In order to clarify the relationship between the horizontal seismic intensity, K_h, and the peak ground acceleration, PGA, on the slope damaged by the 2018 Hokkaido Eastern Iburi Earthquake, K_h were backcalculated. The safety factor of the slopes when back-calculating K_h was set to F_s =1.0. The ground properties of the slip surface used in the back-calculation of K_h were established based on previous investigations, and two cases with relatively strong and weak ground properties were used to verify the influence of the variation in the ground properties. PGA was calculated by the Shi Midorikawa attenuation relationships. K_h was calculated by 3D stability analysis, considering the actual collapse geometry. From these calculated values, equations relating K_h to PGA was obtained. K_h obtained from this relationship. The obtained K_h was compared with the practically used K_h. As a result, it was found that, when weak ground properties are used in the present study area, K_h calculated by the Noda et al. equation gives a more reasonable value for the K_h during a large-scale earthquake than other methods used in practice.

 Inexpensive and compact IoT sensors were installed on an actual bridge and monitored. The target bridge is a two-span continuous girder with RC slabs and five steel main girders in Gunma Prefecture. The IoT sensor uses a Raspberry Pi, a single-board computer. It has a dedicated camera module and can be connected to a network using a USB dongle. The deformation amount of the rubber bearing can be measured by a camera and remotely controlled via the network. The IoT sensor can be operated by solar power, so it can be installed and operated without expensive construction work to secure a power source. The IoT sensor has been installed on the actual bridge since 22nd September 2022, and this paper reports the data obtained on the deformation amount of rubber bearing with contraction of the bridge due to temperature and the width of cracks in the RC slab about ten months after installation.

 This report is based on a girder bridge constructed about 60 years ago and already dismantled. The bearing capacity of the 60-year-old piers that three engineers made the restoration design was investigated. The results showed that, depending on the design results, the yield capacity of the piers with the restored design may be estimated to be higher than that of the piers with the reinforcement revealed at the time of dismantlement. On the other hand, it was found that if the restoration design was performed with reasonable reinforcement quantity and reinforcement arrangement, even if the reinforcement arrangement was slightly different from that of the actual structure, it was unlikely to have a significant impact on the evaluation of the seismic performance of the existing piers.

 In large-scale earthquakes, not only damage that can be confirmed visually, but also many “invisible damages” occur. Typical “invisible damage” on roads is the frequent occurrence of cavities under the pavement, which are known to expand and become shallower over time after an earthquake. For this reason, it is necessary to grasp the situation immediately after an earthquake. Therefore, it is effective to prepare road sinkhole potential map that evaluates the risk of cavities caused by an earthquake in advance for each point on the road. Thus, in this paper, we proposed a procedure to create a road sinkhole potential map due to an earthquake. In the procedure, the ground conditions, the structural conditions, and the level of shakings are considered. In addition, some practical problems such as the difficulties, gathering the details of buried structures are pointed out.