JP4388208B2 - Concrete strain gauge - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a strain measuring instrument for concrete used for investigation of internal behavior of mass concrete and grasping of a crack state in a model specimen.
[0002]
[Prior art]
In conventional strain measurement of concrete, a strain gauge as a strain measuring instrument is affixed to the reinforcing bars designed in the concrete structure to be measured before placing the concrete. ing.
[0003]
This concrete strain measurement method can be used to measure strain inside hardened concrete simply by attaching a strain gauge to the reinforcing bar in advance, so as to investigate the internal behavior of mass concrete and grasp the crack condition in the model specimen, etc. Has been widely used.
[0004]
[Problems to be solved by the invention]
However, in this type of concrete strain measurement method, a reinforcing bar is used as a medium to dispose a strain gauge at a predetermined site in the concrete structure. Therefore, the following is based on the difference in behavior between the concrete and the reinforcing bar. There's a problem.
[0005]
That is, when the reinforcing bar shows plasticity after yielding, the measurement data obtained from the strain gauge is different from the concrete strain to be obtained due to the influence of the behavior of the reinforcing bar.
[0006]
On the other hand, if there is no reinforcing bar at the site where the strain gauge is to be installed, it is unavoidable to add a reinforcing bar and affix the strain gauge to this. Will give a reinforcing effect.
[0007]
Therefore, the problem to be solved by the present invention is to provide a concrete strain measuring instrument that can stably obtain measurement data and does not give a reinforcing effect to the concrete structure.
[0008]
[Means for Solving the Problems]
The strain measuring instrument for concrete according to the present invention is a medium part which is disposed in a concrete structure to be measured and behaves integrally with hardened concrete and is made of glass fiber reinforced plastic, and glass fiber. And a measuring unit attached to the medium unit made of reinforced plastic .
[0009]
According to the concrete strain measuring instrument according to the present invention, the measuring part is attached to the medium part made of glass fiber reinforced plastic that behaves integrally with the hardened concrete, so that it is not affected by the behavior of the reinforcing bar. Therefore, measurement data can be obtained stably. Moreover, since a reinforcing bar is not added and a measurement part is not attached to this, the inconvenience which gives a reinforcement effect with respect to a concrete structure does not arise.
In such technical means, the medium portion may be any shape and structure as long as it is made of glass fiber reinforced plastic and behaves integrally with hardened concrete.
[0010]
The concrete strain measuring instrument according to the second invention is a medium part that is arranged in a concrete structure to be measured and behaves integrally with the hardened concrete from the viewpoint of further improving the integrity with the hardened concrete. A strain measuring instrument for concrete comprising a glass fiber reinforced plastic and a measuring unit attached to the medium part , wherein the medium part has a fine aggregate pasted on its surface. It is characterized by becoming.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.
[0012]
Embodiment 1
FIG. 1 is a perspective view showing a schematic configuration of a concrete strain measuring instrument according to Embodiment 1 of the present invention.
[0013]
In the first embodiment, the concrete strain measuring instrument is configured to include a medium part 1 and a measuring part 2 as shown in FIG. Hereinafter, each component will be described.
[0014]
(1) Media section 1
The medium unit 1 is disposed in the concrete structure in order to achieve the object of disposing the measurement unit 2 at a predetermined site in the concrete structure (not shown) that is a measurement target.
[0015]
As shown in FIG. 1, the medium portion 1 according to the first embodiment has an annular shape, and has an inner surface 1a and an outer surface 1b. Such a shape of the medium unit 1 can be appropriately selected according to the measurement purpose, measurement location, measurement direction, and the like.
[0016]
Long strain gauges 2 a serving as measuring units 2 are alternately attached to the inner surface 1 a and the outer surface 1 b of the medium unit 1. The reason why the long strain gauges 2a are alternately attached is to measure the strain not only by points but also by lines.
[0017]
In addition, the medium unit 1 can exhibit an action that behaves integrally with hardened concrete (not shown).
[0018]
This is because when the medium part 1 to which the measuring part 2 is attached behaves differently from the hardened concrete, the measurement data obtained from the measuring part 2 is affected by the medium part 1 that behaves differently. This is because the effect of the present invention that measurement data can be obtained stably cannot be enjoyed. Further, in the case where the medium portion 1 behaves differently from hardened concrete, the reinforcing effect is given to the concrete structure, and the reinforcing effect is not given to the concrete structure. It is also because it cannot enjoy another effect.
[0019]
Furthermore, the medium portion 1 capable of exhibiting such an action is configured as being made of glass fiber reinforced plastic.
[0020]
