A FRP double-segment concrete arch structure and its construction method

Abstract

The present invention relates to the technical field of arch structures, and in particular to an FRP double-segment concrete arch structure and a construction method thereof. The arch structure comprises an FRP double segment, wherein the FRP double segment comprises an FRP outer segment and an FRP inner segment, wherein the FRP outer segment and the FRP inner segment are arranged in parallel, and the FRP double segment is in an arch shape; a plurality of FRP stirrups, wherein each FRP stirrup is arranged between the FRP double segments; and concrete, wherein the concrete is filled between the FRP double segments. The present invention has the advantages of simple structure, light weight, high strength, and corrosion resistance. In addition to being a tensile member of the structure, the FRP double segment can also be used as a lightweight formwork for concrete pouring, which is convenient for transportation and construction, simplifies the construction process, and improves construction efficiency. In addition to being a shear-resistant member, the FRP stirrup can not only improve the bonding performance of the FRP double segment and concrete, effectively ensure the coordinated operation of the FRP double segment and concrete, but also be an important positioning member of the FRP double segment.

Description

Technical Field

[0001] The invention relates to the technical field of arch structures, and in particular to an FRP double-tube segment concrete arch structure and a construction method thereof. Background Art

[0002] The arch structure is a structure with a long history, which has the advantages of excellent durability and low maintenance and upkeep costs. All over the world, many arch structures with hundreds or even thousands of years of history, represented by arch bridges, are still well preserved or even in service.

[0003] Most of the ancient arch structures were stone arches, which were mainly made of stone and mortar. The durability of its building materials was excellent, which guaranteed the service life of its structure. With the rapid economic development and technological advancement, people's expectations and requirements for civil engineering are getting higher and higher, and the ancient natural building materials cannot meet the needs of the project. In order to overcome the shortcomings of low strength of stone arch structure materials (insufficient compression and tensile properties), long construction period, and high labor costs, a new generation of arch structures such as reinforced concrete arch structures, steel arch structures, and steel tube concrete arch structures came into being. These structural forms can realize large-span arch structures with rapid construction, solving some engineering problems.

[0004] However, the durability problem that follows is the fatal shortcoming of reinforced concrete and steel structures. Many reinforced concrete structures built in the 1960s and 1970s, although designed to have a service life of 100 years, show obvious structural degradation after 20-30 years of service and require high maintenance costs or reconstruction costs. The reason is that the internal steel bars corrode and expand, causing concrete cracks and degradation of the mechanical properties of the structure.

[0005] Therefore, the prior art still needs to be improved and developed. Summary of the invention

[0006] In view of the above-mentioned deficiencies in the prior art, an object of the present invention is to provide an FRP double-segment concrete arch structure and a construction method thereof, aiming to solve the problem of internal steel bar corrosion in the existing reinforced concrete arch structure.

[0007] The technical solution of the present invention is as follows:

[0008] A first aspect of the present invention provides an FRP double-segment concrete arch structure, comprising:

[0009] FRP double tube segments, the FRP double tube segments include FRP outer tube segments and FRP inner tube segments, the FRP outer tube segments and the FRP inner tube segments are arranged in parallel, and the FRP double tube segments are in an arch shape;

[0010] A plurality of FRP stirrups, each of which is arranged between the FRP double tube segments;

[0011] Concrete is filled between the FRP double-tube segments.

[0012] Optionally, the inner wall of the FRP outer segment and the outer wall of the FRP inner segment are both sandblasted.

[0013] Optionally, each FRP stirrup is arranged between the FRP double segments by gluing, the height of each FRP stirrup is slightly smaller than the distance from the inner wall of the FRP outer segment to the outer wall of the FRP inner segment, and glue is applied between the FRP stirrup and the FRP double segment.

[0014] Optionally, for situations where the structural shear resistance requirement is not large, a plurality of FRP stirrups are uniformly arranged longitudinally along the FRP double tube segment, and a plurality of FRP stirrups are uniformly arranged circumferentially along the FRP double tube segment; for areas where shear resistance requirements exist, a plurality of FRP stirrups can be densely arranged or stirrups with larger diameters and stronger stirrups can be used.

