This paper presents an investigation on a series of cyclic loading tests and numerical analyses using pin-ended isolated steel bracing members of large slenderness ratios. The general purpose of the study is to verify the accuracy of both the initial lateral load method (ILLM) and the strain-based seismic verification method (SBSVM) proposed by the authors for the design of slender bracing members in steel bridge structures. The results are expected to be used for expanding the applicability of SBSVM including the low-cycle fatigue strength of bracing members under overall or local buckling occurred. The test results were however such that, although the accuracy of both ILLM and SBSVM are certainly verified, the complete axis load-axial displacement (N-u) relationships up to low-cycle fatigue events were unable to obtain due to sudden decrease in the axial loads caused by overall or local buckling. After a close examination of the test results, to obtain the complete N-u curves, providing an un-buckled member is indispensable in the testing system such as a rigid frame braced by both compression and tension members.

 In order to restore or improve the performance of existing steel bridges, patch plate repair and reinforcement are carried out by adding steel plates using frictional high-strength bolts. In this study, an elasto-plastic analysis was performed to clarify the effects of the patch plate thickness and bolt spacing on the load transferring section of the lower flange of the I girder patched by steel plates which is subjected to bending. In addition, this study examines the effect of patch plate arrangement on the repaired flange. As a result, the load transferring section was shortened as the thickness of the patch plate and the bolt spacing were reduced. Because the number of bolts required for the load transferring section increased as the bolt spacing became smaller, the number of bolts that caused slippage decreased. In the partial patch plate repair of this analysis, two-sided frictional patch plate recovered more than one-side one because the load transferring section of two-side one was shortened by its thickness being half of one-side one.

 This study proposes an edge two-box girder using ultra high strength fiber reinforced concrete slabs for the main girder structure of a multi-span cable-stayed bridge with main span length of 650 m. The feasibility of the cross-section is confirmed by structural design. In addition, wind stability, which is an important issue in realizing the edge two box girder, is examined for various cross-sectional shapes by wind tunnel tests, and the optimum main girder shape is proposed. As a result of the structural design under live load and temperature load, the static structural characteristics were compared with those of the conventional 1 box girder, and it was confirmed that there was no significant difference between them and that the structure was feasible. In addition, the cross-sectional shape of the structure was shown to ensure wind stability against flutter through spring support tests and flutter analysis.

 In September 2018, The Hokkaido Eastern Iburi earthquake caused numerous slope failures in the Azuma river basin. To identify the impacts of increased fine-sediment transport rate on the downstream river-bed of the Azuma River, we conducted a water sampling survey during rainfall in tributaries with different collapse areas, created Q - Qs relational equation using a long-term gauging station data before and after the earthquake. Then, a one-dimensional flow and bed-deformation model was applied to estimate the differences in bed deformation, the particle size of river materials, and sediment runoff rate from the estuaries under the same hydrograph with different Q - Qs equations as before and after the earthquake. The field data showed that the larger collapsed area in the basin of tributary, the higher the fine-sediment production (mainly 0.075 mm or less). Therefore, the Q - Qs equation of the Azuma River also showed an increase in the amount of fine-grained sediment flow after the earthquake. Numerical analysis showed that most of the fine sand was carried to the river mouth without deposition on the riverbed. Though, when the discharge at the Azuma Bridge gauging station increases to about 360m³/s, which exceeds the historical maximum value, the effects of the increase in fine-sediment transport rate after the earthquake became noticeable. Finegrained sediment is mainly deposited within a range of 4 km from the river mouth, and the riverbed material will be finer.

 For the design practice of breakwaters, it is essential to determine the conditions under which the impact wave force is generated. This study examines a machine learning model using sampling with replacement in which ANN is ensemble-averaged, and XGBoost is ensemble-averaged and then corrected by a power function and a learning model in order to represent the nonlinear relationship between the cross-sectional shape parameters of a composite breakwater and the non-dimensional mean wave force intensity. Comparing the results of the calculation for the dimensionless mean wave force strength with the experimental results, it was seen that two kinds of machine learning models have good accuracy. The present model can determine the occurrence of impact breaking wave breaking force, defined as the non-dimensional mean wave force strength exceeding a threshold value of 2.0. The hitting ratios of all models were more significant than 97%, and the missing ratio of ensemble XGBoost was the minimum of 0.1%. The sampling with the replacement method is useful when the data is small for machine learning.

 Previous studies on the flow passing under the gates have exclusively directed towards discharge evaluation, and it seems that there is no study which gives direct information for gate operation. On the recognition that explicit expression of gate opening is most urgently needed information for gate operation, the present study aims to give the opening of sluice gates correspondent to the appointed discharge, water depth(s) of upstream and/or downstream of the gates for outflows on the basis of fundamental hydraulic equations. As for free outflow, expression of gate opening in terms of the discharge (critical depth) and upstream water depth was obtained from momentum theorem the experimental result on the relationship between discharge and upstream depth. As for submerged flow, a fourth order polynomial equation for gate opening with coefficients including the terms of discharge, upstream and downstream depths was obtained from the basic equations the same as those employed by Henry. The derived equations for gate opening showed good agreement with experimental data obtained in the laboratories.

