CN111139934A - Structure and method for improving crack resistance of joint area of prefabricated reinforced concrete beam slab - Google Patents
Structure and method for improving crack resistance of joint area of prefabricated reinforced concrete beam slab Download PDFInfo
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- CN111139934A CN111139934A CN202010047882.2A CN202010047882A CN111139934A CN 111139934 A CN111139934 A CN 111139934A CN 202010047882 A CN202010047882 A CN 202010047882A CN 111139934 A CN111139934 A CN 111139934A
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- 239000011150 reinforced concrete Substances 0.000 title claims abstract description 109
- 238000000034 method Methods 0.000 title claims abstract description 17
- 239000004574 high-performance concrete Substances 0.000 claims abstract description 57
- 239000004567 concrete Substances 0.000 claims abstract description 54
- 229910001294 Reinforcing steel Inorganic materials 0.000 claims abstract description 37
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 30
- 239000010959 steel Substances 0.000 claims abstract description 30
- 238000005192 partition Methods 0.000 claims abstract description 24
- 125000006850 spacer group Chemical group 0.000 claims description 76
- 230000003014 reinforcing effect Effects 0.000 claims description 22
- 229920001971 elastomer Polymers 0.000 claims description 20
- 239000000463 material Substances 0.000 claims description 20
- 239000004033 plastic Substances 0.000 claims description 18
- 229920003023 plastic Polymers 0.000 claims description 18
- 239000011374 ultra-high-performance concrete Substances 0.000 claims description 15
- -1 polyethylene Polymers 0.000 claims description 9
- 239000004698 Polyethylene Substances 0.000 claims description 8
- 229920000573 polyethylene Polymers 0.000 claims description 8
- 230000000149 penetrating effect Effects 0.000 claims description 6
- 230000005540 biological transmission Effects 0.000 abstract description 6
- 238000010276 construction Methods 0.000 description 12
- 238000002955 isolation Methods 0.000 description 5
- 230000002787 reinforcement Effects 0.000 description 4
- 238000005336 cracking Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000002390 adhesive tape Substances 0.000 description 2
- 238000005452 bending Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 239000004568 cement Substances 0.000 description 2
- 229920006247 high-performance elastomer Polymers 0.000 description 2
- 230000001737 promoting effect Effects 0.000 description 2
- 230000004075 alteration Effects 0.000 description 1
- 239000011182 bendable concrete Substances 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 238000009440 infrastructure construction Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 239000003351 stiffener Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 238000003079 width control Methods 0.000 description 1
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- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
- E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
- E04B1/02—Structures consisting primarily of load-supporting, block-shaped, or slab-shaped elements
- E04B1/04—Structures consisting primarily of load-supporting, block-shaped, or slab-shaped elements the elements consisting of concrete, e.g. reinforced concrete, or other stone-like material
- E04B1/043—Connections specially adapted therefor
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A30/00—Adapting or protecting infrastructure or their operation
- Y02A30/30—Adapting or protecting infrastructure or their operation in transportation, e.g. on roads, waterways or railways
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- Engineering & Computer Science (AREA)
- Architecture (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Joining Of Building Structures In Genera (AREA)
Abstract
The invention discloses a structure and a method for improving the crack resistance of a node area of a prefabricated reinforced concrete beam slab, wherein the structure comprises a lower layer reinforced concrete column wall provided with first reinforcing steel bars; the prefabricated reinforced concrete beam slab is hung on the wall of the lower reinforced concrete column and provided with second steel bars, the crossed area of the prefabricated reinforced concrete beam slab and the lower reinforced concrete column wall forms a node area, the second steel bars in the node area are mutually lapped, and the outer side of the position, adjacent to the node area, of the second steel bar at the top is provided with a partition; and the 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 the joint area of the precast reinforced concrete beam slab, the partition piece is arranged on the outer side of the position, close to the joint area, of the second steel bar on the top, so that the second steel bar and high-performance concrete can be prevented from being bonded, and the force transmission between the second steel bar and post-cast section concrete is cut off.
Description
Technical Field
The invention relates to the technical field of structural engineering, in particular to a structure for improving the crack resistance of a node area of a prefabricated reinforced concrete beam slab and a method for improving the crack resistance of the node area of the prefabricated reinforced concrete beam slab.
