JPS5992334A - Detecting method of defective part of construction - Google Patents

Abstract

PURPOSE:To detect a defective part such as a crack and a water leaking part accurately, efficiently, and economically by measuring the surface temperature distribution of a construction through an infrared temperature measuring device. CONSTITUTION:In general, when the sunshine strickes the surface of a construction, the temperature at the part rises, but if there is a crack on the surface, the discontinuous line of the surface temperature appears along the crack. The surface temperature where water stays is lower than that at any other part. The temperature distribution of the surface of the construction is measured by the infrared temperature measuring device which outputs a heat image or heat photograph and the discontinuous line and low-temperature part of the surface temperture are detected to find defective parts such as the crack and water leaking part of the construction. The infrared temperature measuring device photodetects infrared rays radiated from the measured body by a scanner as a heat video camera and converts them into an electric signal to display a heat image with black and white gradations on cathode-ray tube.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a method for accurately, efficiently, and economically detecting defective parts such as cracks in walls of structures and water leaks on rooftops.

(Prior art) Cracks in the exterior of mortar, tiles, etc. on the walls of houses and buildings not only cause water leakage, corrode the steel frame, and accelerate the deterioration of the building, but also cause the exterior to lift up and fall off, causing damage to the exterior. This poses an extremely high risk of direct damage to passersby. Conventionally, relatively thick cracks can be visually detected and repaired, but thin cracks cannot be easily detected, and therefore areas that require repair are often left in the cracks, resulting in accidents. It was often the case that we took action only after a problem occurred.

In addition, it is extremely difficult to detect areas where rainwater has penetrated due to cracks in waterproof sheets or PC (precast concrete) boards installed on the rooftops of hills, etc., or areas where water has accumulated by looking from the surface. Therefore, in the past, the extremely uneconomical method of repairing the entire rooftop was used to repair leaks.

Furthermore, if a crank occurs in a PC board or exposed concrete covering installed on a mountain slope overlooking a mountain road, etc., to prevent landslides, rainwater will infiltrate from that area.
This water or groundwater accumulates under the covering, softening the ground and becoming a major cause of landslides.

Detection of the various defects in structures described above has mainly relied on visual inspection, which is difficult and unreliable, and requires a lot of time and manpower to cover a wide area. .

(Objective of the Invention) The present invention effectively utilizes the temperature difference that occurs between a normal part and a defective part on the surface of a structure to measure the temperature distribution on the surface using an infrared measurement device that can obtain thermal images or photographs. The present invention also provides a method for detecting defective parts of structures, which allows defective parts to be detected accurately, efficiently, and economically. The method of the present invention will be explained in detail below.

(Example) Generally, when sunlight hits the surface of a structure, the temperature of that part increases, but if a crack exists on the surface, a discontinuous line of surface temperature will appear along the crack. In addition, the surface temperature of the area where water accumulates is lower than that of other normal areas.

In the present invention, an infrared temperature measuring device capable of obtaining thermal images or photographs is used to measure the temperature distribution on the surface of the structure. This device is a scanner with a thermal imaging camera that receives infrared radiation emitted from the object being measured, converts it into an electrical signal, and displays a black and white thermal image on a cathode ray tube. You can take pictures of videos. Additionally, if you use a color monitor,
Thermal images can be displayed in 10 colors corresponding to the temperature of each part of the object to be measured, further increasing thermal resolution.
Temperature distribution can be clearly understood.

Example 1 FIG. 1 is a reproduction of a thermal photograph taken of a part of the wall of a five-story apartment using the above-mentioned apparatus, and the white part is the high temperature part. The temperatures in la and lb are high at the protruding part of the staircase landing in the apartment. Also 2
is a window. 3a and 3b are cracks that occurred in the mortar wall, which clearly appeared on the thermal photograph as discontinuous areas in the temperature of the surrounding wall surface.

Example 2 FIG. 2 shows a part of a rooftop covered with a waterproof sheet. 5 is a waterproof sheet, and rainwater collects in a groove 6 and is guided to the ground through a gutter 7. Due to a water leak on this roof,
The temperature distribution on the rooftop was measured from above and the defect locations were investigated.

As a result, the rack 8 as shown in FIG. 2(B),
The portion 9 where the surface temperature is low due to the accumulation of rainwater that entered through this crack could be displayed on the thermal image. By detecting this defective part, it is possible to repair only the necessary parts without having to renovate the entire rooftop as in the past, which is extremely economical.

In addition, the method of the present invention can also detect cracks in a destroyed landslide prevention structure and pools of rainwater or the like that have entered through the cracks. Also, structures such as PC boards where reinforcement is placed relatively shallowly from the surface will have a surface temperature distribution that corresponds to the reinforcement.
According to the method of the present invention, it is possible to inspect whether or not the reinforcement structure is normal.
It is possible to display a wide range of m as one thermal image, and if necessary, the -C range can be narrowed to improve accuracy.

(Effects of the Invention) As explained above, according to the present invention, defects such as cracks and water leaks in structures can be detected extremely efficiently, economically, and with high accuracy. This has the advantage of being able to start repairs quickly and prevent accidents and problems from occurring.

[Brief explanation of drawings]

Fig. 1 is a copy of a thermal photograph taken for detecting wall cracks in one embodiment of the present invention, and Fig. 2 is a diagram showing the results of detecting defects on a rooftop in another embodiment of the present invention. It is. 3, + 3b... Crank that occurred on the mortar wall) 5... Tarpaulin sheet, 8...
・・・・・・Crack, 9・・・・・・・・・A part where the surface temperature is low due to the infiltration of rainwater. Figure 1 Figure 2 (A) +B)

Claims (1)

[Claims] 1. A method for detecting defective parts of a structure, the method comprising detecting defective parts such as cracks and water leakage parts by measuring the temperature distribution on the surface of the structure using an infrared temperature measurement device capable of obtaining thermal images or photographs.