FRP-concrete-steel double-wall hollow composite K-shaped member and construction method thereof

Abstract

This application relates to the technical field of composite components, and provides an FRP-concrete-steel double-wall hollow composite K-shaped component and its construction method. This addresses the problem that existing FRP-concrete-steel double-wall hollow composite components are primarily manufactured using fiber winding technology. Compared to simple straight pipes, the technology for manufacturing node pipes or special-shaped pipes such as tees is not mature. In addition, FRP nodes are generally connected using fiber cloth impregnated with room-temperature curing thermosetting resin. This method has the problems of long curing time, generally requiring more than 24 hours to fully cure, and complicated operation. The method comprises: providing an FRP outer main pipe, and pre-treating the FRP outer main pipe to obtain an FRP outer main pipe patch and an FRP outer main pipe body with an operation hole opened on the outer side; wherein the FRP outer main pipe patch is obtained by opening two through-holes in the operation area patch complementary to the operation hole; providing a steel inner main pipe, inserting the steel inner pipe into the FRP outer main pipe body, and fixing the steel inner pipe to the FRP outer main pipe body.

Description

Technical Field

[0001] The present application relates to the technical field of composite components, and more specifically, to an FRP-concrete-steel double-wall hollow composite K-shaped component and a construction method thereof. Background Art

[0002] The FRP-concrete-steel double-wall hollow composite member, proposed by Professor Jin-Guang Teng of the Hong Kong Polytechnic University, is a new type of composite member consisting of an FRP outer tube, a steel inner tube, and concrete filling between them. In this new composite member, the concrete filling is constrained by both the FRP outer tube and the steel inner tube, resulting in higher compressive strength, better deformation capacity, and greater ductility than unconstrained concrete. The steel tube, constrained by both the outer concrete and the FRP tube, effectively avoids outward buckling, fully utilizing its strength. It can also serve as a formwork for pouring concrete, simplifying the construction process and saving formwork costs. In addition to providing shear resistance, the FRP outer tube also constrains the concrete and steel tube, improving the latter's mechanical properties. It also protects the steel inner tube and concrete from corrosive environments, eliminating subsequent maintenance costs. Because FRP-concrete-steel double-wall hollow composite components have the above-mentioned advantages, and because of their hollow characteristics, they can reduce the deadweight of the structure. They are particularly suitable for application in spatial structures, marine bridges and platforms, etc., and are conducive to the construction of engineering structures with higher bearing capacity, better seismic performance and greater durability, and have important engineering promotion value.

[0003] Currently, FRP-concrete-steel double-wall hollow composite components are mainly manufactured using fiber winding molding technology. Compared with simple straight pipes, the technology for making node pipes or special-shaped pipes such as tees is not mature. In addition, FRP nodes are generally connected using fiber cloth impregnated with room-temperature curing thermosetting resin. This method has a long curing time, generally requiring more than 24 hours to fully cure, and the operation is complicated. In addition, the resin impregnation quality is difficult to control, which limits its large-scale application in engineering structures. Summary of the Invention

[0004] The purpose of the present application is to provide an FRP-concrete-steel double-wall hollow composite K-shaped member and a construction method thereof, so as to solve the problem that the existing FRP-concrete-steel double-wall hollow composite members are mainly manufactured by fiber winding molding technology. Compared with simple straight pipes, the technology for manufacturing node pipes or special-shaped pipes such as tees is not mature, and FRP nodes are generally connected by using fiber cloth impregnated with room-temperature curing thermosetting resin. This method has a long curing time, generally requiring more than 24 hours to fully cure, and complicated operation.

[0005] To achieve the above objectives, the technical solution adopted in the first aspect of the embodiment of the present application is:

[0006] A method for constructing an FRP-concrete-steel double-wall hollow composite K-shaped member, the method comprising:

[0007] Providing an FRP outer main pipe and pre-processing the FRP outer main pipe to obtain an FRP outer main pipe patch and an FRP outer main pipe body having an operation hole on its outer side; wherein the FRP outer main pipe patch is obtained by opening two through holes in the operation area patch that complement the operation hole;

[0008] Providing a steel inner main pipe, inserting the steel inner main pipe into the FRP outer main pipe body, and fixing the steel inner main pipe in the FRP outer main pipe body;

[0009] Provide two steel inner branch pipes, pass one end of each of the two steel inner branch pipes through the operation hole and connect to the steel inner main pipe; wherein a K-shaped steel pipe is formed between the two steel inner branch pipes and the steel inner main pipe;

[0010] Two FRP outer branch pipes are provided. The two FRP outer branch pipes are respectively sleeved outside the corresponding steel inner branch pipes, and pass through the outlet holes corresponding to the operation holes to be sealed and spliced ​​with the FRP outer main pipe patch and the FRP outer main pipe body. A splicing connection line is formed between the two FRP outer branch pipes, the FRP outer main pipe patch, and the FRP outer main pipe body, forming a K-shaped FRP pipe.

[0011] Surface treatment is performed on the K-shaped FRP tube at the splicing connection line, and FRP prepreg tape is bonded thereto, and after curing, a template for forming an FRP-concrete-steel double-wall hollow composite K-shaped member is obtained;

[0012] Concrete is poured into the cavity between the K-shaped FRP tube and the K-shaped steel tube in the template to obtain an FRP-concrete-steel double-wall hollow composite K-shaped component.

