A self-sensing parallel steel wire cable and its manufacturing method

Abstract

This invention provides a self-sensing parallel wire cable and its manufacturing method. The self-sensing parallel wire cable includes a cable body and anchoring components at both ends. The cable body includes multiple parallel steel wires, and one or more of the steel wires have grooves embedded in the grooves, with fiber Bragg grating sensors embedded within the grooves. This invention organically combines fiber Bragg grating sensors with traditional parallel wire cables to form an integrated structure, which can effectively monitor and evaluate the environmental, stress, and loss states of the cable during its use, providing direct information for feedback to guide the cable installation and construction and subsequent safety assessments. The embedded sensors ensure sensor survival rate, reduce the complex procedures of externally attached sensors, eliminate sensor installation errors, and can be widely used for real-time monitoring of cable force in bridge geotechnical structures.

Description

Technical Field

[0001] The invention relates to the technical field of cables for bridge geotechnical structure engineering, in particular to a self-sensing parallel steel wire cable and a manufacturing method thereof. Background Art

[0002] As a tensile component, cables have been widely used in bridges, geotechnical engineering, construction and other projects. Cables mainly include clip anchors, cold cast anchors, hot cast anchors and other forms. In the patent document with the authorization announcement number CN 100354471C, an ultra-high strength parallel steel wire durable cable is recorded, including a cable body and cold cast anchors installed at both ends of the cable body. It adopts a double anchoring method of steel wire end pier head plus grouting material, and has excellent anchoring reliability and anchoring durability. At present, this type of parallel steel wire cable is widely used in large cable-stayed bridges, arch bridges and other bridge structures.

[0003] On the other hand, how to achieve real-time monitoring of the stress and loss status of the bridge geotechnical structure cable and ensure the long-term safety and stability of the cable structure engineering is also the key to the development of bridge geotechnical structure engineering monitoring technology. At present, the main testing methods for the cable force and damage status of cables at home and abroad are flux sensors, pressure sensors, hydraulic sensors, etc. The flux sensor measurement line needs to be powered on, the connecting cable is thick and easily interfered, and it is easily damaged in severe weather conditions such as thunderstorms; the transmission distance is limited by the line resistance, the longer the line, the greater the error, and the longest is only 200 meters; its sensor coil is enameled wire, the durability is questionable, multiple anti-corrosion is required, and long-term monitoring may be aging. After the pressure sensor is installed, the anchor head becomes larger, and the production and maintenance costs are high. The long-term durability and stability of the hydraulic sensor are poor, and long-term and stable monitoring cannot be carried out.

[0004] In the patent document with application number 201710237787.7, a parallel steel wire bridge intelligent inclined cable is recorded, which solves the defect that the cable body in the prior art cannot be monitored in real time, including a cable body formed by twisting multiple strands of steel wire, a groove is arranged on the outer periphery of the central steel wire of the cable body, the groove has a spiral section spiraling along the outer periphery of the central steel wire, a fiber grating strain sensor is arranged in the groove, the fiber grating strain sensor is isolated from the inner wall of the groove by epoxy resin glue, and the groove is filled with epoxy resin glue to fix and protect the fiber grating sensor. According to the manufacturing method, the steel wire with the fiber grating sensor is at the center of the cable, and the fiber grating sensor extends outside the end of the central steel wire, which will inevitably lead to the inability of the steel wire to be headed, affecting the anchoring performance, and the outlet end is arranged outside the wire dividing plate, and the tooling used when installing the anchor cup and other components is easy to crush the fiber outlet end, seriously affecting the survival rate of the self-sensing cable. Although the spiral grooves in the steel wire can reduce the strain of the grating sensor to a certain extent, the overall mechanical properties of the steel wire are inferior to those of the linearly grooved steel wire, and it is easy to be damaged. In addition, the optical fiber is easily damaged when it is picked out from the groove, which makes the manufacturing process difficult. Summary of the invention

[0005] In order to overcome the above-mentioned deficiencies of the prior art, the present invention proposes a self-sensing parallel steel wire cable which is easy to manufacture, has high precision and good durability, and a manufacturing method thereof.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present invention to solve its technical problem is: a self-sensing parallel steel wire cable, including a cable body and anchoring components at both ends, the cable body includes a plurality of parallel steel wires, one or more of the steel wires are provided with grooves, a fiber grating sensor is embedded in the groove, and the fiber grating sensor is a single-mode optical fiber with one or more fiber gratings written therein.