Background
In the related technology, currently, the infrastructure construction of China is developed quickly, and the assembly type building is popularized vigorously. The prefabricated building is mainly spliced on site through prefabricated structural members of a processing plant, and the connection between the prefabricated structural members is ensured through various construction modes. In the fabricated building, the prefabricated reinforced concrete beam slab is easy to crack after being actually built because most of the concrete part of the prefabricated reinforced concrete beam slab near the node is post-cast concrete, and the post-cast concrete shrinks after the casting is finished and is subjected to a large bending moment. Once the reinforced concrete structure cracks, the durability and safety of the structure are greatly influenced. Therefore, the improvement of the crack resistance at the position has very important significance on the structure.
Disclosure of Invention
The present invention is directed to solving at least one of the problems of the prior art. Therefore, an object of the present invention is to provide a structure for improving the crack resistance of a joint region of a prefabricated reinforced concrete beam slab, which is beneficial to prevent the prefabricated reinforced concrete beam slab from cracking in a hogging moment region near the joint region, and is convenient to construct.
The invention also aims to provide a method for improving the crack resistance of the joint area of the prefabricated reinforced concrete beam slab.
The structure for improving the crack resistance of the node area of the prefabricated reinforced concrete beam slab according to the embodiment of the first aspect of the invention comprises the following components: a lower reinforced concrete column wall having first reinforcing bars extending in a vertical direction, the lower reinforced concrete column wall being made of ordinary concrete; the prefabricated reinforced concrete beam slab is hung on the lower reinforced concrete column wall and is provided with second reinforcing steel bars extending along the horizontal direction, the intersected area of the prefabricated reinforced concrete beam slab and the lower reinforced concrete column wall is formed into a node area, the second reinforcing steel bars in the node area are mutually overlapped, and a spacer is arranged on the outer side of the position, adjacent to the node area, of the second reinforcing steel bar at the top; a post-cast section comprising high performance concrete cast in the nodal region and an area adjacent to the nodal region.
According to the structure for improving the crack resistance of the joint area of the precast reinforced concrete beam slab, the partition piece is arranged on the outer side of the position, close to the joint area, of the second steel bar, so that the second steel bar can be isolated from the high-performance concrete, the second steel bar can be prevented from being bonded with the high-performance concrete, the force transmission between the second steel bar and the post-cast section concrete is cut off, the second steel bar is uniformly stressed and becomes a main bearing part of the tension, meanwhile, the internal tension cannot be transmitted to the high-performance concrete, and the stress of the high-performance concrete is greatly reduced.
In addition, the structure for improving the crack resistance of the node area of the prefabricated reinforced concrete beam slab according to the embodiment of the invention also has the following additional technical characteristics:
according to some embodiments of the invention, the spacer is a low modulus of elasticity material and the modulus of elasticity of the spacer is lower than the modulus of elasticity of the ordinary concrete or the modulus of elasticity of the high performance concrete.
Further, the isolating piece is a rubber piece or a polyethylene plastic piece.
Still further, the spacer is configured in the shape of a sleeve, and an opening extending in the axial direction and penetrating through the sleeve in the thickness direction of the sleeve is formed on the sleeve, and the sleeve is adapted to be fastened to the outer side of the second reinforcing bar through the opening.
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 outer side of the second steel bar and fixed by a band member.
In some embodiments of the present invention, the spacer is a rubber or plastic layer wound around the outside of the second steel bar.
According to some embodiments of the present invention, the structure for improving the crack resistance of the joint region of the prefabricated reinforced concrete beam slab further comprises: the upper reinforced concrete column wall is connected with the node area and is opposite to the lower reinforced concrete column wall in the vertical direction, and the upper reinforced concrete column wall is made of common concrete; wherein the high-performance concrete has a tensile strength higher than that of the ordinary concrete, and the high-performance concrete includes one of UHPC and ECC.
According to some embodiments of the present invention, a method for improving crack resistance of a node area of a prefabricated reinforced concrete beam slab comprises: step S1: constructing a lower layer reinforced concrete column wall; step S2: hoisting the prefabricated reinforced concrete beam slab to a designed designated position; step S3: second steel bars are lapped at the node area; step S4: providing a spacer outside the second rebar at the top adjacent the nodal region; step S5: a template is supported, and a post-pouring section is poured by using high-performance concrete; step S6: constructing an upper layer reinforced concrete column wall; wherein the tensile strength of the high-performance concrete is higher than that of ordinary concrete, and the high-performance concrete comprises one of UHPC and ECC.