[0015] Optionally, the arch shape includes one of a circular arc shape, a parabola shape, and a catenary shape.

[0016] Optionally, the fiber direction of the FRP outer tube segment forms an angle of plus or minus 60 degrees to 90 degrees with the longitudinal direction, and the fiber direction of the FRP inner tube segment forms an angle of plus or minus 60 degrees to 90 degrees with the longitudinal direction.

[0017] Optionally, the FRP stirrups are circumferential stirrups and / or spiral stirrups, the FRP stirrups are manufactured using a fiber winding process, and the shape of the FRP stirrups includes one of a rectangular, circular, square, and polygonal shape.

[0018] A second aspect of the present invention provides a construction method of the FRP double-segment concrete arch structure of the present invention, comprising the steps of:

[0019] Provide FRP outer segments, FRP inner segments and several FRP stirrups;

[0020] Assembling the FRP outer tube segment, the FRP inner tube segment and a plurality of FRP stirrups by resin bonding to form a FRP skeleton;

[0021] The FRP frame is transported to a construction site, and concrete is poured into the FRP frame at the construction site to obtain an FRP double-segment concrete arch structure.

[0022] Optionally, the FRP outer tube segments are manufactured by the following method: a FRP outer tube is manufactured by a fiber winding process, and the FRP outer tube is cut into required FRP outer tube segments along the tube circumferential direction;

[0023] The FRP inner tube segments are manufactured by the following method: a FRP inner tube is manufactured by a fiber winding process, and the FRP inner tube is cut into required FRP inner tube segments along the tube circumferential direction;

[0024] The FRP stirrups are manufactured by a fiber winding process.

[0025] Optionally, the inner wall of the FRP outer segment, the outer wall of the FRP inner segment and the inner and outer surfaces of the FRP stirrups are sandblasted respectively, and then the sandblasted FRP outer segment, FRP inner segment and FRP stirrups are assembled by resin bonding to form an FRP skeleton;

[0026] A plurality of concrete pouring holes are opened on the FRP outer segments and / or the FRP inner segments of the FRP skeleton for pouring concrete at the construction site.

[0027] Beneficial effects: The FRP double-segment concrete arch structure of the present invention is composed of two layers of FRP segments (i.e., FRP double segments), a plurality of FRP stirrups arranged between the FRP double segments, and concrete filled between the FRP double segments. In addition to being a tensile member of the structure, the FRP double segments can also be used as a lightweight formwork for concrete pouring, which is convenient for transportation and construction, simplifies the construction process, and improves construction efficiency. In addition to being a shear-resistant member, the FRP stirrups can not only improve the bonding performance of the FRP double segments and concrete, effectively ensure the coordinated operation of the FRP double segments and concrete, but also be an important centering member of the FRP double segments. Concrete is used as a compressive member. The FRP double segments, FRP stirrups and concrete have clear division of labor and work in coordination. The arch structure of the present invention has the advantages of simple structure, safety and reliability, light weight, high strength, corrosion resistance, etc. The arch structure can be used as an arched structure and curved member such as an arch bridge, an underground protection structure, a tunnel lining, a curved beam, etc., especially in coastal areas, marine environments, underground environments, etc., and has strong adaptability under extreme corrosion conditions. In addition, due to its excellent corrosion resistance, the arch structure also has good application prospects in seawater and sea sand concrete marine environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram of a FRP double-segment concrete arch structure;

[0029] Figure 2 Another schematic diagram of the FRP double-segment concrete arch structure;

[0030] Figure 3 It is a schematic diagram of the cross section of the FRP skeleton using rectangular stirrups;

[0031] Figure 4 Schematic diagram of the cross section of the FRP skeleton using circular stirrups;

[0032] Figure 5Schematic diagram of the cross section of the FRP skeleton using polygonal stirrups;

[0033] Figure 6 This is a schematic diagram of pasting FRP stirrups on the FRP outer segment in step 2 of the present invention;