[0007] By adopting the technical solution of the present invention, the fiber grating sensor is organically combined with the traditional parallel steel wire cable to form an integrated structure. The fiber grating sensor is connected to the fiber grating demodulator to transmit the optical signal representing the cable strain sensed by the fiber grating to the fiber grating demodulator, which can effectively monitor and evaluate the environment, force and loss state of the cable during use, and provide direct information for feedback guidance of cable installation construction and safety assessment of the later operation process. The embedded sensor can ensure the survival rate of the sensor, reduce the complex process of external sensor attachment, eliminate sensor installation errors, and can be widely used for real-time monitoring of cable forces in bridge geotechnical structures.

[0008] Furthermore, the steel wire with the groove is located at the outermost side of the steel wire combination in the cable body, and the angle between the opening direction of the groove and the tangent line of the outer circle of the cable body cross section where the steel wire is located is less than or equal to 30°.

[0009] By adopting the above preferred solution, the structure is firm and the optical fiber can be prevented from being cut by the steel wire after being fused.

[0010] Furthermore, after the fiber grating sensor is embedded in the groove, it is encapsulated with epoxy resin glue.

[0011] The above preferred solution has a simple structure and is convenient for protecting the fiber grating sensor.

[0012] Furthermore, when the fiber grating sensor is embedded, the steel wire is pre-tensioned with a pre-tensioning force of 15-25 kN.

[0013] By adopting the above preferred solution, the measuring range of the fiber grating sensor can be improved.

[0014] Furthermore, the anchoring assembly comprises a fixed end anchor component and a tension end anchor component, the fixed end anchor component is sleeved on the fixed end of the cable body, and the tension end anchor component is sleeved on the tension end of the cable body.

[0015] By adopting the above preferred solution, the structure is firm and it is convenient to tension the self-sensing parallel steel wire cables.

[0016] Furthermore, the fixed end anchor component and the tension end anchor component are both cold cast anchors.

[0017] By adopting the above preferred solution, anchoring is reliable.

[0018] Furthermore, the parts of the cable body at both ends anchored to the anchoring assembly are the cable body anchoring sections, the part between the two cable body anchoring sections is the cable body free section, and the groove for embedding the fiber grating sensor is only located in the cable body free section.

[0019] By adopting the above preferred solution, the fiber grating sensor can be deformed in coordination with the cable body, and there is no steel wire slot section in the cable anchoring section, which can effectively ensure the anchoring efficiency.

[0020] Furthermore, PE layer stripping sections are provided at both ends of the cable body, a part of the PE layer stripping section is located inside the anchor assembly and the other part is located outside the anchor assembly, a sleeve is also provided on the cable body, one end of the sleeve is connected to the anchor assembly, and the other end of the sleeve is connected to the sleeve cover, and the sleeve cover is sleeved on the outer circumference of the cable body with a PE layer, the optical fiber end of the fiber grating sensor is led out from the PE layer stripping section outside the anchor assembly and fused with the optical fiber test jumper, and the optical fiber test jumper passes through the sleeve and the sleeve cover and is wound around the cable body.

[0021] By adopting the above preferred solution, the structure is firm, the test is convenient and the test jumper is protected.

[0022] Furthermore, the optical fiber test jumper is connected to a fiber grating demodulator.

[0023] By adopting the above preferred solution, the cable force can be monitored in real time.

