WO2021003862A1

WO2021003862A1 - Fabric-reinforced ecc-steel pipe-steel frame composite member and fabrication method therefor

Info

Publication number: WO2021003862A1
Application number: PCT/CN2019/109877
Authority: WO
Inventors: 尹世平; 李耀; 胡长顺; 赵俊伶; 李传秀
Original assignee: 中国矿业大学
Priority date: 2019-07-10
Filing date: 2019-10-08
Publication date: 2021-01-14
Also published as: CN110331818A

Abstract

A fabric-reinforced ECC-steel pipe-steel frame composite member and a fabrication method therefor, the composite member comprising: a thin-walled steel pipe (3), a fabric-reinforced ECC coated on an outer side of the thin-walled steel pipe (3), a structural steel frame (2) arranged within the thin-walled steel pipe (3) and concrete (1) poured into the thin-walled steel pipe (3). The fabric-reinforced ECC is composed of an ECC (5) and a fiber-woven mesh (4), and the geometric centroids of the thin-walled steel pipe (3) and the structural steel frame (2) coincide. The fabrication method comprises: first pouring the concrete (1) into the thin-walled steel pipe (3), then spraying or applying the ECC (5) onto an outer wall of the thin-walled steel pipe (3), annularly wrapping the fiber-woven mesh (4), and then spraying or applying the ECC (5) onto a surface of the woven mesh (4), as well as a curing step. In the described composite member and fabrication method, the fabric-reinforced ECC is used to annularly wrap the thin-walled steel pipe (3) so that the composite member has high durability, fire resistance and bearing capacity.

Description

Fabric-reinforced ECC-steel-steel composite component and manufacturing method thereof

Technical field

The invention relates to a fabric-reinforced ECC-steel-steel-frame composite component and a manufacturing method thereof, and belongs to the technical field of civil construction structures.

Background technique

In the past ten years, with the development of economy and the improvement of science and technology, concrete-filled steel tube has been widely used in high-rise buildings due to its high bearing capacity, light weight, good seismic performance, and convenient construction, and has achieved a good society And economic benefits. However, in practical engineering applications, concrete-filled steel tubes still have disadvantages such as poor fire resistance, easy corrosion, and local buckling. In addition, thin-walled high-strength steel pipes cannot effectively constrain the concrete in the steel pipes, causing the concrete to appear brittle failure, resulting in insufficient deformability of the composite column.

Steel-reinforced concrete structures are also called rigid concrete structures, which are often used in high-rise buildings to effectively reduce the cross-sectional area of components. The steel-reinforced concrete structure can give full play to the combined effect of steel and concrete, and the outer concrete can effectively inhibit the local buckling of the steel, so that the steel can better exert its mechanical properties. However, steel-reinforced concrete also has certain shortcomings. For example, the external concrete is easy to fall off, which affects the durability of the structure and reduces the service life of the structure. In addition, under the action of an earthquake, the concrete is also prone to brittle failure, making the structure's seismic performance very poor.

Chinese Patent Document CN105781016A discloses a composite column composed of cement-based composite materials and steel pipes. In the composite column, a concrete core is located in a pipe fitting, and the periphery of the pipe fitting is wrapped with a cement-based composite material layer. The composite column has the advantages of good bending resistance, shear resistance, tensile strength and seismic resistance, and corrosion resistance. Although measures have been taken between the cement-based composite material layer and the outer wall of the inner steel pipe in the composite column, the bonding performance between the two is still poor and easy to peel off, and the steel pipe may also be locally buckled.

Based on the above background and on the basis of drawing on the advantages of the above-mentioned structural form, the present invention proposes a fabric-reinforced ECC-steel-steel composite member and a manufacturing method thereof to overcome the defects and deficiencies of the above-mentioned structural form.

