Connecting device, FRP self-balancing bar and installation method and calculation method thereof

Abstract

The application relates to the technical field of building structures, in particular to a connecting device, an FRP self-balancing bar and a mounting method and a calculation method thereof. The connecting device comprises a cable rod which penetrates through the inside of an FRP pipe along the pipe body direction of the FRP pipe, the opposite ends of the cable rod extend out of the opposite ends of the FRP pipe by a distance; an anchor is sleeved on the opposite ends of the cable rod; a bidirectional connecting piece is provided with a sleeve structure at one end and an anchor connecting structure at the opposite end; prestress is applied to the bidirectional connecting piece and the cable rod to form a self-balancing state of the cable rod in tension and the FRP pipe in compression; an end connecting assembly is connected to the end of the anchor and is arranged adjacent to the bidirectional connecting piece, and the end connecting assembly is provided with a connecting position outside the end connecting assembly for being connected with a connecting foundation. The technical problem that the existing FRP component connecting mode can reduce the connecting efficiency, the connecting strength, the bearing capacity and the rigidity of the FRP component is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building structures, and in particular to a connecting device, a FRP self-balanced bar and an installation method and calculation method thereof. BACKGROUND

[0002] Fiber reinforced polymer (FRP) is a composite material formed by winding, molding or pultrusion process, etc. with fiber (such as carbon fiber, glass fiber, basalt fiber, aramid fiber, etc.) as reinforcing material and resin-based material as matrix. This FRP material is widely used in aerospace, automobile, chemical industry and other fields due to its characteristics of light weight, high strength, corrosion resistance and good durability. In recent years, with the maturity of FRP material production process, it has been gradually applied in the field of civil engineering, such as FRP high-strength cable rod for large-span tension structure, FRP profile for replacing metal profile components, FRP reinforcement for replacing steel reinforcement, and FRP cloth for structure reinforcement, etc.

[0003] FRP bar has good application potential in space grid structure due to its high strength-to-weight ratio and corrosion resistance, but FRP composite material has high strength, good corrosion resistance and good compression and tension resistance, but it is ultimately a fiber composite material, which has insufficient shear performance, which leads to the lack of a better FRP bar connection scheme in the prior art.

[0004] The existing FRP bar connection methods mainly include adhesive connection, rivet connection, bolt connection and pre-tightening force tooth connection, etc. However, the above connection methods are first connected with metal joints, and then multiple bars are connected by using the reliable connection performance of the metal. Among them, the adhesive connection is not suitable for the current trend of assembly development of the structure due to the inconvenience of construction, the inability to disassemble and the easy influence of temperature; and the mechanical connection methods such as rivet, bolt and pre-tightening force tooth connection usually make holes or cuttings on the end of the FRP component, which destroys the cross-sectional structure of the FRP bar, reduces the connection efficiency and connection strength, and also reduces the bearing capacity and stiffness of the FRP component due to the insufficient shear performance. SUMMARY

[0005] The present application aims to provide a connecting device, a FRP self-balanced bar and an installation method and calculation method thereof to solve the technical problem that the existing FRP component connection method reduces the connection efficiency, connection strength, bearing capacity and stiffness of the FRP component.

[0006] In a first aspect, the present application provides a connecting device for an internal hollow FRP pipe, the connecting device comprising:

[0007] a cable rod, which is arranged to penetrate the FRP pipe from inside along the direction of the pipe body, and the opposite ends of which are arranged to extend out of the opposite ends of the FRP pipe by a certain distance;

[0008] an anchor, which is arranged to be sleeved on the opposite ends of the cable rod;

[0009] a bidirectional connecting piece, one end of which is arranged to be a sleeve structure for sleeving and clamping the outer periphery of the end of the FRP pipe, and the opposite end of which is arranged to be an anchor connecting structure for fixed connection with the anchor, and the bidirectional connecting piece and the cable rod are applied with prestress to form a self-balancing state in which the cable rod is in tension and the FRP pipe is in compression; and

[0010] an end connecting assembly, which is connected to the end of the anchor and arranged adjacent to the bidirectional connecting piece, and has a connecting site on the outside for connection with a connecting foundation.

[0011] Further, the central axis of the cable rod in the direction of the rod body coincides with the central axis of the FRP pipe in the direction of the pipe body.

[0012] Further, the anchor is an anchor cup with external threads;

[0013] The bidirectional connecting piece is a nut gasket, which comprises a sleeve part and a nut part fixedly connected to each other, the sleeve structure is the sleeve part, the anchor connecting structure is the nut part, the sleeve part is used for sleeving and clamping the outer periphery of the end of the FRP pipe, the nut part has internal threads capable of being connected with the external threads of the anchor cup, and the nut part is threadedly connected and fixed to the outer periphery of the anchor cup.