[0024] A method for manufacturing a self-sensing parallel steel wire cable comprises the following steps:

[0025] Step 1, cutting and braiding: first prepare the steel wire and the steel wire with the embedded fiber Bragg grating sensor in advance, cut them according to the specified length, and then put them together into the wire threading plate to braid them into bundles. The steel wire with the embedded fiber Bragg grating sensor is marked for easy identification;

[0026] Step 2, extrusion: the bundled steel wire is pulled to the extruder for extrusion process, and then enters the cooling water tank for cooling;

[0027] Step 3: Positioning and cutting: Positioning and cutting according to the fixed length of the cable body, and marking the optical fiber outlet end;

[0028] Step 4, stripping PE layer and wiring: according to the specifications of the anchor, determine the length of the PE layer to be stripped and strip the corresponding PE layer; after stripping the PE layer, find the steel wire with the embedded fiber grating sensor, pick out the lead wire hidden in the steel wire with a special tool and fuse it with the fiber test jumper, and fix the fiber jumper on the cable body with tape;

[0029] Step 5, install the anchor assembly: insert the sleeve cover plate, sleeve, and anchor assembly into the cable body in sequence; insert the steel wire into the wire dividing plate in a fixed arrangement and fix the head. After the head is fixed, fix the anchor assembly on the wire dividing plate;

[0030] Step 6, grouting and curing: pour the prepared epoxy iron sand into the anchor assembly, vibrate and compact it, and then put it into a high-temperature curing furnace for curing;

[0031] Step 7, super tension test: after the curing is completed, the super tension test is carried out, which is divided into 10 levels of tension. The fiber Bragg grating sensor is calibrated during the tension process.

[0032] The above-mentioned manufacturing method ensures the anchoring performance of the self-sensing parallel steel wire cable and provides reliable and effective protection for the fiber grating sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1 It is a structural schematic diagram of an implementation mode of the self-sensing parallel steel wire cable of the present invention;

[0035] Figure 2 It is a partial enlarged view of the tensioning end of the self-sensing parallel steel wire cable of the present invention;

[0036] Figure 3 It is a schematic diagram of the cross-sectional structure of the cable body;

[0037] Figure 4 It is a production flow chart of the self-sensing parallel steel wire cable of the present invention.

[0038] The numbers and letters in the figure represent the names of the corresponding parts:

[0039] 1-cable body; 101-steel wire; 102-PE layer; 2-fiber Bragg grating sensor; 3-fiber test jumper; 301-fusion end; 302-outlet end; 4-fixed end anchor component; 5-tension end anchor component; 6-sleeve cover plate; 7-sleeve; 8-fiber Bragg grating demodulator. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] like Figure 1 , 3 As shown, a self-sensing parallel steel wire cable includes a cable body 1 and anchoring components at both ends. The cable body 1 includes multiple parallel steel wires 101. One or more steel wires 101 are provided with grooves. A fiber grating sensor 2 is embedded in the groove. The fiber grating sensor 2 is a single-mode optical fiber with one or more fiber gratings written in it.

[0042] The beneficial effect of adopting the above technical solution is: organically combining the fiber grating sensor with the traditional parallel steel wire cable to form an integrated structure. The fiber grating sensor is connected to the fiber grating demodulator, and the optical signal representing the cable strain sensed by the fiber grating is transmitted to the fiber grating demodulator, which can effectively monitor and evaluate the environment, force and loss state of the cable during use, and provide direct information for feedback guidance of cable installation construction and safety assessment of the later operation process. The embedded sensor can ensure the survival rate of the sensor, reduce the complex process of external sensor attachment, eliminate sensor installation errors, and can be widely used for real-time monitoring of cable forces in bridge geotechnical structures.

[0043] like Figure 3 As shown, in other embodiments of the present invention, the steel wire with the groove is located at the outermost side of the steel wire combination in the cable body, and the angle between the opening direction of the groove and the tangent line of the outer circle of the cable body cross section where the steel wire is located is less than or equal to 30°. The beneficial effect of adopting the above technical solution is: the structure is firm and the optical fiber is prevented from being cut by the steel wire after fusion splicing.

[0044] In some other embodiments of the present invention, the fiber Bragg grating sensor 2 is encapsulated with epoxy resin after being embedded in the groove. The above technical solution has the beneficial effects of simple structure and convenient protection of the fiber Bragg grating sensor.

[0045] In other embodiments of the present invention, when embedding the fiber Bragg grating sensor 2, the steel wire is pre-tensioned with a pre-tensioning force of 15-25 kN. The beneficial effect of adopting the above technical solution is that the measuring range of the fiber Bragg grating sensor can be increased.

