CN110656786A - Prestressed steel-concrete combined pile underpinning node and manufacturing method thereof - Google Patents
Prestressed steel-concrete combined pile underpinning node and manufacturing method thereof Download PDFInfo
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- 239000004567 concrete Substances 0.000 title claims abstract description 190
- 238000009424 underpinning Methods 0.000 title claims abstract description 51
- 238000004519 manufacturing process Methods 0.000 title claims description 11
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 173
- 239000010959 steel Substances 0.000 claims abstract description 173
- 239000010410 layer Substances 0.000 claims description 105
- 239000011241 protective layer Substances 0.000 claims description 21
- 239000000463 material Substances 0.000 claims description 7
- 238000000034 method Methods 0.000 claims description 6
- 230000002787 reinforcement Effects 0.000 claims description 6
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- 239000003351 stiffener Substances 0.000 claims 9
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- 238000002360 preparation method Methods 0.000 claims 1
- 239000002994 raw material Substances 0.000 claims 1
- 239000011150 reinforced concrete Substances 0.000 claims 1
- 238000010276 construction Methods 0.000 abstract description 4
- 230000000694 effects Effects 0.000 description 16
- 238000010008 shearing Methods 0.000 description 6
- 238000004873 anchoring Methods 0.000 description 4
- 230000003014 reinforcing effect Effects 0.000 description 4
- 230000009286 beneficial effect Effects 0.000 description 3
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- E—FIXED CONSTRUCTIONS
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- E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
- E04G23/00—Working measures on existing buildings
- E04G23/06—Separating, lifting, removing of buildings; Making a new sub-structure
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D27/00—Foundations as substructures
- E02D27/32—Foundations for special purposes
- E02D27/48—Foundations inserted underneath existing buildings or constructions
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D35/00—Straightening, lifting, or lowering of foundation structures or of constructions erected on foundations
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D35/00—Straightening, lifting, or lowering of foundation structures or of constructions erected on foundations
- E02D35/005—Lowering or lifting of foundation structures
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/22—Piles
- E02D5/58—Prestressed concrete piles
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- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/22—Piles
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- E04—BUILDING
- E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
- E04G23/00—Working measures on existing buildings
- E04G23/06—Separating, lifting, removing of buildings; Making a new sub-structure
- E04G23/065—Lifting of buildings
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D2250/00—Production methods
- E02D2250/0023—Cast, i.e. in situ or in a mold or other formwork
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D2250/00—Production methods
- E02D2250/0046—Production methods using prestressing techniques
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Abstract
The invention relates to a prestressed steel-concrete combined pile underpinning node which comprises inner-layer concrete, outer-layer concrete and a steel pipe, wherein the inner-layer concrete, the outer-layer concrete and the steel pipe are sequentially arranged from inside to outside, and the inner-layer concrete is wrapped on the outer side of a pile to be underpinned; the prestressed steel-concrete combined pile underpinning node also comprises prestressed steel strands spirally wound on the outer side of the inner layer concrete, and embedded steel bars are arranged at the bottom and the top of the inner layer concrete; and two ends of the prestressed steel strand are respectively connected with the embedded steel bars at the bottom and the top through sleeves. Compared with the prior art, the invention has the advantages of high bearing capacity, high safety, convenient construction and the like.
Description
Technical Field
The invention relates to a underpinning device, in particular to a prestressed steel-concrete combined pile underpinning node and a manufacturing method thereof.
Background
With the continuous development of social cities, the development and utilization of underground spaces are continuously paid attention. The existing building may cause uneven settlement of the foundation under the effect of long-term load, or cause the bearing capacity of the foundation to change near a deeply buried structure, etc., which may affect the safety of the building. The most widely applied underpinning node of the actual project in China is a column type underpinning node, the bearing capacity of the node is limited, the pile underpinning load is usually large, and the commonly used column type underpinning node is not suitable for use. Therefore, some technicians adopt a beam underpinning technology in actual engineering, but the underpinning method is complex in construction, and has certain limitation due to space limitation in actual application. The column type underpinning node is simple in construction, free of space limitation and capable of meeting the bearing capacity requirement, and has important significance.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a prestressed steel-concrete combined pile underpinning node which is simple in construction, free from space limitation and high in bearing capacity.