[0034] Figure 7 This is a schematic diagram of pasting FRP stirrups on the FRP inner tube segment in step 2 of the present invention;

[0035] Figure 8 It is a schematic diagram of step three of the present invention;

[0036] Fig. 9 It is a schematic diagram of step five of the present invention. DETAILED DESCRIPTION

[0037] The present invention provides a FRP double-tube concrete arch structure and a construction method thereof. To make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0038] In order to solve the problem of structural corrosion, fiber reinforced polymer (FRP) has been favored by relevant practitioners as a new type of building material. Compared with traditional building materials, it has the advantages of light weight, high strength, corrosion resistance, and fatigue resistance. In addition to being used in the field of structural reinforcement, FRP-concrete composite structures are also increasingly valued and promoted. Based on this, the present invention provides a concrete arch structure that uses two layers of FRP segments as upper and lower permanent formwork and structural tension members of the arch to improve construction efficiency and enhance mechanical properties.

[0039] Specifically, an embodiment of the present invention provides a FRP double-tube concrete arch structure, such as Figure 1-Figure 2 As shown, including:

[0040] FRP double tube segments, the FRP double tube segments include an FRP outer tube segment 1 and an FRP inner tube segment 2, the FRP outer tube segment 1 and the FRP inner tube segment 2 are arranged in parallel, and the FRP double tube segment is in an arch shape;

[0041] A plurality of FRP stirrups 3, each of which is arranged between the FRP double tube segments;

[0042] Concrete 4, the concrete 4 is filled between the FRP double tube segments.

[0043] In an embodiment of the present invention, the FRP double-segment concrete arch structure is composed of two layers of FRP segments (i.e., FRP double segments), a plurality of FRP stirrups (several refers to 1, 2, or more than 3) arranged between the FRP double segments, and concrete filled between the FRP double segments. In addition to being a tensile member of the structure, the FRP double segment can also be used as a lightweight formwork for concrete pouring, which is convenient for transportation and construction, simplifies the construction process, and improves construction efficiency. In addition to being a shear member, the FRP stirrups can improve the bonding performance of the FRP double segment and concrete, effectively ensure the coordinated operation of the FRP double segment and concrete, and are also an important centering member of the FRP double segment. Concrete serves as a compressive member. The FRP double segment, FRP stirrups, and concrete have clear division of labor and work in coordination.

[0044] The arch structure of the embodiment of the present invention has the advantages of simple structure, safety and reliability, light weight, high strength, and corrosion resistance. The arch structure can be used as an arch bridge, underground protection structure, tunnel lining, curved beam and other arch structures and curved components, especially in coastal areas, marine environments, underground environments and other extreme corrosion conditions, and has strong adaptability. In addition, due to its excellent corrosion resistance, the arch structure has opened up a new way for the production of concrete using seawater and sea sand as raw materials. These raw materials can be obtained locally in coastal areas, providing economic and environmental advantages with application prospects for the construction of coastal cities and marine infrastructure.

[0045] From a construction perspective, the difficulty in constructing an arch structure is to ensure that its shape meets the design requirements. The traditional reinforced concrete arch structure construction process often requires the construction site to locate the arch structure and make the concrete formwork by building scaffolding and on-site formwork support. However, the arch structure proposed in the embodiment of the present invention locates the relative position of the FRP inner and outer segments by FRP stirrups. The FRP outer segments, FRP stirrups and FRP inner segments with fixed relative positions form a whole (FRP skeleton), which can be used as a permanent formwork for concrete pouring. The formwork does not need to be removed, but serves as a load-bearing member with concrete. Compared with the traditional construction process, the formwork removal operation process is eliminated, which improves the construction efficiency. In addition, FRP materials have the characteristics of light weight and high strength, and their density is only 1 / 4 to 1 / 6 of that of steel. FRP lightweight formwork is suitable for some construction scenes with inconvenient transportation, such as remote mountainous areas and outlying islands, which can effectively reduce the difficulty and cost of transportation. In addition, the excellent corrosion resistance of FRP also meets the requirements of long-term service, reduces the maintenance requirements and maintenance costs of the arch structure, and further reduces the life cycle cost of the arch structure, especially for some remote areas. In addition, compared with beam-type spanning structures, arch-type spanning structures can effectively reduce the bending moment value of the cross section, make full use of the excellent compressive properties of concrete, and improve the efficiency of material use. In remote areas, where the transportation cost of raw materials is high and the local collection technology is immature, the demand for raw materials (such as concrete) can be reduced.

