CN117822336A - Relay type steel strand for large-strain monitoring and manufacturing and using methods thereof - Google Patents
Relay type steel strand for large-strain monitoring and manufacturing and using methods thereof Download PDFInfo
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- CN117822336A CN117822336A CN202410007316.7A CN202410007316A CN117822336A CN 117822336 A CN117822336 A CN 117822336A CN 202410007316 A CN202410007316 A CN 202410007316A CN 117822336 A CN117822336 A CN 117822336A
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 146
- 239000010959 steel Substances 0.000 title claims abstract description 146
- 238000012544 monitoring process Methods 0.000 title claims abstract description 59
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 15
- 238000000034 method Methods 0.000 title claims abstract description 13
- 239000000835 fiber Substances 0.000 claims description 161
- 239000013307 optical fiber Substances 0.000 claims description 95
- 230000007704 transition Effects 0.000 claims description 12
- 239000000084 colloidal system Substances 0.000 claims description 6
- 238000002310 reflectometry Methods 0.000 claims description 5
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- 238000005253 cladding Methods 0.000 claims description 3
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- 238000004873 anchoring Methods 0.000 claims 1
- 238000004891 communication Methods 0.000 claims 1
- 239000003292 glue Substances 0.000 description 6
- 239000003822 epoxy resin Substances 0.000 description 5
- 229920000647 polyepoxide Polymers 0.000 description 5
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- 238000000576 coating method Methods 0.000 description 3
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- NJPPVKZQTLUDBO-UHFFFAOYSA-N novaluron Chemical compound C1=C(Cl)C(OC(F)(F)C(OC(F)(F)F)F)=CC=C1NC(=O)NC(=O)C1=C(F)C=CC=C1F NJPPVKZQTLUDBO-UHFFFAOYSA-N 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 1
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Classifications
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- D—TEXTILES; PAPER
- D07—ROPES; CABLES OTHER THAN ELECTRIC
- D07B—ROPES OR CABLES IN GENERAL
- D07B1/00—Constructional features of ropes or cables
- D07B1/14—Ropes or cables with incorporated auxiliary elements, e.g. for marking, extending throughout the length of the rope or cable
-
- D—TEXTILES; PAPER
- D07—ROPES; CABLES OTHER THAN ELECTRIC
- D07B—ROPES OR CABLES IN GENERAL
- D07B1/00—Constructional features of ropes or cables
- D07B1/06—Ropes or cables built-up from metal wires, e.g. of section wires around a hemp core
- D07B1/0693—Ropes or cables built-up from metal wires, e.g. of section wires around a hemp core having a strand configuration
-
- D—TEXTILES; PAPER
- D07—ROPES; CABLES OTHER THAN ELECTRIC
- D07B—ROPES OR CABLES IN GENERAL
- D07B2201/00—Ropes or cables
- D07B2201/20—Rope or cable components
- D07B2201/2001—Wires or filaments
- D07B2201/2002—Wires or filaments characterised by their cross-sectional shape
-
- D—TEXTILES; PAPER
- D07—ROPES; CABLES OTHER THAN ELECTRIC
- D07B—ROPES OR CABLES IN GENERAL
- D07B2201/00—Ropes or cables
- D07B2201/20—Rope or cable components
- D07B2201/2083—Jackets or coverings
-
- D—TEXTILES; PAPER
- D07—ROPES; CABLES OTHER THAN ELECTRIC
- D07B—ROPES OR CABLES IN GENERAL
- D07B2205/00—Rope or cable materials
- D07B2205/30—Inorganic materials
- D07B2205/3021—Metals
- D07B2205/3025—Steel
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- D—TEXTILES; PAPER
- D07—ROPES; CABLES OTHER THAN ELECTRIC
- D07B—ROPES OR CABLES IN GENERAL
- D07B2501/00—Application field
- D07B2501/20—Application field related to ropes or cables
- D07B2501/2015—Construction industries
- D07B2501/203—Bridges
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- Length Measuring Devices By Optical Means (AREA)
- Optical Transform (AREA)
Abstract
The invention discloses a steel strand for relay type large-strain monitoring and a manufacturing and using method thereof, which are suitable for large-strain monitoring of various steel strand components in civil engineering.