[0014] Further, the anchor cup is gradually sleeved on the outer periphery of the end of the cable rod from the bottom to the top, the inner diameter of the anchor cup gradually decreases from the top to the bottom, and the inner periphery of the bottom of the anchor cup is connected with the outer periphery of the cable rod in a gap.

[0015] Further, the gap between the inner periphery of the anchor cup and the outer periphery of the cable rod is filled with a clamping piece and / or an adhesive.

[0016] Further, the end connecting assembly comprises a hollow conical sealing plate, which comprises a conical section and a flat section connected to each other, the flat section has an opening at the bottom, and the inner wall has internal threads capable of being threadedly connected with the external threads of the anchor cup, the flat section is used for threadedly connecting with the outer periphery of the anchor cup and being adjacent to the nut part of the nut gasket, and the conical top of the conical section is provided with a connecting through hole, which is the connecting site for connection with a connecting foundation.

[0017] Further, the end connection assembly further comprises a high-strength bolt, a pressure sleeve and a pin, one end of the high-strength bolt penetrates through the connecting through hole of the conical sealing plate and is embedded into the conical sealing plate, the other end of the high-strength bolt is exposed, the pressure sleeve is sleeved on the outer periphery of the high-strength bolt and abuts against the conical top of the conical sealing plate, the side wall of the pressure sleeve is provided with a fixing through hole, the pin penetrates through the fixing through hole to fasten the high-strength bolt, and the other end of the high-strength bolt is used for connecting with a bolt ball node.

[0018] Further, the cable rod is any one of an FRP cable, an FRP rod, a steel bar and a steel cable; and / or

[0019] The nut gasket and the cable rod are prestressed by means of tightening the nut gasket or by means of jacking the cable rod.

[0020] In a second aspect, the application provides an FRP self-balanced rod, comprising the connecting device and the hollow FRP pipe, the FRP self-balanced rod being a double-stiffness parallel elastic model formed by the FRP pipe and the cable rod of the connecting device, and the total stiffness of the FRP self-balanced rod being the sum of the axial compression stiffness of the FRP pipe and the tensile stiffness of the cable rod.

[0021] In a third aspect, the application provides a mounting method of the FRP self-balanced rod, which is applied to the FRP self-balanced rod and comprises the following steps:

[0022] In step S1, the anchor cup anchor sleeve with external threads is mounted on the opposite ends of the cable rod;

[0023] In step S2, the cable rod with the anchor cups at the two ends is inserted into the FRP pipe, and the central axis of the cable rod is made to coincide with the central axis of the FRP pipe, and the opposite ends of the cable rod are respectively extended out of the opposite ends of the FRP pipe by a distance;

[0024] In step S3, the nut gasket with the nut part and the sleeve part is screwed into the anchor cups at the opposite ends of the cable rod, so that the sleeve part of the nut gasket clamps the end outer periphery of the FRP pipe, and the nut part of the nut gasket is connected and fixed to the outer periphery of the anchor cup and abuts against the end edge section of the FRP pipe;

[0025] In step S4, the nut gasket is continuously screwed to apply prestress, so as to form a self-balanced stress state in which the FRP pipe is compressed and the cable rod is stretched, and the prestress is adjusted by controlling the torque of the nut gasket;

[0026] Step S5, end connection assembly installation, end connection assembly includes a tapered sealing plate with a connecting hole, high-strength bolts, pressure sleeve and pin, after the high-strength bolt is inserted into the tapered sealing plate from the connecting hole, the inner thread of the tapered sealing plate is screwed and connected with the outer thread of the anchor cup; then the pressure sleeve is sleeved on the high-strength bolt and abuts against the tapered top of the tapered sealing plate, and the pin is inserted into the fastening hole of the pressure sleeve and fastened.

[0027] In a fourth aspect, the application provides a calculation method of the FRP self-balanced bar, which is applied to the FRP self-balanced bar described above, the FRP self-balanced bar is a double-rigidity parallel elastic model formed by the FRP tube and the cable bar, and the FRP tube and the cable bar are simplified as a unidirectional compression elastic model and a unidirectional tension elastic model respectively.

[0028] Further, the FRP self-balanced bar can reach a self-balanced state through initial prestress, at this time, the prestress is the initial prestress P, the external force N is 0, and the overall rigidity is K, and the stress calculation method of the FRP self-balanced bar in the self-balanced state is as follows:

[0029] P = F bar = F tube = K bar S P,T,bar = K tube S P,C,tube

[0030] When

[0031] K = K bar + K tube , at this time, N = 0

[0032] Wherein, the axial force is F, the initial prestress is P, the external force is N, the displacement is S, and in the subscript, tube represents the FRP tube, bar represents the cable bar, T represents tension, C represents compression, and P represents the initial prestress in the self-balanced state.

