| In the 2024 Noto Peninsula earthquake (M7.6), many road bridges and their abutment approach were damaged due to its intense ground motion, which was found comparable to the current design spectra. The Public Works Research Institute (PWRI) and the National Institute for Land and Infrastructure Management (NILIM) jointly investigated the damage to road structures, including 135 road bridges, as of March 2024. No major structural damage was found on 44 bridges that were designed according to design standards after the 1995 Kobe earthquake, which require bridges to withstand an M7 shallow earthquake directly below them, while 6 bridges suffered major structural damage among 91 bridges designed under pre-1995 design standards.
Since no findings have been confirmed that would invalidate the current technical standards, the Road Bureau of the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) proposed the following directions to improve the technical standards from the viewpoint of speedy reconstruction.
- Improve the design items and contents in order to realize a damage pattern that enables rapid emergency restoration even in cases where no specific external force can be assumed.
- Ensure a structure that is easy to inspect, diagnose, and rehabilitate after an earthquake, and ensure access to the bridge.
- Consider the development of technical standards for repair, including the establishment of performance requirements and the introduction of the concept of damage control, so as to allow for flexible and appropriate measures.
In this paper, characteristics of the earthquake and observed strong motion records are outlined, then our field survey results of 4 bridges with major damage, namely, Noto, Ohmachi, Karasugawa, and Saida Bridges, are presented. Lastly, related research projects underway at our institute, damage scenario design and quick inspection, are introduced; they are expected to contribute to the improvement of technical standards in line with the directions of the Road Bureau, MLIT. |
