Effective inspection of noise barriers installed along expressways and high-speed railways is required since they can suffer damage due to corrosion of anchor bolts, aging of the anchorage, and external forces caused by earthquakes, typhoons, and traffic. This study focuses on the vibration behavior of noise barrier posts and experimentally reveals that asymmetric vibrations occur due to differences in base constraint conditions. Furthermore, using a multi-degree-of-freedom model with torsional springs, asymmetric vibrations were numerically replicated. As a result of investigating damage detection focusing on modal vibration frequencies and shapes, it was shown that instantaneous vibration frequencies can be identified with less than 1% error from non-contact displacement measurements. Additionally, the potential for assessing the state of anchorage based on instantaneous displacement was demonstrated.

 This paper proposes a method for estimating the cumulative fatigue damage mainly in welded steel members, based on the actual traffic load data measured by the weigh-in-motion devices on main lines. Specifically, first, the actual traffic loading conditions based on the loading data of 26 cross-sections of main lines over a period of approximately one year was investigated. Next, the relationship between the traffic data, for which data is routinely recorded, and the load data was organized, and a method for estimating the cumulative fatigue damage only from traffic data was proposed. The accuracy of the estimation method was verified by comparing it with the cumulative fatigue damage directly obtained from the load data. Finally, the availability of the estimation method was demonstrated by case studies of fatigue cracks in U-rib to deck welded joints of orthotropic steel decks, and an entire network of intercity expressways.

 This study developed a land use-based parameter identification method for a distributed rainfall-runoff model 1K-DHM, by calibrating the soil parameters of all land use types to multi-event and multi-site discharge observations simultaneously. The developed method was applied to the Kikuchi River basin, indicating that the identified parameter sets with the 10 highest Nash coefficient shared the similar value within the same land use type, while they differed among land-use categories. The parameter set with the highest Nash coefficient was validated in 15 basins including Kikuchi River, showing overall high performance with the Nash coefficient between 0.5 to 0.8 at 43 stations and over 0.8 at 44 stations, especially at river basins more than 500 km². Throughout the calibration and validation, this study realized the identification of robust model parameter values that reflect the physical properties of catchment surfaces based on land use types.

 It is useful to know the maximum flood control capacity of existing dam storage in climate change adaptation. Given highly improved accuracy in read-time dam inflow prediction in the future, we assessed the additional flood control capacity of existing dam storage when flood control operations are optimized for predicted dam inflow under future climate change using a large ensemble flood event database from the +4K experiment in d4PDF. Optimized dam operation exhibited high flood control effects during future extreme floods, which was comparable with the redevelopment of dam storage especially in dams with large storable rainfall (> 150 mm). If we realize highly-accurate dam inflow prediction during flooding in the future, optimized dam operation will provide additional flood control effects on dam storage reinforcement.

 Tunnels built using the sheet pile method have a water leakage problem for deterioration over time. To solve this problem, tunnel lining renewal method was developed.

 In this study, seismic analysis was performed using shear elastic wave velocity as a parameter. In the seismic analysis, the shear elastic wave velocity in which the bending curvature of concrete is within the elastic region was determined.

 As a result, it was found that if the shear elastic wave velocity is 400 m/s or more, renewal lining is equivalent to standard design lining and the renewal lining standard design can be applied.

 In this study, we develop a data-driven method for identifying the queuing areas near a signalized intersection using only ETC2.0 probe data. Specifically, vehicle trajectory data accumulated near an intersection for a certain period of time (e.g., one month) are map-matched to road links divided into 20-meter segments, and the time median speed for each link and time period is stabilized by a space-time Kalman filter while considering the correlation among data on adjacent link segments. The threshold value for determining the presence or absence of retention is set not at the customary 20 km/h, but at the point of change of the time median speed with respect to the distance from the intersection during a day. The applicability of this method is demonstrated using the example of monitoring the effects of changing the signal intervals at a congested intersection in Kobe City.

 The recent transition of the place of activity from real space to cyberspace due to digitalization has enabled us to spend our day without going out, which can lead to issues such as compromising health. To shift our lives back into real space —to realize RX (Real Space Transformation)— one key is to increase the number of people who have positive emotions on going out. Here, we focused on the respondents to a survey who did not like going out (n = 588) and analyzed the contributors to the negative attitude towards going out in order to explore ways to counter them. The main negative attitudes were feeling that costs and contacts when going out are burdensome, not valuing going out as a chance to improve health or encounters, highly evaluating cyberspace while feeling that going out is unnecessary, and giving little credit to activities and relationships in real space. The results indicate the need for different measures for different groups of people typified by those factors.

 Various efforts are made to promote digital transformation in the infrastructure field. This research focuses on the use of blockchain technology for quality control at asphalt mixing plants. The purpose was to develop a prototype information system that improves the reliability of test data and streamlines test work, targeting Marshall Stability Test. Additionally, a smartphone application was developed that works with this system to save labor in inputting and organizing data, and its effectiveness was confirmed.

 For the utilization of the wastewater surveillance to understand the prevalence of SARS-CoV-2 infection in the catchment area, it is necessary to apply an efficient sample collection method according to the regional characteristics and epidemic situations. A long-term monitoring of SARS-CoV-2 RNA concentration in the wastewater was conducted using passive samplers made of a cotton ball for eight months from September 2022 to May 2023 in Ube City, Yamaguchi Pref. Significant correlation (correlation coefficient R=0.75) was obtained between the concentrations of SARS-CoV-2 RNA in passive samples and the estimated number of cases within 6 days of onset. The quantifiable concentration data from the passive sampler suggested the possibility of early detection 5 to 6 days prior to the epidemic situation at the catchment area compared with the information from sentinel surveillance.