Further, the isolation piece is a material piece with low elastic modulus, and the elastic modulus of the isolation piece is lower than that of the common concrete or that of the high-performance concrete.
Further, the spacer is made of rubber or polyethylene plastic, wherein the spacer is configured in the shape of a sleeve, an opening extending in the axial direction and penetrating through the sleeve in the thickness direction of the sleeve is formed on the sleeve, and the sleeve is suitable for being buckled on the outer side of the second steel bar through the opening; or the partition comprises a first sub-partition and a second sub-partition, and the first sub-partition and the second sub-partition are respectively sleeved on the outer side of the second steel bar and fixed by a strip-shaped part; or the isolating piece is a rubber piece layer or a plastic piece layer wound on the outer side of the second steel bar.
Compared with the prior art, the invention has the following advantages:
firstly, through the new ideas of 'anti-release combination' and 'best use of things', the bonding between a reinforcing steel bar (such as a second reinforcing steel bar) and concrete (such as high-performance concrete) is locally damaged, the force transmission between the reinforcing steel bar and the concrete is cut off, the reinforcing steel bar is uniformly stressed and becomes a main bearing part of the tensile force, and meanwhile, the internal tensile force is not transmitted to the concrete, so that the stress of the concrete is greatly reduced.
Secondly, the concrete with high tensile property is used at the position which is easy to crack, so that the tensile property of the position is improved. The high-performance concrete has higher construction price, but the application of the high-performance concrete in a proper position greatly improves the crack resistance without excessively increasing the manufacturing cost.
Thirdly, the isolating piece of the low elastic modulus material piece is low in price, excessive extra work is not needed during construction, and engineering quality is easy to guarantee.
Fourthly, compare in traditional construction scheme, the atress performance is superior, and simple structure can not produce too much influence to construction, cost etc. when promoting the performance.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a schematic view of a structure for improving crack resistance of a node region of a prefabricated reinforced concrete beam slab according to an embodiment of the present invention;
fig. 2 is a sectional view of the structure for improving the crack resistance of the node area of the precast reinforced concrete beam panel according to the embodiment of the present invention in fig. 1, taken along the line a-a.
Reference numerals:
a structure 100 for improving the crack resistance of the node area of the precast reinforced concrete beam slab,
a lower reinforced concrete column wall 1, first reinforcing steel bars 11,
the concrete is a mixture of a normal concrete 2,
the prefabricated reinforced concrete beam slab 3, the second reinforcing bars 31,
the concrete column wall comprises a node area 4, a partition 5, a post-cast section 6, high-performance concrete 7 and an upper layer reinforced concrete column wall 8.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
A structure 100 for improving the crack resistance of a node region of a precast reinforced concrete beam panel according to an embodiment of the first aspect of the present invention will be described with reference to the accompanying drawings. The structure 100 for improving the crack resistance of the joint area of the prefabricated reinforced concrete beam slab adopts a local unbonded technology, and has the advantages of reasonable stress distribution, full use of the materials, safety, reliability and convenience in construction.
Referring to fig. 1 and 2, a structure 100 for improving crack resistance of a node region of a precast reinforced concrete beam panel according to an embodiment of the first aspect of the present invention includes: the lower layer reinforced concrete column wall 1, the prefabricated reinforced concrete beam slab 3 and the post-cast section 6.
Specifically, the lower reinforced concrete stud wall 1 has first reinforcing bars 11 extending in a vertical direction, and the lower reinforced concrete stud wall 1 is made of ordinary concrete 2. For example, the lower reinforced concrete stud wall 1 has the first reinforcing bars 11, the first reinforcing bars 11 may extend in the vertical direction, the first reinforcing bars 11 may include a plurality (in the description of the present invention, "a plurality" means two or more), a plurality of the first reinforcing bars 11 may be arranged at intervals in the circumferential direction, and the lower reinforced concrete stud wall 1 may be made of general concrete 2, which is advantageous in terms of cost control.