This is because the material of the medium part 1 that has an action that behaves integrally with the hardened concrete is currently required in view of construction requirements that it is indispensable to manually attach to the reinforcing bars in the concrete structure. Besides glass fiber reinforced plastics that are light and easy to handle, glass fiber reinforced plastics behave linearly and stably obtain measurement data up to at least tens of thousands of micrometers. This is because it has been confirmed experimentally. In the case of a reinforcing bar, if it exceeds 2000 micrometer (yield), measurement data cannot be obtained stably.
In addition, according to the glass fiber reinforced plastic, the shape, rigidity, and the like of the medium portion 1 can be freely selected by changing the composition of the material.
[0021]
In the first embodiment, the medium portion 1 is formed by pasting sand 1c as a fine aggregate on the surface, that is, the inner surface 1a and the outer surface 1b. Specifically, the sand 1c is bonded to the inner side surface 1a and the outer side surface 1b of the medium unit 1 with the measuring unit 2 attached thereto with an epoxy resin or the like (not shown).
[0022]
This is because the unity between the medium portion 1 and the hardened concrete is further improved. In addition, since the epoxy resin etc. which were used for adhesion of the sand 1c covers not only the medium part 1 but also the measurement part 2 attached to the medium part 1, it is possible to adhere the sand 1c with an epoxy resin or the like. This also protects the measuring unit 2.
[0023]
In addition, the medium part 1 is specifically, with respect to the reinforcing bar (not shown) and the formwork (not shown) which are arrange | positioned by design in a concrete structure before concrete placement in concrete structure. Will be attached.
[0024]
(2) Measuring unit 2
The measuring unit 2 is attached to the medium unit 1. As the measurement unit 2 in the first embodiment, a long strain gauge 2a is used.
[0025]
That is, the long strain gauge 2a as the measurement unit 2 is alternately attached to the inner side surface 1a and the outer side surface 1b of the medium unit 1 as described above. As a result, the strain can be measured not only by points but also by lines.
[0026]
Therefore, according to the concrete strain measuring instrument according to the first embodiment, since the measuring section 2 is attached to the medium section 1 made of glass fiber reinforced plastic that behaves integrally with the hardened concrete, it is affected by the behavior of the reinforcing bar. Measurement data can be obtained stably without the need.
Moreover, since the reinforcing bars are not added and the measuring unit 2 is not attached thereto, there is no inconvenience of giving a reinforcing effect to the concrete structure.
[0027]
Embodiment 2
FIG. 2 is a perspective view showing a schematic configuration of a concrete strain measuring instrument according to Embodiment 2 of the present invention. Components similar to those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and detailed description thereof is omitted here.
[0028]
As shown in FIG. 2, the concrete strain measuring instrument according to the second embodiment is substantially the same as the first embodiment. However, unlike the first embodiment, the measuring unit 2 is a long strain gauge 2a. The optical fiber 12a is used instead.
[0029]
The optical fiber 12a in the second embodiment has the same effect as the long strain gauge 2a in the first embodiment in that the strain can be measured not only by a point but also by a line.
[0030]
Also in the second embodiment, the point that the sand 1c is adhered to the inner side surface 1a and the outer side surface 1b of the medium unit 1 with an epoxy resin or the like with the measuring unit 2 attached, The point that covers not only 1 but also the measurement unit 2 attached to the medium unit 1 is a structural feature point, and this point also exhibits the same operation as in the first embodiment.
[0031]
Therefore, according to the concrete strain measuring instrument according to the second embodiment, the same operations and effects as those of the concrete strain measuring instrument according to the first embodiment can be enjoyed.
[0032]
【The invention's effect】
According to this invention, since it comprised as mentioned above, it becomes possible to acquire measurement data stably. In addition, there is no inconvenience of reinforcing the concrete structure.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a schematic configuration of a concrete strain measuring instrument according to Embodiment 1 of the present invention.
FIG. 2 is a perspective view showing a schematic configuration of a concrete strain measuring instrument according to a second embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Medium part 1a ... Inner side 1b ... Outer side 1c ... Sand (fine aggregate)
2 ... Measuring unit 2a ... Long strain gauge 12a ... Optical fiber

Claims (2)

A medium part that is arranged in a concrete structure to be measured and behaves integrally with hardened concrete, and is made of glass fiber reinforced plastic,
Including a measurement unit that is affixed to the medium unit made of glass fiber reinforced plastic ,
Concrete strain measuring instrument. A medium part that is arranged in a concrete structure to be measured and behaves integrally with hardened concrete, and is made of glass fiber reinforced plastic,
A concrete strain measuring instrument including a measuring unit attached to the medium unit ,
The medium part is formed by pasting fine aggregate on the surface,
Strain instrument concrete.

Images