JP2014232050A - Bending deformation amount measurement method and bending deformation amount measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bending deformation amount measurement method capable of accurately measuring a multidirectional bending deformation amount of a measurement object, and to provide a bending deformation amount measurement device having a simple configuration used in the bending deformation amount measurement method.SOLUTION: In the bending deformation amount measurement method, two reference points P1 and P1 and one comparison point P2 are previously set at separate positions on the same straight line LB of a pile 2. After deformation of the pile 2, physical quantity correlating with a perpendicular separation distance of at least two directions between the linear line passing the reference points P1 and P1 and the comparison point P2 is measured, thereby measuring the multidirectional bending deformation amount of the pile 2. A bending deformation amount measurement device used for the measurement method is also provided.

Description

  The present invention relates to a bending deformation amount measuring method and a bending deformation amount measuring apparatus.

  The structure may be damaged by a large external force such as an earthquake. However, it was difficult to confirm the soundness of structural parts buried in the ground, such as piles.

  As methods for confirming the soundness of underground parts such as piles, a method in which the surrounding ground is excavated and visually examined, a method in which an exposed part is struck to generate elastic waves and the reflected waves are analyzed, etc. are adopted. However, there are problems such as large work and uncertain diagnosis.

  Therefore, as a method of measuring the soundness of the pile, a plurality of strain gauges are attached to the predetermined cross-sectional position (height position) of the pile, and the strain generated in the pile is electrically measured using these strain gauges. A measurement method for measuring may be employed.

  Further, in Patent Document 1, a measuring device having a rod-like elastic member embedded in a concrete member and a plurality of strain gauges installed at predetermined intervals in the axial direction on the outer surface of the rod-like elastic member provides elasticity. A measuring method for obtaining the curvature of a concrete member that has undergone bending deformation by measuring the strain of the member is disclosed.

  Patent Document 2 discloses a method of measuring the amount of bending of a concrete member in which bending deformation has occurred by measuring position data between three points using a laser beam measuring instrument.

JP 2006-078214 A JP 2001-124535 A

In the method of arranging a plurality of strain gauges at the same height position, it is necessary to install a plurality of strain gauges by field work.
In the case of concrete piles, since strain gauges are installed on the reinforcing bars, the expansion and contraction strain of the reinforcing bars is actually measured, and when the pile body cracks and the stress acts on the reinforcing bars, the strain increases rapidly. It was easy to be affected locally.

  In addition, in the measurement method described in Patent Document 1, since an elastic member is attached to concrete, when a bending crack that crosses the elastic member occurs in the concrete member, the positional relationship between the crack and the strain gauge In some cases, the detected value of the strain changed greatly, and an appropriate curvature could not be measured.

  Moreover, in the measuring method described in Patent Document 2, the apparatus may be too large to be incorporated into the concrete member, and the apparatus is expensive.

  The present invention has been made to solve the above-described problems, and a bending deformation measuring method capable of measuring the bending deformation of a measurement object with high accuracy, and the bending deformation measuring method. It is an object of the present invention to propose a bending deformation measuring device having a simple configuration used for the above.

  In order to solve the above-mentioned problem, the bending deformation amount measuring method of the present invention sets two reference points and one contrast point at positions separated on the same straight line with respect to the measurement object, and After the deformation of the object, the amount of bending deformation in the multi-direction of the measurement object is measured by measuring a physical quantity that correlates with at least two directions of vertical separation distance between the straight line passing through the two reference points and the contrast point. It is characterized by doing.

  This method of measuring the amount of bending deformation does not measure the local distortion that occurs in the measurement object itself or the reinforcing bars of the measurement object, but is based on the positional relationship between the reference point and the contrast point. The total amount of bending deformation is measured. Therefore, according to the bending deformation amount measuring method according to the present invention, even when a crack occurs in the measurement target range, the entire bending deformation amount of the measurement target range is not affected by the local strain. Can be measured accurately.

  Further, the bending deformation amount measuring device of the present invention is a measurement that detects a single rod disposed in a cylindrical installation hole formed in a measurement object and the multidirectional bending deformation amount of the measurement object. A bending deformation amount measuring device comprising two means and a reference point at positions separated on the same straight line in the installation hole, and the position of the two reference points on the bar. A universal joint that connects the rod and the installation hole is formed, and the measuring means calculates a physical quantity that correlates to a vertical separation distance of the contrast point with respect to a straight line that passes through the two reference points after the measurement object is deformed. It is characterized by measuring.