Summary of the invention

Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides a fabric-reinforced ECC-steel-steel composite component and a manufacturing method thereof. The fabric-reinforced ECC ring-wrapped steel pipe is used to isolate the steel pipe from the external environment and reduce The risk of corrosion of steel pipes is reduced, the composite members have high durability and fire resistance, and the buckling resistance of the section steel frame is enhanced.

Technical solution: In order to achieve the above purpose, the technical solution adopted by the present invention is:

A fabric-reinforced ECC-steel-steel composite component, including a thin-walled steel pipe, a fabric-reinforced ECC coated on the outside of the thin-walled steel pipe, a steel profile arranged in the thin-walled steel pipe, and concrete poured into the thin-walled steel pipe;

Wherein, the fabric-reinforced ECC is composed of ECC and a fiber woven mesh, and the geometric centers of the thin-walled steel pipe and the section steel frame coincide.

Further, the cross-sectional shape of the section steel frame is I-shaped or cross-shaped.

Further, the cross-sectional shape of the thin-walled steel pipe is rectangular, four corners are arcs, and the ratio of the outer diameter to the wall thickness of the thin-walled steel pipe is 40-150.

Further, the cross-sectional shape of the member is rectangular.

Further, between the thin-walled steel pipe and the profiled steel frame, there are evenly spaced slots or studs along the longitudinal direction of the member for realizing the fixed connection between the profiled steel frame and the thin-walled steel pipe.

Further, the proportioning materials of the ECC include P.O 42.5 ordinary Portland cement, first-grade fly ash, 40-80 mesh quartz sand, superplasticizer and PVA fiber, and the PVA content does not exceed 2%.

Further, the ECC mixing ratio is: PVA per cubic meter: cement: quartz sand: fly ash: water: water reducing agent=0.047:1:1:1.182:0.547:0.003.

Further, the types of the fiber woven nets include carbon fiber woven nets, glass fiber woven nets, PBO fiber woven nets, basalt fiber woven nets, aramid fiber woven nets, hybrid fiber woven nets, and the knitting methods of the fiber woven nets include many Shaft stitch knitting, biaxial stitch knitting and warp knitting weft interlining.

A manufacturing method of fabric-reinforced ECC-steel-steel composite component includes the following steps:

1) Pour concrete into the thin-walled steel pipe, while keeping the section steel frame at the center of the thin-walled steel pipe;

2) Sandblast the outer wall of the thin-walled steel pipe, and then use the thin-walled steel pipe as the inner template to spray or apply ECC to the outer wall of the thin-walled steel pipe;

3) Wrap the fiber woven mesh on the surface of the ECC, keep the warp fiber bundles in the fiber woven mesh parallel to the cross section of the component during the wrapping process, and the lap length of the fiber woven mesh should be 1.5 to 2 times the side length of the thin-walled steel pipe. Before wrapping the fiber woven mesh, the cement paste should be used to soak the fiber woven mesh.

4) Spray or smear ECC on the surface of the fiber woven net, the minimum thickness of each layer of ECC should not be less than 5mm;

5) According to the design requirements, repeat steps 3) and 4) to complete the arrangement of the multi-layer fiber woven mesh. After the outermost ECC spray or smear of the component, the component is completed, and the surface of the component is covered with plastic film and cured for 28 days.

Further, when using jet ECC in step 2), the jet sequence should be from bottom to top, the segment length should not be greater than 6m, the distance from the nozzle to the outer wall of the thin-walled steel pipe is 100-300mm, and the spray direction is the normal line of the steel pipe surface The included angle is 15-30 degrees, and the spray overlap is 1/4-1/5.