[0013] According to the above-described method for constructing a FRP-concrete-steel double-wall hollow composite K-shaped member, the steps of providing an FRP outer main pipe and pre-treating the FRP outer main pipe to obtain an FRP outer main pipe patch and an FRP outer main pipe body with an operation hole formed on the outer side thereof specifically include:

[0014] Provide an FRP outer main pipe, and open an operation hole on the outer side of the FRP outer main pipe to obtain the FRP outer main pipe body and the operation area patch;

[0015] Two through holes are opened on the operation area patch to obtain the FRP outer main pipe patch, wherein the through holes are set according to the intersection line between the outer wall of the corresponding FRP outer branch pipe and the surface of the FRP outer main pipe body.

[0016] According to the above-described method for constructing an FRP-concrete-steel double-walled hollow composite K-shaped member, during the steps of providing an inner steel main pipe, inserting the inner steel main pipe into the outer FRP main pipe body, and preliminarily securing the inner steel main pipe within the outer FRP main pipe body, the axis of the outer FRP main pipe body and the axis of the inner steel main pipe are parallel to or coincide with each other, and a first cavity is formed between the outer FRP main pipe body and the inner steel main pipe, the first cavity being used to accommodate concrete.

[0017] According to the above-described method for constructing an FRP-concrete-steel double-wall hollow composite K-shaped member, in the steps of providing two FRP outer branch pipes, respectively sleeved onto the outside of corresponding steel inner branch pipes, and passing through the exit holes corresponding to the operation holes to be spliced ​​with the FRP outer main pipe patch and the FRP outer main pipe body, the axis of the FRP outer branch pipe and the axis of the corresponding steel inner branch pipe are parallel to or coincide with each other, a second cavity is formed between the FRP outer branch pipe and the corresponding steel inner branch pipe, and the second cavity is connected to the first cavity.

[0018] According to the above-described method for constructing an FRP-concrete-steel double-wall hollow composite K-shaped member, the steps of performing surface treatment on the K-shaped FRP tube at the location of the splicing connection line, adhering the FRP prepreg tape, and curing the tube to obtain a template for forming the FRP-concrete-steel double-wall hollow composite K-shaped member specifically include:

[0019] The surface of the K-shaped FRP tube at the splicing connection line is sanded, decontaminated with acetone, and pre-treated with resin glue or primer, and then the splicing connection line is filled with short fiber reinforced resin to make it smoothly transition to the surface of the K-shaped FRP tube;

[0020] A UV-curable resin FRP prepreg tape is pasted on the position of the splicing connection line that smoothly transitions to the surface of the K-shaped FRP tube, and after curing, a template for forming an FRP-concrete-steel double-wall hollow composite K-shaped component is obtained.

[0021] According to the above-described method for constructing an FRP-concrete-steel double-wall hollow composite K-shaped member, the steps of performing surface treatment on the K-shaped FRP tube at the location of the splicing connection line, adhering the FRP prepreg tape, and curing the tube to obtain a template for forming the FRP-concrete-steel double-wall hollow composite K-shaped member specifically include:

[0022] The surface of the K-shaped FRP tube at the splicing connection line is sanded, decontaminated with acetone, and pre-treated with resin glue or primer, and then the splicing connection line is filled with short fiber reinforced resin to make it smoothly transition to the surface of the K-shaped FRP tube;

[0023] A thermosetting resin FRP prepreg tape is pasted on the position of the splicing connection line that smoothly transitions to the surface of the K-shaped FRP tube, and after curing, a template for forming an FRP-concrete-steel double-wall hollow composite K-shaped component is obtained.

[0024] According to the above-described method for constructing an FRP-concrete-steel double-wall hollow composite K-shaped member, in the step of performing surface treatment on the K-shaped FRP tube at the location of the splicing connection line, adhering an FRP prepreg tape, and curing to obtain a template for forming the FRP-concrete-steel double-wall hollow composite K-shaped member, the FRP prepreg tape comprises linear fibers arranged perpendicular to the splicing connection line, first circumferential fibers perpendicular to the axis of the FRP outer main pipe, and second circumferential fibers perpendicular to the axis of the FRP outer branch pipe, wherein the linear fibers are parallel to the axis of the FRP outer branch pipe;

[0025] Wherein, the stiffness of the UV-curable resin FRP prepreg in the fiber direction is not less than the stiffness of the FRP outer main pipe in the fiber direction;

[0026] The stiffness of the FRP prepreg tape in the fiber direction is not less than the stiffness of the FRP outer branch pipe in the fiber direction.

[0027] The technical solution adopted in the second aspect of the embodiment of the present application is:

[0028] An FRP-concrete-steel double-wall hollow composite K-shaped member is produced by the above-mentioned method for constructing the FRP-concrete-steel double-wall hollow composite K-shaped member. The FRP-concrete-steel double-wall hollow composite K-shaped member comprises:

[0029] The FRP outer main pipe comprises an FRP outer main pipe patch and an FRP outer main pipe body with an operation hole formed on the outer side thereof, wherein the FRP outer main pipe patch is formed by forming two through-holes on an operation area patch complementary to the operation hole;

[0030] A steel inner main pipe, which is fixedly disposed inside the FRP outer main pipe;

[0031] Two steel inner branch pipes, one end of each of which passes through the operation hole and is connected to the steel inner main pipe, wherein a K-shaped steel pipe is formed between the two steel inner branch pipes and the steel inner main pipe;

[0032] Two FRP outer branch pipes are respectively sleeved outside the corresponding steel inner branch pipes and pass through the outlet holes corresponding to the operation holes to be sealedly connected to the FRP outer main pipe patch and the FRP outer main pipe body, wherein a splicing connection line is provided between the two FRP outer branch pipes, the FRP outer main pipe patch and the FRP outer main pipe body, thereby forming a K-shaped FRP pipe;

[0033] An FRP prepreg tape is provided on the K-shaped FRP tube at the splicing connection line;

[0034] Concrete is arranged in the cavity between the K-shaped FRP pipe and the K-shaped steel pipe.

