There are many study examples about countermeasures for the train-induced ground vibration. However, many countermeasures are not clear about mechanisms and decreasing value of the vibration. Therefore, in general, we choose the countermeasures based on previous cases or empirical judgments. In this paper, using a numerical simulation consisting of a moving train, a track, supporting structures and the ground, we investigated a method to extract primary factors of the train-induced ground vibration. As the results, it was found that it is possible to extract the primary factors, which increased the train-induced ground vibration, by evaluating source characteristics, vibration characteristics of the viaduct and propagation characteristics of the ground. Furthermore, if the countermeasures increased the vibration of the numerical simulation, we concluded that it is possible to suggest other countermeasures, which are a high decreasing vibration effect, by clearing causes of the increasing vibration.

 Transverse load during a strong earthquake caused plate buckling and breaking of vertical stiffeners on the end support of I shaped girder bridges. A strengthening rib, to prevent plate buckling of web and lower flange plates of the main girder, are also installed to at around the stiffeners. However, installing effects of the strengthening ribs and design scheme of the girder end structure against the transverse load are not clarified. Then in this study, a cyclic loading tests, using partial and scale-downed specimens, and FEM analysis are conducted to clarify the installation effects of the strengthening ribs against the transverse load. These results revealed that the ribs, designed to have an enough height, enhance load bearing capacity of the girder end against the transverse load.

 One of general method to simulate earthquake motion is to use envelope models. However, it restrict the phase characteristics of earthquake motion. Therefore, group delay time has been widely used in recent years as an objective and quantitative parameter to model the phase characteristics. The standard procedure calculates the phase in the frequency domain by integrating group delay time generated with randomness to follow a predetermined probability distribution. We discussed some points to be improved about the envelope shape of the generated wave. Furthermore, to determine the envelope shape and the phase characteristics of generated wave simultaneously, we developed a novel method to simulate earthquake motion using relationship between envelope models and dispersion of group delay time obtained from an observed earthquake motion.

 Toward steady adaptation to a changing climate, this study analyzed the potential of a single run of the 150-year seamless experiment by the Meteorological Research Institute (hereinafter, 150-year experiment) with non-stationary frequency analysis for projecting temporal changes in 100-year basin rainfall in all the class-A river systems in Japan. The methodological validity of non-stationary frequency analysis for estimating the past change ratio of 100-year basin rainfall was examined. Then, its past, near future and future change ratio by 150-year experiment was validated against the stationary frequency analysis of d4PDF, indicating that the estimated change ratio with 150-year experiment and d4PDF were in good agreement for the national mean change ratio, while the 150-year experiment showed larger variability in regional/catchment-scale change ratio. It is essential to increase ensembles to project the future change path of extreme basin rainfall at a catchment-scale.

 Under the global warming condition, intensification of heavy rainfalls are anticipated and it is difficult to realize a flood resilient-society by only structural counter measures (e.g., levee, dam). Flood management on the premise of inundation is indispensable. In Japan, future population decline is predicted and surplus lands will be created in lower flood risk areas. It is expected that the damage of flood disaster will be reduced by utilizing surplus lands in low-risk areas. In this study, based on inundation simulation results, potential flood economic losses were estimated for Kakehashi River basin in Ishikawa Prefecture, Japan. For the condition of population decline, relocation of households and firms were simulated by a computable urban economic (CUE) model. When households and firms relocate under a population decline, the potential flood economic losses were reduced by 14.1%. When relocation from high-flood-risk areas to surplus lands in low-risk areas were promoted in CUE model by changing ratios of urbanization promotion area, the flood economic losses were reduced by 16.4%. In the past study for the Kakehashi River basin, the flood economic losses could be reduced by about 40% when the relocation to the low-risk surplus lands is the maximum. These results indicate that relocation to low-flood-risk areas will not proceed simply by relying on economic principles. Effective relocation measures are indispensable to maximize the utilization of surplus lands and realize flood-resilient society.