According to such a deformation amount measuring apparatus, since it can be configured simply and compactly using low-priced parts, installation is easy and inexpensive.
In addition, the amount of bending deformation of the measurement object can be measured easily and with high accuracy.

  The measuring means comprises a spring member interposed between the rod and the inner wall surface of the installation hole, and a strain gauge installed on the spring member, and a vertical separation between the rod and the contrast point. A physical quantity that correlates with the distance may be measured, or a slide piece that contacts the outer surface of the rod, a spring member interposed between the slide piece and the inner wall surface of the installation hole, and the spring member It may comprise an installed strain gauge and measure a physical quantity that correlates with a vertical separation distance between the bar and the contrast point.

  The reference point is set at one end and a center of the bar, and the measuring means has a recording board fixed to the installation hole, and the recording board is in contact with the other end of the bar. Or may penetrate through the other end of the rod.

  In the deformation amount measuring apparatus, the reference points are set at an upper end portion and a lower end portion of the rod, the contrast point is set at a center portion of the rod, and the contrast point is set on the rod. An abutting member that abuts the inner wall surface of the installation hole at a position is provided, and the measuring means correlates with a vertical separation distance of the contrast point with respect to a straight line passing through the two reference points after the measurement object is deformed. You may measure a physical quantity.

  According to the bending deformation amount measuring method and the bending deformation amount measuring apparatus of the present invention, it is possible to measure the bending deformation amount of the measurement object with high accuracy.

It is sectional drawing which shows typically the pile provided with the bending deformation amount measuring apparatus which concerns on embodiment of this invention. It is a perspective view which shows typically the installation condition of the bending deformation amount measuring apparatus which concerns on 1st embodiment. (A) is a perspective view which shows the bending deformation amount measuring apparatus of FIG. 2, (b) is a schematic diagram of (a). (A) is a plane sectional view showing a measuring means of the deformation measuring device, and (b) is a longitudinal sectional view thereof. (A) is a top view which shows the spring member of the measuring means of FIG. 4, (b) is the longitudinal cross-sectional view. (A) is a side view which shows the deformation | transformation of the pile shown in FIG. 1, (b) is an enlarged view of (a). (A) And (b) is the reference drawing for description of the calculation method of the curvature and bending angle of the pile which the bending deformation produced. It is a figure which shows the bending deformation amount measuring apparatus which concerns on 2nd embodiment, Comprising: (a) is a top view, (b) is a plane sectional view, (c) is a side view, (d) is a cross-sectional view, e) is a plan view showing a restraining ring, and (f) is a plan view showing a slide piece and a ring spring. (A)-(c) is a plane sectional view which shows the measurement condition of the bending deformation amount by the bending deformation amount measuring apparatus shown in FIG. (A) is a perspective view which shows the bending deformation amount measuring apparatus which concerns on 3rd embodiment, (b) is a schematic diagram of (a). FIG. 10A is an enlarged perspective view showing a part of the bending deformation amount measuring apparatus in FIG. 10A, and FIG. 10B is a cross-sectional view of the bending deformation amount measuring apparatus. It is a perspective view which shows the bending deformation amount measuring apparatus which concerns on 4th, 5th embodiment. It is a figure which shows the bending deformation amount measuring apparatus which concerns on 4th embodiment, Comprising: (a) is a perspective view of a measurement means, (b) is sectional drawing of the recording board of the measurement means, (c) is (b). FIG. 10D is a plan view of the recording board of FIG. 10B viewed from above, and FIG. (A) And (b) is the reference drawing for description of the calculation method of the curvature and bending angle of the pile which the bending deformation produced. It is a figure which shows the bending deformation amount measuring apparatus which concerns on 5th embodiment, Comprising: (a) is a perspective view of a measurement means, (b) is a top view which shows the recording board of the measurement means.

<First embodiment>
In the first embodiment, a bending deformation amount measuring apparatus and a bending deformation amount measuring method for confirming the soundness of a pile to which a large external force is applied due to an earthquake or the like will be described.

  As shown in FIG. 1, the bending deformation amount measuring device 1 is disposed at a place where it is desired to measure the bending deformation amount of the pile 2. Moreover, the bending deformation amount measuring apparatus 1 may be provided at the time of construction of the pile 2 or may be provided on the existing pile 2 by post-construction. Reference sign F is a footing.

  As shown in FIG. 2, the bending deformation measuring device 1 is disposed in a cylindrical installation hole 21 formed in the pile 2. In the present embodiment, the installation hole 21 is formed along the axial center of the pile 2 at the center of the cross section of the pile 2. The installation hole 21 may be formed by disposing a cylindrical member when placing concrete, or may be formed by drilling after the pile 2 is formed.