[0033] Further, when the FRP self-balanced bar is in a tension state, the prestress is P, at this time, the external force N T > 0, and the overall rigidity is K T , according to the double-rigidity parallel elastic model, the stress calculation method of the FRP self-balanced bar in the tension state is as follows:

[0034] N T = F bar - F tube

[0035] When S T < S P,C,tube , and

[0036] When S T ≥ S P,C,tube , and

[0037] When S P,T,bar +S T > S T,bar,max , the uniaxial compression elastic model fails in tension, and the rod is damaged;

[0038] When the FRP self-balanced rod is in compression, the prestress is P, at this time the external force N C > 0, the overall stiffness is K C , according to the double stiffness parallel elastic model, the stress calculation method of the FRP self-balanced rod in compression is:

[0039] N C = F tube -F bar

[0040] When S C <S P,T,bar , and

[0041] When S C ≥ S P,T,bar , and

[0042] When S P,C,tube +S C > S C,tube,max , the uniaxial tension elastic model fails in compression, and the rod is damaged;

[0043] Wherein, the axial force is F, the initial prestress is P, the external force is N, the displacement is S, and in the subscript symbol, tube represents FRP pipe, bar represents cable rod, T represents tension, C represents compression, max represents limit state, and P represents initial prestress in self-balanced state.

[0044] Compared with the prior art, the connecting device, the FRP self-balancing bar and the installation method and the calculation method thereof provided by the application are used for connecting the FRP component, the FRP component is the FRP pipe with an internal hollow, the two ends of the connecting device are sleeved with the cable rod with the anchor, are inserted into the FRP pipe along the pipe body direction of the FRP pipe, and the length of the cable rod is ensured to be greater than the length of the FRP pipe, and the opposite two ends of the cable rod are ensured to extend and expose the opposite two ends of the FRP pipe by a distance, then the sleeve structure of one end of the bidirectional connecting piece of the connecting device is sleeved and clamped around the end portion of the FRP pipe, the anchor connecting structure of the other end is fixedly connected with the anchor, the end portion of the cable rod and the end portion of the FRP pipe are fixedly connected through the bidirectional connecting piece and the anchor, then the end connecting assembly with the connecting position is connected to the end portion of the anchor, the connection with other components and the like in the application and the connection with the connection foundation in the engineering are realized through the connecting position, and the connecting device can be installed at the two ends of the FRP pipe.

[0045] By using the connecting device, on the one hand, the direct connection with the FRP pipe is realized through the sleeve structure of the bidirectional connecting piece, which is sleeved and clamped around the end portion of the FRP pipe, and the FRP pipe does not need to be punched or cut, so that the connection section of the FRP pipe is not damaged, and the shearing resistance of the connection section of the FRP pipe is not damaged, and the shearing resistance of the FRP pipe is ensured; on the other hand, the bidirectional tension and compression connection of the bidirectional connecting piece and the insertion of the cable rod into the FRP pipe along the pipe body direction of the FRP pipe ensure that the rod body direction of the cable rod is consistent with the pipe body direction of the FRP pipe, the stress directions of the two are parallel to each other, and the pre-stress is applied to the bidirectional connecting piece and the cable rod, so that the self-balancing state of the cable rod in tension and the FRP pipe in compression is formed, the structure of the double-stiffness parallel elastic model is formed, the FRP pipe using the connecting device forms the FRP self-balancing bar, the total stiffness of the FRP self-balancing bar is the sum of the axial compression stiffness of the FRP pipe and the tension stiffness of the cable rod, so that the bidirectional stiffness of tension and compression is realized, the total stiffness of the FRP component is greatly improved, and the advantages of the FRP material, such as high strength and good tensile and compressive resistance, are fully utilized, and the material disadvantage of the FRP material, such as poor shearing resistance, is avoided and protected. BRIEF DESCRIPTION OF DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the specific embodiments or the prior art of the present application, the drawings needed in the specific embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0047] Figure 1 The structural schematic diagram of the FRP self-balancing bar provided by the embodiments of the present application;

[0048] Figure 2 A-A cross-sectional view shown in Figure 1 Figure 1;

[0049] Figure 3 A-A cross-sectional view shown in Figure 1 Figure 1;

[0050] Figure 4 Figure 1;

[0051] Figure 5 Figure 1;

[0052] Figure 6 Figure 1;

[0053] Figure 7 Figure 1;

[0054] Figure 8 Figure 1;

[0055] Figure 9 Figure 1;

[0056] Figure 10 Figure 1.

