Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
  • G01M5/00—Investigating the elasticity of structures, e.g. deflection of bridges or air-craft wings
  • G01M5/0025—Investigating the elasticity of structures, e.g. deflection of bridges or air-craft wings of elongated objects, e.g. pipes, masts, towers or railways
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
  • G01B11/00—Measuring arrangements characterised by the use of optical techniques
  • G01B11/16—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
  • G01B21/00—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant
  • G01B21/32—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant for measuring the deformation in a solid
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
  • G01B5/00—Measuring arrangements characterised by the use of mechanical techniques
  • G01B5/30—Measuring arrangements characterised by the use of mechanical techniques for measuring the deformation in a solid, e.g. mechanical strain gauge
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
  • G01M5/00—Investigating the elasticity of structures, e.g. deflection of bridges or air-craft wings
  • G01M5/0041—Investigating the elasticity of structures, e.g. deflection of bridges or air-craft wings by determining deflection or stress

Definitions

• the present invention relates to a detector of bending and / or differential settlement (s).
• the present invention also relates to a method for monitoring the bending and / or differential settlement (s) of a structure.
• the invention is particularly interested in certain types of differential deformation encountered in geotechnics, and shape changes in tunnels, for monitoring the geometric stability of structures.
• WO-A-97/42 463 discloses a method consisting in intimately associating with the structure a body - called "model" - elongated in which is incorporated at least one optical fiber.
• model elongated in which is incorporated at least one optical fiber.
• the deformation of the model is detected by a variation in the attenuation of the light transmitted by the optical fiber.
• the bending and / or differential settlement detector (1) is characterized in that it comprises:
• the detector according to the invention is particularly simple to install since it suffices to fix it on the surface of the structure to be monitored. In extreme cases, for example if simple clamps are used to install the detector by fixing, or even if the detector is simply placed on top of a surface, the installation can be assured in a few tens of seconds. This is important in certain applications, for example in environments likely to be radioactive.
• the detector according to the invention delivers a signal corresponding to the angle formed between successive elements at each articulation.
• the long base measurement is based on the observation that for civil engineering works, an integral (in the mathematical sense of the term) of the deformations is more representative of the risk incurred by the structure than this or that deformation measured locally.
• the method for monitoring the bending and / or differential settlement (s) of a structure is characterized in that it is installed along at least part of a surface of the structure several successive elements linked together by means of articulation, and angular deviations between successive elements are detected.
• Figure 1 is a schematic perspective view of the bending and / or differential settlement detector (s) according to the invention
• FIG. 2 illustrates a rapid mounting mode of the detector under a beam belonging to the structure to be monitored
• FIG. 3 is an elevational view of the detector fixed under the beam
• - Figure 4 is a detail view of the embodiment of Figure 3, the beam being in the deformed state;
• - Figure 5 is a view similar to Figure 4 but with the detector mounted on top of the beam;
• FIG. 6 is a cross-sectional view of a tunnel equipped with detectors according to the invention.
• FIG. 7 is a view of a detector according to the invention placed on a ground whose geometry is to be monitored.
• the bending and / or differential settlement detector (s) 10 according to the invention comprises a succession of elements 1 connected together by articulations 2.
• Each element 1 comprises a sole 4 of generally planar shape.
• the articulation axes 3 are substantially located in the plane of the soles 4 and allow the soles 4 to be mutually aligned.
• the soles 4 can thus be pressed all together, by their lower bearing surface 6, against a flat surface of a structure capable of bending.
• Each element 1 has the general shape of an angle iron of which one of the wings is constituted by the sole 4.
• the other wing 7 of the angle iron rises from the sole 4 in the direction opposite to the bearing surface 6
• the wings 7 are coplanar.
• end edges 8 which are oblique with respect to in the plane of the respective sole 4 so as to form between the two edges 8 opposite two adjacent elements 1 a notch 9 in V shape when the soles 4 are coplanar. This allows the elements 1 to pivot with respect to each other around the hinge axes 3 even in the direction where the end edges 8 approach each other from the situation where the flanges 4 are coplanar.
• Each sole 4 comprises means for fixing the element 1 against the surface of the structure.
• each sole 4 has for this purpose two holes 11 located in an intermediate position between the longitudinal ends of the element, and with a certain distance between them measured parallel to the direction of succession of the elements.
• the assembly of the two holes 11 of each element is located at an equal distance between the two ends of the element and with them a relatively small spacing relative to the length of the element.
• this allows to fix the elements to the structure, here a beam 12, by applying the bearing face 6 of the sole 4 against the surface 13 of the structure which is convex, or likely to become convex under the effect of bending.