The prefabricated reinforced concrete beam slab 3 is hung on the lower reinforced concrete column wall 1, the prefabricated reinforced concrete beam slab 3 is provided with second reinforcing steel bars 31 extending along the horizontal direction, wherein the intersection area of the prefabricated reinforced concrete beam slab 3 and the lower reinforced concrete column wall 1 is formed into a node area 4, the second reinforcing steel bars 31 are mutually overlapped in the node area 4, and the outer side of the position, adjacent to the node area 4, of the second reinforcing steel bar 31 at the top is provided with a partition 5.
For example, a prefabricated reinforced concrete beam slab 3 may be hung on the lower reinforced concrete column wall 1, the prefabricated reinforced concrete beam slab 3 has second reinforcing bars 31, and the second reinforcing bars 31 may extend in a horizontal direction. Wherein, the area where the precast reinforced concrete beam slab 3 and the lower reinforced concrete column wall 1 intersect may be formed as a node area 4, in the node area 4, the second reinforcing bars 31 are overlapped with each other, and the outside of the position where the second reinforcing bar 31 at the top is adjacent to the node area 4 is provided with a spacer 5.
For example, in some embodiments of the present invention where the prefabricated reinforced concrete beam 3 is not a single piece, the prefabricated reinforced concrete beam 3 may comprise two beams, typically one on the left and one on the right, wherein each beam has a length of reinforcement (e.g., second reinforcement 31) extending outwardly from the end thereof, and then the beams are lapped over the columns to overlap the second reinforcement 31 of the two beams.
The post-cast section 6 comprises high performance concrete 7 cast in the nodal region 4 and in areas adjacent to the nodal region 4. For example, the post-cast section 6 may include the node zone 4 and an area adjacent to the node zone 4, and the post-cast section 6 may be cast with high performance concrete 7. Therefore, the post-cast section 6 is poured by the high-performance concrete 7, so that the tensile property of the post-cast section 6 is improved, and the high-performance concrete 7 is applied to the post-cast section 6, so that the anti-cracking performance is greatly improved, and the manufacturing cost is not increased too much.
For example, in some embodiments of the invention, the region adjacent to the node region 4 may be located beyond the outermost end of the spacer 5 in the horizontal direction, or the region 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 remote from the node area 4.
In addition, it should be noted that the above description of the area adjacent to the node area 4 is only exemplary and should not be construed as limiting the present invention. The present invention does not limit the specific location of the area adjacent to the node area 4, and the area adjacent to the node area 4 in practical application can be adaptively set according to the needs, which will be understood by those skilled in the art.
According to the structure 100 for improving the crack resistance of the node area of the precast reinforced concrete beam slab, provided by the embodiment of the invention, the partition piece 5 is arranged on the outer side of the position, adjacent to the node area 4, of the second reinforcing steel bar 31 positioned at the top, so that the second reinforcing steel bar 31 can be separated from the high-performance concrete 7, the second reinforcing steel bar 31 and the high-performance concrete 7 can be prevented from being bonded, the force transmission between the second reinforcing steel bar 31 and the post-cast section concrete is interrupted, the second reinforcing steel bar 31 is uniformly stressed and becomes a main bearing part of the tensile force, meanwhile, the internal tensile force is not transmitted to the high-performance concrete 7, and the stress of the high-performance concrete 7 is greatly reduced.
The structure 100 for improving the crack resistance of the joint area of the prefabricated reinforced concrete beam slab, provided by the embodiment of the invention, is beneficial to preventing the prefabricated reinforced concrete beam slab 3 from cracking in the hogging moment area near the joint area, and is convenient to construct.
According to some embodiments of the invention, the spacer 5 is a low modulus of elasticity material, and the modulus of elasticity of the spacer 5 is lower than the modulus of elasticity of normal concrete 2 or the modulus of elasticity of high performance concrete 7. For example, in some embodiments of the invention, the spacer 5 may be a piece of material with a low modulus of elasticity, and the modulus of elasticity of the spacer 5 may be lower than that of ordinary concrete 2. In some embodiments of the invention, the spacer 5 may be a low modulus of elasticity material, and the modulus of elasticity of the spacer 5 may be lower than the modulus of elasticity of the high performance concrete 7.