Description
Technical Field
The invention relates to the technical field of bridge health monitoring. More particularly, the invention relates to a steel strand for relay type large-strain monitoring and manufacturing and using methods thereof.
Background
The effective stress along the prestressed steel strand is monitored reliably and accurately for a long time, so that the structural safety problem caused by the problem of prestress can be avoided to the greatest extent. As a hidden part, the in-vivo prestress steel strand is overlapped by various factors such as material characteristics, pipeline friction, inflection points, uneven grouting and the like, so that the prestress level is reduced and the prestress distribution is uneven, and the along-path stress distribution and change of the in-vivo prestress steel strand are difficult to effectively measure by a conventional monitoring means in actual engineering. In addition, the prestress steel strand is designed and used with high stress level, generally about 1400MPa, and the low-relaxation high-strength steel strand with standard tensile strength of 1860MPa and phi 15.2mm is taken as an example, the corresponding strain can reach more than 7000 mu epsilon, which also puts forward high requirements on the performance of the monitoring element, and when the fiber bragg grating is always in a state of larger tensile strain, the fiber bragg grating has the danger of static fatigue fracture even if the tensile strength is not exceeded.
Disclosure of Invention
It is an object of the present invention to solve at least the above problems and to provide at least the advantages to be described later.
The invention also aims to provide a steel strand for relay type large-strain monitoring and a manufacturing and using method thereof, so as to solve the technical problem that the prestress steel strand in a concrete structure body is difficult to monitor along the large-strain in the prior art.
To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the present invention provides a steel strand for relay type large strain monitoring, which is formed by twisting a plurality of side wires and a central wire, the central wire including a profiled wire, the profiled wire being provided with grooves on an outer side wall thereof, the grooves being parallel to a central axis of the profiled wire and being equally spaced from the profiled wire, the grooves being symmetrically distributed on the profiled wire, and a fiber grating strain sensing fiber a and a fiber grating strain sensing fiber B being respectively fixed in the grooves on both sides thereof, wherein the fiber grating strain sensing fiber a is in a compressed state with the same slack state as the profiled wire, and the profiled wire being provided with a sheath over the outer side thereof.
Preferably, the steel strands are arranged in a segmented manner, corresponding to each segment of the steel strands, two ends of the fiber grating strain sensing optical fiber A are respectively connected with an optical fiber lead a, two ends of the fiber grating strain sensing optical fiber B are respectively connected with an optical fiber lead B, one end of each of the optical fiber leads a and the optical fiber lead B, which are positioned on the same side, penetrating out of the groove is sleeved with a transition protection tube, and the transition protection tube is fixedly connected with the corresponding end of the steel strand.
Preferably, the hinging pitch of the central wire and the side wires is 12-16 times of the nominal diameter of the steel strand.
Preferably, the gratings on the fiber grating strain sensing optical fiber A and the fiber grating strain sensing optical fiber B are respectively arranged at equal intervals, and the reflectivity of each grating is the same and less than or equal to 1%.
Preferably, the diameter of the side wire is not greater than the diameter of the center wire.
On the other hand, the invention provides a manufacturing method of a steel strand for relay type large-strain monitoring, which comprises the following steps:
s1, manufacturing the special-shaped steel wire, wherein the grooves are symmetrically formed in the special-shaped steel wire;
s2, fixing the special-shaped steel wire, ensuring that the tensioning force on the special-shaped steel wire is not more than 1000N, and positioning one groove at the top;
s3, fixedly burying the fiber bragg grating strain sensing fiber A in the groove at the top;
s4, rotating the special-shaped steel wire, placing the other groove at the top, applying tensioning force to the special-shaped steel wire, keeping a tensioning state, and fixedly embedding the fiber bragg grating strain sensing fiber B into the corresponding groove;
s5, cladding the special-shaped steel wire with the sheath to ensure that the grating connection of the fiber grating strain sensing optical fiber A and the fiber grating strain sensing optical fiber B is stable, obtaining the central wire, and then removing the tensioning force to take down the central wire;
s6, hinging the plurality of edge wires with the central wire in the step S5 to form the steel strand;
and S7, respectively connecting the optical fiber lead a with the corresponding fiber grating strain sensing optical fiber A, connecting the optical fiber lead B with the corresponding fiber grating strain sensing optical fiber B at two ends of each section of the steel strand, and installing the transition protective sleeve to obtain the relay type steel strand for large strain monitoring.
