenly stressed and become the main part of the tension. At the same time, the internal tension will not be transmitted to the concrete, thereby greatly reducing the stress of the concrete.

[0019] Secondly, by using high-tensile concrete in areas prone to cracking, the tensile strength of the concrete is improved. High-performance concrete is more expensive, but its application in appropriate locations can significantly improve crack resistance without significantly increasing the cost.

[0020] Third, isolation parts made of low elastic modulus materials are inexpensive, do not require too much additional work during construction, and are easy to ensure project quality.

[0021] Fourthly, compared with traditional construction schemes, it has superior stress-bearing performance and simple structure, which can improve performance without excessive impact on construction and cost.

[0022] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0024] Figure 1 is a schematic diagram of a structure for improving the crack resistance of a precast reinforced concrete beam-slab node area according to an embodiment of the present invention;

[0025] Figure 2 for Figure 1 A cross-sectional view along line AA of a structure for improving the anti-cracking performance of a precast reinforced concrete beam-slab node area according to an embodiment of the present invention.

[0026] Reference numerals:

[0027] Improve the crack resistance of precast reinforced concrete beam-slab joint area structure 100,

[0028] Lower reinforced concrete column wall 1, first steel bar 11,

[0029] Ordinary concrete 2,

[0030] Precast reinforced concrete beam slab 3, second steel bar 31,

[0031] Node area 4, isolation member 5, post-cast section 6, high-performance concrete 7, upper reinforced concrete column wall 8. DETAILED DESCRIPTION

[0032] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0033] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0034] The following describes a structure 100 for improving the crack resistance of precast reinforced concrete beam-slab joints according to a first embodiment of the present invention with reference to the accompanying drawings. The structure 100, which utilizes localized non-bonding technology, offers advantages such as reasonable force distribution, optimal utilization, safety, reliability, and ease of construction.

[0035] Reference Figure 1 and Figure 2 According to the first embodiment of the present invention, a structure 100 for improving the crack resistance of the precast reinforced concrete beam-slab node area includes: a lower reinforced concrete column wall 1, a precast reinforced concrete beam-slab 3 and a post-cast section 6.

[0036] Specifically, the lower reinforced concrete column wall 1 has first steel bars 11 extending in a vertical direction, and the lower reinforced concrete column wall 1 is made of ordinary concrete 2. For example, the lower reinforced concrete column wall 1 has the first steel bars 11, and the first steel bars 11 can extend in a vertical direction. The first steel bars 11 can include a plurality of first steel bars 11 (in the description of the present invention, "plurality" means two or more), and the plurality of first steel bars 11 can be arranged spaced apart in the circumferential direction. The lower reinforced concrete column wall 1 can be made of ordinary concrete 2, which is beneficial for controlling costs.

[0037] The precast reinforced concrete beam slab 3 is hoisted on the lower reinforced concrete column wall 1. The precast reinforced concrete beam slab 3 has a second steel bar 31 extending in the horizontal direction. The area where the precast reinforced concrete beam slab 3 intersects with the lower reinforced concrete column wall 1 forms a node area 4. In the node area 4, the second steel bars 31 overlap each other, and an isolation piece 5 is provided on the outside of the second steel bar 31 located at the top adjacent to the node area 4.

[0038] For example, a precast reinforced concrete beam slab 3 can be hoisted on the lower reinforced concrete column wall 1. The precast reinforced concrete beam slab 3 has second steel bars 31, and the second steel bars 31 can extend horizontally. The area where the precast reinforced concrete beam slab 3 intersects with the lower reinforced concrete column wall 1 can form a node area 4. In this node area 4, the second steel bars 31 overlap each other, and a spacer 5 is provided on the outside of the second steel bar 31 located at the top adjacent to the node area 4.

[0039] For example, in some embodiments of the present invention, the precast reinforced concrete beam slab 3 is not a whole, and the precast reinforced concrete beam slab 3 may include two beam slabs, generally one on the left and one on the right, wherein each beam slab has a section of steel bar (such as the second steel bar 31) extending outward at the end, and then the beam slab is placed on the column, overlapping the second steel bars 31 of the two beam slabs.