  The bending deformation measuring device 1 includes a cylindrical case 10, a reference rod 3 disposed in the cylindrical case 10, spheres 4 and 4 installed at both ends of the reference rod 3, and a cylindrical case 10. And measuring means 5 arranged at a position away from both spheres 4 and 4.

  The cylindrical case 10 is a cylindrical member inserted into the installation hole 21. The cylindrical case 10 is integrally fixed to the pile 2 by filling the gap with the installation hole 21 with a filler such as a resin material. In addition, although the material which comprises the cylindrical case 10 is not limited, the thing provided with the material which changes with a deformation | transformation of the pile 2 (installation hole 21) is used.

  The reference bar 3 has strength and rigidity that is not deformed by its own inertial force or an action force from a contrast point during an earthquake.

  A gap is provided between the outer peripheral surface of the reference rod 3 and the inner peripheral surface of the cylindrical case 10, and the inner peripheral surface of the cylindrical case 10 does not contact the reference rod 3 even when the pile 2 is deformed. It is configured as follows.

  The spherical body 4 has an outer diameter in contact with the inner wall surface of the cylindrical case 10. The spherical body 4 is slidable in the vertical direction with respect to the cylindrical case 10 and constitutes a so-called universal joint (universal joint) that supports the reference rod 3 so as to be tiltable. The cylindrical case 10 is bent and deformed. Even in this case, the linearity of the reference rod 3 can be maintained. That is, in this embodiment, as shown in FIG. 3, both end portions (center of the sphere 4) of the reference bar 3 are set to the reference point P1.

  The measuring means 5 detects the amount of bending deformation of the pile 2 in multiple directions, and is arranged in the middle of the two spheres 4 and 4 (the central portion in the longitudinal direction of the reference bar 3). That is, in the present embodiment, the contrast point P2 is set at the central portion in the longitudinal direction of the reference bar 3.

  As shown in FIG. 4, the measuring means 5 includes an inner ring 51, an outer ring 52, a ring spring (spring member) 53, and a strain gauge 54 (see FIG. 5).

The inner ring 51 is an annular member provided around the outer surface of the reference rod 3.
The inner ring 51 is composed of two circular strips arranged on the top and bottom. The two plate materials are opposed to each other with an interval at which a part of the ring spring 53 can be inserted. The inner ring 51 is fixed to the outer surface of the reference rod 3.

The outer ring 52 is made of an annular member having an inner diameter larger than that of the inner ring 51, and a certain clearance (gap) is provided between the outer ring 52 and the inner ring 51.
The outer ring 52 has an outer diameter equivalent to the inner diameter of the cylindrical case 10, and the outer surface of the outer ring 52 is in contact with the inner wall surface of the cylindrical case 10 (see FIG. 2).

  The outer ring 52 is made of a member having a U-shaped cross section, and is configured such that a part of the ring spring 53 can be inserted.

  The ring spring 53 is a cylindrical member, and is disposed in a clearance formed between the inner ring 51 and the outer ring 52. That is, the ring spring 53 is interposed between the reference rod 3 and the inner wall surface of the cylindrical case 10 via the inner ring 51 and the outer ring 52. Note that the ring spring 53 may be arranged in a state of directly contacting the reference rod 3 and the cylindrical case 10.

  In the present embodiment, four ring springs 53 are arranged at equal intervals so as to surround the reference rod 3. The number and arrangement of the ring springs 53 are not limited. However, from the viewpoint of measuring the amount of bending deformation and the direction of bending deformation, the number of the ring springs 53 is three or more, preferably a multiple of 4, and arranged at equal intervals. It is desirable that

  A part of the ring spring 53 is inserted into the inner ring 51 on the reference rod 3 side, and a part of the ring spring 53 is inserted into the outer ring 52 on the side opposite to the reference rod 3.

The ring spring 53 is fixed to the inner ring 51 through a fixing pin 55 fixed to the inner ring 51 at a portion inserted into the inner ring 51.
The ring spring 53 is fixed to the outer ring 52 via a fixing pin 55 fixed to the outer ring 52 at a portion inserted into the outer ring 52.

The fixing pin 55 penetrates the inner ring 51 or the outer ring 52 and is fixed to the outer surface of the ring spring 53 at a position facing the ring spring 53 on a straight line passing through the center of the ring spring 53.
The method for fixing the ring spring 53 is not limited.

As shown in FIG. 5, strain gauges 54 are attached to each ring spring 53 at two locations.
The strain gauge 54 is attached to the inner surface of the ring spring 53 so that the straight line connecting the two strain gauges 54 is orthogonal to the straight line connecting the fixed pins 55.