Preferably, when the fiber grating strain sensing optical fiber A and the fiber grating strain sensing optical fiber B are fixedly installed, the fiber grating strain sensing optical fiber A and the fiber grating strain sensing optical fiber B are sequentially coated with adhesive colloid, two ends of each grating on the fiber grating strain sensing optical fiber A and the fiber grating strain sensing optical fiber B are positioned in the length range of 0 cm to 5cm, and the grating positions are not coated.
Preferably, in step S4, the applied tension is 30% to 50% of the designed usage load of the steel strand.
The invention also provides a using method of the steel strand for relay type large strain monitoring, before using, the steel strand is connected with demodulation equipment arranged outside through an optical fiber lead, and then a pulling force is applied to the whole steel strand, in this state, the strain monitoring with the first half-section measuring range of 0-4000 mu epsilon is carried out by using the optical fiber grating strain sensing optical fiber A, the strain monitoring with the second half-section measuring range of 4000-8000 mu epsilon is carried out by using the optical fiber grating strain sensing optical fiber B, and the strain monitoring with the whole measuring range of 0-8000 mu epsilon is formed.
The invention at least comprises the following beneficial effects:
(1) The steel strand structure for the sectional relay type large-strain monitoring is based on weak grating sensing, can be suitable for large-strain monitoring of various steel strand components in civil engineering, and can realize quasi-distributed large-strain monitoring within the whole length range of the steel strand structure by embedding the corresponding fiber grating strain sensing optical fibers in corresponding grooves of a special-shaped steel wire in a loose state and a tensioning state, coating the corresponding fiber grating strain sensing optical fibers with glue and wrapping a sheath for fixation and hinging the corresponding fiber grating strain sensing optical fibers with a side wire to form the steel strand, thereby solving the problem that the prestress steel strand in a concrete structure is difficult to monitor along the large-strain.
(2) The steel strand structure for segment relay type large strain monitoring based on weak grating sensing has the advantages of being convenient to quickly connect with demodulation equipment, convenient and quick to use, and easy to popularize and apply.
(3) When the relay type large-strain monitoring steel strand is used, the fiber grating strain sensing optical fiber is not subjected to excessive strain, the durability of the fiber grating strain sensing optical fiber is improved, continuous strain monitoring can be carried out through the fiber grating strain sensing optical fiber A and the fiber grating strain sensing optical fiber B sequentially along with the change of prestress in the steel strand, and the along-path stress distribution and change of the steel strand can be effectively measured.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention.
Drawings
FIG. 1 is a front view block diagram of a segment of a relay type steel strand for large strain monitoring according to the present invention;
FIG. 2 is a side view of the steel strand for relay type large strain monitoring according to the present invention;
FIG. 3 is a side elevational view of the center wire of the present invention;
FIG. 4 is a flowchart of a method for manufacturing a steel strand for relay-type large-strain monitoring according to an embodiment of the present invention;
reference numerals in the specification: 1. steel strand wires, 2, center wire, 3, limit silk, 4, special-shaped steel wire, 5, recess, 6, fiber grating strain sensing optic fibre A,7, fiber grating strain sensing optic fibre B,8, bonding colloid, 9, sheath, 10, transition protection tube, 11, fiber lead a,12, fiber lead B.
Detailed Description
The present invention is described in further detail below with reference to the drawings to enable those skilled in the art to practice the invention by referring to the description.
It should be noted that the experimental methods described in the following embodiments, unless otherwise specified, are all conventional methods, and the reagents and materials, unless otherwise specified, are all commercially available; in the description of the present invention, the terms "transverse", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus are not to be construed as limiting the present invention.
As shown in fig. 1-3, the invention provides a steel strand for relay type large-strain monitoring, which is formed by twisting a central wire 2 and a plurality of edge wires 3, wherein the central wire 2 comprises a special-shaped steel wire 4, the special-shaped steel wire 4 is internally provided with a groove 5 on the outer side wall, the groove 5 is parallel to the central axis of the special-shaped steel wire 4 and is equal to the special-shaped steel wire 4 in length, the groove 5 is symmetrically distributed on the special-shaped steel wire 4, the grooves 5 on two sides are respectively fixed with a fiber grating strain sensing fiber A6 and a fiber grating strain sensing fiber B7, the fiber grating strain sensing fiber A6 is in the same loose state as the special-shaped steel wire 4, the fiber grating strain sensing fiber B7 is in a compression state, and the outer side of the special-shaped steel wire 4 is coated with a sheath 9.
