In steel highway bridges, the multi-layered overlapping coating was adopted in some cases, which applies paint on the sprayed coating. There are many unclear points about the durability and anti-corrosion properties of this overlapped coating film. In this study, to clarify the durability and anti-corrosion characteristics of overlapping layers between Al and Zn thermal sprayed coating and heavy duty paint coating, the specimens of single sprayed coating and overlapping coatings were prepared for the combined cyclic corrosion tests. A cross-cut coating defect was introduced into each specimen. After the test, the coating blister scans and electrochemical measurements on polarization were carried out on specimens, while the cross-section elemental analyses using SEM-EDX, and compound identification by XRD, etc. were also conducted. Test results indicate that the durability of Al overlapping layers is lower than that of the Zn overlapping layer, which deteriorated faster. Moreover, the degradation mechanism of the overlapping coatings between Al- or Zn-based sprayed coating and heavy duty paint coating was investigated, for those exposed to a highly corrosive and salinity environment.

 When high-strength bolted flush end-plate connections are applied to the main girder joints of bridges, horizontal stiffeners must be installed in order to obtain the required joint strength and stiffness. However, the mechanism by which the girder and horizontal stiffener specifications contribute to the increase in joint strength and stiffness has not been clarified in detail. In this study, parametric analysis was carried out by varying the main girder parameters and the horizontal stiffener thickness to investigate the effect of these parameters on the strength and stiffness of the joint. The analysis showed that the increase in joint stiffness was greater for girders with horizontal stiffeners of the same thickness, where the second moment of section of the girder considering the horizontal stiffeners was larger. It was also found that a girder with a small flange cross-sectional area and a large web cross-sectional area was more advantageous for obtaining a large joint strength. Finally, a method for calculating the horizontal stiffener thickness to ensure the stiffness of the main member is proposed.

 This study aims to clarify the applicability of displacement measurement by GNSS (Global Navigation Satellite System) to the safety monitoring of existing bridges, and to investigate the sensor installation method, stability of long-term measurement, and accuracy of displacement measurement. This paper discusses the possibility that this method can be an effective means of understanding the complex displacement behavior of bridges. This paper compares the 3D displacement data acquired by the satellite positioning method with various monitoring data to show that the method can measure the relatively long-term and periodic 3D deformation behavior of bridges caused by deflection and temperature changes in response to applied loads with the necessary accuracy. The paper also reports the results of a study on the possibility of understanding short-term displacement behavior based on the results of structural analysis and analysis of the measured data.

 Suonada is the widest sea area in the Seto Inland Sea. In this study, past typhoons and storm surges that affected the Suonada were organized, and storm surges that caused particularly severe damage were reproduced. Furthermore, the maximum storm surges are investigated by using the multiple typhoon tracks that are made by parallelly moving the actual typhoon one represented by T9918, etc. As a result, the relationship between the development of storm surges along the Suonada coast and the typhoon tracks was clarified.

 It would be possible that a gate which allows the simultaneous flow under and over sluice gate can keep the advantages of these individual flow systems with reducing the week points of them, which gives expectation in the water management. But it seems that none of the previous studies aiming at quantitative evaluation is available for the design of this type of structure. The present paper proposes the calculation method giving total discharge as the sum of the discharge evaluated for both under and over flows individually by rational methods based on hydraulics including submerged outflow. The results obtained by the method proposed in this study was verified using experimental data obtained in the laboratory, and good agreement was obtained.

 In the safety assessment of geological waste disposal, it is important to quantitatively evaluate retardation of radionuclides by sorption in the rock matrix. A reasonable method to directly evaluate retardation properties of radionuclides is a tracer test in a single fracture. However, in-situ tracer test is often difficult to control test conditions such as flow fields in fractures. As a results, it remains unclear the dependence on test conditions and the validation about sorption properties evaluated in-situ tracer tests. Here we constructed the laboratory experiment system with single fracture which has enabled the control of flow fields and conducted tracer tests at different flow rates. We find that estimated retardation factors within matrix are similar regardless of flow rates. In addition, these results may coincide with the results of batch sorption experiments. We suggest that if the in-situ test environment in fractures can be understood and/or controlled, sorption properties which are available for safety assessment may be evaluated from in-situ tracer test.