[0040] The post-cast section 6 includes high-performance concrete 7 cast in the node area 4 and the area adjacent to the node area 4. For example, the post-cast section 6 may include the node area 4 and the area adjacent to the node area 4, and the post-cast section 6 may be cast using high-performance concrete 7. Therefore, by casting the post-cast section 6 with high-performance concrete 7, the tensile strength of the post-cast section 6 is improved. In addition, the application of high-performance concrete 7 in the post-cast section 6 greatly improves the crack resistance without excessively increasing the cost.

[0041] For example, in some specific embodiments of the present invention, in the horizontal direction, the area adjacent to the node region 4 may extend beyond the outermost end of the spacer 5, or the area adjacent to the node region 4 may be flush with the outermost end of the spacer 5. The "outer end" here refers to the end of the spacer 5 away from the node region 4.

[0042] Furthermore, it should be noted that the above description of the region adjacent to node region 4 is merely exemplary and should not be construed as limiting the present invention. The present invention does not limit the specific location of the region adjacent to node region 4. In practical applications, the region adjacent to node region 4 can be adaptively configured as needed, as will be understood by those skilled in the art.

[0043] According to the structure 100 for improving the crack resistance of the node area of ​​the precast reinforced concrete beam and slab according to an embodiment of the present invention, an isolation piece 5 is provided on the outer side of the second steel bar 31 located at the top adjacent to the node area 4, so that the second steel bar 31 can be isolated from the high-performance concrete 7, thereby preventing adhesion between the second steel bar 31 and the high-performance concrete 7, and cutting off the force transmission between the second steel bar 31 and the post-cast concrete, so that the second steel bar 31 is evenly stressed and becomes the main part bearing the tension, while not transmitting the internal tension to the high-performance concrete 7, thereby greatly reducing the stress of the high-performance concrete 7.

[0044] The structure 100 for improving the crack resistance of the precast reinforced concrete beam-slab node area according to an embodiment of the present invention is beneficial for preventing the precast reinforced concrete beam-slab 3 from cracking in the negative bending moment area near the node area and is convenient to construct.

[0045] According to some embodiments of the present invention, the spacer 5 is made of a material with a low elastic modulus, and the elastic modulus of the spacer 5 is lower than the elastic modulus of the ordinary concrete 2 or the elastic modulus of the high-performance concrete 7. For example, in some embodiments of the present invention, the spacer 5 can be made of a material with a low elastic modulus, and the elastic modulus of the spacer 5 can be lower than the elastic modulus of the ordinary concrete 2. In some embodiments of the present invention, the spacer 5 can be made of a material with a low elastic modulus, and the elastic modulus of the spacer 5 can be lower than the elastic modulus of the high-performance concrete 7.

[0046] Furthermore, the spacer 5 may be a rubber member or a polyethylene plastic member. For example, in some embodiments of the present invention, the spacer 5 may be a rubber member such as a high-performance rubber member; in some embodiments of the present invention, the spacer 5 may also be a polyethylene plastic member.

[0047] For example, in some specific embodiments of the present invention, the elastic modulus of the isolation member 5 can be much lower than the elastic modulus of ordinary concrete 2 or the elastic modulus of high-performance concrete 7. Specifically, in some specific embodiments of the present invention, the elastic modulus of concrete is approximately 30 GPa, and the elastic modulus of the isolation member 5 (e.g., a rubber member) is approximately 0.01 GPa, but the present invention is not limited thereto.

[0048] Several specific embodiments of the isolation member 5 in the structure 100 for improving the crack resistance of the precast reinforced concrete beam-slab node area according to the present invention will be described below with reference to the accompanying drawings.

[0049] Example 1:

[0050] In some embodiments of the present invention, the isolation member 5 can be constructed in the shape of a sleeve, on which is formed an opening extending axially and passing through the sleeve along the thickness direction of the sleeve, and the sleeve is suitable for being buckled on the outside of the second steel bar 31 through the opening.