Further, the spacer 5 may be a rubber member or a polyethylene-based 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 or the like; in some embodiments of the present invention, the spacer 5 may also be a polyethylene-based plastic.
For example, in some embodiments of the invention, the modulus of elasticity of the spacer 5 may be much lower than the modulus of elasticity of normal concrete 2 or the modulus of elasticity of high performance concrete 7. In some embodiments of the present invention, the elastic modulus of the concrete is approximately 30GPa, and the elastic modulus of the spacer 5 (e.g., rubber member) is approximately 0.01GPa, but the present invention is not limited thereto.
Several embodiments of the spacer 5 in the structure 100 for improving the crack resistance of the node region of the prefabricated reinforced concrete beam panel according to the present invention will be described with reference to the accompanying drawings.
The first embodiment is as follows:
in some embodiments of the present invention, the spacer 5 may be configured in the shape of a sleeve formed with an opening extending in the axial direction and penetrating the sleeve in the thickness direction thereof, the sleeve being adapted to be fastened to the outside of the second reinforcing bar 31 through the opening.
For example, the spacer 5 may be a one-piece structure, the spacer 5 may be configured in the shape of a sleeve, the sleeve may have an opening formed therein, the opening may extend in an axial direction of the sleeve, and the opening may be provided through the sleeve in a thickness direction of the sleeve, the sleeve being adapted to be fastened to an outer side of the second reinforcing bar 31 through the opening.
Example two:
in some embodiments of the present invention, the spacer 5 includes a first sub-spacer and a second sub-spacer, which are respectively sleeved on the outer side of the second steel bar 31 and fixed by a band member.
For example, in some embodiments of the present invention, the spacer 5 may be a split structure, the spacer 5 may include a first sub-spacer and a second sub-spacer, the first sub-spacer and the second sub-spacer are respectively sleeved on the outer sides of the second reinforcing bars 31, and the first sub-spacer and the second sub-spacer may be fixed by a band member. Thus, the first sub-spacer and the second sub-spacer can be fixed to the outer side of the second reinforcing bar 31 by the band member, and reliability is high.
Wherein the band-shaped member may be, for example, an adhesive tape, a string, or the like.
In some embodiments of the present invention, the first sub-spacer and the second sub-spacer may have symmetrical structures, for example, the first sub-spacer and the second sub-spacer may have the same structure; of course, in some embodiments of the present invention, the first sub-spacer and the second sub-spacer may also be disposed asymmetrically, and the present invention is not limited to this.
Example three:
in some embodiments of the present invention, the spacer 5 is a rubber or plastic layer wound around the outside of the second steel bar 31.
For example, in some alternative embodiments of the present invention, the spacer 5 may be a rubber or plastic layer wound around the outside of the second steel bar 31. The rubber member layer or the plastic member layer may include one or more turns wound around the outside of the second reinforcing bar 31, and the present invention is not particularly limited thereto.
Here, it should be noted that the above description of the specific structure of the spacer 5 is only exemplary and should not be construed as limiting the present invention, which will be understood by those skilled in the art.
According to some embodiments of the present invention, the structure 100 for improving the crack resistance of the node area of the prefabricated reinforced concrete beam slab may further include: the upper reinforced concrete column wall 8, the upper reinforced concrete column wall 8 is connected with the node area 4, the upper reinforced concrete column wall 8 is opposite to the lower reinforced concrete column wall 1 in the up-down direction, and the upper reinforced concrete column wall 8 is made of common concrete 2. For example, referring to fig. 1, an upper reinforced concrete stud wall 8 may be provided above the node region 4, and the upper reinforced concrete stud wall 8 and the lower reinforced concrete stud wall 1 may be disposed opposite to each other in the up-down direction, and the upper reinforced concrete stud wall 8 may be made of ordinary concrete 2, which is advantageous in terms of cost control.
The high performance concrete 7 has a higher tensile strength than the ordinary concrete 2, and 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 ordinary concrete 2, and in some embodiments, the high performance concrete 7 may include UHPC; in some embodiments, the high performance concrete 7 may include ECC.
Among them, UHPC, i.e., Ultra-High Performance Concrete, also called Reactive Powder Concrete (RPC), is an innovative cement-based engineering material in the last thirty years, and realizes a large span of engineering material Performance.