 Soil toughness can be enhanced by mixing short fibers into the soil. Short fibers include natural, artificial, and mineral fibers, yet there is concern that the reinforcement function deteriorates as the fibers degrade over time. Therefore, some techniques to control the degradation are needed to sustain the effects of the fiber in soil. In this study, microorganisms were added to sand samples mixed with naturally occurring and artificial fibers, respectively, and their effects on fiber degradation were investigated. As a result, laboratory experiments revealed that large amounts of carbonate precipitated on/in the fibers in the cases of sand samples mixed with naturally occurring fibers, and that the carbonate protected the fibers. Additionally, numerical simulations based on reaction-diffusion theory clarified that the inhibition of ion diffusion in the solvent is closely related to the protective effect observed in naturally occurring fibers.

 The COVID-19 vaccination has started in Japan on February 17, 2021. However, despite the repeated declarations of a state of emergency, there have been problems such as medical system overload, economic recession and decline in social activities due to refraining from traveling. Furthermore, adequate knowledge about the dangers of the virus and vaccination has not been widely shared, and as a result, the views of the government and the atmosphere of society have greater influences on the process of policy making than the opinions of medical professionals do. This paper therefore conducted a questionnaire survey of medical practitioners in Osaka Prefecture, and 236 responses was used to examine better government assistance policy for medical institutions, the appropriateness of the legal treatment of COVID-19, which are currently equivalent to first and second class infections, and the attitudes toward risks of coronavirus vaccines of health care professionals were statistically examined separately for those with and without the treatment experience of COVID-19.

 In recent years, a problem of transportation such as a declination of public transportation and an increasing of returning a driver's license from an elderly is becoming apparent in Japan.This problem is particularly serious in rural areas, so that ensuring transportation is one of the most important issues from a viewpoint of keeping quality of life and settlement in rural area. Based on these backgrounds, in this study categorized an elderly into eight groups focused on an availability of "walking", "driving", "pick-up and drop-off", and "public transportation" based on a questionnaire survey for the elderly conducted in Tobetsu-cho, Hokkaido. Based on the categorization, we analyzed a feature and seasonality between the groups in terms of living standard evaluation such as frequency of outing, subjective health condition, subjective well-being, settlement intention, and considering out-migrate. Furthermore, it is revealed that an existence of a "preliminary out-migrate group" using cluster analysis based on the questionnaire survey. From these analysis results, in this study presented a suggestion for an importance of ensuring transportation and an direction of local government policies in rural areas.

 This study provides essential knowledge on the future road maintenance and management in local cities by understanding the attitudes of residents living in various areas toward road maintenance and management by road types, such as arterial roads and community roads in local cities, as well as roads in downtown areas, suburban areas, and mountainous areas. The importance of road maintenance and the acceptability of maintenance management methods were surveyed among residents (n=1,039) of the three Tokai prefectures of Aichi, Mie, and Gifu, excluding government ordinance-designated cities.The results showed differences in the relevant awareness depending on the road type and the nature of the area to be maintained, respectively, and that it is crucial to take these trends into account in road maintenance and management.

 This study aims to clarify the factors of human mobility change in the commercial area during the COVID-19 pandemic. First, we employed the change patterns of human mobility based on the mobile big data in 21 cities, including government ordinance-designated cities. Second, we analyzed the change in human mobility considering the spatial relationship between the target commercial area and the origin of human mobility defined by residence information. Lastly, the factors of human mobility change were investigated considering the number of employees in each industry. The major findings are as follows. 1) The human mobility from the same or neighboring districts does not show a significant change, while the human mobility from the remote city shows a great decrease. 2) The increase of human mobility from the same or neighboring districts is prominent in the increased pattern. 3) The major metropolitan areas of Tokyo and Keihanshin show a positive relationship between the number of employees that support daily life and increased pattern, but regional urban areas do not.

 In recent years, street redesigning projects have been planned and implemented to create pedestrian-friendly cities. In order to realize attractive places through the redesign of urban street spaces, practical methodologies are required to enhance the possibility of pedestrians’ space utilisation while ensuring accessibility by automobiles, etc. and traffic safety, and leading to social consensus building. This study details the process for planning and designing coordination and consensus building through the case of Mariahilferstrasse, which is one of the large shared spaces developed in Europe based on the new traffic rule called 'Begegnungszone'. Specifically, the following findings were obtained. (i) Public participation and pilot projects enable the setting of study conditions that prioritise space utilisation, the management of coordination and the qualitative evaluation of provisional proposals. (ii) In realizing shared spaces in the city centre, it is important to coordinate traffic accessibility and safety, and the key point is the realization of autonomous traffic safety by all street users and the flexible operation of the traffic calming rule. (iii) Identifying and convening the appropriate stakeholders involved at each stage of coordination and guiding a complementary dialogue between these actors contribute to achieving consensus building.