  The measurement of the bending deformation amount of the pile using the bending deformation measuring device 1 of the present embodiment is performed by measuring the movement distance of the outer ring 52 with respect to the reference rod 3.

  The amount of displacement of the outer ring 52 can be measured by measuring the deformation of the ring spring 53 with the strain gauge 54. In this embodiment, the temporal change of bending deformation is measured in time series.

  As shown in FIG. 6, when the pile 2 is deformed, the positions of three measurement points (two reference points P1, P1 and one contrast point P2) are displaced, and the linear arrangement is changed. The contrast point P2 is relatively displaced in the direction perpendicular to the reference line LB (see FIG. 3B). In addition, since both ends of the reference rod 3 are supported by the cylindrical case 10 (installation hole 21) via the universal joint (sphere 4), even if the pile 2 is deformed, a straight line The state is maintained, and therefore the relative displacement amount d (two in the vertical direction) relative to the reference line (straight line connecting the reference points P1) LB is measured by measuring the displacement amount of the contrast point P2 (outer ring 52) relative to the reference rod 3. It is possible to measure a physical quantity that correlates to the vertical separation distance of the contrast point P2 with respect to a straight line passing through two reference points. Note that the relationship between the strain amount obtained by the strain gauge 54 and the relative displacement amount d is obtained in advance through experiments and the like.

  As shown in FIG. 7, assuming that the section length between the reference points P1 is L, the curvature 1 / R (curvature) of the bending deformation in the section between the reference points P1 is obtained by using the measured relative displacement d. Radius = R) and the bending angle θ of the straight line connecting the reference point P1 and the contrast point P2 with respect to the reference line LB can be expressed by equations 1 and 2, respectively.

  As described above, according to the bending deformation amount measuring apparatus of the present embodiment, it is possible to measure the curvature and bending angle of bending deformation accompanying the bending deformation of the pile 2, and based on the measurement result, the pile 2 Can understand the soundness of

In addition, the deformation amount measuring device can be easily and compactly configured using low-priced parts, so that it is easy to install and inexpensive.
Moreover, even if it is a case where the crack which arose in the pile 2 is formed so that it may pass through the measuring device 1, the curvature and bending angle which averaged the object area can be measured.

  Since the displacement is measured by receiving the result measured by the strain gauge 54 with a computer or the like, it is possible to easily grasp the soundness of the structure buried in the ground.

<Second Embodiment>
The bending deformation amount measuring apparatus according to the second embodiment measures the temporal change in time series in that it has a mechanism for measuring only the maximum value of the temporal change of bending deformation during an earthquake. This is different from the first embodiment.

  As shown in FIG. 2, the bending deformation measuring device 1 is disposed in a cylindrical installation hole 21 formed in the pile 2. In the present embodiment, the installation hole 21 is formed along the axial center of the pile 2 at the center of the cross section of the pile 2.

The bending deformation measuring device 1 includes a cylindrical case 10, a reference rod 3 disposed in the cylindrical case 10, spheres 4 and 4 installed at both ends of the reference rod 3, and both in the cylindrical case 10. And measuring means 6 disposed at a position distant from the spheres 4 and 4.
Since the cylindrical case 10, the reference rod 3, and the sphere (reference point) 4 are the same as those shown in the first embodiment, detailed description thereof is omitted.

  The measuring means 6 detects the amount of bending deformation of the pile 2 in multiple directions, and is arranged in the middle of the two spheres 4 and 4 (the central portion in the longitudinal direction of the reference bar 3). That is, in the present embodiment, the contrast point P2 is set at the central portion in the longitudinal direction of the reference bar 3 as in the first embodiment.

  As shown in FIG. 8, the measuring means 6 includes a slide control mechanism 61, a displacement storage mechanism 62, a slide piece 63, a ring spring (spring member) 64, a strain gauge 65, and a restraining ring 66. Has been.

As shown in FIGS. 8A and 8C, the slide control mechanism 61 is an annular member having an opening larger than the outer diameter of the reference rod 3.
The slide control mechanism 61 has a gap between the outer surface of the reference bar 3 and is movable in the horizontal direction (direction perpendicular to the reference bar 3).

  As shown in FIG. 8C, the slide control mechanism 61 is disposed above the displacement storage mechanism 62, and is fixed to the displacement storage mechanism 62 via a fixing member 61a.

  The slide control mechanism 61 applies a pressing force to the slide piece 63 disposed on the upper surface of the displacement storage mechanism 62 via a restraining ring 66.

