The pick-up unit of bridge cable condition in damaged and real-time detection method
Technical field
The present invention relates to the bridge field, specifically is a kind of pick-up unit and real-time detection method of bridge cable condition in damaged.
Background technology
Drag-line is the main bearing member in the bridge structures such as cable-stayed bridge, suspension bridge and bowstring arch bridge, and at drag-line during one's term of military service, the force-bearing situation of drag-line and dynamic response directly determine the force-bearing situation and the dynamic response of whole bridge structure.Owing to receive factors such as corrosion and fatigue; Drag-line after using over a long time can receive damage in various degree, and the pulling force that causes drag-line is that axial force descends, and finally causes bearing capacity, the strength degradation of whole bridge structure; There is potential safety hazard, even cave-in accident can occur.So must detect the condition in damaged of drag-line, in time change impaired serious drag-line, stop potential safety hazard.
Prior art to the detection method of bridge cable is: earlier a drag-line is detected; Be that people are fixed on detecting instrument on the single cable; Knock this drag-line then; The vibration frequency of this drag-line of detecting instrument record is brought the length of vibration frequency, this drag-line into size that experimental formula is calculated the axial force of this single cable then, after this detects the size of the axial force of other drag-line in the same way by root; If the axial force of certain the root drag-line that calculates is significantly less than warning value, just change this drag-line.
The pick-up unit of prior art and detection method can't accurately measure the size of drag-line axial force, the measurement result out of true, and measurement effect is poor, and this is caused by a plurality of factors.At first, in the process of the vibration frequency of gathering drag-line with instrument, measurement result is easy to receive the interference of external environment factor such as factors such as wind-force, bridge floor Vehicular vibration, and the vibration frequency that causes measuring is inaccurate; And when knocking short drag-line with hand, the amplitude of vibration is little, and the frequency of vibration is not easy to be gathered by a small margin; And because the drag-line lower end is anchored in the concrete, and this mode of anchoring neither belongs to affixed and does not belong to hinged, and its boundary condition can't be confirmed, so can't obtain drag-line length accurately at all; The drag-line axial force nature out of true of coming out like this, based on coarse vibration frequency and drag-line length computation.In fact, do not have unified formula and standard to go accurately to obtain the axial force of drag-line in the industry at all, but pass through experimental formula; The axial force of rough judgement drag-line, then, for the sake of assurance; Change the drag-line that possibly go wrong even at set intervals whole drag-lines are more changed; So waste is serious, maintenance cost is high, the maintenance process trouble.
And the testing process of prior art is cumbersome, when detecting, need detecting instrument and single cable be fixed at every turn, need detecting instrument and drag-line be thrown off again after having detected, and process is loaded down with trivial details, speed is slow, and efficient is low; Exactly because testing process is more loaded down with trivial details, so the frequency that detects is difficult to hold, if it is too frequent to detect frequency, it is too much to detect number of times, and then the ten minutes trouble wastes time and energy, and it is low to detect frequency, and number of times is few, and interval time is long, can not get rid of potential safety hazard again.
Summary of the invention
The technical matters that the present invention will solve is, provides a kind of and can accurately judge the drag-line condition in damaged so that in time change impaired drag-line and the testing process pick-up unit of bridge cable condition in damaged easily and efficiently.
Technical solution of the present invention is; A kind of pick-up unit of bridge cable condition in damaged is provided; It comprises a plurality of pick-up unit monomers, and each pick-up unit monomer comprises a rigid sleeve, two cables and an amplifier that is electrically connected with display, is provided with an annulus cover with the coaxial piezoelectric of rigid sleeve in the rigid sleeve; The annulus cover is coated with insulation course; Be provided with two endplates in the rigid sleeve, annulus overlaps between two endplates, and endplate is provided with the through hole that current supply cable passes; The inner of a cable is through the through hole of endplate and penetrate insulation course and be electrically connected with the inner peripheral surface of annulus cover; The inner of another root cable is through the through hole of endplate and penetrate insulation course and be electrically connected with the outer circumference surface of annulus cover, and the outer end of two cables all is electrically connected with amplifier, and endplate and annulus put and be equipped with the center pit that is used for branch's steel strand wires fit of drag-line lower end.