 The authors have been conducted model slope experiments to clarify the mechanism of rainfall-induced slope failure based on the relationship between volumetric water content and surface displacement. On the other hand, it is reported that about half of slope failures on highways are related to the failure of drainage structures. In addition, the risk of slope failure due to overflow from drainage structures has increased due to the recent unexpected torrential rainfalls. Therefore, it is necessary to consider the mechanism of slope failure caused by rainfall with overflow from drainage structures. In this study, the infiltration behavior when overflow occurs on a real slope is reproduced by numerical analysis, and the mechanism of slope failure when rainwater infiltrates from the upper part of the slope due to flooding is considered based on a model slope experiment. As a result, it was clarified that the slope failure with overflow has a different infiltration behavior and failure mode from the slope failure caused by rainfall alone.

 A simple method for estimating soil moisture behavior in levee surfaces due to rainfall infiltration was studied using time series of effective rainfall calculated based on hourly rainfall. The similarity between the soil moisture behavior and the time series of effective rainfall was evaluated for 128 rainfall cases measured on the back slope of a first-class river levee, and the half-life of the effective rainfall with the highest correlation coefficient was calculated as the optimum half-life. Short-term and long-term optimum half-lives, which are specific to the levee surface in question, are proposed as short-term and long-term extremes of the optimum half-life. The similarity between the time series of effective rainfall and soil moisture behavior using these optimal half-lives was confirmed for rainfall cases with different cumulative rainfall and maximum hourly rainfall, and the usefulness of effective rainfall as a rainfall indicator for estimating soil moisture behavior in the levee surface was discussed.

 In recent years, infrastructure tourism, which uses infrastructure as a tourist attraction has begun to be developed throughout Japan. Infrastructure tourism is expected to promote understanding of infrastructure as well as to revitalize surrounding areas and promote tourism. In this study, based on questionnaire surveys, interview surveys, and field surveys of infrastructure tourism throughout Japan, the contents and effects of the efforts of each tour have been grasped, and the effects of infrastructure tourism have been categorized. Furthermore, the causal relationship between efforts and effects, and the interrelationships among effects were discussed. We believe that these results contribute to the efficient and smooth implementation of infrastructure tourism.

 In this study, we investigated the effect of the COVID-19 pandemic on people's attitudes toward mono-polar concentration in Tokyo. In this study, we aimed to understand the impact that COVID-19 infection has had on people's attitudes. A panel survey was conducted before and during the spread of COVID-19 (wave 1: January 23 and 24, 2020; wave 2: May 21 to 26, 2021) using a web-based questionnaire (N = 515). The results showed that attitude change toward mono-polar concentration in Tokyo was not significant. Those who changed their attitudes toward mono-polar concentration in Tokyo to positive or maintained positive attitudes did not significantly increase their perceptions of a disadvantage related to the COVID-19 pandemic: the lack of medical and welfare facilities in Tokyo.

 The research targeted the National Association of City Transportation Officials (NACTO) in the U. S. and the Global Designing Cities Initiative (GDCI), which have built domestic and international initiatives centered on the municipality level. They aimed to diffuse street design measures toward livable city goals and have expanded member cities in recent years. The research conducted 1) material surveys related to the initiative activities, publications, and programs, 2) interviews with a director and an officer of a member organization, and 3) aggregation of statistics on the safety and modal share of member cities compared to the national trend. The result clarified the characteristics of the internal function of the association and its contribution to design and engineering diffusion to member cities, especially by enabling municipalities to apply context-sensitive design and metrics for them. As a factor that helped the expansion of domestic and international cooperation, the functional similarities with the ‘Transnational Municipal Network’ in the European region have been confirmed.

 Through the findings gained in the diffusion of street design measures aimed at enhancing the livability by NACTO and GDCI, the significance of the network among domestic and international municipalities was proved to build the capacity of the local department in charge and to accelerate pilot projects. Meanwhile, it indicated challenges from the perspective of the achievement status of outcomes set by NACTO, such as the modal shift to public transportation. Considering the spillover effect of street network conditions surrounding the target area, it is crucial to maximize the impact by implementing design changes to the urban environment through a geographical concentration of the collaborative-policy member organization.

 Under the spread of COVID-19 infection, the government's state of emergency and Semi-emergency coronavirus measures, and local governments' own measures, have led to repeated requests for restaurants to shorten their opening hours or close their businesses. In March 2021, an "order" to shorten hours was issued to restaurants operated by Global Dining, but it is difficult to say whether the order was sufficiently effective to justify it as contributing to public welfare. In addition, how effective the government's state of emergency and other measures were in preventing the spread of COVID-19 in the country and the city as a whole. In this paper, in Analysis 1, we estimate the number of new infections that may have been prevented by Tokyo Metropolitan Government's "order of shortened opening hours" for four days to Global Dining. Next, in Analysis 2 and 3, we analyze how the state of emergency and other measures suppressed the increase in the effective reproduction number in Tokyo.