[0046] In one embodiment, the inner wall of the FRP outer segment 1 and the outer wall of the FRP inner segment 2 are both sandblasted. The inner wall of the FRP outer segment refers to the wall of the FRP outer segment close to the FRP inner segment, that is, the surface in contact with concrete; the outer wall of the FRP inner segment refers to the wall of the FRP inner segment close to the FRP outer segment, that is, the surface in contact with concrete.

[0047] The sandblasting process is used to treat the surface in contact with concrete, which can increase the roughness of the contact surface, thereby increasing the friction generated by the relative sliding between the two, and then improving the bonding strength, and enhancing the synergy and deformation coordination ability between the FRP double tube segment and concrete.

[0048] In one embodiment, each FRP stirrup 3 is arranged between the FRP double segments by gluing, and the height of each FRP stirrup 3 is slightly smaller than the distance from the inner wall of the FRP outer segment 1 to the outer wall of the FRP inner segment 2. Glue is applied between the FRP stirrup 3 and the FRP double segment. Figure 1-Figure 2 That is to say, a number of FRP stirrups are pasted between the FRP double segments, and the height of each FRP stirrup is slightly smaller than the distance from the inner wall of the FRP outer segment to the outer wall of the FRP inner segment.

[0049] In the case where the structural shear resistance requirement is not large, a plurality of FRP stirrups 3 are evenly arranged along the longitudinal direction of the FRP double tube segment, and a plurality of FRP stirrups 3 are evenly arranged along the circumferential direction of the FRP double tube segment, such as Figure 1 As shown; for areas where shear resistance is required, several FRP stirrups 3 can be set densely (see Figure 2 ) or use stirrups with larger diameters and stronger stirrup forms, such as spiral stirrups 5, such as Figure 2 The longitudinal direction of the FRP double tube segment refers to the direction perpendicular to the arch plane, and the circumferential direction of the FRP double tube segment refers to the direction along the arch axis.

[0050] The existing FRP-concrete composite structure has the problem of insufficient bonding strength between FRP and concrete. Unlike the existing FRP-concrete composite structure, the FRP stirrups arranged in the arch structure of the embodiment of the present invention can be used as "shear keys" to resist the relative slip between different components, improve the bonding strength between the FRP double tube segment and concrete, and thus improve the collaborative working ability of the arch structure.

[0051] The FRP stirrups can be selected as circumferential stirrups or spiral stirrups 5 as needed. Figure 2 As shown. The FRP stirrups can be manufactured by a fiber winding process to ensure the performance of the stirrups. The shape of the FRP stirrups is not limited to a rectangle, and can also be selected into a circular, square, polygonal or other suitable symmetrical and asymmetrical shapes according to actual needs. Figure 3 is a typical square hoop cross section. Figure 4 is a typical circular hoop cross section, Figure 5 It is a typical polygonal hoop cross section.