The purpose of the invention can be realized by the following technical scheme:
a prestressed steel-concrete combined pile underpinning node comprises an inner layer concrete, an outer layer concrete and a steel pipe which are sequentially arranged from inside to outside, wherein the inner layer concrete is wrapped on the outer side of a pile to be underpinned; the prestressed steel strand is spirally wound on the outer side of the inner layer concrete, and embedded steel bars are arranged at the bottom and the top of the inner layer concrete; and two ends of the prestressed steel strand are respectively connected with the embedded steel bars positioned at the bottom and the top.
And the embedded steel bars in the inner-layer concrete are spirally wound and arranged along the circumferential direction of the inner-layer concrete.
Preferably, the embedded steel bars in the inner layer concrete are spirally wound on the inner layer concrete for at least one circle.
The inner layer concrete is provided with the embedded steel bars at the connecting positions of the prestressed steel bars, the diameter of the embedded steel bars is matched with that of the prestressed steel strands, and in order to ensure that the embedded steel bars are not bonded and slid under the action of prestress, the embedded steel bars are spirally wound on the inner layer concrete for at least one circle.
The prestressed steel strand is connected with the embedded steel bars through a connecting sleeve.
The pitch of the prestressed steel strand spirally wound on the outer side of the inner layer concrete is 50-200 mm.
In order to ensure the action effect of the prestressed steel strand, 1 strand of 7 prestressed steel strands is preferably adopted, and the nominal diameter is preferably 15.20 mm.
Before the prestressed steel strands are tensioned, the outer surface of the inner layer concrete is polished and washed for two to three times by using clear water so as to reduce the friction loss of the prestressed steel strands.
Still be equipped with a plurality of connecting reinforcement along the radial arrangement of inlayer concrete in the inlayer concrete, this connecting reinforcement's vertical interval is multiple relation with the pitch of prestressing force steel strand to this vertical interval is not more than 200 mm.
The connection between the inner layer concrete and the outer layer concrete can be enhanced by arranging the connecting steel bars, so that the inner layer concrete and the outer layer concrete are prevented from relative sliding under the action of load; the diameter of the connecting steel bar is preferably 8-12 mm.
And longitudinal steel bars and spiral stirrups are also arranged in the inner-layer concrete.
The inner concrete adopts ordinary concrete, and inner concrete is inside to set up vertical reinforcing bar and stirrup for satisfy inner concrete atress requirement, adopt spiral stirrup can strengthen the constraint effect to inside concrete.
The outer layer concrete is made of micro-expansion concrete.
The outer layer concrete generates compressive stress on the underpinning interface under the constraint action of the steel pipe by adopting the expansive concrete, and the expansion rate of the expansive concrete is determined according to the design requirement, and is preferably 0.025%.
Be equipped with the protective layer that thickness is 20 ~ 50mm between inlayer concrete and the outer concrete, the material of this protective layer is mortar or grout material, can ensure the closely knit effect of protective layer.
The protective layer is arranged to ensure that the prestressed steel strands do not generate prestress loss due to expansion of outer concrete.
The inner wall of the steel pipe is provided with an annular stiffening rib and a longitudinal stiffening rib, wherein the annular stiffening rib and the longitudinal stiffening rib form a grid, and the intersection of the annular stiffening rib and the longitudinal stiffening rib keeps the continuity of the annular stiffening rib to cut off the longitudinal stiffening rib; the wall thickness of the steel pipe is not less than 20mm, and the size of a cell formed by the circumferential stiffening ribs and the longitudinal stiffening ribs is 200-600 mm multiplied by 200-600 mm; the thickness of the circumferential stiffening rib and the longitudinal stiffening rib is 6-8 mm, and the length of the circumferential stiffening rib and the longitudinal stiffening rib is 50-100 mm.
The steel pipe provides boundary constraint for the expansive concrete, and stiffening ribs are preferably arranged on the inner wall of the steel pipe in the circumferential direction and the longitudinal direction in order to ensure that the steel pipe does not generate local buckling under the action of the expansive concrete; the circumferential stiffening ribs and the longitudinal stiffening ribs are arranged to enhance the bonding effect of the steel pipe and the outer concrete layer.