[0057] Reference signs:

[0058] 1000 - FRP self-balanced bar member

[0059] 100 - connecting device

[0060] 10 - cable-strut

[0061] 21 - anchor cup

[0062] 22 - clamping piece

[0063] 23 - adhesive

[0064] 30 - nut gasket

[0065] 31 - sleeve portion

[0066] 32 - nut portion

[0067] 40 - conical sealing plate

[0068] 41 - tapered section;

[0069] 42 - straight section;

[0070] 51 - high-strength bolt;

[0071] 52 - pressure sleeve;

[0072] 53 - pin;

[0073] 200 - FRP pipe;

[0074] 301 - one-way compression elastic model;

[0075] 302 - one-way tensile elastic model. DETAILED DESCRIPTION

[0076] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some but not all of the embodiments of the present application. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0077] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative labor fall within the scope of protection of the present application.

[0078] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0079] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly placed when the product of the application is used, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" and the like are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0080] In addition, the terms "horizontal", "vertical", "overhang" and the like do not mean that the components must be absolutely horizontal or overhanging, but can be slightly inclined. For example, "horizontal" only means that it is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0081] In the description of the present application, it should be further pointed out that unless otherwise explicitly specified and limited, the terms "arrangement", "installation", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0082] Some embodiments of the present application will be described in detail below with reference to the accompanying drawings. The following examples and features in the examples can be combined with each other without conflict.

[0083] As shown in Figure 1 The present application provides a connecting device 100, an FRP self-balancing rod member using the connecting device 100, and a mounting method and a calculation method of the FRP self-balancing rod member. The connecting device 100 provided by the embodiments of the present application is used for an FRP member, which is specifically provided as an FRP pipe 200 with an internal hollow. The FRP pipe 200 can be a circular pipe or a square pipe. The FRP self-balancing rod member includes the FRP pipe 200 and the connecting device 100 connected and mounted at opposite ends of the FRP pipe 200. The FRP mentioned above is the English abbreviation of Fiber Reinforced Polymer, which is a composite material formed by using fiber (such as carbon fiber, glass fiber, basalt fiber, aramid fiber, etc.) as reinforcing material and resin-based material as matrix through winding, molding or pultrusion forming process.

[0084] As shown in Figures 1 to 7As shown, the connecting device 100 provided by the embodiment of the present application comprises a cable rod 10 which is used to penetrate the inside of the FRP pipe 200 in the direction of the pipe body of the FRP pipe 200, and the opposite ends of the cable rod 10 respectively extend out of the opposite ends of the FRP pipe 200 by a distance, so the length of the rod body of the cable rod 10 is greater than the length of the pipe body of the FRP pipe 200; an anchoring installation anchor is further sleeved on the opposite ends of the cable rod 10, and the anchor can be specifically an anchor cup 21 with external threads, which can be supported by a metal material and can be externally machined with mechanical external threads. The cable rod 10 can be specifically any one of FRP cables (including FRP parallel cables and FRP twisted cables), FRP rods (including FRP threaded rod and FRP round rod), steel bars and steel cables, and other alloy cable rods can also be used, and the cable rod with good strength, rigidity, tensile, compressive and shearing performance is preferred.

[0085] As shown in Figure 2 , Figure 4 and Figure 7 , the connecting device 100 further comprises a bidirectional connecting piece, one end of the bidirectional connecting piece is provided as a sleeve structure for sleeving and clamping the outer periphery of the end of the FRP pipe 200, and the opposite end of the bidirectional connecting piece is provided as an anchor connecting structure for fixed connection with the anchor; specifically, the bidirectional connecting piece can be a nut gasket 30 which can include a sleeve part 31 and a nut part 32 with internal threads capable of being threadedly connected with the external threads of the anchor cup 21, the sleeve structure can be specifically the sleeve part 31, and the anchor connecting structure can be specifically the nut part 32, the sleeve part 31 is used to sleeve and clamp the outer periphery of the end of the FRP pipe 200, and the nut part 32 is threadedly connected and fixed to the outer periphery of the anchor cup 21, the nut gasket 30 is used to support the anchor at the end cross section of the FRP pipe 200 and to clamp the FRP pipe 200 through the sleeve part 31 to ensure the stability of the axis of the anchor. Then, prestress is applied to the bidirectional connecting piece (which can be specifically the nut gasket 30) and the cable rod 10 to form a self-balancing state of the cable rod 10 in tension and the FRP pipe 200 in compression, so as to achieve bidirectional tension and compression, and the prestress can be applied by tightening the nut gasket 30 in a tensioning manner or by a jack in a tensioning manner, and the nut part 32 can be specifically a hexagonal nut for facilitating tightening operation.

[0086] As shown in Figures 1 to 4 , the connecting device 100 further comprises an end connecting assembly which is connected to the end of the anchor and is arranged adjacent to the bidirectional connecting piece, and the end connecting assembly has a connecting position on the outside for connection with a connecting foundation, which can be specifically other components used in engineering.