[0051] For example, the isolator 5 can be an integrated structure, and the isolator 5 can be constructed in the shape of a sleeve, an opening is formed on the sleeve, the opening can extend along the axial direction of the sleeve, and the opening can be set through the sleeve along the thickness direction of the sleeve, and the sleeve is suitable for being buckled on the outside of the second steel bar 31 through the opening.

[0052] Example 2:

[0053] In some embodiments of the present invention, the spacer 5 includes a first sub-spacer and a second sub-spacer, and the first sub-spacer and the second sub-spacer are respectively sleeved on the outside of the second steel bar 31 and fixed by a strip component.

[0054] For example, in some embodiments of the present invention, the spacer 5 can be a split structure, including a first sub-spacer and a second sub-spacer. The first sub-spacer and the second sub-spacer are respectively sleeved on the outside of the second steel bar 31, and the first sub-spacer and the second sub-spacer can be fixed by a strip-shaped member. In this way, the first sub-spacer and the second sub-spacer can be fixed to the outside of the second steel bar 31 by the strip-shaped member, which improves reliability.

[0055] The strip-shaped component may be, for example, an adhesive tape, a rope, or the like.

[0056] In some embodiments of the present invention, the structures of the first sub-isolator and the second sub-isolator may be symmetrical, for example, the structures of the first sub-isolator and the second sub-isolator may be the same; of course, in some embodiments of the present invention, the first sub-isolator and the second sub-isolator may also be asymmetrically arranged, and the present invention does not specifically limit this.

[0057] Example 3:

[0058] In some embodiments of the present invention, the isolation member 5 is a rubber layer or a plastic layer wrapped around the outside of the second steel bar 31 .

[0059] For example, in some optional embodiments of the present invention, the isolation member 5 may be a rubber layer or a plastic layer wrapped around the outside of the second steel bar 31. The rubber layer or the plastic layer may include one or more turns wrapped around the outside of the second steel bar 31, and the present invention is not specifically limited to this.

[0060] It should be noted here that the above description of the specific structure of the isolation member 5 is merely exemplary and cannot be construed as limiting the present invention, which is understandable to those skilled in the art.

[0061] According to some embodiments of the present invention, the structure 100 for improving the crack resistance of the precast reinforced concrete beam-slab node area may further include: an upper reinforced concrete column wall 8, the upper reinforced concrete column wall 8 is connected to the node area 4, and the upper reinforced concrete column wall 8 is opposite to the lower reinforced concrete column wall 1 in the upper and lower directions, and the upper reinforced concrete column wall 8 is made of ordinary concrete 2. For example, referring to Figure 1 The upper reinforced concrete column wall 8 can be arranged above the node area 4, and the upper reinforced concrete column wall 8 and the lower reinforced concrete column wall 1 can be arranged relative to each other in the upper and lower directions. The upper reinforced concrete column wall 8 can be made of ordinary concrete 2, which is conducive to controlling costs.

[0062] The high-performance concrete 7 has a higher tensile strength than the conventional concrete 2. The high-performance concrete 7 may include one of UHPC and ECC. For example, the high-performance concrete 7 may have a higher tensile strength than the conventional concrete 2. In some embodiments, the high-performance concrete 7 may include UHPC; in some embodiments, the high-performance concrete 7 may include ECC.

[0063] Among them, UHPC, namely Ultra-High Performance Concrete, also known as Reactive Powder Concrete (RPC), is the most innovative cement-based engineering material in the past three decades, achieving a major leap in the performance of engineering materials.

[0064] UHPC is an ultra-high-strength cement-based material with high strength, high toughness, and low porosity. Its basic formulation principle is to minimize internal defects (pores and microcracks) by increasing the fineness and activity of the components, eliminating the use of coarse aggregate, and achieving ultra-high strength and durability.

[0065] UHPC is a highly durable engineering material. With appropriate reinforcement, its mechanical properties approach those of rigid structures, while also offering excellent wear and explosion resistance. Therefore, UHPC is particularly well-suited for long-span bridges, explosion-resistant structures (such as military projects and bank vaults), thin-walled structures, and applications in highly abrasive and corrosive environments. Currently, UHPC has been applied in a number of practical projects, including long-span pedestrian overpasses, highway and railway bridges, thin-walled silos, nuclear waste tanks, cable anchor reinforcement plates, and ATM protective casings.