[0052] The specific selection of FRP stirrup parameters follows the following principles: First, based on the structural force perspective, it is necessary to perform structural shear design calculations according to the existing FRP reinforced concrete structure design specifications (such as ACI 440.1R or GB 50608). In the dangerous area with large shear force, the diameter and spacing of FRP stirrups are selected according to the calculation to meet the shear bearing capacity requirements of the structure. The arrangement spacing needs to meet the structural requirements, that is, the spacing is generally not greater than half the thickness of the concrete interlayer. Second, for the case where the structural shear demand is not large, that is, the concrete itself can provide sufficient shear resistance without the need for additional shear FRP stirrups, it is still necessary to consider the construction perspective. The FRP stirrups can be spaced at a larger interval, and a small number of stirrups are evenly arranged along the longitudinal and circumferential directions of the FRP segments. At this time, the role of the stirrups is not to provide shear resistance, but to serve as positioning parts to facilitate the positioning of the relative positions of the inner and outer FRP segments during the FRP skeleton production process. At this time, the spacing and diameter of the FRP stirrups mainly depend on the stiffness response of the FRP skeleton production and concrete pouring process, which is related to parameters such as the thickness and elastic modulus of the FRP segments and the thickness of the concrete interlayer. The selection of FRP stirrup parameters should ensure that the deformation of the pipe segments during the FRP skeleton production and concrete pouring process does not exceed 1 / 500 of the thickness of the arch structure to ensure the accuracy of the structural dimensions. In addition, under normal circumstances, circumferential stirrups can meet engineering requirements, and spiral stirrups can be selected in the following situations: First, in local densification areas with denser stirrup spacing, spiral stirrups can be used instead of circumferential stirrups to effectively avoid the tedious workload caused by the separate positioning of circumferential stirrups; second, when there are higher engineering requirements for structural strength and ductility, spiral stirrups can be used instead of circumferential stirrups to improve the compressive strength and compressive ductility of the core concrete surrounded by spiral stirrups. It is worth mentioning that in different areas of an arch structure, you can choose to use no stirrups, configure circumferential stirrups, or configure spiral stirrups according to your needs.

[0053] By customizing the shape (mainly rectangular, but also circular, square, polygonal or other suitable symmetrical and asymmetrical shapes can be selected according to actual needs) and size of the winding mandrel, the required inner cross-sectional size of the FRP stirrup can be obtained. The manufacturing process of the FRP stirrup selects the fiber winding process instead of the traditional pultrusion process. The production of FRP stirrups using the traditional pultrusion process usually involves the use of mechanical bending to manufacture the bending section at the corner of the stirrup, which will cause the fibers on the inside of the bending section to wrinkle or relax before solidification, affecting the strength of the stirrup. The fiber winding process is a process based on laying fiber bundles layer by layer, which effectively avoids this problem. In addition, the cross-section of the FRP stirrups produced by the traditional pultrusion process is usually circular or rectangular, while the FRP stirrups produced by the fiber winding process can be designed as a cross-section with a relatively small thickness to width ratio, which effectively improves the ratio of the radius of curvature of the bending section to the cross-sectional height, reduces the strength reduction of the bending section and delays the premature failure caused by stress concentration in the bending section, thereby improving the strength of the FRP stirrups.

[0054] For circumferential stirrups, the fiber winding angle is usually designed to be close to 90 degrees, and the solidified wound fiber tube is cut into multiple independent closed stirrups along the tube axis according to the designed stirrup width. The FRP stirrups produced by the traditional pultrusion process are usually open stirrups, while this new type of stirrup is closed, which can effectively avoid premature damage caused by the slippage of the overlapping sections of the open stirrups, thereby improving the use efficiency and ultimate strength of the stirrups. For spiral stirrups, the fiber winding angle is designed to be the same as the inclination angle of the spiral stirrups, and the spiral stirrups do not require additional cutting procedures.

[0055] The FRP double tube segment is in the shape of an arch. The specific arch shape can be customized according to the needs of the project, including arc, parabola, catenary and other curved molds for production. The principle of shape selection should not only meet the aesthetic and functional requirements of the design, but also should be based on the load distribution and direction under different load conditions, optimize the axis of the arch structure as much as possible, reduce the eccentricity of each section, so as to improve the bearing capacity and stiffness response of the arch structure. Taking the arc arch structure as an example, the center angle and radius of the FRP tube segment can be designed according to the span, span ratio and section height of the arch structure design, and its length can be determined according to the longitudinal length of the arch structure design. The strength, elastic modulus, thickness and fiber direction of the FRP outer tube segment and the FRP inner tube segment can be designed according to the structural force requirements. The fiber direction of the FRP outer tube segment and the FRP inner tube segment is mostly selected to be at an angle of plus or minus 60 to 90 degrees with the longitudinal direction to provide the strength in the span direction required by the arch structure, as well as a certain longitudinal strength.