The wall thickness of the steel pipe and the size parameters of the stiffening ribs are optimized, so that the integral rigidity of the steel pipe can be enhanced, and the constraint effect of the steel pipe is enhanced.
The invention also provides a manufacturing method of the prestressed steel-concrete combined pile underpinning node, which comprises the following steps:
the method comprises the following steps: binding longitudinal steel bars, stirrups, embedded steel bars and connecting steel bars of inner-layer concrete on the outer side of the pile to be underpinned;
step two: pouring concrete on the outer side of the pile to be underpinned to form inner-layer concrete;
step three: after the inner layer concrete is initially set, arranging prestressed steel strands, and connecting the prestressed steel strands with embedded steel bars at the bottom of the inner layer concrete through connecting sleeves;
step four: after the strength of the inner layer concrete reaches 75% of the design strength, tensioning the prestressed steel strand, and connecting the prestressed steel strand with the embedded steel bar at the top through a connecting sleeve after the design tensile stress is reached;
step five: pouring a protective layer;
step six: manufacturing a steel pipe, an annular stiffening rib and a longitudinal stiffening rib inside the steel pipe, and installing the steel pipe and the circumferential stiffening rib and the longitudinal stiffening rib on the outer side of the inner layer concrete;
step seven: pouring outer layer concrete;
step eight: and after finishing the final setting of the outer layer concrete, obtaining the prestressed steel-concrete combined pile underpinning node, and then carrying out subsequent operations such as pile cutting or jacking.
Compared with the prior art, the invention has the following beneficial effects:
(1) the invention adopts the compressive stress generated by the prestressed steel strand at the underpinning interface as the shearing-resistant bearing capacity of the underpinning node, and the prestressed steel strand can adopt different tension control stresses according to the underpinning load required, even adopts over-tension, so the invention is suitable for pile underpinning with larger load.
(2) The expansion concrete is arranged between the inner layer concrete and the steel pipe, and the constraint action of the expansion concrete on the steel pipe can generate pressure stress on the underpinning interface, so that the expansion concrete can be used as the shearing-resistant bearing capacity of the underpinning node, the shearing-resistant bearing capacity can be used as the safe storage of the underpinning node, and the safety degree of the underpinning node is improved.
Drawings
FIG. 1 is a schematic structural view of the present invention;
FIG. 2 is a cross-sectional view taken along line A-A of FIG. 1;
FIG. 3 is a schematic view of a connection structure of a prestressed steel strand and an embedded steel bar in the present invention;
FIG. 4 is a cross-sectional view B-B of FIG. 3;
FIG. 5 is a schematic structural view of a steel pipe in the present invention;
FIG. 6 is a cross-sectional view C-C of FIG. 5;
FIG. 7 is a schematic view of the contact interface of the inner concrete layer, the outer concrete layer and the protective layer;
fig. 8 is a schematic view showing the arrangement position of the connection bars;
in the figure, 1 is inner concrete, 2 is outer concrete, 3 is the steel pipe, 31 is the pipe wall, 32 is hoop stiffening rib, 33 is vertical stiffening rib, 4 is prestressing force steel strand wires, 5 is the protective layer, 6 is the connecting sleeve, 7 is embedded reinforcing bar, 8 is connecting reinforcement.
Detailed Description
The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications can be made by persons skilled in the art without departing from the spirit of the invention. All falling within the scope of the present invention.
Example 1
A prestressed steel-concrete combined pile underpinning node is shown in figures 1 and 2 and comprises an inner layer concrete 1, prestressed steel strands 4 spirally wound on the outer side of the inner layer concrete 1, a protective layer 5, an outer layer concrete 2 and a steel pipe 3 which are sequentially arranged from inside to outside, wherein the inner layer concrete 1 is wrapped on the outer side of a pile to be underpinned; longitudinal steel bars, stirrups, embedded steel bars 7 and connecting steel bars 8 are arranged in the inner layer concrete 1; in order to meet the tensioning and anchoring requirements of the prestressed steel strands, the bottom of the inner layer concrete 1 is provided with embedded steel bars 7 serving as tensioning ends of the prestressed steel strands 4, and the top of the inner layer concrete 1 is provided with the embedded steel bars 7 serving as anchoring ends of the prestressed steel strands 4.
