Structure and Material investigation

Structural survey

Many structures and facilities built during the period of high economic growth have deteriorated, making efficient maintenance an urgent necessity. We contribute to extending their lifespan by accurately grasping their current state through "inspection, investigation, testing, and analysis" and proposing appropriate measures according to the condition.

Inspection

Bridge, tunnel and building inspection

Inspection is the most important and most popular method for maintaining bridges, tunnels and buildings.
Specialized engineers carry out inspections of a variety of structures, including civil engineering structures such as bridges and tunnels, buildings such as apartment complexes and schools, and plant facilities.

Drone inspection

Drones are used to inspect locations where it is difficult for people to approach. By using drones, it is possible to inspect not only bridges, but also structures such as chimneys and slopes that have been difficult to inspect in the past. Drones can also be equipped with infrared cameras in addition to regular image sensors (cameras), allowing them to meet a variety of inspection needs.

Non-destructive structural inspection

Rebar detection

We investigate the location of rebar inside the concrete and the cover (shortest distance from the concrete surface to the rebar).

1 Electromagnetic wave radar method

It can detect up to relatively deep depths (about 30 cm) and can detect not only rebar but also non-magnetic materials such as cavities and PVC pipes.
2 Electromagnetic Induction Method

By determining either the rebar cover or the diameter of the rebar, it is possible to estimate the other with relatively high accuracy. The electromagnetic induction method makes it possible to detect magnetic bodies such as rebars at a detection depth of about 10 cm and estimate the diameter of the rebars.

Ultrasonic measurements

The strength of concrete in structures and internal cracks are measured using ultrasonic sensors.

1 Estimation of concrete strength using ultrasonic waves

Based on the "Procedure for measuring the strength of concrete in new structures using ultrasonic testing (PWRI method) (draft)," a qualified person (a participant of the training course: PWRI) will estimate the strength.
2 Measurement of crack depth using ultrasonic waves

Using the property of ultrasound being diffracted at the tip of the crack, the crack depth can be estimated based on the sensor distance and propagation time.

Infrared survey

Deteriorated areas where the concrete surface has become peeled or cracked have different thermal properties from healthy areas. These are investigated using infrared rays.

1 Inspection of deteriorated areas using infrared thermography

This is a method to confirm the difference in thermal characteristics that occurs when the outside temperature changes, as an infrared image. By using infrared thermography, it is possible to survey a wide area from a long distance.

Natural potential/Polarization resistance

"Rebar corrosion deterioration" in structures using reinforced concrete has structural impacts such as a decrease in load-bearing capacity. Estimating the corrosion level and calculating the corrosion rate are important for the maintenance and management of structures.

Natural potential measurement

When rebar corrodes in concrete, the potential changes to the negative side, and this can be measured to estimate the possibility of corrosion. A reference electrode is placed on the concrete surface to measure the natural potential that changes due to rebar corrosion, and the possibility of rebar corrosion inside the concrete can be estimated.
Polarization resistance

Electrodes are placed on the surface of the concrete and a current is passed through the rebar. The polarization resistance is detected from the change in voltage that occurs when a small change is made in the current, and the "rebar corrosion rate (μA/cm2)" is calculated.

Concrete testing

In order to estimate the current physical properties of structures and the causes of deterioration, tests are conducted using test pieces taken during construction, inspection, investigation, etc. The results obtained from tests, observations, and analyses are used for appropriate construction management and repair design.

Physical property testing

Using samples (such as test cores) taken from structures, we perform various physical property tests such as those listed below. We can also perform physical property tests on materials such as rocks and resins.

Compressive strength, static elastic modulus test
Measurement of carbonation depth
Chloride ion content test
Expansion test (JCI method, Canadian method)
Aggregate alkali-silica reactivity test, etc.

Scanning electron microscope (SEM) observation

Aggregates in concrete deteriorated by alkali-silica reaction contain reaction products (such as silica gel). The characteristics of the reaction products are observed with a scanning electron microscope (SEM) to determine whether the deterioration is due to alkali-silica reaction.