[0035] According to the above-described FRP-concrete-steel double-wall hollow composite K-shaped member, the FRP prepreg tape has linear fibers arranged perpendicular to the splicing connection line, first circumferential fibers perpendicular to the axis of the FRP outer main pipe, and second circumferential fibers perpendicular to the axis of the FRP outer branch pipe. The linear fibers are parallel to the axis of the FRP outer branch pipe.

[0036] According to the above-mentioned FRP-concrete-steel double-wall hollow composite K-shaped member, the axis of the FRP outer main pipe body and the axis of the steel inner main pipe are parallel to or coincide with each other, and a first cavity is formed between the FRP outer main pipe body and the steel inner main pipe, and the first cavity is used to accommodate the concrete;

[0037] The axis of the FRP outer branch pipe is parallel to or coincides with the axis of the corresponding steel inner branch pipe. A second cavity is formed between the FRP outer branch pipe and the corresponding steel inner branch pipe, and the second cavity is connected to the first cavity.

[0038] The FRP-concrete-steel double-wall hollow composite K-shaped member and its construction method provided in this application have at least the following beneficial effects:

[0039] This application provides a method for constructing an FRP-concrete-steel double-wall hollow composite K-shaped member, and manufactures the FRP-concrete-steel double-wall hollow composite K-shaped member using this method. The construction method is simple and easy to manufacture, and the application utilizes a method of bonding an FRP prepreg tape to the K-shaped FRP tube at the splicing connection line. The prepreg tape is an intermediate material used in the production of FRP composite materials. It refers to a semi-finished product obtained by using continuous fibers or fabrics as reinforcements and then immersing the reinforcements in (or passing through) molten resin while the resin matrix is ​​in a molten state. The resin or fiber content is controlled to ensure uniform distribution of the resin impregnated into the reinforcements. The resin in the FRP prepreg tape is pre-impregnated into the fibers. Compared to fiber cloth and room-temperature curing thermosetting resins, which require long curing times, the FRP prepreg tape of this application has stable quality, does not require resin mixing and impregnation, and significantly reduces curing time, significantly shortening the construction workload and construction period of the node. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0041] Figure 1 A flowchart of a method for constructing an FRP-concrete-steel double-wall hollow composite K-shaped member provided in an embodiment of the present application.

[0042] Figure 2 A structural schematic diagram of an FRP-concrete-steel double-wall hollow composite K-shaped member in a construction method of an FRP-concrete-steel double-wall hollow composite K-shaped member provided in an embodiment of the present application, wherein the left side of the figure is set as a cross-sectional view.

[0043] Figure 3 Schematic diagram of cutting the FRP outer main pipe in a method for constructing an FRP-concrete-steel double-wall hollow composite K-shaped member provided in an embodiment of the present application.

[0044] Figure 4 A structural schematic diagram of a method for constructing an FRP-concrete-steel double-wall hollow composite K-shaped member provided in an embodiment of the present application, wherein the left side of the figure is set as a cross-sectional view.

[0045] Figure 5 A structural schematic diagram of a steel inner branch pipe connected to a steel inner main pipe in a method for constructing an FRP-concrete-steel double-wall hollow composite K-shaped member provided in an embodiment of the present application, wherein the left side of the figure is set as a cross-sectional view.

[0046] Figure 6 A structural schematic diagram of splicing an FRP outer branch pipe and an FRP outer main pipe patch with an FRP outer main pipe body in a construction method of an FRP-concrete-steel double-wall hollow composite K-shaped member provided in an embodiment of the present application, wherein the left side of the figure is set as a cross-sectional view.

[0047] Figure 7 This is a structural schematic diagram of the surface treatment of the K-shaped FRP tube at the splicing connection line in the construction method of an FRP-concrete-steel double-wall hollow composite K-shaped component provided in an embodiment of the present application.

[0048] Figure 8 A schematic diagram of the arrangement of the centerline fibers in the K-shaped FRP tube at the splicing connection line in a method for constructing an FRP-concrete-steel double-wall hollow composite K-shaped member provided in an embodiment of the present application.

[0049] Figure 9A schematic diagram of the arrangement of the first circumferential fibers in a K-shaped FRP tube at a splicing connection line in a method for constructing an FRP-concrete-steel double-wall hollow composite K-shaped member provided in an embodiment of the present application.

[0050] Figure 10 A schematic diagram of the arrangement of the second circumferential fibers in a K-shaped FRP tube at a splicing connection line in a method for constructing an FRP-concrete-steel double-wall hollow composite K-shaped member provided in an embodiment of the present application.

[0051] Among them, the reference numerals in the figures are:

[0052] 1. FRP outer main pipe; 11. FRP outer main pipe body; 12. FRP outer main pipe patch; 13. Operation hole; 14. Through hole; 15. Splicing connection line; 2. Steel inner main pipe; 3. Steel inner branch pipe; 4. FRP outer branch pipe; 5. FRP prepreg tape; 51. Linear fiber; 52. First hoop fiber; 53. Second hoop fiber; 6. Short fiber reinforced resin; 7. Concrete. DETAILED DESCRIPTION

[0053] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0054] It should be noted that when a component is referred to as being "fixed on" or "disposed on" another component, it may be located directly or indirectly on the other component. When a component is referred to as being "connected to" another component, it may be directly or indirectly connected to the other component. The directions or positions indicated by the terms "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are based on the directions or positions shown in the accompanying drawings and are only for the convenience of description and cannot be understood as limitations on this technical solution. The terms "first" and "second" are only used for the purpose of convenience of description and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features. "Multiple" means two or more, unless otherwise clearly and specifically defined.