[0046] In some other embodiments of the present invention, the anchor assembly includes a fixed end anchor component 4 and a tension end anchor component 5, the fixed end anchor component 4 is sleeved on the fixed end of the cable body 1, and the tension end anchor component 5 is sleeved on the tension end of the cable body 1. The beneficial effect of adopting the above technical solution is: the structure is firm and it is convenient to tension the self-sensing parallel steel wire cable.

[0047] In some other embodiments of the present invention, both the fixed end anchor component 4 and the tension end anchor component 5 are cold cast anchors. The beneficial effect of adopting the above technical solution is that the anchoring is reliable.

[0048] In other embodiments of the present invention, the parts of the cable body 1 at both ends that are anchored to the anchoring assembly are the cable body anchoring sections, the part between the two cable body anchoring sections is the cable body free section, and the groove for embedding the fiber grating sensor is only located in the cable body free section. The beneficial effects of the above technical solution are: the fiber grating sensor can be deformed in coordination with the cable body, there is no steel wire slot section in the cable anchoring section, and the anchoring efficiency can be effectively guaranteed.

[0049] In some other embodiments of the present invention, PE layer stripping sections for stripping the PE layer 102 on the outer periphery of the cable body are provided at both ends of the cable body 1, a portion of the PE layer stripping section is located inside the anchor assembly, and the other portion is located outside the anchor assembly. A sleeve 7 is also sleeved on the cable body 1, one end of the sleeve 7 is connected to the anchor assembly, and the other end of the sleeve 7 is connected to the sleeve cover 6, and the sleeve cover 6 is sleeved on the outer circumference of the cable body having the PE layer. The optical fiber end of the fiber grating sensor is led out from the PE layer stripping section outside the anchor assembly and fused with the optical fiber test jumper 3, and the optical fiber test jumper 3 passes through the sleeve 7 and the sleeve cover 6 and is wound around the outer periphery of the cable body 1. In order to clearly illustrate the position of the optical fiber test jumper 3, Figure 2 The fusion end 301 of the optical fiber test jumper 3 and the optical fiber is marked, and the external outlet end 302 of the optical fiber test jumper 3 is marked. The beneficial effects of adopting the above technical solution are: the structure is firm, the test is convenient, and the test jumper is protected.

[0050] In some other embodiments of the present invention, the optical fiber test jumper 3 is connected to the optical fiber Bragg grating demodulator 8. The beneficial effect of adopting the above technical solution is that the cable force can be monitored in real time.

[0051] like Figure 4 As shown, a method for making a self-sensing parallel steel wire cable comprises the following steps:

[0052] Step 1, cutting and braiding: first prepare the steel wire and the steel wire with the embedded fiber Bragg grating sensor in advance, cut them according to the specified length, and then put them together into the wire threading plate to braid them into bundles. The steel wire with the embedded fiber Bragg grating sensor is marked for easy identification;

[0053] Step 2, extrusion: the bundled steel wire is pulled to the extruder for extrusion process, and then enters the cooling water tank for cooling;

[0054] Step 3: Positioning and cutting: Positioning and cutting according to the fixed length of the cable body, and marking the optical fiber outlet end;

[0055] Step 4, stripping PE layer and wiring: according to the specifications of the anchor, determine the length of the PE layer to be stripped and strip the corresponding PE layer; after stripping the PE layer, find the steel wire with the embedded fiber grating sensor, pick out the lead wire hidden in the steel wire with a special tool and fuse it with the fiber test jumper, and fix the fiber jumper on the cable body with tape;

[0056] Step 5, install the anchor assembly: insert the sleeve cover plate, sleeve, and anchor assembly into the cable body in sequence; insert the steel wire into the wire dividing plate in a fixed arrangement and fix the head. After the head is fixed, fix the anchor assembly on the wire dividing plate;

[0057] Step 6, grouting and curing: pour the prepared epoxy iron sand into the anchor assembly, vibrate and compact it, and then put it into a high-temperature curing furnace for curing;

[0058] Step 7, super tension test: after the curing is completed, the super tension test is carried out, which is divided into 10 levels of tension. The fiber Bragg grating sensor is calibrated during the tension process.