Further, as shown in FIG. 8D, the slide control mechanism 61 is formed of a hollow member, and an electromagnet 61b is disposed therein.
The electromagnet 61b develops a magnetic force when energized, and pulls up the restraining ring 66 toward the slide control mechanism 61.

As shown in FIGS. 8B and 8C, the displacement storage mechanism 62 is an annular member having an opening larger than the outer diameter of the reference rod 3.
The displacement storage mechanism 62 has a gap with respect to the outer surface of the reference bar 3 and can move in the horizontal direction with respect to the reference bar 3.

  The displacement storage mechanism 62 is an annular plate material formed in an annular shape, and includes a recess 62a that opens to the upper surface and the inner peripheral surface, as shown in FIG. 8B. Four recesses 62a are formed at equal intervals. In addition, the number and arrangement | positioning of the recessed part 62a are not limited.

  As shown in FIG. 8D, a ring spring 64 is disposed in the recess 62a, and a part of the slide piece 63 is inserted.

  The slide piece 63 is disposed between the slide control mechanism 61 and the displacement storage mechanism 62. In the present embodiment, the four slide pieces 63 are arranged so as to surround the four sides of the reference bar 3 in accordance with the arrangement of the recesses 62 a of the displacement storage mechanism 62.

As shown in FIGS. 8B and 8D, the slide piece 63 is formed in a rectangular parallelepiped and is in contact with the outer surface of the reference bar 3.
A holding ring 66 is disposed on the upper surface of the slide piece 63.

As shown in FIG. 8E, the restraining ring 66 is made of a metal annular member, and a leaf spring 66a is fixed to the outer edge. The restraining ring 66 applies a restraining force (pressing force in the direction of the displacement storage mechanism 62) to the slide piece 63 via the leaf spring 66a.
The slide piece 63 is held by the displacement storage mechanism 62 and the holding plate 66.

  The ring spring 64 is disposed in the recess 62a of the displacement storage mechanism 62, and is in contact with the slide piece 63 and the side surface of the recess 62a.

  As shown in FIG. 8 (f), the ring spring 64 is fixed to the displacement storage mechanism 62 via a fixing pin 64a erected on the bottom surface in the recess 62a.

A strain gauge 65 is attached to each ring spring 64.
In the present embodiment, the strain gauge 65 is fixed to the slide piece 63 side of the inner surface of the ring spring 64, but the arrangement of the strain gauge 65 is not limited.

  According to the deformation amount measuring apparatus 1 of the present embodiment, as shown in FIG. 9, when an external force is applied during an earthquake or the like, the measuring means 6 moves (relative displacement) with respect to the reference bar 3. A slide piece 63 disposed on the opposite side of the moving direction of the means 6 is pushed into the recess 62 a by the reference bar 3.

  Since the sliding of the slide piece 63 is controlled by the holding force of the holding ring 66, the maximum value of the movement amount (the maximum value of the relative displacement) is held.

  That is, as shown in FIG. 9B, when a force that moves the measuring means 6 in the lower right direction acts on the reference rod 3, slide pieces 63a disposed on the left and upper sides of the reference rod 3 are provided. 63b is pushed into the recess 62a.

Furthermore, as shown in FIG. 9 (c), when the force that moves the measuring means 6 to the left acts on the reference rod 3, the slide piece 63c disposed on the right side of the reference rod 3 is formed in the recess 62a. It will be pushed in.
Even if the reference bar 3 is separated from the slide pieces 63a to 63d, the positions of the slide pieces 63a to 63d are held by the holding ring 66.

  Then, by measuring the deformation of the ring spring 64 with the strain gauge 65, the vertical maximum relative displacement amount d (the vertical separation distance between the reference bar 3 and the contrast point P2) with respect to the reference line (straight line connecting the reference points P1) LB. (Physical quantity correlating with) can be measured.

Using the maximum relative displacement d and the section length L between the reference points P1, the curvature 1 / R (curvature radius = R) of the bending deformation in the section between the reference points P1 and the reference point with respect to the reference line LB The bending angle θ of the straight line connecting P1 and the contrast point P2 is calculated.
In addition, since the calculation method of the curvature 1 / R (curvature radius = R) of bending deformation and the bending angle θ is the same as that shown in the first embodiment, detailed description thereof is omitted.

  If the electromagnet 61a is energized after the maximum relative displacement amount d is measured, the restraining ring 66 is pulled up, so that the slide piece 63 is pushed back from the recess 62a using the restoring force of the ring spring 64, and the measuring means for the reference rod 3 is measured. 6 is returned to its original state (see FIG. 9A).

