Health assessments

Structural Health Inspections of
Mass Concrete with Improved
Seismic Exploration
(Concrete Tomography)


New technology to accurately determine deterioration status of erosion control weirs

There are more than 60,000 erosion control weirs in Japan, many of which are 30-50 years old, or even older. In mass concrete structures such as erosion control weirs, the concrete must be accurately assessed for deterioration as it progresses to take appropriate measures. We at Yachiyo Engineering have improved the prevailing geological surveying technique in seismic exploration and developed a new method for assessing deterioration. First, receivers are placed around the perimeter of the dam, enabling analysis of elastic waves passing vertically and horizontally through the mass concrete in mesh units. Our developed method is to comprehensively visualize the elastic wave velocity structures through this analysis, and using the elastic wave velocities for each mesh square to quantitatively evaluate the state of deterioration.

Winner of the Infrastructure Maintenance Award in Japan This award recognizes outstanding work and technological developments in infrastructure maintenance in Japan, introducing them as best practices. Upon evaluation of experts from various sectors for their outstanding initiatives and technological development, ministerial awards, special awards, and awards of excellence are decided for facilities under the jurisdiction of the Japanese government. In 2021, the 5th award for excellence was awarded to Mass Concrete Health Inspections with Improved Seismic Exploration (Concrete Tomography).

Our Services

Effective and efficient structural health assessment

The prevailing method for accurately assessing the state of deterioration in weirs and other mass concrete structures is to conduct boring surveys based on appearance inspections. However, boring surveys only inspect points and do not allow for a comprehensive assessment of structural health. Thus, we focused on an effective and efficient method for structural health assessment.

Health assessments, visualized

▶Enables objective assessment using elastic wave velocity as an index in facility inspections, which have been carried out based on visual inspections
▶The elastic wave velocity distribution is comprehensively expressed as a color mesh or contour to visualize locations where deterioration has progressed

Fast on-site measurements

▶Measurement for concrete weirs 50-80 m in length and 15 m or less in height can be completed in 1-2 days
▶All necessary survey equipment can be transported by hand
▶With no temporary scaffolding required, survey costs are reduced (Fig. 3)
▶Environmentally friendly with no turbidity or noise