The steel strand 1 is formed by hinging a central wire 2 which is packaged with 2 fiber grating strain sensing optical fibers and a side wire 3 which is wound around the central wire 2, two grooves 5 of a special-shaped steel wire 4 are respectively arranged along the axial direction of the surface of the steel wire, inflection points of the grooves 5 are rounded, the section size of the grooves 5 is larger than the outer diameters of the fiber grating strain sensing optical fibers A6 and the fiber grating strain sensing optical fibers B7, the fiber grating strain sensing optical fibers A6 and the fiber grating strain sensing optical fibers B7 are fixed in one groove 5 in parallel and equal length, and then a sheath 9 is coated to ensure that the fiber grating strain sensing optical fibers do not fall out of the grooves 5.
When the fiber grating strain sensing optical fiber A6 and the fiber grating strain sensing optical fiber B7 are arranged, firstly, the fiber grating strain sensing optical fiber A6 is installed and fixed in a natural relaxation state, which is equivalent to the fact that the tightness state of the fiber grating strain sensing optical fiber A6 is basically the same as that of the special-shaped steel wire 4, then the special-shaped steel wire 4 is tensioned in an optical fiber bearing range, the fiber grating strain sensing optical fiber A6 in the groove 5 generates tensioning deformation along with the tensioning deformation, then the fiber grating strain sensing optical fiber B7 is installed and fixed, after the tensioning force is removed, the special-shaped steel wire 4 and the fiber grating strain sensing optical fiber A6 are restored to an initial relaxation state, and at the moment, the fiber grating strain sensing optical fiber B7 is compressed under the fixing action and the retracting action of the special-shaped steel wire 4 and is in a compression state.
Therefore, the fiber bragg grating strain sensing fiber A6 and the fiber bragg grating strain sensing fiber B7 realize relay expansion of strain ranges due to different continuity states of the synchronous steel strands 1, when the steel strands 1 are strained in the first stage, the fiber bragg grating strain sensing fiber A6 is used for monitoring, the fiber bragg grating strain sensing fiber B7 gradually reduces the shrinkage, when the steel strands 1 are strained in the second stage and reach the upper limit of the monitoring range of the fiber bragg grating strain sensing fiber A6, the fiber bragg grating strain sensing fiber B7 is used for continuing strain monitoring, and the fiber bragg grating strain sensing fiber A6 and the fiber bragg grating strain sensing fiber B7 in different installation states are combined, so that quasi-distributed large strain monitoring in the whole length range of the fiber bragg grating strain sensing fiber B7 can be realized, the strain monitoring range is up to 8000 mu epsilon, and the problem that the prestressed steel strands 1 in a concrete structure are difficult to monitor along the large strain is solved.
In another technical scheme, as shown in fig. 1, the steel strands 1 are arranged in sections, corresponding to each section of the steel strands 1, two ends of the fiber bragg grating strain sensing optical fiber A6 are respectively connected with a fiber lead a 11, two ends of the fiber bragg grating strain sensing optical fiber B7 are respectively connected with a fiber lead B12, the fiber leads a 11 and B12 on the same side are sleeved with a transition protection tube 10 at one end penetrating out of the groove 5, and the transition protection tube 10 is fixedly connected with the corresponding end of the steel strands 1.
Through setting up the optic fibre lead wire that corresponds, be convenient for be connected with the demodulation equipment of outside, accomplish the grafting out of optic fibre signal, the transition protection tube 10 of setting, anchor is at steel strand wires 1 both ends to guarantee that optic fibre is not destroyed at the end in special-shaped steel wire 4.
In another technical scheme, as shown in fig. 1, the hinging pitch of the central wire 2 and the side wires 3 is 12-16 times of the nominal diameter of the steel strand 1.
In another technical scheme, as shown in fig. 1-3, gratings on the fiber grating strain sensing optical fiber A6 and the fiber grating strain sensing optical fiber B7 are respectively arranged at equal intervals, and the reflectivity of each grating is the same and less than or equal to 1%.