As described above, according to the bending deformation amount measuring apparatus 1 of the present embodiment, it becomes possible to measure the curvature and bending angle of bending deformation accompanying the bending deformation of the pile 2, and based on this measurement result, the pile The health level of 2 can be grasped.
Moreover, since the deformation measuring device 1 can be configured simply and compactly using low-cost parts, it is easy to install and inexpensive.
Since only the maximum value of displacement is measured after bending deformation occurs in the pile 2, it is less expensive than the case of constant measurement.

<Third embodiment>
The bending deformation amount measuring apparatus according to the third embodiment is the first in that the elastic rod that bends and deforms along with the bending deformation of the pile 2 (deformation of the installation hole 21) is used as the reference rod 3. It is different from the embodiment.

  As shown in FIG. 2, the bending deformation measuring device 1 of the present embodiment is disposed in a cylindrical installation hole 21 formed in the pile 2. In the present embodiment, the installation hole 21 is formed along the axial center of the pile 2 at the center of the cross section of the pile 2.

As shown in FIG. 10A, the bending deformation amount measuring device 1 includes a cylindrical case 10, a reference rod 3 disposed in the cylindrical case 10, and a sphere 4 installed at both ends of the reference rod 3. , 4 and measuring means 7 disposed at a position away from both spheres 4, 4 in the cylindrical case 10.
Since the cylindrical case 10 and the sphere (reference point) 4 are the same as those shown in the first embodiment, detailed description thereof is omitted.

  The reference rod 3 is formed of a so-called elastic body, and is configured so that the reference point P1 at both ends is used as a base point when the pile 2 is bent and deformed, as shown in FIG. 10 (b).

  The measuring means 7 detects the amount of bending deformation of the pile 2 in multiple directions, and is disposed in the middle of the two spheres 4 and 4 (the central portion in the longitudinal direction of the reference bar 3). That is, in the present embodiment, the contrast point P2 is set at the center of the reference bar 3 as in the first embodiment.

As shown in FIG. 11, the measuring unit 7 includes a contact member 71 and a strain gauge 72.
The contact member 71 is a disk provided around the reference rod 3. The outer edge of the contact member 71 contacts the inner surface of the cylindrical case 10 and also contacts the outer peripheral surface of the reference bar 3.

On the inner edge of the contact member 71 (the contact surface with the reference bar 3), a recess 71a for disposing the strain gauge 72 is formed.
In the present embodiment, the four recesses 71a are formed at equal intervals, but the arrangement of the number of recesses is not limited.

  The recess 71a has a shape larger than that of the strain gauge 72, and is configured so that the contact member 71 and the strain gauge 72 do not come into contact with each other.

  The strain gauge 72 is fixed to the outer surface of the reference rod 3, and is configured to be able to measure the amount of bending strain of the reference rod. In the present embodiment, four strain gauges 72 are arranged at equal intervals around the outer periphery of the reference bar 3.

The type of strain gauge is not limited, but a resistance wire type strain gauge is desirable.
By disposing the four strain gauges 72 at equal intervals, the amount of strain corresponding to the bending deformation in two directions can be measured.

  When the bending deformation occurs in the pile 2, the measuring means 7 of the present embodiment causes the reference rod 3 to be bent via the contact member 71. That is, the contrast point P2 (the central portion in the longitudinal direction of the reference bar 3) is displaced with respect to the straight line connecting the reference points P1 and P1. Since the reference bar 3 bends according to the dynamic law of a simple beam, the displacement amount (deflection amount) d at the contrast point P2, the bending moment M generated at the contrast point portion, and the bending strain amount ε of the reference bar 3 are expressed by the following equation. A relationship of 3 to 5 is established.

  Equation 6 is derived from Equations 3 to 5, and by measuring the bending strain of the reference rod 3 at the contrast point P2, the displacement amount d at the contrast point P2 (the relative displacement amount in the vertical direction with respect to the straight line connecting the reference points P1) d) As is apparent from Equation 6, the displacement d at the contrast point P2 is determined by the span length L of the reference bar 3 and the dimension (diameter) D of the cross section of the reference bar 3.

As described above, according to the bending deformation measuring apparatus 1 of the present embodiment, the displacement at the contrast point P2 accompanying the bending deformation of the pile 2 (the vertical separation distance of the contrast point P2 with respect to the straight line passing through the two reference points). Correlated physical quantities) can be measured, and the soundness of the pile 2 can be grasped based on the measurement result.
Moreover, since the deformation measuring device 1 can be configured simply and compactly using low-cost parts, it is easy to install and inexpensive.

