JPS58140639A - Stress measuring method of concrete - Google Patents

Abstract

PURPOSE:To measure stresses accurately, by fixing a diaphragm type stress gage beforehand with a concrete block, curing the block approximately at a specified temp. and embedding such block in concrete. CONSTITUTION:A diaphragm type stress gage 7 is beforehand embedded and held in a concrete block 8. Mortar is poured in the block 8 and the block is formed at the temp. which is kept constant during setting by underwater curing or the like, so that no abnormal stresses are generated at the boundary between a pressure receiving surface 2 and the concrete. In using the block 8 wherein such gage 7 is fixed, the block is installed in the measuring position in the form of a structure, and the concrete for forming the structure is placed thereon, whereby the block is formed integrally with the structural concrete. The formation of gap, between the pressure receiving surface and the concrete is thus eliminated and the accurate measurement is made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION This article A relates to a method for determining stress #R in concrete.

As a method of constant internal stress in conocrete structures;
A method of placing strain needles in the concrete to keep the strain constant and multiplying it by the elastic modulus of the concrete to find the stress.
A method of creating a concrete structure @ 0 stress by inserting reinforcing bars and a spring body of l1illfli# into a part of the jlc droplet and measuring this strain.1lrlflConstructed of a flat spring (diaphragm) with a small thickness relative to the side. Methods such as enclosing pressure needles in concrete to keep the stress constant are commonly used.

Among the above three methods, the method using strain needles is difficult to use because the elastic modulus of concrete is not constant and
Since it is not possible to know the exact value of , the disadvantage is that the stress of ^ cannot be determined. Further, in the method using an iron fan needle, stress concentration occurs in the iron 11 in the concrete 1, so the true stress of the concrete cannot be determined.

On the other hand, the diaphragm area of the Diamond 7 Tsum imaginary stress needle is large (because the thickness is small and the influence of the difference in the elastic modulus of concrete on the stress concentration is small, so there is no foreshadowing) The key is to maintain accurate stress at a constant level even when working in concrete.

This 7-diamond stress needle is shown in Figure 1.

The cylindrical integral body 10*pressure wi3 is made of a thin metal plate that has almost no reaction force against the external pressure PK, and the relationship with the filter body 1 is coated with traces of mercury, oil, etc. I am a Km person. Reference numeral 3 denotes a shim 7 with a pressure lll- smaller than the receiving pressure w2, which is made constant by the deflection t and displacement detection Wh4 of this die book 5-.

When the external pressure r acts on the receiving pressure #2, the liquid is pressed through the pressure receiving plate 2, and a pressure fR4 is applied to the secondary diamond 7, causing a deflection t proportional to the liquid pressure.

Since the receiving pressure 1 [2 is a large 4-ring on both sides like the Upper Release, by reducing the product of the secondary die 7 limb 30 with respect to the external pressure, the deflection of the secondary die Jr 7 limb string is 14 = J
The third advantage is that it is possible to reduce the volume ratio by ltDm and to increase the impact force of the pressure needle as seen from the external pressure.

While ρ1, this pressure needle is in the concrete, and due to the reaction of concrete, the body is #
The pressure leakage will push the concrete. Pressure receiving 4
As t is displaced and the volume increases, the hydraulic pressure decreases, so the reaction force due to pushing the concrete increases and IILJE decreases due to the contour of the concrete. In structure 11, the iI degree of concrete changes as the temperature rises, so 1. This maple symbol is a value line, but the concrete has sufficiently hardened by the time the -ffK concrete reaction heat reaches its peak of 4, so after that,
From the point when 11 degrees reaches 1F, the volume of the liquid gradually decreases and stress is released, and eventually, as shown in Figure 2, separation occurs between the concrete 6 and the receiving pressure vR2.

As described above, the stress needle itself has excellent responsive bone properties, but it has a low resistance to the relationship between the Diamond 7 Tsum and concrete, which receive pressure due to the raw heat of the concrete installed in the concrete. *Because of this, it is not possible to accurately measure the stress in the concrete.