[0066] ECC, which stands for Engineered Cementitious Composite, is an engineering cement-based reinforced composite material. It is a fiber-reinforced cement-based composite material with high ductility and strict crack width control.

[0067] According to the structure 100 for improving the crack resistance of the node area of ​​the precast reinforced concrete beam and slab according to an embodiment of the present invention, an isolation piece 5 is provided on the outer side of the second steel bar 31 located at the top adjacent to the node area 4, so that the second steel bar 31 can be isolated from the high-performance concrete 7, thereby preventing adhesion between the second steel bar 31 and the high-performance concrete 7, and cutting off the force transmission between the second steel bar 31 and the post-cast concrete, so that the second steel bar 31 is evenly stressed and becomes the main part bearing the tension, while not transmitting the internal tension to the high-performance concrete 7, thereby greatly reducing the stress of the high-performance concrete 7.

[0068] According to the second embodiment of the present invention, the method for improving the crack resistance of the node area of ​​precast reinforced concrete beams and slabs includes: step S1: constructing the lower reinforced concrete column wall; step S2: hoisting the precast reinforced concrete beams and slabs to the designated design position; step S3: overlapping the second steel bars in the node area; step S4: setting an isolation piece on the outside of the second steel bar located at the top adjacent to the node area; step S5: supporting the formwork and pouring the post-cast section with high-performance concrete; step S6: constructing the upper reinforced concrete column wall.

[0069] The high performance concrete has a higher tensile strength than ordinary concrete, and the high performance concrete includes one of UHPC and ECC.

[0070] Here, the post-casting section may include a node area and an area adjacent to the node area.

[0071] Furthermore, the spacer is made of a material with a low elastic modulus, and the elastic modulus of the spacer is lower than the elastic modulus of the ordinary concrete or the elastic modulus of the high-performance concrete. For example, in some embodiments of the present invention, the spacer can be made of a material with a low elastic modulus, and the elastic modulus of the spacer can be lower than the elastic modulus of ordinary concrete. In some embodiments of the present invention, the spacer can be made of a material with a low elastic modulus, and the elastic modulus of the spacer can be lower than the elastic modulus of high-performance concrete.

[0072] Furthermore, the isolating member is a rubber member or a polyethylene plastic member. In some embodiments of the present invention, the isolating member can be a rubber member such as a high-performance rubber member; in some embodiments of the present invention, the isolating member can also be a polyethylene plastic member.

[0073] For example, in some embodiments of the present invention, the elastic modulus of the isolation member can be much lower than that of ordinary concrete or high-performance concrete. Specifically, in some embodiments of the present invention, the elastic modulus of concrete is approximately 30 GPa, and the elastic modulus of the isolation member (e.g., rubber member) is approximately 0.01 GPa, but the present invention is not limited thereto.

[0074] The isolating member is configured in the shape of a sleeve, and an opening is formed on the sleeve, extending axially and penetrating the sleeve along the thickness direction of the sleeve. The sleeve is suitable for being buckled onto the outer side of the second steel bar through the opening.

[0075] For example, in some embodiments of the present invention, the isolator can be an integrated structure, and the isolator can be constructed in the shape of a sleeve, an opening is formed on the sleeve, the opening can extend along the axial direction of the sleeve, and the opening can be set through the sleeve along the thickness direction of the sleeve, and the sleeve is suitable for being buckled on the outside of the second steel bar through the opening.

[0076] The present invention is not limited thereto. In some optional embodiments of the present invention, the isolator includes a first sub-isolator and a second sub-isolator. The first sub-isolator and the second sub-isolator are respectively sleeved on the outside of the second steel bar and fixed by a strip component.