[0087] Compared with the prior art, the connecting device 100 for connecting the FRP member, the FRP self-balanced bar 1000 and the installation method and calculation method thereof provided by the embodiments of the present application, the FRP member is the FRP pipe 200 with an internal hollow, the two ends of the connecting device 100 are sleeved with the cable rod 10 with an anchor, and the cable rod 10 is inserted into the FRP pipe 200 along the pipe body direction of the FRP pipe 200, and the length of the cable rod 10 is ensured to be greater than the length of the FRP pipe 200, and the opposite ends of the cable rod 10 are ensured to extend out of the opposite ends of the FRP pipe 200 by a distance, then the sleeve structure of one end of the bidirectional connecting piece of the connecting device 100 is sleeved around the outer periphery of the end of the FRP pipe 200, and the anchor connecting structure of the other end is fixedly connected with the anchor, so that the end of the cable rod 10 and the end of the FRP pipe 200 are fixedly connected through the bidirectional connecting piece and the anchor, then the end connecting assembly with a connecting position is connected to the end of the anchor, and the connection with other members and the like in the application and the connection with the connection foundation in the project is realized through the connecting position, and the connecting device 100 can be installed at the two ends of the FRP pipe 200.

[0088] With the connecting device 100, on the one hand, the direct connection with the FRP pipe 200 is through the sleeve structure of the bidirectional connecting piece sleeved around the outer periphery of the end of the FRP pipe 200, and the FRP pipe 200 does not need to be perforated or cut, so that the connection section of the FRP pipe 200 is not damaged, and the shear resistance of the connection section of the FRP pipe 200 is not damaged, and the shear resistance of the FRP pipe 200 is ensured; on the other hand, the bidirectional tensile and compressive connection of the bidirectional connecting piece and the insertion of the cable rod 10 into the FRP pipe 200 along the pipe body direction of the FRP pipe 200 ensure that the rod body direction of the cable rod 10 is consistent with the pipe body direction of the FRP pipe 200, the stress directions of the two are parallel to each other, and the pre-stress is applied to the bidirectional connecting piece and the cable rod 10, so that the self-balanced state of the cable rod 10 in tension and the FRP pipe 200 in compression is formed, the double-stiffness parallel elastic model structure is formed, the FRP pipe 200 with the connecting device 100 is formed into the FRP self-balanced bar 1000, the total stiffness of the FRP self-balanced bar 1000 is the sum of the axial compression stiffness of the FRP pipe 200 and the tensile stiffness of the cable rod 10, so that the bidirectional stiffness in tension and compression is realized, the total stiffness of the FRP member is greatly improved, and the advantages of the FRP material, such as high strength and good tensile and compressive resistance, are fully utilized, and the disadvantage of the FRP material, such as poor shear resistance, is avoided and protected.

[0089] Preferably, the central axis of the rod body direction of the aforementioned cable rod 10 coincides with the central axis of the tube body direction of the aforementioned FRP tube 200, that is, the length direction center points of both the FRP tube 200 and the cable rod 10 are aligned, so that the bidirectional tensile and compressive stiffness characteristics of the double-stiffness parallel elastic model construction characteristics can be better exerted, the model utilization rate is higher, and the overall stiffness of the FRP component is greatly improved.

[0090] The anchor can adopt adhesive anchoring, mechanical anchoring or composite anchoring. A specific embodiment is that the aforementioned anchor cup 21 can be gradually sleeved on the outer periphery of the end of the aforementioned cable rod 10 from the bottom to the top, the inner diameter cross section of the anchor cup 21 gradually decreases from the top to the bottom, so that a gap is formed between the inner periphery of the anchor cup 21 and the outer periphery of the cable rod 10, and the bottom inner periphery of the anchor cup 21 is connected with the outer periphery of the cable rod 10. Preferably, the gap between the inner periphery of the anchor cup 21 and the outer periphery of the cable rod 10 is filled with a clamping piece 22 and / or an adhesive 23 to connect and anchor, thereby enhancing the anchoring strength of the anchor.

[0091] A preferred embodiment is that, as shown in Figures 2 to 4 The aforementioned end connecting assembly can specifically include a hollow conical sealing plate 40, which includes a conical section 41 and a flat section 42 connected to each other, the flat section 42 is open at the bottom and has an inner thread capable of being threadedly connected with the outer thread of the aforementioned anchor cup 21, the flat section 42 is used for being threadedly connected with the outer periphery of the anchor cup 21 and adjacent to the nut part 32 of the nut washer 30, and the conical top of the conical section 41 is provided with a connecting through hole, which is the connecting position of the aforementioned end connecting assembly and is used for being connected with a connecting base, which can be other components used in engineering, so as to realize the connection and use of the FRP self-balancing rod 1000 in engineering.

