JP3779722B1 - Anchor bolt required adhesion strength confirmation device and anchor bolt necessary adhesion strength confirmation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and a method capable of accurately and easily confirming whether or not an anchor bolt has a required adhesion strength even in a narrow state where the nut can only be loosened or tightened in order to confirm the presence or absence of the required adhesion strength of an existing anchor bolt To do.
A compression test of an elastic-plastic body to be used is performed in advance, its elastic-plastic deformation characteristics are grasped, a necessary cross-sectional area is calculated, and a cylindrical elastic-plastic processed product is created. Next, the elasto-plastic processed product is again subjected to a compression test to grasp its elasto-plastic deformation characteristics. The elastic-plastic workpiece is attached to an existing anchor bolt as shown in 1 of FIG. 3, and the elastic-plastic workpiece is shifted to plastic deformation to a preset length unless the anchor bolt is pulled out. Continue tightening this nut until it reaches. Thereafter, an apparatus and method for confirming that the required adhesion strength can be obtained by loosening the nut, removing the elastic-plastic processed product, measuring the length with a caliper or the like, and confirming the amount of plastic deformation.
[Selection] Figure 3

Description

  The present invention relates to an apparatus and a method for confirming the presence or absence of a required adhesion strength of an anchor bolt.

In order to confirm the presence or absence of the required adhesion strength of the anchor bolt, a method of confirming the axial force of the anchor bolt when the nut is tightened can be used. Among conventional bolt axial force confirmation methods, there is a method using a torque wrench as a method that can be confirmed even when the bolt is installed in a narrow place. However, since the torque coefficient value is unknown for an anchor bolt, accurate measurement cannot be performed. (See Non-Patent Document 1.) In addition, there is a method using an ultrasonic bolt axial force meter, but since it is an indirect test method of stress, there is a sense of uncertainty in accuracy. (See Patent Document 1. ) In addition, there is a method in which an elastic body is tightened with a nut and the bolt axial force is confirmed using its elastic deformation characteristics. I can't. (See Patent Document 2. )
Published by Japan Association of Public Architectural Building Construction Supervision Guidelines 2004, page 555 JP 2003-227768 A JP2001-074018

In the method for confirming the bolt axial force according to Patent Document 2 , the bolt axial force is confirmed by tightening a cylindrical and soft workpiece such as rubber with a nut and visually confirming the amount of elastic deformation. It is not suitable for checking the axial force. Moreover, in order to visually recognize a large axial force that is about the allowable stress of the bolt, even if the processed product is made of an elastic body having a compressive strength greater than that of rubber, the amount of elastic deformation is small and it is difficult to visually recognize the bolt axial force. It is. In addition, since there is nothing other than a photograph or recorded document that verifies the visual recognition result, it cannot be reliably verified after the test. An object of the present invention is to increase the accuracy of confirmation of bolt axial force in order to confirm the required adhesion strength of anchor bolts, and to make it possible to leave a verification product of the confirmation result after confirmation of the bolt axial force.

In order to achieve the above object, an anchor bolt required adhesion strength confirmation device according to claim 1 of the present invention includes an anchor bolt partially protruded from a surface of a fastened body or a structure, and the above-described protrusion of the anchor bolt. A nut that is screwed into a portion, and is inserted between a surface of the fastened body or structure and the nut to form a cylindrical shape, and the nut is attached by a predetermined amount corresponding to the required adhesion strength of the anchor bolt. An elasto-plastic material for confirming the required adhesion strength of the anchor bolt, which is configured to be plastically deformed in the axial direction by an amount recognizable by measurement with a caliper by tightening, and an elastic for confirming the required adhesion strength of the anchor bolt and the anchor bolt. Annular soft elastic body processing for holding the position of the elastic bolt processed product for confirming the required adhesion strength of the anchor bolt inserted between the processed plastic product When and is characterized by comprising a.
The anchor bolt required adhesion strength confirmation device according to claim 2 is the anchor bolt required adhesion strength confirmation device according to claim 1, wherein flat washer is provided on both sides in the axial direction of the elasto-plastic material for confirming the anchor bolt requirement adhesion strength. It is characterized by being mounted.
According to a third aspect of the present invention, there is provided the anchor bolt required adhesion strength confirmation device according to claim 1 or 2, wherein the anchor bolt is elastically plastically deformed in the axial direction by a preset amount. A square bar having a square cross section with one side corresponding to the length in the axial direction of the elastoplastic body processed product for confirming the required adhesion strength of the bolt is provided, and the elastoplastic material processed product for confirming the required adhesion strength of the anchor bolt by the square bar. It is characterized in that it is confirmed that the length in the axial direction is a predetermined length.
According to a fourth aspect of the present invention, there is provided a method for confirming the required adhesion strength of an anchor bolt, wherein a nut is attached to a protruding portion of the anchor bolt while an elastic-plastic processed product for confirming the required adhesive strength of an anchor bolt is mounted via an annular soft elastic material processed product. Tightening the nut until the anchor bolt required adhesion strength confirmation member has a predetermined axial length, and axial plastic deformation of the anchor bolt necessary adhesion strength confirmation elastic-plastic product And a step of confirming the required adhesion strength of the anchor bolt according to the amount.