As shown in fig. 3 and 4, the prestressed steel strands 4 are connected with the embedded steel bars 7 through the connecting sleeves 6, and the embedded steel bars 7 in the inner-layer concrete 1 are spirally wound and arranged along the circumferential direction of the inner-layer concrete 1; and the diameter of the embedded steel bar 7 should be matched with the diameter of the prestressed steel strand 4, and simultaneously, in order to reduce the bonding slippage of the embedded steel bar 7 under the action of prestress, the embedded steel bar 7 is spirally wound on the inner layer concrete for at least one circle. The prestressed steel strand structure should adopt 1 strand of 7, and the nominal diameter adopts 15.20mm, and prestressing tendons pitch is 50mm for guarantee prestressed steel strand's effect. In order to reduce the friction loss of the prestressed steel strands, the outer surface of the inner layer concrete is polished clean before the prestressed steel strands are tensioned, and the inner layer concrete is washed for two to three times by using clear water.
As shown in fig. 8, for the connection between the reinforced inner concrete 1 and the reinforced outer concrete 2, the inner concrete and the outer concrete are prevented from sliding relatively under the action of load, the connecting steel bar 8 is arranged between the reinforced inner concrete 1 and the reinforced outer concrete 2, the connecting steel bar 8 is arranged along the radial direction, the vertical distance is preferably the multiple of the pitch of the prestressed steel strand 4, the vertical distance is not more than 200mm, specifically 40mm, and the diameter of the connecting steel bar is preferably 8 mm.
In order to make the outer layer concrete 2 generate compressive stress on the underpinning interface under the constraint action of the steel pipe, the outer layer concrete 2 adopts expansive concrete, and the expansion rate of the expansive concrete is determined according to the design requirement, and is preferably 0.025%.
As shown in fig. 7, in order to ensure that the prestressed steel strands do not generate prestress loss due to expansion of the outer concrete 2, a protective layer is arranged between the contact interface of the inner concrete and the outer concrete, and the thickness of the protective layer is preferably 20 mm. In order to ensure the compact effect of the protective layer, mortar or grouting material is adopted as the protective layer material.
As shown in fig. 5 and 6, in order to ensure that the steel pipe 3 does not have local buckling under the action of the expanded concrete of the outer layer, the inner wall of the steel pipe 3 is provided with a circumferential stiffening rib 32 and a longitudinal stiffening rib 33, wherein the circumferential stiffening rib 32 and the longitudinal stiffening rib 33 form a grid, and in order to enhance the beneficial effect of the circumferential stiffening rib and the longitudinal stiffening rib on preventing the local buckling of the steel pipe, the intersection of the circumferential stiffening rib 32 and the longitudinal stiffening rib 33 keeps the circumferential stiffening rib 32 continuous, and cuts off the longitudinal stiffening rib 33; the wall thickness of the pipe wall 31 of the steel pipe 3 is not less than 20mm, specifically 20mm, and the size of the cell formed by the circumferential stiffening rib 32 and the longitudinal stiffening rib 33 is 200mm multiplied by 200 mm; the thickness of the circumferential stiffening rib 32 and the longitudinal stiffening rib 33 is 6mm, the length is 50mm, and the overall rigidity of the steel pipe can be enhanced through the size design, so that the constraint effect of the steel pipe is enhanced. The steel pipe 3 is arranged on the outer side of the outer layer concrete 2 and used for providing boundary constraint for the outer layer concrete 2; the circumferential and longitudinal stiffening ribs are arranged to enhance the bonding effect of the steel pipe and the outer concrete 2.
The manufacturing method of the prestressed steel-concrete combined pile underpinning node comprises the following steps:
the method comprises the following steps: binding longitudinal steel bars, stirrups, embedded steel bars 7 and connecting steel bars 8 of the inner layer concrete 1 on the outer side of the pile to be underpinned according to design requirements;
step two: manufacturing common concrete according to the designed mixing proportion, and pouring the common concrete on the outer side of the underpinning pile to form inner-layer concrete 1;
step three: after the inner layer concrete 1 is initially set, arranging prestressed steel strands 4, and connecting the prestressed steel strands with embedded steel bars 7 at the bottom of the inner layer concrete 1 through connecting sleeves 6;
step four: after the strength of the inner layer concrete 1 reaches 75% of the design strength, tensioning the prestressed steel strand 4, and after the design tensile stress is reached, connecting the prestressed steel strand 4 with the embedded steel bar 7 at the top through a connecting sleeve 6;
step five: pouring a protective layer 5;
step six: manufacturing the steel pipe 3, the internal circumferential stiffening rib 32 and the internal longitudinal stiffening rib 33 according to the design requirements, and installing the steel pipe outside the inner layer concrete 1;
step seven: manufacturing and pouring the outer concrete 2 according to the outer concrete expansion rate required by the design;
step eight: and after the final setting of the outer layer concrete 2 is finished, performing subsequent operations such as pile cutting or jacking and the like.