[0055] The FRP-concrete-steel double-wall hollow composite member, proposed by Professor Jin-Guang Teng of the Hong Kong Polytechnic University, is a new type of composite member consisting of an FRP outer tube, a steel inner tube, and concrete filling between them. In this new composite member, the concrete filling is constrained by both the FRP outer tube and the steel inner tube, resulting in higher compressive strength, better deformation capacity, and greater ductility than unconstrained concrete. The steel tube, constrained by both the outer concrete and the FRP tube, effectively avoids outward buckling, fully utilizing its strength. It can also serve as a formwork for pouring concrete, simplifying the construction process and saving formwork costs. In addition to providing shear resistance, the FRP outer tube also constrains the concrete and steel tube, improving the latter's mechanical properties. It also protects the steel inner tube and concrete from corrosive environments, eliminating subsequent maintenance costs. Because FRP-concrete-steel double-wall hollow composite components have the above-mentioned advantages, and because of their hollow characteristics, they can reduce the deadweight of the structure. They are particularly suitable for application in spatial structures, marine bridges and platforms, etc., and are conducive to the construction of engineering structures with higher bearing capacity, better seismic performance and greater durability, and have important engineering promotion value.

[0056] Currently, FRP-concrete-steel double-wall hollow composite components are mainly manufactured using fiber winding molding technology. Compared with simple straight pipes, the technology for making node pipes or special-shaped pipes such as tees is not mature. In addition, FRP nodes are generally connected using fiber cloth impregnated with room-temperature curing thermosetting resin. This method has a long curing time, generally requiring more than 24 hours to fully cure, and the operation is complicated. In addition, the resin impregnation quality is difficult to control, which limits its large-scale application in engineering structures.

[0057] To this end, the first aspect of the present application provides a method for constructing an FRP-concrete-steel double-wall hollow composite K-shaped member, which includes providing an FRP outer main pipe and pre-treating the FRP outer main pipe to obtain an FRP outer main pipe patch and an FRP outer main pipe body with an operation hole on the outer side; wherein the FRP outer main pipe patch is obtained by opening two through holes on an operation area patch complementary to the operation hole; providing a steel inner main pipe, inserting the steel inner main pipe into the FRP outer main pipe body, and fixing the steel inner main pipe in the FRP outer main pipe body; providing two steel inner branch pipes, passing one end of the two steel inner branch pipes through the operation hole respectively, and connecting them to the steel inner main pipe; wherein, the two steel inner branch pipes are connected to the steel inner main pipe. A K-shaped steel pipe is formed; two FRP outer branch pipes are provided, the two FRP outer branch pipes are respectively sleeved on the outside of the corresponding steel inner branch pipes, and the two FRP outer branch pipes are passed through the outlet holes corresponding to the operation holes to be sealed and spliced ​​with the FRP outer main pipe patch and the FRP outer main pipe body; wherein a splicing connection line is provided between the two FRP outer main pipe patches and the FRP outer main pipe body, thereby forming a K-shaped FRP pipe; the K-shaped FRP pipe is surface treated at the position of the splicing connection line, and an FRP prepreg tape is bonded thereto, and after curing, a template for forming an FRP-concrete-steel double-wall hollow composite K-shaped component is obtained; concrete is poured into the cavity between the K-shaped FRP pipe and the K-shaped steel pipe in the template to obtain an FRP-concrete-steel double-wall hollow composite K-shaped component.

[0058] This embodiment uses the above-described method to fabricate a double-walled hollow FRP-concrete-steel composite K-shaped member. This construction method is simple and easy to manufacture. In this embodiment, FRP prepreg tape is bonded to the K-shaped FRP tube at the splicing connection line. Prepreg tape is an intermediate material used in the production of FRP composite materials. It refers to a semi-finished product obtained by impregnating (or passing) the reinforcement into (or through) a molten resin matrix while the resin matrix is ​​molten, using continuous fibers or fabric as reinforcement. The resin or fiber content is controlled to ensure uniform distribution of the impregnated resin. The resin in the FRP prepreg tape is pre-impregnated into the fibers. Compared to fiber cloth and room-temperature curing thermosetting resins, which require long curing times, the FRP prepreg tape in this embodiment has stable quality and requires no resin mixing or impregnation. This significantly reduces curing time, significantly shortening the construction workload and duration of the node.

[0059] See Figure 1 、 Figure 2 and Figure 3 In one embodiment, regarding the construction method of the FRP-concrete-steel double-wall hollow composite K-shaped member, the construction method specifically includes:

[0060] S10, providing an FRP outer main pipe and pre-processing the FRP outer main pipe to obtain an FRP outer main pipe patch and an FRP outer main pipe body having an operation hole opened on the outer side thereof; wherein the FRP outer main pipe patch is obtained by opening two through holes on the operation area patch complementary to the operation hole.