[0056] The FRP outer tube segment and the FRP inner tube segment can both use a fiber winding process such as a reciprocating fiber winding process and a continuous fiber winding process to manufacture the entire FRP round tube, and then use a cutting process to cut it into tube segments of the desired shape. Based on the process characteristics of fiber winding, unlike the pultrusion process that is currently more commonly used in the field of civil engineering, the FRP tube segment can be customized according to design requirements, without the need to customize the cross-sectional dimensions of the pultruded profile each time or splice standardized products of pultruded profiles of different sizes. In the fiber winding process, the main controlled parameters include the number of fiber winding layers (corresponding to the thickness of the FRP tube) and the fiber winding angle (corresponding to the fiber direction of the FRP tube). Among them, the fiber winding angle is usually selected to be an angle of plus or minus 60 degrees to 90 degrees with the longitudinal direction. For arch structures, in addition to the in-plane strength bearing capacity (mainly relying on the annular fibers of the FRP tube), the tensile member (FRP tube segment) also needs to provide some out-of-plane stiffness and strength (relying on the longitudinal fibers of the FRP tube), especially for some working conditions that need to consider out-of-plane loads (such as torsion), out-of-plane strength design and verification are required. The advantage of controllable fiber angles in the fiber winding process allows the segments to be designed to meet in-plane and out-of-plane bearing capacity requirements at the material level without the need for design and arrangement at the component level. This simplifies the process to a certain extent, reduces the need for connections between different components, and avoids the problem of difficult FRP connections.

[0057] The construction method of the FRP double-segment concrete arch structure comprises the following steps:

[0058] Step 1: Factory prefabrication: The factory manufactures FRP double segments (including FRP outer segments and FRP inner segments) and FRP stirrups of the required size.

[0059] FRP double pipe segment production: FRP outer pipe and FRP inner pipe are produced by fiber winding process, and the FRP outer pipe and FRP inner pipe are cut into the required FRP outer pipe segment and FRP inner pipe segment respectively along the pipe circumferential direction. The above cutting process can be selected by using hand-held cutting machine or water jet cutting. According to the designed concrete pouring position, multiple concrete pouring holes 6 are opened on the FRP outer pipe segment 1 (see Fig. 9 ), used for pouring concrete at construction sites.

[0060] FRP stirrup production: The fiber winding process is used to produce the wound fiber tube for FRP annular stirrups or FRP spiral reinforcement. Among them, for FRP annular stirrups, they are cut into stirrups of the required width along the tube axis after solidification.

[0061] The inner wall of the FRP outer segment, the outer wall of the FRP inner segment and the inner and outer surfaces of the FRP stirrups are sandblasted.

[0062] The traditional sandblasting process is often used for the surface treatment of FRP reinforcement products produced by the pultrusion process. However, for FRP pipe products produced by the fiber winding process, due to the differences in production processes and product requirements, there has been no related application on FRP pipes before. The specific steps of the sandblasting treatment described in the present invention are as follows: for the treatment of the inner wall of the FRP outer tube segment, the resin and 20-40 mesh quartz sand are mixed, stirred evenly, and then applied to the inner wall of the FRP outer tube segment that is cured and cut into the form of tube segments with a roller; for the treatment of the outer wall of the FRP inner tube segment, when the fiber winding is completed but the resin is not completely cured, as the FRP inner tube rotates on the winding machine, 20-40 mesh quartz sand is evenly sprinkled on the outer surface of the FRP inner tube and wait for the resin to cure. The curing process of the two different sandblasting processes is basically the same, which is to naturally cure at room temperature for about 12 hours. If conditions permit, it can be appropriately heated (about 60 degrees Celsius) to shorten the curing time. For FRP stirrups produced by the fiber winding process, sandblasting can be used for surface treatment to improve its bonding performance with concrete. The sandblasting process is the same as the treatment process of the FRP segments, the outer section is the same as the treatment process of the outer wall of the FRP inner segment, and the inner section is the same as the treatment process of the inner wall of the FRP outer segment.