  According to the present invention, it is possible to confirm the presence or absence of the required adhesion strength of the existing anchor bolt even in such a narrow state that only the nut can be loosened or tightened.

  According to the present invention, the presence or absence of the required adhesion strength of existing anchor bolts can be confirmed with the above-mentioned elastic-plastic processed product that can be mass-produced at low cost, and can be confirmed with a simple operation.

  According to the present invention, it is possible to leave the elasto-plastic body processed product plastically deformed as a confirmation result of the presence or absence of the required adhesion strength of the existing anchor bolt as a verification product of the confirmation result.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a front view of the elasto-plastic processed product of the present invention. Select an elastoplastic material that has a tensile strength moderately smaller than the allowable tensile stress of the material such as anchor bolts and flat washers to be used to confirm the required adhesion strength, and that has high toughness. Examples of the elastic-plastic body include aluminum A1050.

  In advance, a compression test of the elastoplastic material is performed in advance, and a compression stress-strain curve is obtained. A necessary cross-sectional area is calculated based on the elasto-plastic deformation characteristics, and a cross-section of the elasto-plastic workpiece is determined. When determining the cross section of the elastic-plastic processed product, the inner diameter is increased by about 4 mm from the anchor bolt shaft diameter. Also, use a flat washer or the like that is larger than about 4 mm larger than the outer diameter of the elasto-plastic processed product, and when the elasto-plastic processed product undergoes elasto-plastic deformation, it will not be pressed by the anchor bolt. In addition, the axial force can be appropriately received from the flat washer or the like.

  FIG. 2 is a side view of the elasto-plastic processed product. The length of the elasto-plastic processed product is about 5 to 20 mm, and it is necessary to improve the accuracy of confirmation by making the length so as not to locally buckle when elasto-plastic deformation occurs. If it is too short, the measurement error becomes large, and if it is too long, the anchor bolt tightening length is insufficient.

  After producing the elasto-plastic processed product, the compression test is sufficiently performed, the compressive stress-strain curve and the amount of plastic deformation after decompression are grasped, and deformation is performed with a force corresponding to the required adhesion strength of the anchor bolt. The elasto-plastic deformation amount of the elasto-plastic processed product and the plastic deformation amount after decompression are obtained, and the elasto-plastic deformation amount of the elasto-plastic processed product is defined as a predetermined deformation amount. (See Figure 4.)

  In order to confirm the predetermined deformation amount, a square bar having a square cross section with one side of the length of the elasto-plastic processed product at the predetermined deformation amount, that is, a preset length is prepared.