Electron probe microanalyzer (EPMA) analysis

In order to ascertain the depth to which deterioration factors have permeated the concrete, the collected cores are cut in half and an "area analysis" is performed using an EPMA*1 to measure the distribution of the deterioration factors.

*1 An electron probe micro analyzer (EPMA) is a device that irradiates a sample with a finely focused electron beam, disperses the element-specific X-rays that are generated with an X-ray spectrometer, and measures the wavelength and intensity of each to determine what elements are present. In addition, the method of investigating element distribution by fixing the X-ray spectrometer to a specific element and scanning the sample with the electron beam in two dimensions is called "area analysis."

Radar exploration

Using electromagnetic radar, we can detect the location and depth of various buried objects such as underground pipes, structural foundations, cavities, etc. Because it is a non-destructive test, we can quickly estimate the condition of the underground and the back of the tunnel lining without excavation, and there is no need to worry about noise or vibration.

Ground-penetrating radar

The location and depth of buried pipes, cavities, etc. can be estimated from the characteristics of amplitude, phase, reflection pattern, etc. of the waveform data obtained when scanning with a probe using electromagnetic radar. The following are typical applications.

Underground exploration

We explore and estimate pipes and cavities buried underground.

Tunnel lining back cavity inspection

The gap (cavity) between the tunnel lining and the ground is explored and estimated.

Imaging diagnosis

The condition of the concrete surface is photographed using drones or high-definition cameras, and cracks are automatically detected from the images using AI technology.

"Crack Detection" - an automatic crack detection technology using AI

An orthomosaic image is created from images taken of the concrete surface, and cracks are detected from the image using "Crack Detection," an automatic crack detection technology that uses AI.

Traveling tunnel continuous image capture system (tunnel tracer)

The lining surface of road tunnels, etc. can be photographed without traffic restrictions. By simultaneously photographing the target with multiple high-definition video cameras or line sensor cameras, high-quality unfolded images can be obtained in a short time. The obtained unfolded images can be used to check the deterioration state and create deformation diagrams, etc.

Mechanical testing

Mechanical testing is important for understanding the physical properties of materials and machine parts, and is essential in the design and manufacture of machine parts, ensuring safety, etc. We have ample experience and a proven track record in non-standard tests and tests using mockups, and can meet a variety of needs.

Typical mechanical tests include the following. We have a track record of testing a wide variety of samples and can flexibly respond to various testing needs.

Compression Test
Bending test
Shear Test
Fatigue Testing

Material survey

When products or machines are damaged, it can seriously affect production plans and quality, so rapid and accurate investigation and identification of the cause are required. With our extensive experience and track record, we strive to propose investigation items and solve problems that suit our customers' purposes.

Appearance inspection

We visually and microscopically observe and investigate the damage and surrounding conditions of products and parts to confirm the state of deformation and its expansion.

Fracture surface analysis

The cause of fracture (ductile fracture, brittle fracture, fatigue fracture, stress corrosion cracking, etc.) is identified by macro-fracture surface inspection using a microscope and micro-fracture surface inspection using a scanning electron microscope (SEM).

Shape measurement

We use 3D shape measuring machines and image measurement software to measure the shape and dimensions of components, as well as surface irregularities (roughness measurements), and compare them with design values and sound products.

Metal structure observation

Metal structure is examined under a microscope to check for cracks, structural abnormalities (such as poor heat treatment), inclusions, casting defects, etc.

Hardness measurement

To confirm the mechanical properties of a microscopic area, measurements are performed using hardness testers. Hardness testers include Vickers hardness testers, Rockwell hardness testers, Brinell hardness testers, and on-site hardness measurement (Equotip).

EPMA/EDX analysis

Using electron probe microanalyzer analysis (EPMA) and energy dispersive X-ray fluorescence analysis (EDX), we perform component analysis to confirm materials, corrosion factors, and even local analysis (qualitative, quantitative, mapping, and line analysis) to analyze microscopic areas such as foreign matter, adhesions, and inclusions.

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