Beneficial effects: Compared with the prior art, a fabric-reinforced ECC-steel-steel composite member and a manufacturing method thereof provided by the present invention have the following advantages:

1) The fabric-reinforced ECC enhances the hoop effect of the steel pipe, so that the composite member has superior seismic performance and improves the load-bearing capacity and ductility of the member;

2) The fabric-reinforced ECC ring-wrapped steel pipe reduces the risk of corrosion of the steel pipe, makes the composite components have high durability, and improves the service life of the composite components;

3) The fabric-reinforced ECC further improves the fire resistance of the composite components and reduces the cost of the fire protection structure of the structure;

4) The steel frame and the concrete are in a three-way compression state, which improves the bonding performance between the two, while effectively preventing and preventing the local buckling of the steel frame, thereby improving the deformation and bearing capacity of the two.

Description of the drawings

Figure 1 is a schematic cross-sectional view of Embodiment 1 of a fabric-reinforced ECC-steel-steel-frame composite member with a rectangular cross-section built-in rectangular steel pipe and cross-shaped steel frame of the present invention;

2 is a schematic cross-sectional view of Embodiment 2 of a fabric-reinforced ECC-steel-steel frame composite member with a rectangular cross-section built-in rectangular steel pipe and I-shaped steel frame of the present invention;

The picture includes: 1, concrete, 2, steel frame, 3, thin-walled steel pipe, 4, fiber woven mesh, 5, ECC, 6, card slot or stud.

Detailed ways

The present invention will be further explained below in conjunction with the drawings.

Example 1

Figure 1 shows a fabric-reinforced ECC-steel-steel composite member, including a thin-walled steel pipe 3, a fabric-reinforced ECC coated on the outside of the thin-walled steel pipe 3, and a steel profile 2 arranged in the thin-walled steel pipe 3 And the concrete 1 poured in the thin-walled steel pipe 3;

Wherein, the fabric-reinforced ECC is composed of ECC5 and fiber woven mesh 4, and the geometric centers of the thin-walled steel pipe 3 and the profiled steel frame 2 coincide; between the thin-walled steel pipe 3 and the profiled steel frame 2 along the longitudinal direction of the member Slots or studs 6 are arranged at equal intervals for realizing the fixed connection between the profiled steel frame 2 and the thin-walled steel pipe 3.

In this embodiment, the cross-sectional shape of the section steel frame 2 is cross-shaped, the cross-sectional shape of the thin-walled steel pipe 3 is rectangular (including square), the four corners are arcs, and the outer side of the thin-walled steel pipe 3 The ratio of diameter to wall thickness is 40-150; the cross-sectional shape of the member is rectangular (including square).

The materials in the ECC mix ratio are PO 42.5 ordinary Portland cement, first grade fly ash, 40-80 mesh quartz sand, superplasticizer and PVA fiber (polyvinyl alcohol fiber), and the PVA content does not exceed 2 %. The mixing ratio of ECC per cubic meter is: PVA: Cement: Quartz Sand: Fly Ash: Water: Water Reducer = 0.047:1:1:1:1182:0.547:0.003.

The types of the fiber woven net 4 include carbon fiber woven net 4, glass fiber woven net 4, PBO fiber woven net 4, basalt fiber woven net 4, aramid fiber woven net 4, hybrid fiber woven net 4, and fiber woven net 4 The knitting methods include multi-axis stitching, biaxial stitching and warp knitting weft inserts.

1) Pour concrete into the thin-walled steel pipe while keeping the cross-shaped steel frame at the center of the thin-walled steel pipe;

In step 1), in order to achieve the best utilization of steel, the steel pipe is a thin-walled steel pipe with a ratio of outer diameter to steel pipe wall thickness of 40-150, and the thin-walled steel pipe is a rectangular steel pipe (including square). Welding is used and arcs are formed at 4 corners to avoid stress concentration, which is not conducive to the effect of the outer fabric reinforced ECC layer; in order to be able to fix the position of the steel frame in the thin-walled steel pipe, a slot is set along the longitudinal direction of the member Make the section steel and the steel pipe tightly fasten together or set the studs at 0.5m or 1m equal intervals along the longitudinal direction of the member. The two ends of the stud are welded to the section steel frame and the thin-walled steel pipe. When pouring concrete, if the member is too long longitudinally To avoid quality problems such as honeycombs, pockmarked surfaces, holes, etc., it needs to be poured and vibrated in sections.