 In this study, I focused on “Tokugawa Jikki”, the official record of the Edo Shogunate. In AD 1666, the first statute called “Sansen Okite”, referring to landslide and flood control measures, was published in the “Tokugawa Jikki”. Therefore, in this study, we first extracted all matters related to rivers up to AD 1666.

 As a result, it became clear that in AD 1645, about 20 years before the first appearance of the “Sansen Okite”, there existed legal references to erosion and flood control measures. In addition, from AD 1666 to AD 1742, I extracted legal matters related to the “Sansen Okite”. These included that the cultivation of fields and the cutting down of trees were prohibited in the upper reaches of rivers and in the mountains that served as water sources. There were also orders banning the development of new rice fields along the lower reaches of rivers, as well as cutting down trees at the water’s edge. Further investigation revealed that 6 items related to the “Sansen Okite” were published, and laws and ordinances concerning landslide control measures were promulgated about every 20 to 30 years.

 Even today, we should think about managing both forestry and flood control in an integrated manner, like the “Sansen Okite”. In this study, I showed that there are many points that we, who live in the present, should consult the policies of the Edo Shogunate regarding.

 The spread of the COVID-19 caused many changes in various aspects of people’s daily lives. This paper mainly aims to clarify changes in ordinal people’s behaviors and attitudes of grocery shopping and in the evaluation structure of inconvenience of the shopping in Tokyo metropolitan area. We set three periods for analysis as 1) before pandemic period, 2) the period from the beginning of the pandemic when there was the greatest difficulty in grocery shopping, and 3) the very recent days. The findings about people’s behavioral changes are useful for consider countermeasures for good shopping environment against similar pandemic cases in the future.Using the data of an online questionnaire survey conducted in Tokyo, we analyzed the changes in people's purchasing behavior (e.g., store selection, transportation ways, shopping frequency, etc...) and attitudes for grocery shopping, and revealed how much they diverged from the before pandemic situation.

 In previous studies on bond behavior of FRP sheets attached on concrete, bond test specimens which contain relatively lower stiffness of FRP sheet were used. In actual strengthening design, however, the greater stiffness of FRP sheets are required because the scale of the structure is very large. Therefore, in this study, bond tests were conducted using specimens with a wide range of sheet stiffness and polyurea resin. As a result, the bond strength increases as the stiffness increases with multi-ply CFRP sheets and, however, existing bond strength models overestimate its bond strength when the stiffness exceeds 200 kN/mm. In addition, 3D scan measurement for patterned indented concrete thin layer behind CFRP sheet delaminated brought the fact that the interfacial fracture energy is strongly related to the surface area of the concrete thin layer neither being determined by the CFRP sheet stiffness nor resin properties.

 Fatigue crack is one of the most critical damages in the maintenance of steel bridges. Since the main cause of fatigue cracks is high strain caused by live load, it is essential to understand the actual loading condition, such as the vehicle weight and the number. Although there are various methods to measure the number of traveling vehicles, this study proposes a method to detect the axle passing time using acceleration sensors. The observed acceleration response includes not only the pulse-wave-like peak response that occurs when an axle passes directly over the sensor but also responses transmitted from the opposite pier side and adjacent lanes. The F value, which is the harmonic mean of the recall and the precision, was 54.4 % by a detection method using only the threshold, while the proposed method improved the F value to 94.1 %, indicating that axle detection can be performed with high accuracy.

 In October 2020, Mr. Yoshihide Suga, Prime Minister of Japan, announced a goal of carbon neutrality by 2050, followed by additional announcement by the Government of Japan on a goal of reducing greenhouse gas emissions by 46% from FY2013 in 2030. To reduce greenhouse gases in the sector of civil engineering and building, especially in the construction phase, the authors firstly aim to research and organize information on low-carbon technologies and solutions in Japanese construction-related firms, and to contribute to policy-making in the relevant fields based on the research. Specifically, this paper examined required policies including unified evaluation on the emissions, technical standards on relevant fields, life cycle assessment (LCA), and supportive procurement policy.