• Fastening elements 14 are used for this which are not shown in detail but which may be bolts. Thanks to the two fixing means each corresponding to one of the holes 11 of each element, the bearing face 6 of the sole 4 of each element is held substantially tangent to the surface 13 in the middle of each element. It is thus ensured that the succession of soles 4 fairly faithfully reproduces, in the form of a broken line, the curvilinear profile of the surface 13.
• the elements 1 must therefore not flex with the structure. Their angle shape helps prevent them from sagging. It is possible that the detector must in certain applications be installed on non-planar surfaces or on surfaces which should be planar but which have flatness defects. To this end, as shown in FIG.
• the soles 4 can have one or more adjustable support means 16 (only one is shown, on one of the elements), for example each consisting of a screw 17 which can be more or less screwed into a threaded hole in the sole 4 so that its bearing end 18 makes an adjustable projection on the surface 6.
• the bearing means 16 are adjusted so that each element is pressed stably on the structure .
• Means 19 for detecting the angular deviation between successive elements 1 are mounted with a body 21 fixed to the wing 7 of an element 1 and an end 22 for capturing movement fixed to the wing 7 of the neighboring element 1 .
• the points of the two wings 7 where the body 21 and the end 22 are respectively fixed are chosen so that the line 23 along which a displacement is detected passes at a distance from the axis 3 of the corresponding joint 2, in other words that line 23 and axis 3 are not intersecting.
• the angular deviation between neighboring elements 1 is detected by detecting the variation in distance between the neighboring elements 1 along line 23.
• the detection means 19 is preferably a sensor conforming to DE 39 02 997 or to the Japanese application filed under the number JP 6-291 249.
• an optical fiber forms a turn around two studs mounted in the housing 21 , one being fixed relative to the housing and the other mounted on a slide integral with the motion-sensing end 22.
• the sections of coil extending between the two studs form a sinuosity whose curvature varies when the distance varies between the housing 21 and the capture end 22.
• One of the ends 24 of the optical fiber is supplied by a light source 26.
• the other end 27 of the optical fiber is connected to a means 28 for detecting the intensity light received.
• the capture end 22 moves relative to the housing 21 of the corresponding sensor 19. This changes the curvature of the sinuosity or sinuosities of the optical fiber in the housing 21 and this changes the attenuation of light in the optical fiber. This modification of attenuation is detected in the device 28.
• the light intensities detected by the device 28 are transmitted, for example in digital form, to a processing unit 29 which can for example view on a screen 31 the deformed profile 32 of the surface 13 of the structure, or even provide results numerical, for example deflection measurements at different points along the length of the surface 13, or even corresponding stress values.
• FIG. 2 shows that the device according to the invention can be fixed very quickly to the structure 12 by means of simple clamps 33, for example one per element 1 of the detector. We managed to mount the detector in a few tens of seconds.
• Figure 3 shows that the elements 1 can be very different in length from each other. Very short elements 1 can be placed in areas where large deformations are expected, or with large variations in deformation between points close to each other, for example in the vicinity of a pillar supporting the beam 12 or a load applied to the beam 12.
• Figure 3 also shows that the detector 10 may only extend over part of the beam 12 or other structure to be monitored. One can for example place the detector 10 in an area likely to be the most constrained. It is also possible that the deformations of the rest of the beam 12 can be deduced from the deformations of the zone associated with the detector, by extrapolation.
• FIG. 5 shows that the detector 10 can also be placed on a surface 34 which is concave or capable of becoming concave under the effect of the deformation.
• the elements 1 it is preferred to fix the elements 1 by means 36 not shown in detail, which coincide with the joints 2. This allows the zone of the elements 1 and in particular to the zone of the soles 4 which is distant from their joints 2, to deviate as necessary from the surface 34 according to the concavity.
• a detector 10 is placed on a ground 44 to detect any differential settlement.
• the detector 10 rests on the ground by gravity, ie by its own weight, the elements 1 can be made relatively heavy to ensure good coupling between each element 1 and the part of the ground 44 on which the element 1 rests .
• the detector does not need to include fixing means.
• the invention is not limited to the examples described and shown.
• the joints may be replaced by 'pseudo-joints, for example in the form of resiliently flexible links.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Aviation & Aerospace Engineering (AREA)
• Testing Or Calibration Of Command Recording Devices (AREA)
• Length Measuring Devices By Optical Means (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=8849350

Family Applications (1)

Country Status (7)

Families Citing this family (2)

Family Cites Families (10)

• 2000
  • 2000-04-17 FR FR0004950A patent/FR2807829B1/fr not_active Expired - Fee Related
• 2001
  • 2001-04-17 JP JP2001576405A patent/JP2004501345A/ja active Pending
  • 2001-04-17 EP EP01927975A patent/EP1295082A1/de not_active Withdrawn
  • 2001-04-17 AU AU2001254859A patent/AU2001254859A1/en not_active Abandoned
  • 2001-04-17 WO PCT/FR2001/001169 patent/WO2001079783A1/fr not_active Application Discontinuation
  • 2001-04-17 CN CN 01808254 patent/CN1425126A/zh active Pending
  • 2001-04-18 TW TW90109104A patent/TW505780B/zh not_active IP Right Cessation

Non-Patent Citations (1)

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