In the embodiment, the compressive stress generated by the prestressed steel strand at the underpinning interface is used as the shearing-resistant bearing capacity of the underpinning node, and the prestressed steel strand can adopt different tension control stresses according to the underpinning load required, even adopts ultra-tension, so that the method is suitable for pile underpinning with larger load. The expanded concrete is arranged between the inner layer concrete and the steel pipe, and the constraint action of the expanded concrete on the steel pipe can generate pressure stress on the underpinning interface, so that the expanded concrete can be used as the shearing-resistant bearing capacity of the underpinning node, the shearing-resistant bearing capacity can be used as the safe storage of the underpinning node, and the safety degree of the underpinning node is improved.
Example 2
A prestressed steel-concrete combined pile underpinning node is shown in figures 1 and 2 and comprises an inner layer concrete 1, prestressed steel strands 4 spirally wound on the outer side of the inner layer concrete 1, a protective layer 5, an outer layer concrete 2 and a steel pipe 3 which are sequentially arranged from inside to outside, wherein the inner layer concrete 1 is wrapped on the outer side of a pile to be underpinned; longitudinal steel bars, stirrups, embedded steel bars 7 and connecting steel bars 8 are arranged in the inner layer concrete 1; in order to meet the tensioning and anchoring requirements of the prestressed steel strands, the bottom of the inner layer concrete 1 is provided with embedded steel bars 7 serving as tensioning ends of the prestressed steel strands 4, and the top of the inner layer concrete 1 is provided with the embedded steel bars 7 serving as anchoring ends of the prestressed steel strands 4.
As shown in fig. 3 and 4, the prestressed steel strands 4 are connected with the embedded steel bars 7 through the connecting sleeves 6, and the embedded steel bars 7 in the inner-layer concrete 1 are spirally wound and arranged along the circumferential direction of the inner-layer concrete 1; and the diameter of the embedded steel bar 7 should be matched with the diameter of the prestressed steel strand 4, and simultaneously, in order to reduce the bonding slippage of the embedded steel bar 7 under the action of prestress, the embedded steel bar 7 is spirally wound on the inner layer concrete for at least one circle. The prestressed steel strand structure should adopt 1 strand of 7, and the nominal diameter adopts 15.20mm, and prestressing tendons pitch is 200mm for guarantee prestressed steel strand's effect. In order to reduce the friction loss of the prestressed steel strands, the outer surface of the inner layer concrete is polished clean before the prestressed steel strands are tensioned, and the inner layer concrete is washed for two to three times by using clear water.
As shown in fig. 8, in order to enhance the connection between the inner layer concrete 1 and the outer layer concrete 2 and prevent the relative slippage of the inner layer concrete and the outer layer concrete under the load action, the connecting steel bars 8 are arranged between the inner layer concrete 1 and the outer layer concrete 2, the connecting steel bars 8 are arranged along the radial direction, and the vertical distance is preferably the multiple of the pitch of the prestressed steel strand 4 and is not more than 150 mm. The connecting bars are preferably 12mm in diameter.
In order to make the outer layer concrete 2 generate compressive stress on the underpinning interface under the constraint action of the steel pipe, the outer layer concrete 2 adopts expansive concrete, and the expansion rate of the expansive concrete is determined according to the design requirement, and is preferably 0.025%.
As shown in fig. 7, in order to ensure that the prestressed steel strands do not generate prestress loss due to expansion of the outer concrete 2, a protective layer is arranged between the contact interface of the inner concrete and the outer concrete, and the thickness of the protective layer is preferably 50 mm. In order to ensure the compact effect of the protective layer, mortar or grouting material is adopted as the protective layer material.