 In Japan, many residential dry masonry retaining walls have been damaged by huge earthquakes. However, there is no optimal reinforcement method for residential retaining walls due to issues of workability and construction cost. Therefore, we suggested a method in which tilting piles were installed to the existing retaining wall from top of the retaining wall and the top of them are connected at the top of the existing retaining wall for reinforcement. Therefore, this study aimed to confirm how the different reinforcement angles and reinforcement areas effect on the degree of reinforcement of the retaining wall by conducting centrifuge tilting test. As a result, the reinforced retaining wall with a shorter distance between the piles and the retaining wall showed higher reinforcement effect, since a large axial force in the tensile direction was generated in the reinforcement material and a force in the compressive direction was given to the retaining wall. On the other hand, the reinforced retaining wall with a longer distance between the piles and the retaining wall experienced internal collapse, which occurred within the reinforced area.

 A liquefied stabilized soil (LSS) is a useful material for constructing embankments that needs execution in narrow space or rapid execution thanks to the characteristics of LSS, which have high strength and fluidity. But LSS is rarely applied to railway embankments because of limited knowledge on durability against cyclic train load and the effect of drying of LSS on strength and deformation characteristics. In this study, the authors propose a specification of the LSS for applying the part of the earth structure affected by the repeated train load based on FEM analysis. This study also clarifies the required strength and deformation characteristics of LSS as the railway embankments by conducting a series of laboratory tests and test construction. It is found from the study that LSS can behave stably against repeated train load by achieving sufficient density and stress ratio, which is the ratio of the unconfined compressive strength to the vertical stress acting on the surface of LSS. Laboratory tests and long-term monitoring of test constructed LSS also show that the construction of a protective layer above the LSS layer is highly effective in keeping the LSS in wet conditions and reducing the vertical stress acting on the surface of the LSS in the proposed specification.

 To evaluate the compaction characteristics of field fill materials containing large gravel particles, it is desirable to conduct large-scale compaction tests on field materials. However, due to many restrictions, it is usual to conduct laboratory compaction tests on specimens with reduced maximum particle sizes and correct the obtained results using the Walker-Holtz equation (W&H Eq.) to the field value. It is known that the W&H Eq. has limitations in its accuracy, while its trend varies from soil to soil. In this study, to accurately estimate the compaction characteristics of fill materials in the field, a series of laboratory compaction tests were conducted on specimens of different gravelly soil types prepared by changing the maximum particle size, producing different particle size distribution curves and mixing different soil types. It was revealed that the ratio of the dry density predicted by the W&H Eq. to the measured value increases linearly with an increase in the gravelly particle mass ratio, while the prediction by the W&H Eq. becomes less accurate with an increase in the coefficient of uniformity or fines content before mixing of gravelly particles and with an increase in the angularity of mixed gravel particles with well-graded samples. In addition, a method was proposed to correct the W&H Eq. and estimate the compaction density of field fill materials containing large gravel particles.

 This study aims at developing an efficient simulator of ground leveling operation with a bulldozer. First, a series of field experiments and Discrete Element simulations have been conducted to find the following three mechanisms: (a) local soil swelling movement occurs in front of the blade at the initial stage of the leveling, (b) at later stage shear plane is formed in the soil mound and the soil above the plane is pushed out as a rigid mass, and (c) the pushed mass causes the subsequent slope failure at the far side slope of the mound. Then, based on the above observation, we construct a simple algorithm to model the above deformation mechanisms, in which the soil mound is described as a collection of soil columns, and the height of the columns are evolved by (a) the local swelling deformation, (b) the rigid motion of soils above the shear plane computed by Coulomb earth pressure theory, and (c) the slope modification modeled by diffusion equation, respectively. The proposed model is verified by a theoretical earth pressure problem, and validated by comparing to both the DEM simulations and the field experiments.

 This paper analyzes the features of the planning process of the first phase of the Hiji River local environment development, “Kawa-machizukuri,” plan to renovate river management facilities such as revetments for the purpose of promoting river use, focusing on the relationship between the characteristics of the stakeholders involved, such as their motivation for participating in the study and their interest in the project, and the discussion of the contents of the development plans through the councils and workshops. The purpose of this paper is to clarify the characteristics of the planning process for river management facilities in Japan’s “Kawa-machizukuri” policy, cutting-edge effort in Japan to encourage river development with reflection of the local needs through the various stakeholders’ participation, in order to address the practical issues of the “River Culture” approach, an international planning concept for promoting cooperation between river management and local revitalization.