  FIG. 3 shows a state in which the elasto-plastic processed product is attached to an anchor bolt. A ring-shaped soft elastic body processed product is previously attached to the anchor bolt at a position shown in FIG. 3 so that the elastic-plastic processed product can be maintained at an appropriate position. Thereafter, the elasto-plastic processed product is sandwiched between the flat washers or the like, attached to the anchor bolt, and a nut is attached. Unless the anchor bolt is pulled, if the nut is continuously tightened, the elastic-plastic processed product shifts from elastic deformation to plastic deformation. That the elasto-plastic deformation amount reaches the predetermined deformation amount (see the elasto-plastic deformation amount in FIG. 4), that is, the length of the elasto-plastic workpiece is equal to one side length of the square bar. Continue tightening the nut until it is confirmed. At this time, the error in confirming the length of the elasto-plastic processed product has a small gradient indicated by compressive stress / strain as shown in FIG. 4 due to plastic deformation, and the error of the converted compressive stress relative to the amount of elasto-plastic deformation can be reduced. , Can improve the accuracy of confirmation. Thereafter, the nut is loosened, the elasto-plastic workpiece is removed, the length of the plastic deformation is measured with calipers, etc., and compared with the amount of plastic deformation after depressurization (see plastic deformation amount in FIG. 4). By doing so, the compressive stress applied to the elasto-plastic processed product can be confirmed, and the anchor bolt axial force which is the reaction force is also found, and it can be confirmed that the anchor bolt has the required adhesion strength that is equivalent to it.

  According to the present invention, the presence or absence of the required adhesion strength of the existing anchor bolt can be confirmed with the above-mentioned elastic-plastic processed product that can be mass-produced at low cost, and can be confirmed with a simple operation, and thus has industrial applicability.

  According to the present invention, the elasto-plastic processed product plastically deformed as a result of confirming whether or not the required anchor strength of the existing anchor bolts is present can be left as a verified product of the confirmation result, and thus has industrial applicability.

It is a front view of the elastoplastic processing product by one embodiment of the present invention. It is a side view of the elastoplastic processing product by one embodiment of the present invention. It is the side view which attached the elastic-plastic processed product by one embodiment of this invention to the anchor bolt. It is a graph of the compressive stress-strain curve of the elastoplastic processing product by one embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Elasto-plastic processed product which is the present invention 2 Ring-shaped soft elastic processed product 3 Flat washer, etc. 4 Nut 5 Anchor bolt 6 Surface of the body to be fastened or the surface of the wall or foundation structure

Claims (4)

An anchor bolt partially protruded from the surface of the fastened body or the structure, and a nut screwed into the protruded portion of the anchor bolt;
It is inserted between the surface of the body to be fastened or the structure and the nut, has a cylindrical shape, and can be recognized by measuring with a caliper by tightening the nut by a predetermined amount corresponding to the required adhesion strength of the anchor bolt. An anchor bolt that is configured to be plastically deformed in the axial direction by a certain amount, and an elastic-plastic processed product for confirming the required adhesion strength
A ring-shaped soft elastic body processed product that is interposed between the anchor bolt and the elastic bolt processed product for confirming the required adhesion strength of the anchor bolt and holds the position of the elastic bolt processed product for confirming the required adhesive strength of the anchor bolt. When,
An anchor bolt required adhesion strength confirmation device characterized by comprising: In the anchor bolt required adhesion strength confirmation device according to claim 1,
An anchor bolt required adhesion strength confirmation device characterized by mounting flat washers on both sides in the axial direction of the elasto-plastic processed product for confirming the required adhesion strength of the anchor bolt. In the anchor bolt required adhesion strength confirmation device according to claim 1 or claim 2,
A square bar having a square cross section with a length corresponding to the length in the axial direction of the elastic bolt processed product for confirming the necessary adhesion strength after the anchor bolt has been elastically plastically deformed in the axial direction by a predetermined amount,
An anchor bolt required adhesion strength confirmation device characterized by confirming that the length in the axial direction of the elastic-plastic processed product for confirming the required adhesion strength of the anchor bolt has reached a predetermined length by the square bar. Attaching the nut to the protruding portion of the anchor bolt while attaching the elastic bolt processed product for confirming the required adhesion strength of the anchor bolt through the annular soft elastic processed product;
Tightening the nut until the anchor bolt required adhesion strength confirmation member has a preset axial length; and
Confirming the required adhesion strength of the anchor bolt by the amount of plastic deformation in the axial direction of the elasto-plastic body processed product for confirming the required adhesion strength of the anchor bolt;
The anchor bolt required adhesion strength confirmation method characterized by comprising.

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