As shown in fig. 5 and 6, in order to ensure that the steel pipe 3 does not have local buckling under the action of the expanded concrete of the outer layer, the inner wall of the steel pipe 3 is provided with a circumferential stiffening rib 32 and a longitudinal stiffening rib 33, wherein the circumferential stiffening rib 32 and the longitudinal stiffening rib 33 form a grid, and in order to enhance the beneficial effect of the circumferential stiffening rib and the longitudinal stiffening rib on preventing the local buckling of the steel pipe, the intersection of the circumferential stiffening rib 32 and the longitudinal stiffening rib 33 keeps the circumferential stiffening rib 32 continuous, and cuts off the longitudinal stiffening rib 33; the wall thickness of the pipe wall 31 of the steel pipe 3 is not less than 20mm, specifically 40mm, and the size of the cell formed by the circumferential stiffening rib 32 and the longitudinal stiffening rib 33 is 600mm multiplied by 600 mm; the thickness of the circumferential stiffening rib 32 and the longitudinal stiffening rib 33 is 8mm, the length is 100mm, and the overall rigidity of the steel pipe can be enhanced by the size design, so that the constraint effect of the steel pipe is enhanced. The steel pipe 3 is arranged on the outer side of the outer layer concrete 2 and used for providing boundary constraint for the outer layer concrete 2; the circumferential and longitudinal stiffening ribs are arranged to simultaneously enhance the bonding effect of the steel pipe and the outer layer concrete 2;
the foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes and modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention.
Claims (10)
1. A prestressed steel-concrete combined pile underpinning node comprises an inner layer concrete (1), an outer layer concrete (2) and a steel pipe (3) which are sequentially arranged from inside to outside, wherein the inner layer concrete (1) is wrapped on the outer side of a pile to be underpinned; it is characterized in that the preparation method is characterized in that,
the concrete-reinforced concrete composite material is characterized by also comprising prestressed steel strands (4) spirally wound on the outer side of the inner layer concrete (1), wherein embedded steel bars (7) are arranged at the bottom and the top of the inner layer concrete (1); and two ends of the prestressed steel strand (4) are respectively connected with embedded steel bars (7) positioned at the bottom and the top.
2. The prestressed steel-concrete combined pile underpinning node as claimed in claim 1, wherein embedded steel bars (7) in the inner layer concrete (1) are spirally wound and arranged along the circumferential direction of the inner layer concrete (1); preferably, the embedded steel bars (7) in the inner layer concrete (1) are spirally wound on the inner layer concrete (1) for at least one circle.
3. The prestressed steel-concrete combined pile underpinning node as claimed in claim 1, wherein the prestressed steel strands (4) are connected with the embedded steel bars (7) through connecting sleeves (6).
4. The prestressed steel-concrete combined pile underpinning node as claimed in claim 1, wherein the pitch of the prestressed steel strand (4) spirally wound on the outer side of the inner layer concrete (1) is 50-200 mm.
5. A prestressed steel-concrete combined pile underpinning node according to claim 1, characterized in that a plurality of connecting steel bars (8) are arranged in the inner layer concrete (1) along the radial direction of the inner layer concrete (1), the vertical spacing of the connecting steel bars (8) is multiple relation with the pitch of the prestressed steel strand (4), and the vertical spacing is not more than 200 mm.
6. A prestressed steel-concrete combined pile underpinning node according to claim 1, characterized in that said inner layer concrete (1) is also provided with longitudinal reinforcement and helical stirrups.
7. A prestressed steel-concrete composite pile underpinning node as claimed in claim 1, characterized in that the raw material of said outer layer concrete (2) is micro-expansion concrete.
8. The prestressed steel-concrete combined pile underpinning node as claimed in claim 1, wherein a protective layer (5) with a thickness of 20-50 mm is arranged between the inner layer concrete (1) and the outer layer concrete (2), and the protective layer (5) is made of mortar or grouting material.