[0063] Step 2: Factory prefabrication: The top of some FRP stirrups 3 is glued to the inner wall of the FRP outer tube segment 1 with epoxy resin glue, as shown in the partial figure. Figure 6 As shown in the figure, the direction of the arrow in the figure is the forward direction of the FRP stirrup 3 pasted to the FRP outer tube segment 1; the bottom ends of the remaining FRP stirrups 3 are pasted on the outer wall of the FRP inner tube segment 2 in the same way, as shown in the partial figure Figure 7 As shown, the direction of the arrow in the figure is the forward direction of the FRP stirrup 3 being pasted to the FRP inner pipe segment 2.

[0064] Step 3, factory prefabrication: According to the FRP stirrups pasted on the FRP double segments, the distance between the FRP double segments can be determined, and the FRP double segments can be aligned. After the alignment is completed, the bottom end of the FRP stirrup 3 pasted on the inner wall of the FRP outer segment 1 is glued to the outer wall of the FRP inner segment 2 with epoxy resin glue, and the top end of the FRP stirrup 3 pasted on the outer wall of the FRP inner segment 2 is glued to the inner wall of the FRP outer segment 1 with epoxy resin glue. The partial figure is shown in the figure below. Figure 8 As shown, the direction of the arrow in the figure is the forward direction of the FRP inner pipe segment 2. After the pasting work is completed, the FRP double pipe segment provided with FRP stirrups is left to stand for a period of time, waiting for the epoxy resin glue to solidify and harden to form an FRP skeleton.

[0065] The two pasting processes described in step 2 and step 3 may select the following three solutions, and the pasting process includes but is not limited to the following three solutions:

[0066] First, the FRP stirrups are immersed in the epoxy resin glue and then arranged on the pipe wall of the FRP double pipe segment; second, the FRP stirrups are arranged after the entire inner wall of the FRP outer pipe segment and the outer wall of the FRP inner pipe segment are painted with a brush dipped in epoxy resin glue; third, one end of the FRP stirrup in the height direction is painted with a brush dipped in epoxy resin glue and pasted on the pipe wall of the FRP double pipe segment.

[0067] Step 2 and step 3 can be combined into one step according to actual needs, that is, the top and bottom ends of each FRP stirrup are respectively pasted to the inner wall of the FRP outer segment and the outer wall of the FRP inner segment at the same time.

[0068] Among them, the two pasting processes described in the above steps 2 and 3 can be fully automated. The production steps are to set up a pasting workbench for fixing FRP stirrups, put the FRP pipe segment on the roller, and the motor of the roller drives the roller and the FRP pipe segment on the roller to rotate. As the FRP pipe segment rotates, the pasting workbench of the FRP stirrups takes out the FRP stirrups soaked in epoxy resin glue and pastes them on the FRP pipe segment. After pasting one circle, the roller can drive the FRP pipe segment to move forward along the axial direction of the roller, so as to continue pasting the next circle.

[0069] Step 4: On-site construction: transport the FRP frame to the construction site and install it as a concrete pouring formwork at the construction site to ensure the stability and positioning accuracy of the FRP frame during the construction process.

[0070] Step 5: On-site construction: pour concrete from the concrete pouring holes 6 of the FRP outer tube segment 1 described in step 1, such as Fig. 9 As shown. Concrete should be poured and vibrated in layers to avoid voids and honeycombs in the concrete interlayer and ensure that the concrete fills the space between the inner and outer segments. Since FRP materials have a certain degree of transparency, sufficient lighting equipment, such as high-brightness LED lights, can be installed on the outside of the FRP segments to monitor the pouring status and compaction of the internal concrete through the light-transmitting FRP segments.