 As a result of the study, the relationship between the planning process of each development plan and the opinions of the river users and local residents was clarified. The results of this study pointed out the importance of sharing the specific river use issues in the initial stages of planning process in order to provide a basis for the necessity of the renovation plan of river management facilities. In addition, in order to increase the effectiveness of the renovation plan, it is important to promote the active participation of a variety of stakeholders, including those who do not use the river, by starting the planning process at a time when the interest of local residents who are responsible for community development activities has increased. Finally, the characteristics of the stakeholders and local characteristics that should be considered in the practical development of the “River Culture” approach were discussed.

 Rapid economic growth in developing countries has led to the increase in the number of private cars and motorcycles. While it’s projected that the people would shift from motorcycles to private cars when the income reaches a certain level, some cities show unique growth patterns, such as the shift from motorcycle to car not occurring or motorcycle ownership increasing further. In this study, a database on car and motorcycle ownership in Asian megacities was developed to enable international comparison and analysis over time, in order to investigate the influential factors of the motorization progress pattern.

 Through the comparative analysis, population density and road development level can be considered as the influential factor. For densely populated cities with insufficient road space, the shift from motorcycle to private car may not occur, and such cities may become more motorcycle-oriented. It is important to develop the database for road development level, to predict future motorization and discuss on transport policies.

 This study aims to better understand the questions and comments made by the participants at explanatory meetings for NIMBY (Not in My Backyard) projects. The study analyzed the meeting minutes of 14 NIMBY projects and used codes to classify the content of the discussions. The results revealed that high NIMBY projects tend to have more diverse and numerous resident voices. Participants in high Nimby projects also had more questions about decision-making processes and risk management, as well as more doubts about decisions. Additionally, there were more instances of slander and offensive comments from local residents. Based on these findings, it was suggested that those leading the explanatory meetings should prepare themselves mentally and physically, and provide clear explanations using simple language to better facilitate consensus building with local residents.

 The Cadastral Survey investigating the owner and surveying the boundary of land parcels enhances the efficiency of land acquisition process required for city developments and construction of public infrastructure. However, the progress of the Survey varies depending on each municipality, and as the total only 52% of area of interest has been surveyed in the project duration of 70 years so far. The government has been placed various project enhancement strategies, yet these are focusing on dealing problems on the surface not the systematic problems built and grown within laws and regulations. In order to identify causes of delay in the Cadastral Survey Project, this paper organizes and reviews the current known problems extracted from exiting research and past news articles, as well as transcripts of the national diet and municipal councils. The research reveals some flaws in the current Real Property Registration Act and the National Land Investigation Act, together with their operations have created the ground which defects the cadastral system of Japan. Most importantly, the central government’s budget shortage that have been warn multiple times since the beginning of the project is the main reason that the Cadastral Surveying Project is only half done.

 In Switzerland, a railway policy for main lines named Bahn 2000 was started in 1987. In this policy, a little construction of high-speed line and many route improvement projects were implemented with a minimum investment. As outcomes of the policy, the connection time at major stations was shortened, and the number of passengers has increased. In an old study leading up to this paper, an analysis comparing the traveling time just before and after policy implementation was conducted. However, the former research has the following assignments: shortage of checks for policy background, no analysis of trial measures taken before Bahn 2000, and remaining undeveloped sections in 2005 just after provisional completion of the policy. This recent research addresses these issues. As a result of this new paper, it was found that the number of trains was increased and regular interval operation were installed in 1982 before the implementation of Bahn 2000 on major routes, and therefore, waiting time or transfer time was greatly reduced. By changing the evaluation year after policy implementation to 2015, it was possible to consider the route development that had progressed during the period. Due to this alteration, the transfer improvement effect could be evaluated more accurately.

 The effect of travel-based multitasking on reducing the disutility or increasing the utility of travel has conventionally been examined based on the activity types and tools. This study referred to individuals’ “reasons” for conducting travel-based multitasking and “perceptions” toward multitasking as “Subjective Meanings of Travel-based Multitasking” (SMTM) and examined what kinds of SMTM have the effect on reducing the disutility or increasing the utility of travel. The result of investigation on relationship between SMTM and intention to shorten travel time shows that travel-based multitasking contributes to the desire to maintain travel time in the case that the multitasking is conducted for the purpose of not “passing the time” but conducting the activity itself “because I want to conduct”, and to the desire to shorten it in the case that the multitasking is conducted for the purpose of “passing the time” or is not conducted “because I want to conduct.” It can be guessed that only in the former case multitasking has the effect on reducing the disutility or increasing the utility of travel.