Another technical matters that the present invention will solve is, provides a kind of and can accurately judge the drag-line condition in damaged so that in time change impaired drag-line and the observation process real-time detection method of bridge cable condition in damaged easily and efficiently.
Another technical solution of the present invention is, a kind of real-time detection method of bridge cable condition in damaged is provided, and its step comprises:
A, prefabricated a plurality of pick-up unit monomers; Each pick-up unit monomer comprises the annulus cover of a rigid sleeve, two cables and a piezoelectric; The annulus cover is positioned at rigid sleeve and coaxial with rigid sleeve; The inner of a cable is electrically connected with the inner peripheral surface of annulus cover, and the inner of another root cable is electrically connected with the outer circumference surface of annulus cover, and rigid sleeve is stretched out in the outer end of two cables;
The broadening formation duct that bridge anchorage zone concrete is reserved is passed in the lower end of b, single cable that upper end and pontic are fixed, and in the broadening formation duct, drag-line is branched into many steel strand wires;
C, put a pick-up unit monomer for every steel strand wires in the broadening formation duct;
D, two cables of each pick-up unit monomer are inserted external power supplys, under the effect of external supply voltage, make the annulus cover of this pick-up unit monomer that deformation take place, finally make this annulus cover and the tight fit of steel strand wires;
E, two cables and the external power supply of each pick-up unit monomer broken away from, again two cables are electrically connected with amplifier, and amplifier is electrically connected with display;
F, the every steel strand wires lower end and the anchor slab of this drag-line are fixed;
G, fill slip casting to the broadening formation duct of anchor slab top from the grout hole of anchor slab; Make each root steel strand wires of this drag-line be anchored in the anchorage zone fully; And concrete slurry is because two endplates obstructs of rigid sleeve outermost end; Can not get in the rigid sleeve, at this moment, the sealing off and covering anchorage process of this drag-line and pick-up unit installation process are accomplished;
The normal vibration of h, drag-line and each root steel strand wires of drag-line lower end; Can produce radial force; The radial force of every steel strand wires can be compressed the annulus cover of the piezoelectric that tightly is linked on the steel strand wires, produces voltage between the inside and outside periphery that makes annulus overlap, and this voltage amplifies through cable transmission, amplifier; Finally conduct on display, and on display, form one about the time of these root steel strand wires and the waveform of voltage;
I, after bridge completion, and on the display about the peak value of the waveform of steel strand wires at sampling time section T
1When interior maintenance is stablized, write down this peak A
0Standard peak value as steel strand wires;
The radial force of j, steel strand wires can increase and progressively decay along with active time, and the true peak on the display can constantly be decayed too, when true peak at sampling time section T
1When interior maintenance is stablized, write down the comparison peak A of this peak value as steel strand wires
1
K, with the comparison peak value divided by the standard peak value, if the ratio of acquisition greater than warning value, then this steel strand wires condition in damaged is reasonable; The drag-line of these steel strand wires need not to change; In case the ratio that obtains judges then that less than warning value these steel strand wires are impaired, must more change the drag-line at this steel strand wires place.
The principle of this real-time detection method is: impaired and even axial force drag-line of the radial force of drag-line and drag-line is that the pulling force situation is interrelated; In case drag-line is impaired; The radial force of drag-line and axial force all can decay, so compare the radial force of drag-line, just can accurately judge the condition in damaged of drag-line.
The pick-up unit of bridge cable condition in damaged of the present invention and real-time detection method compared with prior art have following remarkable advantage and beneficial effect:
Utilize this device to adopt this method to avoid the technical barrier that accurately to measure the drag-line axial force in the industry, but mode of comparing is adopted in creationary proposition, compare divided by ratio and warning value that the base peak value obtains with the comparison peak value; Thereby can accurately monitor the condition in damaged of drag-line; Thereby judge accurately whether drag-line needs to change, customer service prior art can't accurately calculate the drag-line axial force, can't accurately judge the technical barrier of condition in damaged; So neither can produce potential safety hazard because missing impaired drag-line; Can not cause waste again, simplify maintenance process, reduce maintenance cost owing to having changed not impaired drag-line; And; This method only need be in the drag-line lower end the disposable pick-up unit monomer that installs during sealing off and covering anchorage; Just can measure for a long time; And measuring process only is from display, to draw two kinds of peak values to compare and get final product, and need not as the every survey of prior art the one-shot measurement instrument to be installed on every drag-line once, so measuring method of the present invention is simple and convenient intuitively; Again because real-time detection method of the present invention is simple and convenient, so can more consider that according to safety factor measurement drag-line condition in damaged is as far as possible repeatedly further stopped potential safety hazard; Also because pick-up unit monomer when installing, the annulus of piezoelectric is enclosed within the effect of charge compensation, is adjacent to the steel strand wires of drag-line, so further accurate measurement result.