9. A prestressed steel-concrete composite pile underpinning node according to claim 1, characterized in that the steel pipe (3) is provided with circumferential stiffeners (32) and longitudinal stiffeners (33) on its inner wall, wherein the circumferential stiffeners (32) and the longitudinal stiffeners (33) form a grid, and the circumferential stiffeners (32) are continuous with the longitudinal stiffeners (33) at the intersection of the circumferential stiffeners (32) and the longitudinal stiffeners (33), and the longitudinal stiffeners (33) are cut off; wherein the wall thickness of the steel pipe (3) is not less than 20mm, and the size of a cell formed by the annular stiffening rib (32) and the longitudinal stiffening rib (33) is 200-600 mm multiplied by 200-600 mm; the thickness of the circumferential stiffening rib (32) and the longitudinal stiffening rib (33) is 6-8 mm, and the length is 50-100 mm.
10. A method for manufacturing a prestressed steel-concrete combined pile underpinning node as claimed in claim 1, characterized by comprising the following steps:
the method comprises the following steps: binding longitudinal steel bars, stirrups, embedded steel bars (7) and connecting steel bars (8) of the inner layer concrete (1) on the outer side of the pile to be underpinned;
step two: pouring concrete on the outer side of the pile to be underpinned to form inner layer concrete (1);
step three: after the inner layer concrete (1) is initially set, arranging prestressed steel strands (4) and connecting the prestressed steel strands with embedded steel bars (7) at the bottom of the inner layer concrete (1) through connecting sleeves (6);
step four: after the strength of the inner layer concrete (1) reaches 75% of the design strength, tensioning the prestressed steel strand (4), and after the design tensile stress is reached, connecting the prestressed steel strand with the embedded steel bar (7) at the top through a connecting sleeve (6);
step five: pouring a protective layer (5);
step six: manufacturing a steel pipe (3), an annular stiffening rib (32) and a longitudinal stiffening rib (33) inside the steel pipe, and installing the steel pipe and the longitudinal stiffening rib on the outer side of the inner layer concrete (1);
step seven: pouring outer layer concrete (2);
step eight: and after the final setting of the outer layer concrete (2) is finished, the prestressed steel-concrete combined pile underpinning node is obtained.
Priority Applications (1)
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114808767A (en) * | 2022-05-19 | 2022-07-29 | 安徽省交通控股集团有限公司 | Steel wire rope hoop prestress construction method |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102661056A (en) * | 2012-03-12 | 2012-09-12 | 河海大学 | Apparatus for underpinning reinforced concrete column by adopting prestress technology |
| CN103061364A (en) * | 2013-01-15 | 2013-04-24 | 广州市市政工程设计研究院 | Prestressed pile foundation underpinning structure and construction method thereof |
| CN109372011A (en) * | 2018-12-03 | 2019-02-22 | 中铁三局集团有限公司 | Large-volume prestressed beam underpinning structure and the method for carrying out pile foundation underpinning with the structure |
| CN110056204A (en) * | 2019-04-19 | 2019-07-26 | 同济大学建筑设计研究院(集团)有限公司 | A kind of out no-conhesion prestressing underpins node |
| CN211257916U (en) * | 2019-10-22 | 2020-08-14 | 同济大学建筑设计研究院(集团)有限公司 | Prestressed steel-concrete combined pile underpinning node |
-
2019
- 2019-10-22 CN CN201911005593.XA patent/CN110656786B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102661056A (en) * | 2012-03-12 | 2012-09-12 | 河海大学 | Apparatus for underpinning reinforced concrete column by adopting prestress technology |
| CN103061364A (en) * | 2013-01-15 | 2013-04-24 | 广州市市政工程设计研究院 | Prestressed pile foundation underpinning structure and construction method thereof |
| CN109372011A (en) * | 2018-12-03 | 2019-02-22 | 中铁三局集团有限公司 | Large-volume prestressed beam underpinning structure and the method for carrying out pile foundation underpinning with the structure |
| CN110056204A (en) * | 2019-04-19 | 2019-07-26 | 同济大学建筑设计研究院(集团)有限公司 | A kind of out no-conhesion prestressing underpins node |
| CN211257916U (en) * | 2019-10-22 | 2020-08-14 | 同济大学建筑设计研究院(集团)有限公司 | Prestressed steel-concrete combined pile underpinning node |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114808767A (en) * | 2022-05-19 | 2022-07-29 | 安徽省交通控股集团有限公司 | Steel wire rope hoop prestress construction method |
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