[0061] Specifically, the FRP outer main pipe 1 is pre-processed as follows: an operation hole 13 is opened (cut) on the outer side surface of the FRP outer main pipe 1 to obtain the FRP outer main pipe body 11 and an operation area patch (not shown in the figure), wherein the operation area patch is what is left after the operation hole 13 is cut out of the FRP outer main pipe 1, that is, the FRP outer main pipe body 11 and the operation area patch are combined to form the FRP outer main pipe 1; two through-holes 14 are opened on the operation area patch to obtain the FRP outer main pipe patch 12, wherein the through-holes 14 are set according to the intersection line of the outer wall of the corresponding FRP outer branch pipe 4 and the surface of the FRP outer main pipe body 11, to ensure that the FRP outer branch pipe 4 can be overlapped on the FRP outer main pipe body 11.

[0062] S20, providing a steel inner main pipe, inserting the steel inner main pipe into the FRP outer main pipe body, and fixing the steel inner main pipe in the FRP outer main pipe body.

[0063] For details, see Figure 4 The interior of the FRP outer main body 11 is a hollow cavity, and openings are formed at both ends of the FRP outer main body 11, which are connected to the cavity inside the FRP outer main body 11. The steel inner main body 2 is inserted into the FRP outer main body 11 through the opening at one end of the FRP outer main body 11 and temporarily fixed to the FRP outer main body 11. The temporary fixing of the steel inner main body 2 to the FRP outer main body 11 facilitates the fixing of the two steel inner branch pipes 3 to the steel inner main body 2.

[0064] Optional, see Figure 5 and Figure 6 In one embodiment, during the steps of providing a steel inner main pipe 2, inserting the steel inner main pipe 2 into the FRP outer main pipe body 11, and fixing the steel inner main pipe in the FRP outer main pipe body 11, the axis of the FRP outer main pipe body 11 and the axis of the steel inner main pipe 2 are parallel to or coincide with each other, and a first cavity is formed between the FRP outer main pipe body 11 and the steel inner main pipe 2, and the first cavity is used to accommodate the concrete 7.

[0065] S30, providing two steel inner branch pipes, passing one end of each of the two steel inner branch pipes through the operation holes, and connecting them to the steel inner main pipe; wherein, a K-shaped steel pipe is formed between the two steel inner branch pipes and the steel inner main pipe.

[0066] For details, see Figure 6 and Figure 7Insert one end of each of the two inner steel branch pipes 3 through the access holes 13 and securely connect them to the inner steel main pipe 2 via welding or one-way bolts. Separate the inner steel main pipe 2, which is temporarily secured within the outer FRP main pipe body 11. The final position of the inner steel main pipe 2 and the outer FRP main pipe body 11 is determined and re-secured. The two inner steel branch pipes 3 are symmetrically positioned along the centerline between them, forming a K-shaped steel pipe with the inner steel main pipe 2.

[0067] S40, provide two FRP outer branch pipes, respectively sleeve the two FRP outer branch pipes on the outside of the corresponding steel inner branch pipes, and pass through the outlet holes corresponding to the operation holes to be sealed and spliced ​​with the FRP outer main pipe patch and the FRP outer main pipe body; wherein, there is a splicing connection line between the two FRP outer branch pipes, the FRP outer main pipe patch and the FRP outer main pipe body, and a K-shaped FRP pipe is formed.

[0068] For details, see Figure 7 After the two FRP outer branch pipes 4 are sleeved on the corresponding steel inner branch pipes 3, the two FRP outer branch pipes 4, the FRP outer main pipe patch 12 and the FRP outer main pipe body 11 are sealed and bonded together by adhesive to prevent the FRP prepreg tape 5 from leaking into the FRP outer main pipe body 11 when bonding the FRP prepreg tape 5. After the two FRP outer branch pipes 4, the FRP outer main pipe patch 12 and the FRP outer main pipe body 11 are sealed and bonded together, a K-shaped FRP pipe is formed. In addition, a splicing connection line 15 is also formed between the two FRP outer branch pipes 4, the FRP outer main pipe patch 12 and the FRP outer main pipe body 11 due to the sealed splicing.

[0069] The adhesive may be a structural adhesive, and the resin type of the adhesive is the same as the resin type of the FRP outer main pipe 1 .

[0070] Optional, see Figure 6 and Figure 7 In one embodiment, in the steps of providing two FRP outer branch pipes 4, respectively sleeved outside the corresponding steel inner branch pipes 3, and passing through the outlet holes 14 corresponding to the operation holes 13 to be spliced ​​with the FRP outer main pipe patch 12 and the FRP outer main pipe body 11, the axes of the FRP outer branch pipes 4 and the axes of the corresponding steel inner branch pipes 3 are parallel to or coincide with each other, and a second cavity is formed between the FRP outer branch pipes 4 and the corresponding steel inner branch pipes 3. The second cavity is connected to the first cavity and is used to form a cavity between the K-shaped FRP pipe and the K-shaped steel pipe in the formwork of the FRP-concrete-steel double-wall hollow composite K-shaped member. The cavity is used to pour (fill) concrete 7 to solidify and form the FRP-concrete-steel double-wall hollow composite K-shaped member.

[0071] S50, performing surface treatment on the K-shaped FRP tube at the splicing connection line, and bonding the FRP prepreg tape, and obtaining a template for forming an FRP-concrete-steel double-wall hollow composite K-shaped member after curing.

[0072] For details, see Figure 2 The surface treatment includes sanding the surface of the K-shaped FRP tube at the splicing connection line 15, cleaning with acetone, and pre-treating with resin glue or primer, and then filling the splicing connection line 15 with short fiber reinforced resin 6 to make it smoothly transition to the surface of the K-shaped FRP tube, so that the FRP prepreg tape 5 can be better adhered to the splicing connection line 15 of the K-shaped FRP tube.