As improvement, each pick-up unit monomer also comprises two spacing dividing plates, and the interval of two spacing dividing plates equals the thickness of annulus cover; Annulus overlaps between two spacing dividing plates; Also be provided with through hole that current supply cable passes and the center pit that is used for the steel strand wires fit on the spacing dividing plate, like this, two spacing dividing plates can be with the axial limiting of annulus cover along rigid sleeve; Avoid annulus to overlap axial slippage and produce measuring error; And the concrete of two endplates of outer end can prevent sealing off and covering anchorage the time gets into rigid sleeve, dead steel strand wires of anchor and annulus cover, interferometry.
As improving again; Also be provided with a supporting clapboard between every endplate and the adjacent spacing dividing plate, also be provided with through hole that current supply cable passes and the center pit that is used for the steel strand wires fit on the supporting clapboard, like this; Supporting clapboard is carrying cable effectively, prevents that cable tangles knotting.
As improving again, the annulus cover of piezoelectric is the annulus cover of barium titanate ceramics material again, and this material piezoelectric property is good, and cost is inexpensive.
As further improvement, the sampling time section T described in step I and the step j
1Be any one numerical value between 45 seconds to 75 seconds, the sampling time, sampled result was more accurate in this scope.
As preferably, the sampling time section T described in step I and the step j
1Be 60 seconds, in such sampling time, sampled result is the most accurate.
As improving again, the warning value among the step k is between 0.8 to 0.9, and under this numerical value, judged result is more accurate.
As further improving again, the warning value among the step k is 0.9, draws in the tangible repeated tests of this numerical value, and judged result is the most accurate.
Description of drawings
Fig. 1 is the half section structural representation of the pick-up unit of bridge cable condition in damaged of the present invention.
Fig. 2 is that the side that the annulus of the pick-up unit of bridge cable condition in damaged of the present invention overlaps is analysed and observe the structure for amplifying synoptic diagram.
Fig. 3 is the structural representation that the pick-up unit of bridge cable condition in damaged of the present invention is installed in the anchor-hold district.
Shown in the figure 1, rigid sleeve, 2, cable, 3, the annulus cover, 3.1, insulation course, 4, endplate, 5, through hole, 6, drag-line, 6.1, steel strand wires, 7, center pit, 8, supporting clapboard, 9, the broadening formation duct, 10, anchor slab, 11, spacing dividing plate.
Embodiment
Below in conjunction with accompanying drawing and specific embodiment the present invention is described further.
Like Fig. 1, Fig. 2, shown in Figure 3, the pick-up unit of bridge cable condition in damaged of the present invention, it comprises a plurality of pick-up unit monomers.Drag-line 6 is twisted into by many steel strand wires 6.1, in the lower end of drag-line 6, twists into 6.1 fens forks of each steel strand wires of drag-line 6.And the every steel strand wires 6.1 of each pick-up unit monomer and drag-line 6 are corresponding one by one.Each pick-up unit monomer comprises a rigid sleeve 1, two cables 2 and amplifiers that are electrically connected with display.Be provided with an annulus cover 3 with the coaxial piezoelectric of rigid sleeve 1 in the rigid sleeve 1, the annulus cover 3 of piezoelectric be that the annulus of barium titanate ceramics material overlaps 3.Annulus cover 3 is coated with insulation course 3.1.Be provided with two endplates 4 in the rigid sleeve 1, annulus cover 3 is between two endplates 4.Each pick-up unit monomer comprises that also the interval of 11, two spacing dividing plates 11 of two spacing dividing plates equals the thickness of annulus cover 3, and annulus cover 3 is between two spacing dividing plates 11.Also be provided with a supporting clapboard 8 between every endplate 4 and the adjacent spacing dividing plate 11; That is to say; One side of annulus cover 3 is from an interior spacing dividing plate 11, a supporting clapboard 8 and endplate 4 of being provided with successively outward, and the opposite side of annulus cover 3 is also from an interior spacing dividing plate 11, a supporting clapboard 8 and endplate 4 of being provided with successively outward.Be equipped with the through hole 5 that current supply