UHPC is an ultra-high strength cement-based material with high strength, high toughness and low porosity. The basic preparation principle is as follows: by increasing the fineness and activity of the components, coarse aggregate is not used, and defects (pores and microcracks) in the material are minimized, so that ultrahigh strength and high durability are obtained.
The UHPC can be called as an engineering material with good durability, the mechanical property of the UHPC with proper reinforcement is close to that of a rigid structure, and meanwhile, the UHPC has excellent wear resistance and anti-explosion performance. Therefore, UHPC is particularly suitable for use in large span bridges, blast resistant structures (military engineering, bank vaults, etc.) and thin-walled structures, as well as in highly abrasive, highly corrosive environments. Currently, UHPC has been used in practical projects such as large-span pedestrian overpasses, highway and railway bridges, thin-walled silos, nuclear waste tanks, wire rope anchor stiffeners, ATM protective casings, and the like.
ECC, Engineered Cementitious composites, which are fiber reinforced Cementitious composites, have high ductility and tight fracture width control.
According to the structure 100 for improving the crack resistance of the node area of the precast reinforced concrete beam slab, provided by the embodiment of the invention, the partition piece 5 is arranged on the outer side of the position, adjacent to the node area 4, of the second reinforcing steel bar 31 positioned at the top, so that the second reinforcing steel bar 31 can be separated from the high-performance concrete 7, the second reinforcing steel bar 31 and the high-performance concrete 7 can be prevented from being bonded, the force transmission between the second reinforcing steel bar 31 and the post-cast section concrete is interrupted, the second reinforcing steel bar 31 is uniformly stressed and becomes a main bearing part of the tensile force, meanwhile, the internal tensile force is not transmitted to the high-performance concrete 7, and the stress of the high-performance concrete 7 is greatly reduced.
The method for improving the crack resistance of the node area of the prefabricated reinforced concrete beam slab according to the embodiment of the second aspect of the invention comprises the following steps: step S1: constructing a lower layer reinforced concrete column wall; step S2: hoisting the prefabricated reinforced concrete beam slab to a designed designated position; step S3: second steel bars are lapped at the node area; step S4: providing a spacer outside the second rebar at the top adjacent the nodal region; step S5: a template is supported, and a post-pouring section is poured by using high-performance concrete; step S6: and constructing an upper layer reinforced concrete column wall.
Wherein the tensile strength of the high-performance concrete is higher than that of ordinary concrete, and the high-performance concrete comprises one of UHPC and ECC.
Here, the post-cast section may include a node area and an area adjacent to the node area.
Further, the isolation piece is a material piece with low elastic modulus, and the elastic modulus of the isolation piece is lower than that of the common concrete or that of the high-performance concrete. For example, in some embodiments of the invention, the spacer may be a low modulus of elasticity material and the modulus of elasticity of the spacer may be lower than that of ordinary concrete. In some embodiments of the invention, the spacer may be a low modulus of elasticity material and the modulus of elasticity of the spacer may be lower than the modulus of elasticity of the high performance concrete.
Further, the isolation piece is a rubber piece or a polyethylene plastic piece. In some embodiments of the invention, the spacer may be a rubber member such as a high performance rubber member or the like; in some embodiments of the invention, the spacer may also be a polyethylene-based plastic.
For example, in some embodiments of the invention, the modulus of elasticity of the spacer may be much lower than that of ordinary concrete or that of high performance concrete. In some embodiments of the present invention, the elastic modulus of the concrete is approximately 30GPa, and the elastic modulus of the spacer (e.g., rubber member) is approximately 0.01GPa, but the present invention is not limited thereto.
Wherein the spacer is configured in the shape of a sleeve, an opening extending in the axial direction and penetrating through the sleeve in the thickness direction of the sleeve is formed on the sleeve, and the sleeve is suitable for being buckled on the outer side of the second steel bar through the opening.
For example, in some embodiments of the present invention, the spacer may be a one-piece structure, the spacer may be configured in the shape of a sleeve, the sleeve may be formed with an opening, the opening may extend in an axial direction of the sleeve, and the opening may be disposed through the sleeve in a thickness direction of the sleeve, and the sleeve may be adapted to be fastened to an outer side of the second reinforcing bar through the opening.