[0092] On the basis of the aforementioned embodiment, more preferably, the end connecting assembly can further include a high-strength bolt 51, a pressure-bearing sleeve 52 and a pin 53, one end of the high-strength bolt 51 penetrates through the connecting through hole of the aforementioned conical sealing plate 40 and is inserted into the inside of the conical sealing plate 40, the other end of the high-strength bolt 51 is exposed, the pressure-bearing sleeve 52 is sleeved on the outer periphery of the high-strength bolt 51 and abuts against the conical top of the conical sealing plate 40, the side wall of the pressure-bearing sleeve 52 is provided with a fixing through hole, and the pin 53 penetrates through the fixing through hole to fasten the high-strength bolt 51, and the other end of the high-strength bolt 51 is used for being connected with a bolt ball node, so as to realize the connection of the FRP self-balancing rod 1000 with the bolt ball node in engineering, and further realize the bolt ball node connection of a plurality of FRP self-balancing rods 1000.

[0093] As shown in Figures 4 to 7As shown, the embodiment of the present application also provides a mounting method of the FRP self-balanced bar, which is applied to the aforementioned FRP self-balanced bar 1000, and is a kind of assembly mounting method, which realizes the assembly mounting of the FRP self-balanced bar 1000, and the mounting method comprises the following steps:

[0094] Step S1, the anchor cup anchor sleeve with external thread is mounted on the opposite ends of the cable rod;

[0095] Step S2, the cable rod with the anchor cup installed on both ends is inserted into the FRP pipe, and the central axis of the cable rod is ensured to coincide with the central axis of the FRP pipe, and the opposite ends of the cable rod extend out of the opposite ends of the FRP pipe by a distance respectively;

[0096] Step S3, the nut gasket with the nut part and the sleeve part is screwed through the anchor cups on the opposite ends of the cable rod, so that the sleeve part of the nut gasket clamps the outer periphery of the end part of the FRP pipe, and the nut part of the nut gasket is connected and fixed to the outer periphery of the anchor cup and abuts against the end part edge section of the FRP pipe;

[0097] Step S4, the nut gasket is continuously screwed to apply prestress, so as to form a self-balancing stress state of the FRP pipe under compression and the cable rod under tension, and the size of the prestress is adjusted by controlling the torque of the nut gasket;

[0098] Step S5, the end part connecting assembly is installed, the end part connecting assembly comprises a conical sealing plate with a connecting through hole, a high-strength bolt, a pressure bearing sleeve and a pin, after the high-strength bolt is inserted into the conical sealing plate through the connecting through hole, the high-strength bolt is screwed and tightened through the internal thread of the conical sealing plate and the external thread of the anchor cup; then the pressure bearing sleeve is sleeved on the high-strength bolt and abuts against the conical top of the conical sealing plate, and the pin is inserted and fastened through the fastening through hole of the pressure bearing sleeve.

[0099] The FRP self-balanced bar 1000 assembled by the sequence of the above mounting method can realize 100% full mechanical assembly production and node connection, is fast, efficient and highly reliable, can realize factory unified production, greatly improves the production construction efficiency, and enhances the practicality and universality.

[0100] As shown, Figures 8 to 10 The embodiment of the present application also provides a calculation method of the FRP self-balanced bar, and it should be noted that the basic symbols of the following calculation method are as follows: the elastic stiffness is K, the axial force is F, the initial length is L, the initial length is the length of the cable rod end extending out of the FRP pipe end, the initial prestress is P, the end part external force is N, the end part displacement is S, the elastic modulus is E, and the tensile and compressive part cross-sectional area is A.

[0101] The subscript symbol is as follows: tube represents the FRP tube, bar represents the cable rod, T represents tension, C represents compression, and P represents the initial prestress in the self-balanced state. The symbol values in the following calculation method are all positive numbers, and the force direction and force state are indicated by the subscript symbol.

[0102] The configuration of the FRP self-balanced bar member forms a double-stiffness parallel elastic model formed by the FRP tube and the cable rod. The following calculation method simplifies the FRP tube and the cable rod into a complete one-way compression elastic model 301 and a one-way tension elastic model 302, respectively, without considering the yield stage of the material. The working mechanism of the double-stiffness parallel elastic model is as follows:

[0103] Parallel total stiffness: K T = K C = K tube + K bar ;

[0104] One-way compression elastic stiffness: K tube = E tube A tube / L;

[0105] One-way tension elastic stiffness: K bar = E bar A bar / L;

[0106] As can be seen from the calculation formula of the working mechanism of the above-mentioned double-stiffness parallel elastic model, the total stiffness of the FRP self-balanced bar member is the sum of the axial compression stiffness of the FRP tube and the tension stiffness of the cable rod, realizing the bidirectional stiffness of tension and compression and fully utilizing the advantages of high strength and good tensile and compressive properties of the FRP material.