cable 2 passes on endplate 4, supporting clapboard 8 and the spacing dividing plate 11; The inner of a cable 2 is successively through the through hole 5 of the through hole 5 of the through hole 5 of endplate 4, supporting clapboard 8 and spacing dividing plate 11 and penetrate insulation course 3.1 and be electrically connected with the inner peripheral surface of annulus cover 3; Also successively through the through hole 5 of the through hole 5 of the through hole 5 of endplate 4, supporting clapboard 8 and spacing dividing plate 11 and penetrate insulation course 3.1 and be electrically connected with the outer circumference surface of annulus cover 3, the outer end of two cables 2 all is electrically connected with amplifier in the inner of another root cable 2.Be equipped with the center pit 7 that is used for branch's steel strand wires 6.1 fits of drag-line 6 lower ends on endplate 4, supporting clapboard 8, spacing dividing plate 11 and the annulus cover 3; Specifically; The aperture of the center pit 7 on endplate 4, supporting clapboard 8, spacing dividing plate 11 and the annulus cover 3 equals the external diameter of steel strand wires 6.1 or is slightly larger than the external diameter of steel strand wires 6.1, is 1.05 times of external diameter like the aperture.
Like Fig. 1, Fig. 2, shown in Figure 3, the real-time detection method of bridge cable condition in damaged of the present invention, its step is following.
A, prefabricated a plurality of pick-up unit monomers; Each pick-up unit monomer comprises the annulus cover 3 of a rigid sleeve 1, two cables 2 and a piezoelectric; Annulus cover 3 is positioned at rigid sleeve 1 and coaxial with rigid sleeve 1; The inner of a cable 2 is successively through the through hole 5 of the through hole 5 of the through hole 5 of endplate 4, supporting clapboard 8 and spacing dividing plate 11 and penetrate insulation course 3.1 and be electrically connected with the inner peripheral surface of annulus cover 3; The inner of another root cable 2 is successively through the through hole 5 of the through hole 5 of the through hole 5 of endplate 4, supporting clapboard 8 and spacing dividing plate 11 and penetrate insulation course 3.1 and be electrically connected with the outer circumference surface of annulus cover 3, and rigid sleeve 1 is stretched out in the outer end of two cables 2.
The broadening formation duct 9 that bridge anchorage zone concrete is reserved is passed in the lower end of b, single cable 6 that upper end and pontic are fixed, and in broadening formation duct 9, drag-line 6 is branched into many steel strand wires 6.1.
C, put a pick-up unit monomer for the every steel strand wires 6.1 in the broadening formation duct 9; Its concrete steps do, steel strand wires 6.1 are passed successively center pit 7, the center pit 7 of opposite side supporting clapboard 8 and the center pit 7 of opposite side endplate 4 of the spacing dividing plate 11 of center pit 7, opposite side of center pit 7, the annulus cover 3 of center pit 7, a lateral confinement position dividing plate 11 of center pit 7, a side supporting clapboard 8 of a side dividing plate 4.
D, two cables of each pick-up unit monomer 2 are inserted external power supplys, under the effect of external supply voltage, make the annulus cover 3 of this pick-up unit monomer that deformation take place, finally make this annulus cover 3 and steel strand wires 6.1 tight fits.
E, two cables of each pick-up unit monomer 2 and external power supply are broken away from; Again two cables 2 are electrically connected with amplifier; And amplifier is electrically connected with display, specifically, is exactly that amplifier with a plurality of pick-up unit monomers is electrically connected with same display; Or the amplifier of a plurality of pick-up unit monomers is electrically connected with many different displays, every display can show the waveform of the steel strand wires 6.1 that the pick-up unit monomer that is electrically connected with it belongs in real time.
F, every steel strand wires 6.1 lower ends and anchor slab 10 anchors of this drag-line 6 are fixing.
G, fill slip castings to the broadening formation duct 9 of anchor slab 10 tops from the grout hole of anchor slab 10; Make each root steel strand wires 6.1 of this drag-line 6 be anchored in the anchorage zone fully; And concrete slurry is because two endplates, 4 obstructs of rigid sleeve 1 outermost end; Can not get in the rigid sleeve 1, at this moment, the sealing off and covering anchorage process of this drag-line 6 and pick-up unit installation process are accomplished.
