JPS60230476A - Measurement of shearing strength of joint of brick structure - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] "Industrial Application Field" □The present invention relates to a method for measuring the shear strength of joints in brick walls and the like.

``Conventional technology'' Buildings constructed by combining and stacking bricks have excellent durability, fire resistance, and structural effects, but in recent years, as these brick structures have aged, However, there is a need to strengthen the structure in order to cope with earthquakes.

By the way, prior to reinforcing such a structure, the strength of the structure is investigated.

The strength of this type of #If structure is related to the strength of the bricks that make up the structure and the strength of the joints that connect the bricks, but it is often determined by the shear strength or adhesive strength of the joints. It is important to know the strength of Therefore, the conventional method for measuring the joint strength of brick structures is to prepare a specimen made of the same masonry as the structure to be tested, and apply shear force to the specimen to determine the shear strength of the joints. This test measures strength, and it was difficult to remove specimens from actual structures. In addition, when removing a specimen from an existing brick structure, the wall surrounding the specimen must be largely demolished using chisels, etc.
Problems arise in that the work is time-consuming and costly, and repairs after taking out the specimen are troublesome.

"Problems to be Solved by the Invention" The problems to be solved by the present invention are that when a test specimen is extracted from a brick structure, the damage to the structure becomes large and repairs after extraction become troublesome; Another problem is that the workability becomes poor when extracting the specimen.

The present invention was made in view of the above circumstances, and its purpose is to reduce the damage caused to brick structures, facilitate repair after specimen removal, and improve workability. The objective is to measure the shear strength of joints in brick structures accurately.

"Means for Solving the Problem" The present invention includes a step of handling a specimen including at least two opposing joints from a brick structure by core poling, and punching out a portion of the specimen between the joints. step, measuring the breaking load when the part between the joints is pushed and handled, and calculating the average cross-sectional area of the two opposing fracture surfaces of the specimen.

"Example" Hereinafter, an example of the present invention will be described with reference to the drawings.
As shown in Fig. 1, when measuring the shear strength of the horizontal joints 2 of a brick wall 1, core polling is performed so that the two opposing upper and lower horizontal joints 2 are evenly included, as shown in Fig. 2. , take out the specimen 3. That is, the position of a cylindrical diamond bit is adjusted so that the lengths of the upper and lower horizontal joints 2 are approximately the same, and the specimen 3 is extracted by rotating this bit. The size of the specimen 3 is determined by the size of the pit 1, but it is preferable that the length be 2 to the diameter 1 of the specimen 3.

Moreover, as shown in FIG. 4, this specimen 3
The cores are extracted by core poling in a manner that is approximately symmetrical to the left and right with respect to the line, and roughly symmetrical in the vertical direction to the W-W- line. Further, the thickness of the portion outside the X-X' line and the Y-Y' line is preferably approximately 1/4 or more of the diameter of the specimen 3.

Next, as shown in FIGS. 3 and 4, the brick wall 1 is
The cylindrical specimen 3 taken out from the
The upper surface of the figure shows the part 3a between the horizontal joints 2.2 (i.e. the part between the lines x-x' and Y-Y' in Figure 4), and the lower surface shows the part 3b outside the horizontal joints 2.2. are smoothed with sea stones (stone wax), iron plates 4 are applied to these smoothed parts, set in an Amsler type testing machine, and the area between the horizontal joints 2 is applied by applying force as shown by the arrows in Figure 3. Push out part 3a. At this time, the load P when the portion 3a of the horizontal joint 2 is pushed out is measured using an Amsler tester.

Then, as shown in FIG. 5, the outer part 3 of the horizontal joint 2
From b, the lateral length at of the two fracture surfaces.

Measure a2 and vertical length l)+, b2, respectively,
Calculating the average cross-sectional area A of the fracture surface, we get A-(at X
b+ +az Xb2)/2 (cm')...
(1) Represented by 5-. Further, from the breaking load P, the average shear strength τ is expressed by the following formula.

τ-P/2A (kof/cm') ・・・・・・(
2) By the way, in the shear strength measurement method according to the present invention, the most important step is the step of taking out the specimen 3 for the shear test from the brick structure (brick wall 1 in the illustrated example). As mentioned above, in the invention, the brick is extracted from the brick wall 1 by core poling using a cylindrical diamond bit, so there is no need to significantly demolish the surrounding wall of the specimen as in the past, and the bit can be removed easily. With core polling, diameters up to 500 mm are possible, but usually 150 to 2
Since the specimen 3 can be removed by simply opening a gap (approximately 0.0111 m), repairs after removal are easy and workability is improved, and the specimen 3 can be extracted without giving any impact. Therefore, the specimen 3 will not be damaged. Furthermore, since the specimen 3 having two facing joints 2 can be extracted from an existing brick structure and the shear strength of the joints can be measured, more accurate earthquake resistance diagnosis is possible.

"Effects of the Invention" As explained above, according to the present invention, the following excellent effects can be achieved.

(a> Since the specimen for measuring shear strength is extracted by core poling, damage to the brick structure can be reduced, repair after extraction can be made easier, and workability has been improved. can do.

(b) Remove the specimen from the existing brick structure,
By measuring the shear strength of joints, accurate earthquake resistance diagnosis is possible.

[Brief explanation of the drawing]

The drawings are shown to explain one embodiment of the measuring method according to the present invention. Fig. 1 is a front view of a brick wall, Fig. 2 is a perspective view of a sample taken out, and Fig. 3 is a perspective view of a brick wall. FIG. 4 is a front view of the specimen, FIG. 4 is a plan view thereof, and FIG. 5 is a perspective view of the specimen shown for determining the average cross-sectional area of the fracture surface. 1... Brick wall (brick structure), 2...
...Horizontal joint, 3...Specimen, 3a...
The part between the horizontal joints, 3b...The part outside the horizontal joints, 4...The iron plate. Applicant: Shimizu Corporation

Claims (1)

[Claims] A method for measuring the joint shear strength of a brick structure joined through joints, which includes the steps of extracting a specimen including at least two opposing joints from the brick structure by core poling, and Pushing out the part between the joints (step, measuring the breaking load when pushing out the part between the joints, and calculating the average cross-sectional area of the two opposing fracture surfaces of the specimen) A method for measuring joint shear strength of a brick structure having a process.