[0107] The following calculation method only considers the compression deformation of the simplified one-way compression elastic model 301 of the FRP tube, and believes that when the compression force decreases to 0, the end will be separated due to tension and cannot bear the tensile force, so it is believed that the one-way compression elastic model does not bear the tensile force but only bears the compression force. Only the tensile deformation of the simplified one-way tension elastic model of the cable rod is considered, and it is believed that when it is compressed, it will lose stability due to the small cross section and cannot bear the compression force, so it is believed that the one-way tension elastic model does not bear the compression force but only bears the tensile force.

[0108] For the simplified one-way compression elastic model 301 of the FRP tube, the stiffness and bearing capacity calculation method is as follows, wherein, F tube,max is the ultimate axial compression bearing capacity.

[0109]

[0110]

[0111] For the simplified one-way tensile elastic model 302 of cable-strut, the stiffness and bearing capacity calculation method is as follows, where F bar,max is the ultimate tensile bearing capacity.

[0112]

[0113]

[0114] According to the above analysis and calculation method, the bearing capacity and stiffness calculation method of FRP self-balancing bar under tension and compression state are derived.

[0115] FRP self-balancing bar can reach self-balancing state through initial prestress, as shown in Figure 8 , the prestress is P, at this time the external force N = 0, the overall stiffness is K, according to the double stiffness parallel elastic model, the stress calculation method of FRP self-balancing bar under self-balancing state is as follows:

[0116] P = F bar = F tube = K bar S P,T,bar = K tube S P,C,tube

[0117] When

[0118] Overall stiffness: K = K bar + K tube , at this time N = 0

[0119] FRP self-balancing bar is in tension state, as shown in Figure 9 , the prestress is P, at this time the external force N T > 0, the overall stiffness is K T .When the overall bar is in tension state, according to the double stiffness parallel elastic model, the stress calculation method of FRP self-balancing bar under tension state is as follows:

[0120] N T = F bar -F tube

[0121] When S T <S P,C,tube , and

[0122] When S T ≥ S P,C,tube , and When S P,T,bar + S T > S T,bar,max , the one-way compression elastic model is in tension failure, and the bar is damaged.

[0123] FRP self-balanced bar in compression, as shown in Figure 10 , the prestress is P, at this time the external force N C > 0, the overall stiffness is K C When the overall bar is in compression, according to the double stiffness parallel elastic model, the stress calculation method of FRP self-balanced bar in compression is as follows:

[0124] N C = F tube -F bar

[0125] When S C <S P,T,bar , and

[0126] When S C ≥ S P,T,bar , and When S P,C,tube +S C >S C,tube,max , the uniaxial tensile elastic model is in compression failure, and the bar is destroyed.

[0127] Finally, it should be pointed out that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A connecting device, characterized in that, For internally hollow FRP pipes, the connection device includes: A cable rod, which is used to penetrate the interior of the FRP tube along the tube body direction, and its opposite ends extend out of the opposite ends of the FRP tube for a certain distance; Anchors are fitted and anchored to the opposite ends of the cable rod; A bidirectional connector, one end of which is configured as a clamping structure for fitting and clamping the outer periphery of the FRP pipe end, and the opposite end of which is configured as an anchor connection structure for fixed connection with the anchor, applies prestress to the bidirectional connector and the cable rod to form a self-balancing state in which the cable rod is under tension and the FRP pipe is under compression; and An end connection assembly is connected to the end of the anchor and disposed adjacent to the bidirectional connector, and the end connection assembly has a connection position on the outside for connecting to the connection base; The anchor is an anchor cup with external threads; The bidirectional connector is a nut washer, which includes a sleeve portion and a nut portion that are connected and fixed together. The sleeve portion is the clamping structure, and the nut portion is the anchor connection structure. The sleeve portion is used to clamp the outer periphery of the end of the FRP pipe. The nut portion has an internal thread that can be connected to the external thread of the anchor cup. The nut portion is threadedly fixed to the outer periphery of the anchor cup. The end connection assembly includes an internally hollow conical sealing plate. The conical sealing plate includes an intersecting conical section and a straight section. The straight section has an open bottom and an internal thread on its inner wall that can be threaded to the external thread of the anchor cup. The straight section is used to thread onto the outer periphery of the anchor cup and is adjacent to the nut portion of the nut washer. The conical top of the conical section has a connecting through hole, which is the connection position for connecting to the connection base.

2. The connecting device according to claim 1, characterized in that, The central axis of the cable in the direction of the rod coincides with the central axis of the FRP pipe in the direction of the pipe.

3. The connecting device according to claim 1 or 2, characterized in that, The anchor cup is gradually fitted onto the outer periphery of the end of the cable rod from its bottom to its top. The inner diameter of the anchor cup gradually decreases from its top to its bottom, and the bottom inner periphery of the anchor cup is connected to the outer periphery of the cable rod with a gap.