The present invention is not limited thereto, and in some alternative 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 outer side of the second steel bar and fixed by a band member.
For example, in some embodiments, the spacer may have a split structure, the spacer may include a first sub spacer and a second sub spacer, the first sub spacer and the second sub spacer are respectively sleeved on the outer side of the second steel bar, and the first sub spacer and the second sub spacer may be fixed by a band member. Therefore, the first sub-isolator and the second sub-isolator can be fixed on the outer side of the second reinforcing steel bar through the strip-shaped component, and the reliability is good.
Wherein the band-shaped member may be, for example, an adhesive tape, a string, or the like.
In some embodiments of the present invention, the structures of the first sub-spacer and the second sub-spacer may be symmetrical, for example, the structures of the first sub-spacer and the second sub-spacer may be the same; of course, in some embodiments of the present invention, the first sub-spacer and the second sub-spacer may also be asymmetrically disposed.
In some optional embodiments of the invention, the spacer is a rubber or plastic layer wound around the outside of the second steel bar. For example, in some embodiments of the invention, the spacer may comprise a layer of rubber or plastic wrapped around the outside of the second rebar. The rubber member layer or the plastic member layer may include one or more turns wound around the outside of the second reinforcing bar, and the present invention is not particularly limited thereto.
Compared with the prior art, the invention has the following advantages:
firstly, through the new ideas of 'anti-release combination' and 'best use of things', the bonding between a reinforcing steel bar (such as a second reinforcing steel bar) and concrete (such as high-performance concrete) is locally damaged, the force transmission between the reinforcing steel bar and the concrete is cut off, the reinforcing steel bar is uniformly stressed and becomes a main bearing part of the tensile force, and meanwhile, the internal tensile force is not transmitted to the concrete, so that the stress of the concrete is greatly reduced.
Secondly, the concrete with high tensile property is used at the position which is easy to crack, so that the tensile property of the position is improved. The high-performance concrete has higher construction price, but the application of the high-performance concrete in a proper position greatly improves the crack resistance without excessively increasing the manufacturing cost.
Thirdly, the isolating piece of the low elastic modulus material piece is low in price, excessive extra work is not needed during construction, and engineering quality is easy to guarantee.
Fourthly, compare in traditional construction scheme, the atress performance is superior, and simple structure can not produce too much influence to construction, cost etc. when promoting the performance.
The method for improving the crack resistance of the prefabricated reinforced concrete beam slab joint area according to the embodiment of the second aspect of the invention belongs to the field of structural engineering. The method for improving the crack resistance of the node area of the prefabricated reinforced concrete beam slab comprises the following key steps: the method comprises the steps of firstly constructing a lower-layer structure column wall, hoisting a prefabricated reinforced concrete beam slab after the structure reaches a certain strength, lapping reinforcing steel bars in a node area (for example, lapping second reinforcing steel bars with first reinforcing steel bars), then arranging a partition outside the second reinforcing steel bars at the top of the adjacent node area, wherein the partition is favorable for ensuring that the reinforcing steel bars and post-cast concrete are not bonded, and finally pouring high-performance concrete with high tensile strength into a concrete node (for example, a post-cast section).
According to the method for improving the crack resistance of the joint area of the prefabricated reinforced concrete beam slab, the local unbonded technology is adopted, the bonding between the second steel bar and the post-cast section in the joint area of the prefabricated reinforced concrete beam slab is broken, the tensile stress of the second steel bar is prevented from being transmitted to the concrete, so that the internal tensile stress of the concrete is reduced, meanwhile, the high-performance concrete with higher tensile strength is used in the negative bending moment area, the tensile capacity of the part of concrete is improved, and the crack resistance of the part of concrete is comprehensively improved.
The method for improving the crack resistance of the joint area of the prefabricated reinforced concrete beam slab, provided by the embodiment of the invention, has the advantages of simple structure, convenience in construction and good technical and economic benefits.
Other constructions and operations of the structure and method for improving the crack resistance of the joint region of the precast reinforced concrete beam slab according to the embodiment of the present invention are known to those skilled in the art and will not be described in detail herein.
In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the invention.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.