<Fourth embodiment>
The bending deformation amount measuring apparatus 1 according to the fourth embodiment is provided with a mechanism that measures only the maximum value of bending deformation, but the second embodiment is that it does not return to the original state after the measurement. Is different.

  As shown in FIG. 12, the bending deformation measuring device 1 of the present embodiment is disposed in a cylindrical installation hole 21 formed in the pile 2. In the present embodiment, the installation hole 21 is formed along the axial center of the pile 2 at the center of the cross section of the pile 2.

The bending deformation amount measuring device 1 includes a cylindrical case 10 disposed in an installation hole 21, a reference rod 3 disposed in the cylindrical case 10, and a sphere disposed at a lower end portion and a central portion of the reference rod 3. 4 and 4 and a measuring means 8 disposed on the upper part of the cylindrical case 10. That is, in this embodiment, the reference point P1 is set at the lower end (one end) and the center of the bending deformation measuring device 1, and the contrast point P2 is set at the upper end (the other end).
The details of the cylindrical case 10, the reference rod 3, and the sphere 4 (reference point P1) are the same as those shown in the first embodiment, and thus detailed description thereof is omitted. Further, the reference point P1 may be set at the upper end portion and the center portion of the bending deformation amount measuring apparatus 1, and similarly, the contrast point P2 may be set at the lower end portion of the bending deformation amount measuring apparatus 1.

  The measuring means 8 includes an imaging mechanism 81 for imaging the relative displacement amount of the contrast point P2 with respect to the reference line (reference bar 3), and a measurement mechanism 82 that leaves the maximum value of the relative displacement amount without using electricity (FIG. 13). (See (a)).

The photographing mechanism 81 is disposed at the upper end (end of the contrast point side) of the cylindrical case 10, and includes a camera 81a and a light source 81b.
The camera 81a images the measurement mechanism 82. The light source 81b shines light on the measurement mechanism 82 during shooting by the camera 81a.

  As shown in FIG. 13, the measuring mechanism 82 is disposed above the reference bar 3 so as to contact the marking needle 82a provided at the upper end (the other end) of the reference bar 3 and the marking needle 82a. And a recording board 82b. Note that the member provided at the upper end of the reference bar 3 does not necessarily have to be the scribing needle 82a, for example, an ink pen.

The recording board 82 b is made of a transparent glass plate and is fixed to the cylindrical case 10.
The surface of the recording board 82b on the side of the marking needle 82a is coated with a paint 82c that can be scraped off by the marking needle 82a, and the scale line 82d is drawn on the surface of the camera 81a side.

  The recording board 82b is not necessarily coated with the paint 82c. For example, when the ink pen is provided at the upper end of the reference bar 3 instead of the marking needle 82a, the recording board 82b may constitute the drawing surface.

According to the bending deformation amount measuring apparatus 1 of the present embodiment, when bending deformation occurs in the pile 2, as shown in FIG. 13 (d), the scribing needle 82a scrapes the paint 82c of the recording board 82b, Line marks remain on the recording board 82b.
Since the camera 81a captures the striations of the recording board 82b together with the scale line 82d, the magnitude of the relative displacement amount between the extension line of the straight line connecting the reference points P1 and the contrast point P2 is read based on the capturing result. Can do.

  As shown in FIG. 14, when the distance from the reference point P1 (lower side) disposed at the lower end of the bending deformation amount measuring device 1 to the contrast point P2 is L, the measured relative displacement amount e is used. By doing so, the curvature 1 / R (curvature radius = R) of the bending deformation in the section between the lower reference point P1 and the contrast point P2, and the center (upper) reference point P1 and the contrast point P2 Can be expressed by equations 7 and 8, respectively.

As described above, according to the bending deformation measuring apparatus 1 of the present embodiment, the displacement at the contrast point P2 accompanying the bending deformation of the pile 2 (the vertical separation distance of the contrast point P2 with respect to the straight line passing through the two reference points). Correlated physical quantities) can be measured, and the soundness of the pile 2 can be grasped based on the measurement result.
Since the deformation measuring device 1 uses electricity only at the time of photographing, it is economical.

<Fifth embodiment>
The bending deformation amount measuring apparatus 1 according to the fifth embodiment is different from the bending deformation amount measuring apparatus according to the fourth embodiment in that the reference bar 3 penetrates the recording board 83 at the contrast point P2. .

  The recording board 83 is configured by, for example, forming a plastic material such as clay into a disk shape, and is disposed so as to shield the cylindrical case 10.