[0077] For example, in some embodiments, the spacer can be a split structure, including a first sub-spacer and a second sub-spacer. The first sub-spacer and the second sub-spacer are respectively sleeved on the outside of the second steel bar, and the first sub-spacer and the second sub-spacer can be fixed by a strip-shaped member. In this way, the first sub-spacer and the second sub-spacer can be fixed to the outside of the second steel bar by the strip-shaped member, which improves reliability.

[0078] The strip-shaped component may be, for example, an adhesive tape, a rope, or the like.

[0079] In some embodiments of the present invention, the structures of the first sub-isolator and the second sub-isolator may be symmetrical. For example, the structures of the first sub-isolator and the second sub-isolator may be the same. Of course, in some embodiments of the present invention, the first sub-isolator and the second sub-isolator may also be asymmetrically arranged.

[0080] In some optional embodiments of the present invention, the isolation member is a rubber layer or a plastic layer wrapped around the outside of the second steel bar. For example, in some embodiments of the present invention, the isolation member may include a rubber layer or a plastic layer wrapped around the outside of the second steel bar. The rubber layer or the plastic layer may include one or more wraps around the outside of the second steel bar, which is not specifically limited in the present invention.

[0081] The present invention has the following advantages over the prior art:

[0082] First, through the new idea of ​​"combining resistance and release" and "making full use of resources", the bond between the steel bars (such as the second steel bars, etc.) and the concrete (such as high-performance concrete, etc.) is partially destroyed, and the force transmission between the steel bars and the concrete is cut off, so that the steel bars are evenly stressed and become the main part of the tension. At the same time, the internal tension will not be transmitted to the concrete, thereby greatly reducing the stress of the concrete.

[0083] Secondly, by using high-tensile concrete in areas prone to cracking, the tensile strength of the concrete is improved. High-performance concrete is more expensive, but its application in appropriate locations can significantly improve crack resistance without significantly increasing the cost.

[0084] Third, isolation parts made of low elastic modulus materials are inexpensive, do not require too much additional work during construction, and are easy to ensure project quality.

[0085] Fourthly, compared with traditional construction schemes, it has superior stress-bearing performance and simple structure, which can improve performance without excessive impact on construction and cost.

[0086] The method for improving the crack resistance of the node area of ​​precast reinforced concrete beams and slabs according to the embodiment of the second aspect of the present invention belongs to the field of structural engineering. The method for improving the crack resistance of the node area of ​​precast reinforced concrete beams and slabs includes the following key steps: first, construct the lower structure column wall, when the structure reaches a certain strength, hoist the precast reinforced concrete beams and slabs, overlap the steel bars in the node area (for example, overlap the second steel bar with the first steel bar), and then set an isolation piece on the outside of the second steel bar at the top of the adjacent node area. The isolation piece is conducive to ensuring that the steel bar and the post-cast concrete are not bonded, and finally, high-performance concrete with higher tensile strength is used to cast the concrete node (for example, the post-cast section).

[0087] According to an embodiment of the present invention, a method for improving the crack resistance of a precast reinforced concrete beam-slab node area adopts a local non-bonding technology to destroy the bond between the second steel bar and the post-cast section in the precast reinforced concrete beam-slab node area, thereby preventing the tensile stress of the second steel bar from being transferred to the concrete, thereby reducing the tensile stress in the concrete. At the same time, high-performance concrete with higher tensile strength is used in the negative bending moment area to improve the tensile resistance of this part of the concrete, thereby comprehensively improving its crack resistance.

[0088] The method for improving the crack resistance of the precast reinforced concrete beam-slab node area according to the embodiment of the present invention has a simple structure, convenient construction, and good technical and economic benefits.

[0089] Other components and operations of the structure and method for improving the crack resistance of precast reinforced concrete beam-slab node areas according to the embodiments of the present invention are well known to those skilled in the art and will not be described in detail here.