[0059] The above-mentioned manufacturing method ensures the anchoring performance of the self-sensing parallel steel wire cable and provides reliable and effective protection for the fiber grating sensor.

[0060] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable ordinary technicians in the field to understand the content of the present invention and implement it. They cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A self-sensing parallel steel wire cable, characterized in that: It includes a cable body and anchoring components at both ends, wherein the cable body includes a plurality of parallel steel wires, one or more of the steel wires are provided with a groove, and a fiber grating sensor is embedded in the groove, wherein the fiber grating sensor is a single-mode optical fiber with one or more fiber gratings written therein; When embedding the fiber grating sensor, the steel wire is pre-tensioned with a pre-tensioning force of 15-25 kN; The steel wire with the groove is located at the outermost side of the steel wire combination in the cable body, and the angle between the opening direction of the groove and the tangent line of the outer circle of the cross section of the cable body where the steel wire is located is less than or equal to 30°; The parts of the cable body anchored to the anchoring assembly at both ends are the cable body anchoring sections, the part between the two cable body anchoring sections is the cable body free section, and the groove for embedding the fiber grating sensor is only located in the cable body free section; PE layer stripping sections are provided at both ends of the cable body, a part of the PE layer stripping section is located in the anchoring assembly, and the other part is located outside the anchoring assembly. A sleeve is also provided on the cable body, one end of the sleeve is connected to the anchoring assembly, and the other end of the sleeve is connected to the sleeve cover plate, and the sleeve cover plate is sleeved on the outer circumference of the cable body with a PE layer. The optical fiber end of the fiber grating sensor is led out from the PE layer stripping section located outside the anchoring assembly and fused with the optical fiber test jumper, and the optical fiber test jumper passes through the sleeve and the sleeve cover plate and is wound around the cable body.

2. The self-sensing parallel steel wire cable according to claim 1, characterized in that: After being embedded in the groove, the fiber grating sensor is packaged with epoxy resin glue.

3. The self-sensing parallel wire cable according to claim 1, characterized in that: The anchoring assembly comprises a fixed end anchor component and a tension end anchor component. The fixed end anchor component is sleeved on the fixed end of the cable body, and the tension end anchor component is sleeved on the tension end of the cable body.

4. The self-sensing parallel steel wire cable according to claim 3, characterized in that: The fixed end anchor component and the tension end anchor component are both cold cast anchors.

5. The self-sensing parallel steel wire cable according to claim 1, characterized in that: The optical fiber test jumper is connected to the optical fiber Bragg grating demodulator.

6. A method for manufacturing a self-sensing parallel steel wire cable, characterized in that: The method for manufacturing the self-sensing parallel steel wire cable as claimed in any one of claims 1 to 5 comprises the following steps: Step 1, cutting and braiding: first prepare the steel wire and the steel wire with the embedded fiber Bragg grating sensor in advance, cut them according to the specified length, and then put them together into the wire threading plate to braid them into bundles. The steel wire with the embedded fiber Bragg grating sensor is marked for easy identification; Step 2, extrusion: the bundled steel wire is pulled to the extruder for extrusion process, and then enters the cooling water tank for cooling; Step 3: Positioning and cutting: Positioning and cutting according to the fixed length of the cable body, and marking the optical fiber outlet end; Step 4, stripping PE layer and wiring: According to the specifications of the anchor, determine the length of the PE layer to be stripped and strip the corresponding PE layer; after stripping the PE layer, find the steel wire with the embedded fiber grating sensor, pick out the lead wire hidden in the steel wire with a special tool and fuse the fiber optic test jumper, and fix the fiber optic jumper on the cable body with tape; Step 5, install the anchor assembly: insert the sleeve cover plate, sleeve, and anchor assembly into the cable body in sequence; insert the steel wire into the wire dividing plate in a fixed arrangement and fix the head. After the head is fixed, fix the anchor assembly on the wire dividing plate; Step 6, grouting and curing: pour the prepared epoxy iron sand into the anchor assembly, vibrate and compact it, and then put it into a high-temperature curing furnace for curing; Step 7, super tension test: after the curing is completed, the super tension test is carried out, which is divided into 10 levels of tension. The fiber Bragg grating sensor is calibrated during the tension process.

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