[0073] After surface treatment of the K-shaped FRP tube at the splicing connection line 15, it is necessary to adhere a thermosetting resin FRP prepreg tape or a UV-curing resin FRP prepreg tape to the K-shaped FRP tube at the splicing connection line 15 until the thermosetting resin FRP prepreg tape or the UV-curing resin FRP prepreg tape is cured, thereby obtaining a template for forming an FRP-concrete-steel double-wall hollow composite K-shaped member.

[0074] It is worth noting that because the K-shaped FRP tube is located at the splicing connection line 15, which is an uneven turning area, if the thermosetting resin FRP prepreg tape or the UV-curing resin FRP prepreg tape is directly pasted at this position, the thermosetting resin FRP prepreg tape or the UV-curing resin FRP prepreg tape is likely to wrinkle or become hollow at the splicing connection line 15. At this time, by using short fiber reinforced resin 6, a transition area can be filled, allowing the UV-curing resin FRP prepreg tape to be better adhered to the FRP tube.

[0075] The short fiber reinforced resin 6 comprises short fibers and a thermosetting resin that cures at room temperature. The resin type of the short fiber reinforced resin 6 is the same as the resin type of the K-shaped FRP tube.

[0076] Conventionally, the curing time of the fiber cloth impregnated with room-temperature-curing thermosetting resin applied externally is more than 24 hours under normal temperature and pressure, while the curing time of the thermosetting resin FRP prepreg used in this embodiment is only 2 hours under hot pressure, and the curing time of the UV-curing resin FRP prepreg used is only 15 minutes under specified conditions. It can be foreseen that the curing speed of the thermosetting resin FRP prepreg or UV-curing resin FRP prepreg in this embodiment has a significant advantage over the curing speed of the fiber cloth impregnated with room-temperature-curing thermosetting resin applied externally, and can ensure the reliable connection of the formwork of the resulting FRP-concrete-steel double-wall hollow composite K-shaped component.

[0077] Optionally, in one embodiment, the specific steps of adhering the thermosetting resin FRP prepreg tape to the position of the splicing connection line 15 on the surface of the K-shaped FRP tube are as follows: laying a thermosetting prepreg tape layer at the position of the splicing connection line 15 on the surface of the K-shaped FRP tube, performing roller degassing on the thermosetting prepreg tape layer, laying a filter membrane and a vacuum bag, and sealing, vacuuming and heating and curing are performed, and after curing, a template for forming an FRP-concrete-steel double-wall hollow composite K-shaped component is obtained.

[0078] Optionally, in one embodiment, the specific steps of adhering the UV-curing resin FRP prepreg to the position of the splicing connection line 15 on the surface of the K-shaped FRP tube are as follows: applying a UV-curing resin primer to the position of the splicing connection line 15 on the surface of the K-shaped FRP tube, laying the UV-curing resin FRP prepreg at the position of the UV-curing resin primer, performing roller degassing and UV-light irradiation treatment on the UV-curing resin FRP prepreg, and obtaining a template for forming an FRP-concrete-steel double-wall hollow composite K-shaped component after curing.

[0079] S60, pouring concrete into the cavity between the K-shaped FRP tube and the K-shaped steel tube in the template to obtain an FRP-concrete-steel double-wall hollow composite K-shaped member.

[0080] Specifically, a first cavity is formed between the FRP outer main pipe body 11 and the steel inner main pipe 2, a second cavity is formed between the FRP outer branch pipe 4 and the corresponding steel inner branch pipe 3, the second cavity is connected to the first cavity, and the cavity between the K-shaped FRP pipe and the K-shaped steel pipe is a connected first cavity and a second cavity. The FRP-concrete-steel double-wall hollow composite K-shaped member is composed of a K-shaped FRP pipe, a K-shaped steel pipe and a concrete 7 between the two. The concrete 7 in the FRP-concrete-steel double-wall hollow composite K-shaped member is constrained by the K-shaped FRP pipe and the K-shaped steel pipe, and has a higher compressive strength than the unconstrained concrete 7. Strength, better deformation capacity and better ductility; since the K-shaped steel pipe is constrained by the concrete 7 and the K-shaped FRP pipe on the outside at the same time, it can effectively avoid outward buckling and make full use of its strength. It can also be used together with the K-shaped FRP pipe as a formwork for pouring concrete 7, simplifying the construction process and saving formwork costs; in addition to providing shear resistance, the K-shaped FRP pipe also provides constraints on the concrete 7 and the K-shaped steel pipe, improving the latter's stress performance, and at the same time protecting the K-shaped steel pipe and concrete 7 from erosion by the corrosive environment, eliminating the cost of subsequent maintenance. The FRP-concrete-steel double-wall hollow composite K-shaped component structure of this embodiment has a stable connection.

[0081] Optional, see Figure 8 、 Figure 9 and Figure 10In one embodiment, the FRP prepreg tape 5 has linear fibers 51 arranged perpendicular to the splicing connection line 15, first circumferential fibers 52 perpendicular to the axis of the FRP outer main pipe 1, and second circumferential fibers 53 perpendicular to the axis of the FRP outer branch pipe. The linear fibers 51 are parallel to the axis of the FRP outer branch pipe.

[0082] Optionally, in one embodiment, the stiffness of the FRP prepreg tape 5 in the fiber direction is not less than the stiffness of the FRP outer main pipe 1 in the fiber direction, and the stiffness of the FRP prepreg tape 5 in the fiber direction is not less than the stiffness of the FRP outer branch pipe in the fiber direction.