In another embodiment, as shown in fig. 1-2, the diameter of the side wire 3 is not larger than the diameter of the center wire 2. The number ratio of the side wires 3 to the central wire 2 is 6:1, and the 6 side wires 3 are closely and symmetrically arranged relative to the central wire 2 in the cross section.
The invention also provides a manufacturing method of the steel strand for relay type large-strain monitoring, which is shown in combination with figures 1-4 and comprises the following steps:
s1, manufacturing the special-shaped steel wire 4, wherein the grooves 5 are symmetrically formed in the special-shaped steel wire 4; the grooves 5 may be drawn by special dies or mechanically ground on round wires.
S2, fixing the special-shaped steel wire 4, ensuring that the tensioning force on the special-shaped steel wire 4 is not more than 1000N, and positioning one groove 5 at the top; is fixed by a tensioning mount that facilitates the application of tension to the steel strand 1.
S3, fixedly burying the fiber bragg grating strain sensing fiber A6 in the groove 5 at the top; the fiber bragg grating strain sensing fiber A6 is completely positioned in the groove 5, so that the wiring direction is ensured, the fixation is good, and the groove 5 is not overflowed.
S4, rotating the special-shaped steel wire 4, placing the other groove 5 at the top, then applying tensioning force to the special-shaped steel wire 4, keeping a tensioning state, and fixedly burying the fiber bragg grating strain sensing fiber B7 into the corresponding groove 5. The special-shaped steel wire 4 is stretched to a certain force, and the fiber grating strain sensing fiber A6 synchronously stretches and changes along with the special-shaped steel wire 4.
S5, the special-shaped steel wire 4 is coated with the sheath 9, so that the stable grating connection of the fiber bragg grating strain sensing optical fiber A6 and the fiber bragg grating strain sensing optical fiber B7 is ensured, the central wire 2 is obtained, and then the central wire 2 is taken down by removing the tensioning force.
S6, hinging the side wires 3 and the central wire 2 in the step S5 to form the steel strand 1.
And S7, respectively connecting the optical fiber lead a 11 with the corresponding optical fiber grating strain sensing optical fiber A6, connecting the optical fiber lead B12 with the corresponding optical fiber grating strain sensing optical fiber B7 at two ends of each section of the steel strand 1, and installing the transition protective sleeve 9 to obtain the relay type steel strand 1 for large strain monitoring.
The manufactured steel strand structure for sectional relay type large-strain monitoring based on weak grating sensing can be suitable for large-strain monitoring of various steel strand components in civil engineering, the steel strand formed by embedding the corresponding fiber bragg grating strain sensing optical fibers in the corresponding grooves of the special-shaped steel wire in a loose state and a tensioning state, coating the corresponding fiber bragg grating strain sensing optical fibers with glue and wrapping a sheath for fixation and hinging the corresponding fiber bragg grating strain sensing optical fibers with side wires can realize quasi-distributed large-strain monitoring within the whole length range of the steel strand, the problem that the prestress steel strand in a concrete structure is difficult to monitor along the large-strain is solved, and in addition, the steel strand structure for sectional relay type large-strain monitoring based on the weak grating sensing is provided with the optical fiber lead, is convenient and fast to use and easy to popularize and apply.
In another technical scheme, as shown in fig. 3, when the fiber bragg grating strain sensing fiber A6 and the fiber bragg grating strain sensing fiber B7 are fixedly installed, the fiber bragg grating strain sensing fiber A6 and the fiber bragg grating strain sensing fiber B7 are sequentially coated by using an adhesive colloid 8, two ends of each grating on the fiber bragg grating strain sensing fiber A6 and the fiber bragg grating strain sensing fiber B7 are positioned within the length range of 0 cm to 5cm, and the grating positions are not coated. The adhesive colloid 8 is epoxy resin colloid, after each gluing, after waiting for complete solidification, the next operation is carried out, the sheath 9 is used for wrapping the surface of the special-shaped steel wire 4, and the position of the non-glued optical fiber is ensured not to fall out of the groove 5 to be damaged.