[0071] In summary, the present invention provides an FRP double-segment concrete arch structure and a construction method thereof, wherein the arch structure comprises an FRP outer segment, an FRP inner segment, a plurality of FRP stirrups and concrete filled between the double segments. The inner wall of the FRP outer segment and the outer wall of the FRP inner segment are both sandblasted. A plurality of FRP stirrups are pasted between the FRP double segments, and the height thereof is slightly less than the distance from the inner wall of the FRP outer segment to the outer wall of the FRP inner segment. For the case where the structural shear resistance requirement is not large, the FRP stirrups are uniformly arranged longitudinally and circumferentially along the FRP double segment; for areas where there is a shear resistance requirement, the FRP stirrups can be densely arranged or use stirrups with larger diameters and stronger stirrups. The present invention has the advantages of simple structure, light weight, high strength, and corrosion resistance. In addition to being a tensile member of the structure, the FRP double segment can also be used as a lightweight formwork for concrete pouring, which is convenient for transportation and construction, simplifies the construction process, and improves construction efficiency. In addition to being a shear-resistant component, FRP stirrups can not only improve the bonding performance between FRP double tube segments and concrete, effectively ensure the coordinated operation of FRP double tube segments and concrete, but also serve as an important positioning component of FRP double tube segments.

[0072] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A construction method of a FRP double-segment concrete arch structure, characterized in that: The FRP double-segment concrete arch structure comprises: FRP double tube segments, the FRP double tube segments include FRP outer tube segments and FRP inner tube segments, the FRP outer tube segments and the FRP inner tube segments are arranged in parallel, and the FRP double tube segments are in an arch shape; A plurality of FRP stirrups, each of which is arranged between the FRP double tube segments; Concrete, the concrete is filled between the FRP double tube segments; The construction method of the FRP double-segment concrete arch structure comprises the following steps: Provide FRP outer segments, FRP inner segments and several FRP stirrups; Assembling the FRP outer tube segment, the FRP inner tube segment and a plurality of FRP stirrups by resin bonding to form a FRP skeleton; The FRP skeleton is transported to a construction site, and concrete is poured into the FRP skeleton at the construction site to obtain an FRP double-segment concrete arch structure; The FRP outer tube segments are manufactured by the following method: a FRP outer tube is manufactured by a fiber winding process, and the FRP outer tube is cut into the required FRP outer tube segments along the tube circumferential direction; The FRP inner tube segments are manufactured by the following method: a FRP inner tube is manufactured by a fiber winding process, and the FRP inner tube is cut into required FRP inner tube segments along the tube circumferential direction; The FRP stirrups are manufactured by a fiber winding process.

2. The construction method of the FRP double-segment concrete arch structure according to claim 1, characterized in that: A plurality of FRP stirrups are evenly arranged along the longitudinal direction of the FRP double-tube segment, and a plurality of FRP stirrups are evenly arranged along the circumferential direction of the FRP double-tube segment.

3. The construction method of the FRP double-segment concrete arch structure according to claim 1, characterized in that: The arch shape includes one of a circular arc shape, a parabola shape, and a catenary shape.

4. The construction method of the FRP double-segment concrete arch structure according to claim 1, characterized in that: The fiber direction of the FRP outer tube sheet forms an angle of plus or minus 60 degrees to 90 degrees with the longitudinal direction, and the fiber direction of the FRP inner tube sheet forms an angle of plus or minus 60 degrees to 90 degrees with the longitudinal direction.

5. The construction method of the FRP double-segment concrete arch structure according to claim 1, characterized in that: The FRP stirrups are circumferential stirrups and / or spiral stirrups, and the shape of the FRP stirrups includes one of a circle and a polygon.

6. The construction method of the FRP double-segment concrete arch structure according to claim 1, characterized in that: The inner wall of the FRP outer segment, the outer wall of the FRP inner segment and the inner and outer surfaces of the FRP stirrups are sandblasted respectively, and then the sandblasted FRP outer segment, FRP inner segment and FRP stirrups are assembled by resin bonding to form an FRP skeleton; A plurality of concrete pouring holes are opened on the FRP outer segments and / or the FRP inner segments of the FRP skeleton for pouring concrete at the construction site.

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