 The ticket pass data in railway stations contain information on entry and exit at stations for each ticket unit over a long period of time, making it possible to obtain individual travel behavior data such as frequency and time of use. The purpose of this study is to clarify the characteristics of the decrease in habitual railway usage by focusing on changes in frequency and time of use by individuals who are considered to have decreased their habitual railway usage due to the recent rapid changes in social conditions. First, the relationship between the amount of each change and the attributes of each individual, such as age, gender, and ticket type, is summarized. Then, following characteristics are clarified quantitatively by multiple regression analysis: (1) among those whose habitual railway usage has decreased, the change in usage habits may be considered to be greater among younger people, and (2) while the time of day when younger people ride the train has changed, the time of day when elderly people ride the train may not have changed at all.

 In this study, we conducted a questionnaire survey at Ishinomaki Minamihama Tsunami Memorial Park about half a year after the park has opened, in order to identify attributes of visitors, the situation, their behavior and impressions. Furthermore, as a result of classification of the visitors based on perception, “daily use and mourning”, “memorial and tradition”, “disaster prevention learning”, “recollection of the place”, “recreation-oriented”, and “various recall” were extracted as the 6 types. These cannot be explained by a single index and each type was analyzed by regression analysis.

 Reinforced concrete structures are designed with ever increasing reinforcing steel owing to the complexities of structures and the strict design requirements. Congestion of reinforcement commonly occurs at connections between RC column footings and RC piles where the horizontal reinforcement arranged on a bottom surface of a footing crosses the vertical reinforcement of piles. Due to the complicated failure mechanisms, it is difficult to avoid reinforcing congestion by improving the arrangement based on the investigation of structural capacity of footings. This paper presents numerical analyses of RC footings supported piles to evaluate the load carrying capacity and the failure mechanisms. The effects of the shear span-to-effective depth ratio, the amount of shear reinforcement, and the reinforcing arrangement are investigated, then the suitable arrangement of horizontal reinforcement on a bottom surface of a footing is proposed to improve RC construction productivity.

 In the Japanese construction industry, as the labor force population is declining, the shortage of engineers is becoming more serious due to the mass retirement of construction engineers, the low employment rate of young people, and the high turnover rate. Work-style reforms and improvements in the work environment have been promoted. However, the motivation of construction engineers has not necessarily improved as the working environment changes due to the increase in work volume such as disasters and infrastructure renewal, and the spread of COVID-19. Improving work motivation is an extremely important issue in further improving productivity. The purpose of this study is to clarify the transition of the work motivation of construction engineers using the life story method, and to evaluate the degree of autonomy and analyze the transition process by using the organic integration theory.

 The information of traffic volume of aircraft in daily operations at airport surface may be useful to improve the efficiency and timeliness of maintenance of airport pavements. In this paper, we propose the method to create the traffic volume data of airport taxiways, based on the aircraft position data obtained from multilateration surveillance system. Using the traffic volume data, we discuss the relationship between the traffic volume and the number of pavement repairs. Further applicability of traffic volume data to the maintenance of airport pavement is also discussed.

 In recent years, severe sediment-related disasters have occurred due to heavy rains. In the event of the disaster, a prompt survey is required. Therefore, the authors have developed the disaster investigation support system that aims to enhance the safety of investigators and their work efficiency by using a multi-band receiver. In this paper, the fixed-point positioning accuracy of some RTK receivers was compared at the site in Hiroshima Prefecture. The results of the multi-band receiver showed the horizontal positioning error of 22 mm or less (2DRMS) in the experiment on check dam. In another experiment in the forest, the horizontal positioning error was 0.65 m or less (2DRMS). As a result, the usefulness of the multi-band receiver in the sediment-related disaster investigation was confirmed.

 Changes in water temperature (WT) due to climate change occurs in sea and river areas, therefore, the impact on diadromous fishes that use both as habitats is concerning. However, river ecological impact assessments considering WT in both sea and river have not yet been conducted. In this study, public WT data in sea and river estuaries in class A river systems in Japan was obtained to estimate the gradients of these long-term changes. Using this data, a statistical model for habitat probability was built with a classification tree model for three species of representative diadromous fishes widely, but unevenly, distributed in the Japanese archipelago. The importance of habitat condition variables, including WT, was evaluated for each species using the random forest model. In addition, the probability of habitat in the future WT environment was assessed by assuming the obtained WT fluctuation gradient in the sea and river areas and compared it between the rivers. Consequently, the gradient based on the observation was more significant in the river estuary area (+3.93℃/100 yrs) than in the sea area (+1.29℃/100 yrs). Sea WT was selected as the variable most strongly influencing the estimated population probability for Rheopresbe kazika and Gymnogobius petschiliensis, however, the river WT was selected for Gymnogobius opperiens, which has a more river-like lifecycle. Assuming the observation-based WT gradient, WT in the river will be a more substantial control factor for the target habitat due to greater increases in WT in the river.