In another technical scheme, in the step S4, the applied tension is 30% -50% of the designed use load of the steel strand. The tensioning force is set according to the maximum tensile force and compression amount which can be borne by the fiber bragg grating strain sensing optical fiber, the measuring range of the fiber bragg grating strain sensing optical fiber is combined, the range can be expanded by 2 times, of course, different tensioning forces can be set according to the number of grooves 5 and corresponding monitoring optical fibers on the special-shaped steel wire 4 according to the condition of the fiber bragg grating strain sensing optical fiber, and the method also provides a research guiding direction for the subsequent increase of the strain range.
The invention also provides a using method of the steel strand 1 for relay type large strain monitoring, before using, the steel strand 1 is connected with demodulation equipment arranged outside through an optical fiber lead, and then a pulling force is applied to the whole steel strand 1, in this state, strain monitoring with the front half-section measuring range of 0-4000 mu epsilon is carried out by using the optical fiber grating strain sensing optical fiber A6, strain monitoring with the rear half-section measuring range of 4000-8000 mu epsilon is carried out by using the optical fiber grating strain sensing optical fiber B7, and strain monitoring with the whole measuring range of 0-8000 mu epsilon is formed.
Referring specifically to fig. 1-4, a specific example of the manufacture and use of the segmented relay type large strain monitoring steel strand based on weak grating sensing according to the present invention is given below, and the following operation sequence is performed:
(1) A special-shaped steel wire with a nominal diameter of 5.2mm and a groove width and a groove depth of 1mm is manufactured.
(2) The profiled steel wire is fixed horizontally on the pedestal, ensuring that one groove thereof is positioned at the top, and the tensioning force is not more than 1000N.
(3) The fiber grating strain sensing optical fibers A with the diameter of 250 mu m, the reflectivity of 0.6 per mill and the grating spacing of 1m and the grating length of 2cm are arranged in parallel and equal length in the groove at the top of the special-shaped steel wire, then epoxy resin glue is sequentially coated in the length range of 5cm at the two ends of each grating of the fiber grating strain sensing optical fibers A, and the grating positions are not glued.
(4) After the epoxy resin glue is completely cured for 2 hours, rotating the special-shaped steel wire to place the lower groove at the top, applying a tensioning force of 12000N on a pedestal, arranging the fiber bragg grating strain sensing fibers B with the diameter of 250 mu m, the reflectivity of 0.6 per mill and the grating spacing of 1m and the grating length of 2cm in parallel and equal length in the groove at the top of the special-shaped steel wire, and sequentially coating the fiber bragg grating strain sensing fibers B with the epoxy resin glue within the length range of 5cm at the two ends of each grating of the fiber bragg grating strain sensing fibers B, wherein the grating positions are not glued.
(5) After the epoxy resin glue is completely solidified for 2 hours, wrapping the surface of the special-shaped steel wire by using a transparent adhesive tape, ensuring that the position of the non-glued optical fiber does not fall out of the groove, and then removing the tensioning force to take down the special-shaped steel wire.
(6) And hinging the special-shaped steel wire with 6 side wires with the diameter of 5mm to form steel strands with the pitch of 228mm, wherein the diameter of the steel strands is 15.2mm.
(7) And respectively installing an optical fiber lead transition protection tube, an optical fiber lead a and an optical fiber lead b at two ends of the steel strand to form the sectional relay type steel strand structure for large strain monitoring based on weak grating sensing.
(8) The segmented relay type steel strand structure for large strain monitoring based on weak grating sensing is connected with demodulation equipment through an optical fiber lead. And the tensile force is applied to the fiber bragg grating strain sensing fiber A for measuring 0-4000 mu epsilon in the first half section, the fiber bragg grating strain sensing fiber B for measuring 4000-8000 mu epsilon in the second half section, and 0-8000 mu epsilon can be realized through accumulation, namely, the large strain monitoring of the steel strand structure is realized.
Although embodiments of the present invention have been disclosed above, it is not limited to the details and embodiments shown and described, it is well suited to various fields of use for which the invention would be readily apparent to those skilled in the art, and accordingly, the invention is not limited to the specific details and illustrations shown and described herein, without departing from the general concepts defined in the claims and their equivalents.