[0083] The FRP-concrete-steel double-wall hollow composite K-shaped member provided in the second aspect of the embodiment of the present application is produced by the construction method of the FRP-concrete-steel double-wall hollow composite K-shaped member as described above, see Figure 5 The FRP-concrete-steel double-wall hollow composite K-shaped member includes an FRP outer main pipe, a steel inner main pipe, two steel inner branch pipes, two FRP outer branch pipes, FRP prepreg tape, and concrete. The FRP outer main pipe includes an FRP outer main pipe patch and an FRP outer main pipe body with an operation hole opened on the outer side. The FRP outer main pipe patch is obtained by opening two through holes on the operation area patch that complements the operation hole. The steel inner main pipe is fixedly installed in the FRP outer main pipe. One end of the two steel inner branch pipes passes through the operation hole and is connected to the steel inner main pipe. A K-shaped steel pipe is formed between the two steel inner branch pipes and the steel inner main pipe, and the two FRP outer branch pipes are respectively sleeved on the outside of the corresponding steel inner branch pipes, and pass through the outlet holes corresponding to the operation holes to be sealed and connected with the FRP outer main pipe patch and the FRP outer main pipe body. A splicing connection line is provided between the two FRP outer branch pipes, the FRP outer main pipe patch and the FRP outer main pipe body to form a K-shaped FRP pipe, the FRP prepreg tape is arranged on the K-shaped FRP pipe at the splicing connection line, and concrete is arranged in the cavity between the K-shaped FRP pipe and the K-shaped steel pipe.

[0084] Optionally, in one embodiment, the FRP prepreg tape may be configured as a thermosetting resin FRP prepreg tape and an ultraviolet light curing resin FRP prepreg tape.

[0085] Optionally, in one embodiment, the FRP prepreg tape has linear fibers arranged perpendicular to the splicing connection line, first annular fibers perpendicular to the axis of the FRP outer main pipe, and second annular fibers perpendicular to the axis of the FRP outer branch pipe, and the linear fibers are parallel to the axis of the FRP outer branch pipe.

[0086] Optionally, in one embodiment, the axis of the FRP outer main pipe body is parallel to or coincides with the axis of the steel inner main pipe, and a first cavity is formed between the FRP outer main pipe body and the steel inner main pipe, the first cavity is used to accommodate the concrete, the axis of the FRP outer branch pipe is parallel to or coincides with the axis of the corresponding steel inner branch pipe, a second cavity is formed between the FRP outer branch pipe and the corresponding steel inner branch pipe, and the second cavity is connected to the first cavity.

[0087] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A method for constructing a double-walled hollow composite K-shaped member made of FRP-concrete-steel, characterized in that: The construction method comprises: Providing an FRP outer main pipe and pre-processing the FRP outer main pipe to obtain an FRP outer main pipe patch and an FRP outer main pipe body having an operation hole on its outer side; wherein the FRP outer main pipe patch is obtained by opening two through holes in the operation area patch that complement the operation hole; Providing a steel inner main pipe, inserting the steel inner main pipe into the FRP outer main pipe body, and fixing the steel inner main pipe in the FRP outer main pipe body; Provide two steel inner branch pipes, pass one end of each of the two steel inner branch pipes through the operation hole and connect to the steel inner main pipe; wherein a K-shaped steel pipe is formed between the two steel inner branch pipes and the steel inner main pipe; Two FRP outer branch pipes are provided. The two FRP outer branch pipes are respectively sleeved outside the corresponding steel inner branch pipes, and pass through the outlet holes corresponding to the operation holes to be sealed and spliced ​​with the FRP outer main pipe patch and the FRP outer main pipe body. A splicing connection line is formed between the two FRP outer branch pipes, the FRP outer main pipe patch, and the FRP outer main pipe body, forming a K-shaped FRP pipe. Surface treatment is performed on the K-shaped FRP tube at the splicing connection line, and FRP prepreg tape is bonded thereto, and after curing, a template for forming an FRP-concrete-steel double-wall hollow composite K-shaped member is obtained; Concrete is poured into the cavity between the K-shaped FRP tube and the K-shaped steel tube in the template to obtain an FRP-concrete-steel double-wall hollow composite K-shaped component.

2. The method for constructing a FRP-concrete-steel double-wall hollow composite K-shaped member according to claim 1, wherein: The steps of providing an FRP outer main pipe and pre-treating the FRP outer main pipe to obtain an FRP outer main pipe patch and an FRP outer main pipe body with an operation hole opened on the outer side specifically include: Provide an FRP outer main pipe, and open an operation hole on the outer side of the FRP outer main pipe to obtain the FRP outer main pipe body and the operation area patch; Two through holes are opened on the operation area patch to obtain an FRP outer main pipe patch, wherein the through holes are set according to the intersection line between the outer wall of the corresponding FRP outer branch pipe and the surface of the FRP outer main pipe body.

3. The method for constructing a FRP-concrete-steel double-wall hollow composite K-shaped member according to claim 1, wherein: In the steps of providing a steel inner main pipe, inserting the steel inner main pipe into the FRP outer main pipe body, and preliminarily fixing the steel inner main pipe into the FRP outer main pipe body, the axis of the FRP outer main pipe body and the axis of the steel inner main pipe are parallel to or coincide with each other, and a first cavity is formed between the FRP outer main pipe body and the steel inner main pipe, and the first cavity is used to accommodate the concrete.