The purpose of this development is to ensure that when four stress needles are installed in four concretes, there will be no relationship between the pressure leakage of the stress needles and the concrete.

Before placing the diamond 7 stress needles in concrete, this corner is hardened in advance with a dipping block and cured at an approximately constant temperature using an axillary block. This is a concrete stress constant method in which blocks are dug in needle-sealed concrete.

Embodiments of the present invention will be explained below with reference to Figures 0 and 4. Reference numeral 7 denotes a stress needle body, which has a structure similar to that of the stress needle in Figure 1. 8 shows an integral plotter forming an integral structure with the stress needle.

= Futarito Glock 8 holds the stress needle 7 in a rolling pin (not shown) and injects mortar into the mold.
By forming the concrete in the same way, normal stress will not be generated at the boundary between the pressure-receiving pressure 2 and the concrete, and the pressure needle 7 can be set in place with a thud in a rough roofing process. Note that 9 in the figure indicates the output pull of the stress needle 1.

The block 8 with the stress needle 1 is installed at a fixed position within the structure frame, and is integrated with structural concrete by pouring the cottalite that forms the structure.

In combination with the structural horn cleat, it is also possible to have a structure in which four protruding shoulders W such as iron bars are inserted as shown in γ4 country.

In this structure as well, the fluid pressure inside the stress needle 7 increases due to the heat generated by the structural concrete, but since the area around the stress needle 7 has been hardened in advance with the concrete slab 8, even if the fluid pressure increases, the pressure cannot be received. There will be no misalignment between the surface and the contact surface with the concrete.

When a pressure needle with a direct application of 1 and a mercury tI & body of Nanami KO, 2■ is restrained in concrete with an elastic modulus of 2 0' 4/-, I! The pressure generated when the temperature rises by 1 degree Celsius is 1.8 to 2 (-), so there is no fear of mismatch in cases where the concrete has hardened.

Concrete stress needles can be used in areas with large stress, where the stress reaches a Even though it has a large pressure wire strength, the needle side - the target is often a small stress IJIA - for example, a rock or concrete plate that is bitten on top of the IJIA! In the specific pressure distribution needle, the azui pressure body is the 4th castle of clause V-, and both the S acid type and the 4th structure have a large elasticity v.
Since it has a k-thickness, a stress needle in concrete is advantageous as a needle stopper. It was believed that it would take only one step to obtain the expected constant value if m was installed in directly suitable concrete with a resultant stress of t#, but this book, A. M., has found a way to solve this 114 point. He was a powerful Heike.

As mentioned above, at this beginning, stress #tt'4 is placed in the concrete block circle in advance, and the axillary prots I'4I! : By keeping the stress at a fixed level, no stress will be generated between the pressure receiving surface of the needle and the concrete.Therefore, by relaxing the concrete block with this block, the stress in its structure can be reduced. I can do #llA311 accurately.

[Brief explanation of drawings]

J-1- is a cross-sectional view showing the diaphragm 4 stress meter, and Figure 2 shows the stress needle of Figure 11 in concrete. Figure 1 shows an example of a conventional example with one installed, and Figure 1 shows an example of an axle load of -SA.
．． ? 411ii1 is a diagram showing an example of this failure. 7... Stress form 8... 2 people outside the concrete block Figure 1 Figure 2 Figure 2 3aa @ 4aa Procedural amendment Sho right 1 ra Q ” 17th Japan Patent Office Commissioner Shima 1) Indication of the case Showa Ute Seise Application No. 023719 2 Todoroki's Stress Haze Determination Method for Concrete 3, Person making amendment Patent applicant related to the case Address: Kyoto, 11-ku, Ogi-4-cho, 8-13, name: Sakaerden-Bou 2★sha 4, agent ``Dere,''

Claims (1)

[Claims] When installing the diamond 72mm stress needle f = During smooth 1 con/i-F! I'll forgive you; I'll give you a certain way to respond.