Claims (9)
1. The utility model provides a big steel strand wires for monitoring that meets an emergency of relay formula, a serial communication port, by the center wire and a plurality of limit silk system of setting are twisted, the center wire includes the special-shaped steel wire, inwards set up flutedly on the lateral wall, the recess is parallel with the axis of special-shaped steel wire and with the equal length setting of special-shaped steel wire, the recess is on special-shaped steel wire symmetric distribution, be fixed with fiber grating strain sensing optic fibre A and fiber grating strain sensing optic fibre B in the recess of both sides respectively, wherein fiber grating strain sensing optic fibre A is the same with the relaxation state of special-shaped steel wire, fiber grating strain sensing optic fibre B is in compression state, special-shaped steel wire outside cladding is provided with the sheath.
2. The steel strand for relay type large strain monitoring according to claim 1, wherein the steel strand is arranged in sections, corresponding to each section of the steel strand, two ends of the fiber bragg grating strain sensing fiber a are respectively connected with a fiber lead a, two ends of the fiber bragg grating strain sensing fiber B are respectively connected with a fiber lead B, one end of the fiber lead a and one end of the fiber lead B, which are positioned on the same side, penetrating out of the groove are sleeved with a transition protection tube, and the transition protection tube is connected with the corresponding end of the steel strand in an anchoring manner.
3. The steel strand for relay type large strain monitoring according to claim 1, wherein the hinging pitch of the center wire and the side wires is 12 to 16 times the nominal diameter of the steel strand.
4. The steel strand for relay type large strain monitoring according to claim 1, wherein the gratings on the fiber grating strain sensing fiber a and the fiber grating strain sensing fiber B are respectively arranged at equal intervals, and the reflectivity of each grating is the same and less than or equal to 1%.
5. The relay high strain monitoring steel strand according to claim 1, wherein the diameter of the side wire is not greater than the diameter of the center wire.
6. The method for manufacturing a steel strand for relay-type large-strain monitoring according to claim 2, comprising the steps of:
s1, manufacturing the special-shaped steel wire, wherein the grooves are symmetrically formed in the special-shaped steel wire;
s2, fixing the special-shaped steel wire, ensuring that the tensioning force on the special-shaped steel wire is not more than 1000N, and positioning one groove at the top;
s3, fixedly burying the fiber bragg grating strain sensing fiber A in the groove at the top;
s4, rotating the special-shaped steel wire, placing the other groove at the top, applying tensioning force to the special-shaped steel wire, keeping a tensioning state, and fixedly embedding the fiber bragg grating strain sensing fiber B into the corresponding groove;
s5, cladding the special-shaped steel wire with the sheath to ensure that the grating connection of the fiber grating strain sensing optical fiber A and the fiber grating strain sensing optical fiber B is stable, obtaining the central wire, and then removing the tensioning force to take down the central wire;
s6, hinging the plurality of edge wires with the central wire in the step S5 to form the steel strand;
and S7, respectively connecting the optical fiber lead a with the corresponding fiber grating strain sensing optical fiber A, connecting the optical fiber lead B with the corresponding fiber grating strain sensing optical fiber B at two ends of each section of the steel strand, and installing the transition protective sleeve to obtain the relay type steel strand for large strain monitoring.
7. The method for manufacturing a steel strand for relay type large strain monitoring according to claim 6, wherein when the fiber grating strain sensing optical fiber a and the fiber grating strain sensing optical fiber B are fixedly installed, an adhesive colloid is sequentially coated on the fiber grating strain sensing optical fiber a and the fiber grating strain sensing optical fiber B, wherein both ends of each grating are positioned within the length range of 0 cm to 5cm, and the grating positions are not coated.
8. The method for manufacturing a steel strand for relay-type large-strain monitoring according to claim 7, wherein the tension applied in step S4 is 30 to 50% of the designed use load of the steel strand.
9. The method for using a steel strand for relay type large strain monitoring as set forth in claim 6, wherein before use, the steel strand is connected with an externally provided demodulation device through an optical fiber lead, and then a pulling force is applied to the whole steel strand, in this state, strain monitoring with the first half range of 0 to 4000 με is performed by using the optical fiber grating strain sensing optical fiber a, strain monitoring with the second half range of 4000 to 8000 με is performed by using the optical fiber grating strain sensing optical fiber B, and strain monitoring with the whole range of 0 to 8000 με is formed.
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