4. The method for constructing a FRP-concrete-steel double-wall hollow composite K-shaped member according to claim 3, wherein: In the step of providing two FRP outer branch pipes, respectively sleeved on the outside of the corresponding steel inner branch pipes, and passing through the outlet holes corresponding to the operation holes to be spliced ​​with the FRP outer main pipe patch and the FRP outer main pipe body, the axis of the FRP outer branch pipe and the axis of the corresponding steel inner branch pipe are parallel to or coincide with each other, a second cavity is formed between the FRP outer branch pipe and the corresponding steel inner branch pipe, and the second cavity is connected to the first cavity.

5. The method for constructing a FRP-concrete-steel double-wall hollow composite K-shaped member according to claim 1, wherein: The steps of performing surface treatment on the K-shaped FRP tube at the location of the splicing connection line, bonding the FRP prepreg tape, and curing the tube to obtain a template for forming an FRP-concrete-steel double-wall hollow composite K-shaped member specifically include: The surface of the K-shaped FRP tube at the splicing connection line is sanded, decontaminated with acetone, and pre-treated with resin glue or primer, and then the splicing connection line is filled with short fiber reinforced resin to make it smoothly transition to the surface of the K-shaped FRP tube; A UV-curable resin FRP prepreg tape is pasted on the position of the splicing connection line that smoothly transitions to the surface of the K-shaped FRP tube, and after curing, a template for forming an FRP-concrete-steel double-wall hollow composite K-shaped component is obtained.

6. The method for constructing a FRP-concrete-steel double-wall hollow composite K-shaped member according to claim 1, wherein: The steps of performing surface treatment on the K-shaped FRP tube at the location of the splicing connection line, bonding the FRP prepreg tape, and curing the tube to obtain a template for forming an FRP-concrete-steel double-wall hollow composite K-shaped member specifically include: The surface of the K-shaped FRP tube at the splicing connection line is sanded, decontaminated with acetone, and pre-treated with resin glue or primer, and then the splicing connection line is filled with short fiber reinforced resin to make it smoothly transition to the surface of the K-shaped FRP tube; A thermosetting resin FRP prepreg tape is pasted on the position of the splicing connection line that smoothly transitions to the surface of the K-shaped FRP tube, and after curing, a template for forming an FRP-concrete-steel double-wall hollow composite K-shaped component is obtained.

7. The method for constructing a FRP-concrete-steel double-wall hollow composite K-shaped member according to claim 1, wherein: In the step of performing surface treatment on the K-shaped FRP tube at the location of the splicing connection line, adhering an FRP prepreg tape, and curing to obtain a template for forming an FRP-concrete-steel double-wall hollow composite K-shaped member, the FRP prepreg tape comprises linear fibers arranged perpendicular to the splicing connection line, first circumferential fibers perpendicular to the axis of the FRP outer main tube, and second circumferential fibers perpendicular to the axis of the FRP outer branch tube, wherein the linear fibers are parallel to the axis of the FRP outer branch tube; wherein the stiffness of the FRP prepreg tape in the fiber direction is not less than the stiffness of the FRP outer main pipe in the fiber direction; The stiffness of the FRP prepreg tape in the fiber direction is not less than the stiffness of the FRP outer branch pipe in the fiber direction.

8. An FRP-concrete-steel double-wall hollow composite K-shaped member, characterized in that: The K-shaped FRP-concrete-steel double-wall hollow composite member is produced by the construction method of any one of claims 1 to 7, wherein the K-shaped FRP-concrete-steel double-wall hollow composite member comprises: The FRP outer main pipe comprises an FRP outer main pipe patch and an FRP outer main pipe body with an operation hole formed on the outer side thereof, wherein the FRP outer main pipe patch is formed by forming two through-holes on an operation area patch complementary to the operation hole; A steel inner main pipe, which is fixedly disposed inside the FRP outer main pipe; Two steel inner branch pipes, one end of each of which passes through the operation hole and is connected to the steel inner main pipe, wherein a K-shaped steel pipe is formed between the two steel inner branch pipes and the steel inner main pipe; Two FRP outer branch pipes are respectively sleeved outside the corresponding steel inner branch pipes and pass through the outlet holes corresponding to the operation holes to be sealedly connected to the FRP outer main pipe patch and the FRP outer main pipe body, wherein a splicing connection line is provided between the two FRP outer branch pipes, the FRP outer main pipe patch and the FRP outer main pipe body, thereby forming a K-shaped FRP pipe; An FRP prepreg tape is provided on the K-shaped FRP tube at the splicing connection line; Concrete is arranged in the cavity between the K-shaped FRP pipe and the K-shaped steel pipe.

9. The FRP-concrete-steel double-wall hollow composite K-shaped member according to claim 8, characterized in that: The FRP prepreg tape has linear fibers arranged perpendicular to the splicing connection line, first circumferential fibers perpendicular to the axis of the FRP outer main pipe, and second circumferential fibers perpendicular to the axis of the FRP outer branch pipe. The linear fibers are parallel to the axis of the FRP outer branch pipe.

10. The FRP-concrete-steel double-wall hollow composite K-shaped member according to claim 8, characterized in that: The axis of the FRP outer main pipe body is parallel to or coincides with the axis of the steel inner main pipe, and a first cavity is formed between the FRP outer main pipe body and the steel inner main pipe, wherein the first cavity is used to accommodate the concrete; The axis of the FRP outer branch pipe is parallel to or coincides with the axis of the corresponding steel inner branch pipe. A second cavity is formed between the FRP outer branch pipe and the corresponding steel inner branch pipe, and the second cavity is connected to the first cavity.

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