Claims (10)
1. The utility model provides a promote structure of prefabricated reinforced concrete beam slab nodal region crack resistance ability which characterized in that includes:
a lower reinforced concrete column wall having first reinforcing bars extending in a vertical direction, the lower reinforced concrete column wall being made of ordinary concrete;
the prefabricated reinforced concrete beam slab is hung on the lower reinforced concrete column wall and is provided with second reinforcing steel bars extending along the horizontal direction, the intersected area of the prefabricated reinforced concrete beam slab and the lower reinforced concrete column wall is formed into a node area, the second reinforcing steel bars in the node area are mutually overlapped, and a spacer is arranged on the outer side of the position, adjacent to the node area, of the second reinforcing steel bar at the top;
a post-cast section comprising high performance concrete cast in the nodal region and an area adjacent to the nodal region.
2. The structure for improving the crack resistance of the node area of the precast reinforced concrete beam slab as claimed in claim 1, wherein the spacer is a material with low elastic modulus, and the elastic modulus of the spacer is lower than that of the ordinary concrete or that of the high-performance concrete.
3. The structure for improving the crack resistance of the node area of the precast reinforced concrete beam slab as claimed in claim 2, wherein the spacer is a rubber member or a polyethylene-based plastic member.
4. The structure for improving the crack resistance of the node area of the precast reinforced concrete beam slab as recited in claim 3, wherein the spacer is constructed in a shape of a sleeve, the sleeve being formed with an opening extending in an axial direction and penetrating the sleeve in a thickness direction thereof, the sleeve being adapted to be fastened to an outer side of the second reinforcing bars through the opening.
5. The structure for improving the crack resistance of the node area of the precast reinforced concrete beam slab as claimed in claim 3, wherein the partition comprises a first sub-partition and a second sub-partition, and the first sub-partition and the second sub-partition are respectively sleeved outside the second reinforcing bars and fixed by a band member.
6. The structure for improving the crack resistance of the node zone of the precast reinforced concrete beam slab as claimed in claim 3, wherein the spacer is a rubber or plastic member layer wound on the outer side of the second reinforcing steel bar.
7. The structure for improving the crack resistance of the node area of the precast reinforced concrete beam slab as recited in any one of claims 1 to 6, further comprising:
the upper reinforced concrete column wall is connected with the node area and is opposite to the lower reinforced concrete column wall in the vertical direction, and the upper reinforced concrete column wall is made of common concrete;
wherein the high-performance concrete has a tensile strength higher than that of the ordinary concrete, and the high-performance concrete includes one of UHPC and ECC.
8. A method of improving crack resistance of a precast reinforced concrete beam panel node zone according to any one of claims 1 to 7, wherein the method comprises:
step S1: constructing a lower layer reinforced concrete column wall;
step S2: hoisting the prefabricated reinforced concrete beam slab to a designed designated position;
step S3: second steel bars are lapped at the node area;
step S4: providing a spacer outside the second rebar at the top adjacent the nodal region;
step S5: a template is supported, and a post-pouring section is poured by using high-performance concrete;
step S6: constructing an upper layer reinforced concrete column wall;
wherein the tensile strength of the high-performance concrete is higher than that of ordinary concrete, and the high-performance concrete comprises one of UHPC and ECC.
9. The method for improving the crack resistance of the node area of the precast reinforced concrete beam slab as claimed in claim 8, wherein the spacer is a material with low elastic modulus, and the elastic modulus of the spacer is lower than that of the ordinary concrete or that of the high-performance concrete.
10. The method for improving the crack resistance of the node area of the precast reinforced concrete beam slab as claimed in claim 9, wherein the spacer is a rubber member or a polyethylene-based plastic member,
wherein the spacer is configured in the shape of a sleeve, an opening extending along the axial direction and penetrating through the sleeve along the thickness direction of the sleeve is formed on the sleeve, and the sleeve is suitable for being buckled on the outer side of the second reinforcing steel bar through the opening; or,
the partition comprises a first sub-partition and a second sub-partition, and the first sub-partition and the second sub-partition are respectively sleeved on the outer side of the second steel bar and fixed by a strip-shaped part; or,
the isolating piece is a rubber piece layer or a plastic piece layer wound on the outer side of the second steel bar.
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