The normal vibration of h, drag-line 6 and each root steel strand wires 6.1 of drag-line 6 lower ends; Can produce radial force; The radial force of every steel strand wires 6.1 can be compressed the annulus cover 3 that tightly is linked in the piezoelectric on the steel strand wires 6.1, make to produce voltage between the inside and outside periphery of annulus cover 3, this voltage through cable 2 transmit, amplifier amplifies; Finally conduct on display, and on display, form one about the time of these root steel strand wires 6.1 and the waveform of voltage; Because the magnitude of voltage of the waveform that shows on the radial force of every steel strand wires 6.1 and the display is proportional; So time dependent waveform of radial force of these steel strand wires 6.1 of demonstration that just can be directly perceived true and reliable on this display about the waveform of time and voltage; That is to say; Waveform on the display equates all that with cycle, frequency, the phase place of the time dependent waveform of radial force of steel strand wires 6.1 peak value of the waveform of display can truly reflect the peak value of steel strand wires 6.1 radial forces.
The magnitude of voltage of the waveform that shows on the radial force of steel strand wires 6.1 and the display is proportional, this be because:
Receive radial force F and do the time spent; Annulus
cover 3 produces charge Q; Relational expression between radial force F and the charge Q is
; D is a piezoelectric constant; Be a definite value of selecting according to material, as the piezoelectric constant of too sour barium material, get
; And the formula of the voltage U that
annulus cover 3 produces is
; And
; Wherein, S is the compression area of piezoelectric; It is to have the size of piezoelectric itself to determine; The piezoelectric annulus of confirming for concrete size overlaps; S is exactly a definite value; Equally;
is the thickness of piezoelectric, and for the annulus cover of concrete size,
also is a definite value;
is permittivity of vacuum; It was exactly a definite value originally, and
is the piezoelectric relative dielectric constant, also was a definite value of selecting according to material; For the too sour barium of concrete material;
also is definite value, promptly owing to
,
,
, S are definite values, so Ca also is a definite value; Annulus overlaps the voltage
of 3 stressed generations; D, Ca are definite values, so U is directly proportional with F, the voltage of 3 generations can be exaggerated device and display amplifies and annulus overlaps; Last voltage
on display; Wherein n is an enlargement factor, and it is by the concrete model decision of display, amplifier, in other words; As far as concrete display and amplifier, n also is a definite value.To sum up; Voltage on the display
; Because n, d, Ca are definite value, so the voltage U y on radial force F and the display is proportional.
I, after bridge completion, and when keeping stablizing in sampling time section T1 about the peak value of the waveform of steel strand wires 6.1 on the display, write down this peak A
0As the standard peak value of steel strand wires 6.1, in other words, at sampling time section T
1In, the peak value of a plurality of adjacent periods of waveform equates on the display, this peak value is just as the standard peak value; Sampling time section T
1Be any one numerical value between 45 seconds to 75 seconds, as in 45 seconds, in 50 seconds or in 70 seconds or the like, sampling time section T
1Preferred 60 seconds.
The radial force of j, steel strand wires 6.1 can increase and progressively decay along with active time, and the true peak on the display can constantly be decayed too, when true peak at sampling time section T
1When interior maintenance is stablized, write down the comparison peak A of this peak value as steel strand wires 6.1
1In other words, at sampling time section T
1In, the peak value of a plurality of adjacent periods of waveform equates on the display, this peak value is just as the comparison peak value; Sampling time section T
1Be any one numerical value between 45 seconds to 75 seconds, as in 45 seconds, in 50 seconds or in 70 seconds or the like, sampling time section T
1Preferred 60 seconds.
K, usefulness comparison peak value are divided by normal peak; If the ratio that obtains is greater than warning value; Then these steel strand wires 6.1 conditions in damaged are reasonable, and the drag-line 6 at these steel strand wires 6.1 places need not to change, in case the ratio that obtains is less than warning value; Judge that then these steel strand wires 6.1 are impaired, must more change the drag-line 6 at these steel strand wires 6.1 places; Warning value is between 0.8 to 0.9, preferred 0.9.