2) Sandblast the outer wall of the thin-walled steel pipe, and use the thin-walled steel pipe as the inner template to spray or apply ECC to the outer wall of the thin-walled steel pipe. The thickness of the spray or paint is determined according to the design requirements, but the minimum thickness of each layer should not be less than 5mm;

In step 2), the sandblasting abrasive adopts quartz sand with a particle size of 0.5-1.5mm, uniform particle size, dryness, and no oil pollution. Each time before putting it into the sand tank, it must be screened and sorted. If the abrasive is found to be agglomerated or severely rusted, it must be removed. During the spraying process, the distance from the nozzle to the surface of the base metal is 100-300mm, the angle between the spraying direction and the surface normal of the steel pipe is 15-30 degrees, and the spray overlap is preferably 1/4-1/5.

The materials in the ECC mix ratio are P.O 42.5 ordinary Portland cement, first-grade fly ash, 40-80 mesh quartz sand, superplasticizer and PVA fiber (polyvinyl alcohol fiber). The mixing ratio of ECC per cubic meter is: PVA: Cement: Quartz Sand: Fly Ash: Water: Water Reducer = 0.047:1:1:1:1182:0.547:0.003.

When using jet ECC, the jet sequence should be from bottom to top, and the segment length should not be greater than 6m. The spraying speed should be appropriate to facilitate the compaction of the concrete; when spraying, keep a proper distance between the nozzle and the sprayed surface, and the spraying angle should be as close to 90 degrees as possible to obtain the maximum compaction and minimum rebound; the nozzle should be continuous and slow in a horizontal circle Move, press half a circle in one circle.

3) Wrap the fiber woven mesh on the surface of the ECC. During the loop wrapping process, the warp fiber bundles in the fiber woven mesh should be kept parallel to the cross section of the test piece. The overlap length of the fiber woven mesh should be 1.5 to 2 times the side length of the thin-walled steel pipe;

In step 3), the cement paste should be used to infiltrate the fiber woven net before the loop-wrapped fiber woven net; the types of the fiber woven net include: carbon fiber woven net, glass fiber woven net, PBO fiber woven net, basalt fiber woven net , Aramid fiber woven net, hybrid fiber woven net.

4) Spray or smear ECC on the surface of the fiber woven net. The thickness of the spray or smear is determined according to the design requirements, but the minimum thickness of each layer should not be less than 5mm;

5) According to engineering needs, repeat steps 3) and 4) to complete the arrangement of multi-layer fiber woven mesh.

In step 5), after the outermost ECC spraying or coating of the component is completed, the component is completed, and the surface of the component is covered with a plastic film and cured for 28 days.

Example 2: Figure 2 shows a form of a fabric-reinforced ECC-steel-steel composite component. The implementation of this component is basically the same as that of Example 1, except that the shape of the steel frame in step 1 in this example is an I-shape. .

The invention provides a fabric-reinforced ECC-steel pipe-steel composite member and a manufacturing method thereof. The fabric-reinforced ECC, steel pipe, steel frame and concrete are used to form a composite member, which fully utilizes the advantages of various materials, and at the same time They interact with each other to further improve the performance of the composite component, so that the composite component has superior seismic performance, and improves the load-bearing capacity and ductility of the component; the use of fabric to enhance the ECC ring-wrapped steel pipe isolates the steel pipe from the external environment and reduces the corrosion of the steel pipe The risk of high durability and fire resistance of the composite component; the buckling resistance of the steel section steel is enhanced. In addition, composite components can reduce casualties and property losses caused by earthquakes, and at the same time reduce reinforcement and maintenance costs during normal use.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications are also It should be regarded as the protection scope of the present invention.