[0090] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0091] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative uses of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0092] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A structure for improving the crack resistance of precast reinforced concrete beam-slab joints, characterized in that: include: a lower reinforced concrete column wall, wherein the lower reinforced concrete column wall has first steel bars extending in a vertical direction and is made of ordinary concrete; a precast reinforced concrete beam slab, the precast reinforced concrete beam slab being hoisted on the lower reinforced concrete column wall, the precast reinforced concrete beam slab having second steel bars extending in a horizontal direction, wherein an area where the precast reinforced concrete beam slab intersects with the lower reinforced concrete column wall forms a node area, the second steel bars are overlapped in the node area, and an isolation piece is provided on the outer side of the second steel bar located at the top adjacent to the node area; A post-cast section, wherein the post-cast section includes high-performance concrete cast in the node area and the area adjacent to the node area; characterized in that the isolation member is a material member with a low elastic modulus, and the elastic modulus of the isolation member is lower than the elastic modulus of the ordinary concrete or the elastic modulus of the high-performance concrete; the isolation member is used to isolate the second steel bar from the high-performance concrete, thereby preventing the second steel bar and the high-performance concrete from bonding.

2. The structure for improving the crack resistance of precast reinforced concrete beam-slab node areas according to claim 1 is characterized in that: The isolating member is a rubber member or a polyethylene plastic member.

3. The structure for improving the crack resistance of precast reinforced concrete beam-slab node areas according to claim 2 is characterized in that: The spacer is configured in the shape of a sleeve. The sleeve is provided with an opening extending in the axial direction and penetrating the sleeve along the thickness direction of the sleeve. The sleeve is adapted to be buckled onto the outer side of the second steel bar through the opening.

4. The structure for improving the crack resistance of precast reinforced concrete beam-slab node areas according to claim 2 is characterized in that: The spacer includes a first sub-spacer and a second sub-spacer, wherein the first sub-spacer and the second sub-spacer are respectively sleeved on the outside of the second steel bar and fixed by a belt-shaped component.

5. The structure for improving the crack resistance of precast reinforced concrete beam-slab node areas according to claim 2 is characterized in that: The isolation member is a rubber layer or a plastic layer wrapped around the outer side of the second steel bar.

6. The structure for improving the crack resistance of precast reinforced concrete beam-slab joints according to any one of claims 1 to 5, characterized in that: Also includes: an upper reinforced concrete column wall, the upper reinforced concrete column wall being connected to the node area, the upper reinforced concrete column wall being opposite to the lower reinforced concrete column wall in the upper and lower directions, and the upper reinforced concrete column wall being made of ordinary concrete; The high performance concrete has a higher tensile strength than the ordinary concrete, and the high performance concrete includes one of UHPC and ECC.

7. A method for improving the crack resistance of precast reinforced concrete beam-slab joints according to any one of claims 1 to 6, characterized in that: The method comprises: Step S1: constructing the lower reinforced concrete column wall; Step S2: hoisting the precast reinforced concrete beam and slab to the designated design location; Step S3: Lapping the second steel bar in the node area; Step S4: providing an isolation member on the outer side of the second reinforcement located at the top adjacent to the node area; Step S5: supporting the formwork and pouring the post-cast section with high-performance concrete; Step S6: constructing upper reinforced concrete column walls; The high-performance concrete has a higher tensile strength than ordinary concrete, and the high-performance concrete includes one of UHPC and ECC. The isolation member is a member of a material with a low elastic modulus, and the elastic modulus of the isolation member is lower than the elastic modulus of the ordinary concrete or the elastic modulus of the high-performance concrete. The isolation member is used to isolate the second steel bar from the high-performance concrete, thereby preventing adhesion between the second steel bar and the high-performance concrete.

8. The method for improving the crack resistance of precast reinforced concrete beam-slab node areas according to claim 7, characterized in that: The isolation piece is a rubber piece or a polyethylene plastic piece. The spacer is configured in the shape of a sleeve, the sleeve is provided with an opening extending in the axial direction and penetrating the sleeve along the thickness direction of the sleeve, and the sleeve is adapted to be buckled onto the outer side of the second steel bar through the opening; or The spacer comprises a first sub-spacer and a second sub-spacer, wherein the first sub-spacer and the second sub-spacer are respectively sleeved on the outside of the second steel bar and fixed by a strip-shaped member; or The isolation member is a rubber layer or a plastic layer wrapped around the outer side of the second steel bar.

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