4. The connecting device according to claim 3, characterized in that, The gap between the inner circumference of the anchor cup and the outer circumference of the cable rod is filled with clips and / or adhesive.

5. The connecting device according to claim 4, characterized in that, The end connection assembly further includes a high-strength bolt, a pressure-bearing sleeve, and a pin. One end of the high-strength bolt passes through the connecting through hole of the conical sealing plate and abuts against the interior of the conical sealing plate. The other end of the high-strength bolt is exposed. The pressure-bearing sleeve is fitted around the outer periphery of the high-strength bolt and abuts against the conical top of the conical sealing plate. The side wall of the pressure-bearing sleeve is provided with a fixing through hole. The pin passes through the fixing through hole to fasten the high-strength bolt. The other end of the high-strength bolt is used for connection with a bolt ball joint.

6. The connecting device according to claim 1 or 2, characterized in that, The cable is any one of FRP cable, FRP rod, reinforcing bar, and steel cable; and / or Prestress is applied to the nut and the cable rod by tightening the nut and washer or by tensioning the cable rod with a jack.

7. An FRP self-balancing rod, characterized in that, The device includes the connecting device according to any one of claims 1 to 6 and the internally hollow FRP tube. The FRP self-balancing rod is a dual-stiffness parallel elastic model formed by the FRP tube and the cable rod of the connecting device. The total stiffness of the FRP self-balancing rod is the sum of the bidirectional axial compressive stiffness of the FRP tube and the tensile stiffness of the cable rod.

8. A method for installing an FRP self-balancing rod, characterized in that, Applied to the FRP self-balancing bar of claim 7, comprising: Step S1: Install the anchor cup with external thread on the opposite ends of the cable rod. Step S2: Insert the cable rod with anchor cups installed at both ends into the FRP pipe, and ensure that the central axis of the cable rod coincides with the central axis of the FRP pipe, and that the opposite ends of the cable rod extend out of the opposite ends of the FRP pipe by a certain distance. Step S3: Screw the nut washer with the nut part and the sleeve part into the anchor cups at opposite ends of the cable rod, so that the sleeve part clamps the outer periphery of the end of the FRP pipe, and then screw its nut part to connect and fix it to the outer periphery of the anchor cup and abut against the edge section of the end of the FRP pipe. Step S4: Continue to tighten the nut and washer to apply prestress, forming a self-balanced force state in which the FRP pipe is compressed and the cable is tensile. The magnitude of the prestress is adjusted by controlling the torque of tightening the nut and washer. Step S5: Install the end connection assembly. The end connection assembly includes a tapered sealing plate with a connection through hole, a high-strength bolt, a pressure-bearing sleeve, and a pin. After inserting the high-strength bolt into the tapered sealing plate through the connection through hole, tighten it by connecting the internal thread of the tapered sealing plate with the external thread of the anchor cup. Then, insert the pressure-bearing sleeve into the high-strength bolt and abut it against the tapered top of the tapered sealing plate. Finally, insert the pin through the fastening through hole of the pressure-bearing sleeve to tighten it.

9. A calculation method for FRP self-balancing members, characterized in that, The FRP self-balancing member described in claim 8 is a dual-stiffness parallel elastic model formed by the FRP tube and the cable, and the FRP tube and the cable are simplified into a uniaxial compressive elastic model and a uniaxial tensile elastic model, respectively.

10. The calculation method according to claim 9, characterized in that, The FRP self-balancing member can achieve self-equilibrium through initial prestress. At this time, the prestress is the initial prestress P, the external force N=0, and the overall stiffness is K. The force calculation method for the FRP self-balancing member in the self-equilibrium state is as follows: Wherein, the axial force is F, the initial prestress is P, the external force is N, the displacement is S, and in the subscript symbols, tube represents FRP pipe, bar represents cable rod, T represents tension, C represents compression, and P represents the initial prestress under self-balancing conditions.

11. The calculation method according to claim 10, characterized in that, When the FRP self-balancing member is in tension, the prestress is P, and the external force is N. T >0, overall stiffness is K T According to the dual-stiffness parallel elastic model, the force calculation method for FRP self-balancing members under tension is as follows: ； When the FRP self-balancing member is under compression, the prestress is P, and the external force is N. C >0, overall stiffness is K C According to the dual-stiffness parallel elastic model, the force calculation method for FRP self-balancing members under compression is as follows: Wherein, the axial force is F, the initial prestress is P, the external force is N, the displacement is S, and in the subscript symbols, tube represents FRP pipe, bar represents cable rod, T represents tension, C represents compression, max represents ultimate state, and P represents initial prestress under self-balancing state.

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