A transparent glass plate 82e on which scale lines 82d are drawn is disposed above the recording board 83, and the recording board 83 can be photographed by the camera 81a.
Since the configuration of the bending deformation amount measuring apparatus 1 according to the other fifth embodiment is the same as that of the bending deformation amount measuring apparatus 1 shown in the fourth embodiment, detailed description thereof is omitted.

  According to the bending deformation amount measuring apparatus 1 of the present embodiment, when bending deformation occurs in the pile 2, the reference bar 3 presses the plastic material constituting the recording disk 83 as shown in FIG. Therefore, the maximum displacement of the reference bar 3 at the contrast point remains as a compression mark.

  Since the camera 81a captures the compression mark of the recording board 83 together with the graduation line 82d, the relative displacement between the straight extension line connecting the reference points P1 (spheres 4) and the contrast point P2 is read based on the capturing result. be able to.

  As described above, according to the bending deformation measuring apparatus 1 of the present embodiment, the displacement at the contrast point accompanying the bending deformation of the pile 2 (correlated to the vertical separation distance of the contrast point P2 with respect to the straight line passing through the two reference points). Physical quantity) can be measured, and the soundness of the pile 2 can be grasped based on the measurement result.

As mentioned above, although embodiment of this invention was described, this invention is not restricted to the said embodiment, In the range which does not deviate from the meaning of this invention, it can change suitably.
For example, although the said embodiment demonstrated the case where a bending deformation amount measuring apparatus was installed in a pile, the measurement object which measures with a bending deformation amount measuring apparatus is not limited to a pile.

The bending deformation measuring device may be installed in a measurement object in advance as an integrated product in a factory or the like, or may be assembled on site.
In addition, the bending deformation amount measuring device may be embedded at the time of construction of the measurement object, or the existing measurement object may be drilled and arranged.

  The configuration of the measuring means is not limited to that shown in each of the above embodiments as long as it can measure a physical quantity correlated with the separation distance of the contrast point with respect to the reference line.

In each said embodiment, although the universal joint was formed with the spherical body, the structure of a universal joint is not limited.
The spring member is not limited to a ring spring.

1 Bending deformation measuring device 2 Pile (object to be measured)
21 Installation hole 3 Standard rod (bar)
4 Sphere 5 Measuring means 53 Ring spring (spring member)
54 Strain gauge 6 Measuring means 63 Slide piece 64 Ring spring (spring member)
65 Strain gauge 7 Measuring means 71 Abutting member 72 Strain gauge 8 Measuring means 82b, 83 Recording board P1 Reference point P2 Contrast point

Claims (6)

For the measurement object, set two reference points and one contrast point at distant positions on the same straight line.
After the measurement object is deformed, the amount of bending deformation in the multi-direction of the measurement object is measured by measuring a physical quantity that correlates with a vertical separation distance between at least two directions of the straight line passing through the two reference points and the contrast point. A method for measuring a bending deformation, characterized in that A single rod arranged in a cylindrical installation hole formed in the measurement object;
A bending deformation measuring device comprising a measuring means for detecting a bending deformation amount in multiple directions of the measurement object,
Two reference points and contrast points are set at positions separated on the same straight line in the installation hole,
The bar is formed with a universal joint that connects the bar and the installation hole at the position of the two reference points.
The measuring means measures a physical quantity that correlates with a vertical separation distance of the contrast point with respect to a straight line passing through the two reference points after the measurement object is deformed.   The measuring means includes a spring member interposed between the rod and the inner wall surface of the installation hole, and a strain gauge installed on the spring member, and a vertical separation distance between the rod and the contrast point The apparatus for measuring a bending deformation according to claim 2, wherein a physical quantity that correlates with the measured value is measured.   The measuring means comprises a slide piece in contact with the outer surface of the rod, a spring member interposed between the slide piece and the inner wall surface of the installation hole, and a strain gauge installed in the spring member, The bending deformation measuring apparatus according to claim 2, wherein a physical quantity correlated with a vertical separation distance between the bar and the contrast point is measured. The reference point is set at one end and the center of the rod,
The measuring means has a recording board fixed to the installation hole,
3. The bending deformation amount measuring apparatus according to claim 2, wherein the recording board is in contact with the other end of the bar or penetrates the other end of the bar. The reference points are set at the upper end and the lower end of the rod,
The contrast point is set at the center of the bar,
The bar is provided with a contact member that contacts the inner wall surface of the installation hole at the position of the contrast point,
The bending deformation amount according to claim 2, wherein the measurement unit measures a physical quantity correlated with a vertical separation distance of the contrast point with respect to a straight line passing through the two reference points after the measurement object is deformed. Measuring device.

Images