Claims

A fabric-reinforced ECC-steel-steel composite component, which is characterized by comprising a thin-walled steel pipe (3), a fabric-reinforced ECC coated on the outside of the thin-walled steel pipe (3), Steel profile steel frame (2) and concrete (1) poured in thin-wall steel pipe (3);

Wherein, the fabric-reinforced ECC is composed of ECC (5) and fiber woven mesh (4), and the geometric center of the thin-walled steel pipe (3) and the section steel frame (2) coincide.
The fabric-reinforced ECC-steel-steel frame composite member according to claim 1, wherein the cross-sectional shape of the section steel frame (2) is I-shaped or cross-shaped.
The fabric-reinforced ECC-steel-steel composite member according to claim 1, wherein the cross-sectional shape of the thin-walled steel pipe (3) is rectangular, and the four corners are circular arcs and thin-walled The ratio of the outer diameter to the wall thickness of the steel pipe (3) is 40-150.
The fabric-reinforced ECC-steel-steel composite component according to claim 1, wherein the cross-sectional shape of the component is rectangular.
The fabric-reinforced ECC-steel-steel frame composite member according to claim 1, wherein the thin-walled steel pipe (3) and the profiled steel frame (2) are provided with clamps at equal intervals along the longitudinal direction of the member. Grooves or studs (6) are used for realizing the fixed connection between the profiled steel frame (2) and the thin-walled steel pipe (3).
The fabric-reinforced ECC-steel-steel composite member according to claim 1, wherein the proportioning materials of the ECC (5) include PO 42.5 ordinary Portland cement, first-grade fly ash, 40 ～80 mesh quartz sand, superplasticizer and PVA fiber, and the PVA content does not exceed 2%.
The fabric-reinforced ECC-steel-steel composite member according to claim 6, wherein the ECC (5) mix ratio is: PVA per cubic meter: cement: quartz sand: fly ash: water : Water reducing agent=0.047:1:1:1:1.182:0.547:0.003.
The fabric-reinforced ECC-steel-steel composite member according to claim 1, wherein the types of the fiber woven mesh (4) include carbon fiber woven mesh (4), glass fiber woven mesh (4), PBO fiber woven net (4), basalt fiber woven net (4), aramid fiber woven net (4), hybrid fiber woven net (4), and the knitting method of fiber woven net (4) includes multi-axis stitching, double Shaft stitch knitting and warp knitting weft interlining.
A method for manufacturing a fabric-reinforced ECC-steel-steel composite component, which is characterized in that it comprises the following steps:

1) Pour concrete into the thin-walled steel pipe, while keeping the section steel frame at the center of the thin-walled steel pipe;

2) Sandblast the outer wall of the thin-walled steel pipe, and then use the thin-walled steel pipe as the inner template to spray or apply ECC to the outer wall of the thin-walled steel pipe;

3) Wrap the fiber woven mesh on the surface of the ECC, keep the warp fiber bundles in the fiber woven mesh parallel to the cross-section of the component during the loop wrapping process, and take 1.5 to 2 times the side length of the thin-walled steel pipe as the overlap length of the fiber woven mesh. Before weaving the net, use cement paste to infiltrate the fiber woven net;

4) Spray or smear ECC on the surface of the fiber woven net, the minimum thickness of each layer of ECC is not less than 5mm;

5) According to the design requirements, repeat steps 3) and 4) to complete the arrangement of the multi-layer fiber woven mesh. After the outermost ECC spray or smear of the component, the component is completed, and the surface of the component is covered with plastic film and cured for 28 days.
The method for fabricating a fabric-reinforced ECC-steel-steel composite member according to claim 1, wherein when spraying ECC is used in step 2), the spraying sequence should be from bottom to top, and the segment length is not More than 6m, the distance between the nozzle and the outer wall surface of the thin-walled steel pipe is 100-300mm, the angle between the spray direction and the surface normal of the steel pipe is 15-30 degrees, and the spray beam overlap is 1/4-1/5.