 Currently, the Japanese government is working to build connections between the Tokyo area and the local communities in order to reduce the concentration of people in Tokyo. The "related population," which has been the focus of attention in the building connections with the local communities, is related to people’s territorial bond and blood relationship. The term "hometown" is often used to describe the awareness of residents who have a connection to local, but the actual situation of residents' awareness of "hometown" has not been sufficiently clarified. The purpose of this research is to clarify how people think about their hometowns. In this study, we focused on "hometown" and conducted a survey in Saitama Prefecture. As a result of the survey, it was found that most of the people born and raised in Saitama Prefecture think Saitama Prefecture as their "hometowns", not the area where their grandparents and parents were born and raised. And few people had no definite “hometown”.

 The purpose of this research is to describe the process of the severe disaster special emergency project in the Tsukumi River and to clarify the measures to achieve landscape consideration. As a result, 1) Set goals based on the actual conditions and create a forum for sharing ideas among the maintenance and management entities at an early stage of the project, 2) A system to take over the design policy by municipality and to consistently supervise the work, 3) The devising to utilize the flexible grant at the same time as the project period while keeping in mind the integrated development with the city, as an effective strategy to realize landscape considerations in disaster control projects.

 Stormwater management, which is now under pressure from both climate change and impervious surface expansion, is one of the critical issues to be tackled in the city. Raingardens as a small-scale, spatially-distributed stormwater green infrastructure have been widely installed in urban areas all over the world, which should be in harmony with local nature and culture. This study is to observe and evaluate the rainwater management functions that a traditional Japanese dry garden of Shokokuji Temple in Kyoto apparently has had; it is also to show a design guide for installing raingardens in Japanese cities based on the performance monitoring and evaluation of the garden. The finding obtained are as follows: 1) The dry pond in the garden can retain up to 307.5mm of rainwater, which exceeds the depth of the estimated 100-year rainfall in Kyoto (242mm). 2) The infiltration ratios when the water increases in the pond are 87.8% in average and 57.8% at minimum; the infiltration rates when water recedes in the pond are 32.7mm/h in average and 14.1mm/h at minimum. 3) The garden’s infiltration works in response to a variety of rainfall patterns. 4) The materials forming the foundation of the garden includes the gravels of up to 100-150mm in diameter; the distribution in the size of materials contributes to sustaining the high performance of rainwater infiltration in the garden.

 In this study, population-level travel demand data were generated assuming different urban structures with concentrated or dispersed population and facility distribution in addition to the current distribution in the target area. Comparative evaluation of the convenience and transportation efficiency of shared automated vehicle (SAV) services in different urban structures and impact analysis of regional implementation of SAV were conducted. Agent-based simulations were conducted based on a mode choice model estimated from a stated preference survey that asked about the intention to use SAVs. For this analysis, a regional city in the northern part of Gunma prefecture was set as the target area. Results revealed that as the distribution was concentrated in the centeral city, the convenience and transportation efficiency increased, and the positive influence on the operation of automated driving services became stronger. On the other hand, regarding the regional disparity in convenience, the results showed that the waiting time was considerably longer in the low population areas far from the central city area.

 Municipalities manage a lot of social infrastructures, and are facing a difficult situation to maintain them. In particular, deterioration due to chloride attack and alkali silica reaction (ASR) is likely to occur at concrete structures in Hokuriku region, and immediate action is required. Based on above background, this paper reports support for reasonable maintenance for road bridges managed by municipalities in collaboration with local university and technical college faculty members. First, interview surveys were conducted for 41 municipalities in Joetsu district of Niigata prefecture, Toyama prefecture, Ishikawa prefecture, and Fukui prefecture. Next, in order to improve these, a procedure plan for inspection, diagnosis, and measures was proposed for concrete bridges with a short span, technical exhibitions were held in Hokuriku region, and the evaluation of the repair effect was tried using actual bridges. These unique actions started from the requirements of municipalities might be achieve rational maintenance of road bridges with government-academia collaboration.