A pre-flexed beam is a pre-stressed structure due to bending moment, consists of a steel I-girder, lower flange concrete and concrete slab. In order to apply the pre-flexed beams to large span bridges, a segmental prefabrication method dividing into three parts, of which the steel girders are connected with splice plates during the lower flange concrete casting and concrete hardening, is taken at fabrication factory. After concrete hardening and to carry the beam to election site, the pre-flexion load is removed and is divided into three members. At the time, sometimes a few small cracks are observed at the ends of concrete flange of the central beam. In this pater, the authors investigate the mechanism the crack occurrence and prevention methods through FE analyses and loading tests on full-sized specimens. The best method is to give one set system of attaching thin sponge filler on the lower flange edges, using separated end shear connectors of rectangular steel bars and putting headed studs shear connectors at the end parts of about one meter.

 The CERS methods have been proposed as one of the methods to realize health monitoring of structures and ground. Here, the CERS methods are applied to measure the physical properties of a concrete dam. The target of this study was the Okura Dam, located in the Tohoku region of Japan, which is the only double arch dam in Japan constructed in 1961. In this dam, seismic observations have been conducted at the crest of the thrust block placed between the two arches and at the inspection gallery.

 On March 11, 2011, 50 years after its completion, this dam was attacked by the 2011 Tohoku earthquake (Mw9.0), but no damage was reported. In this paper, the wave propagation velocities between observation points at the crest of the thrust block and in the inspection gallery are directly measured by the CERS methods from published strong motion records, and changes in physical properties are discussed.

 As a result, it was confirmed that the stiffness of the thrust block dropped to about 60% of that before the earthquake during the Mw9.0 strong motion, and recovered to about 70% by the end of the recording. Also, it can show the influence of the reservoir level on the variation and damping of the physical properties. The CERS methods applied in this study can directly measure the variation of wave propagation velocity and damping factor in real time from the observed waveforms, and can be useful to determine the seismic health of dams and other structures.

 A basic process for introducing topology optimization into seismic design of railway structures is proposed. In the proposed method, seismic design of structures is first carried out based on the current general method. Then, several candidates of structural topology are created by topology optimization, and range of pareto-optimal solutions is narrowed down in terms of cost and performance. Finally, designers select the optimal structural topology from the narrowed range of the solutions based on budget, constructability, and maintainability. In order to confirm the effectiveness of the method, the proposed method was applied to the concrete pier with the column height of 6m. As a result, it is confirmed that the several structural topology can be obtained as the pareto-optimal solutions, and that the structural topology selected from the range of the solutions has advantages in terms of performance and cost compared with the conventional one.

 Steel truss bridges do not have high structural redundancy compared to other bridge types, and damage to the main structural members may lose the structural stability of the entire bridge. On the other hand, since steel truss bridges consist of many frame members, there are a lot of the patterns of corrosion damage. For this reason, a quantitative method for diagnosing soundness based on the mechanical rationality of the damaged part has not been established. The cross sections of the diagonal members of truss bridges are often joined to steel plates by fillet welding or partial penetration welding. For this reason, if corrosion reduction occurs in the weld, it may separate, and if the range of corrosion break is long, there is a possibility of local buckling of the plate constituting the compression diagonal member.

 Therefore, the soundness level is classified according to the coupled buckling strength of the global buckling of the compression diagonal as a column and the local buckling of the plate that composes the diagonal. In addition, we propose a buckling strength formula and a coupled buckling evaluation formula for plates containing corrosion break.

 In UAV-based photogrammetry of shallow water bottom, the water depth is underestimated due to the light refraction at the water surface. As a countermeasure, it is widely practiced to multiply the underestimated water depth by a spatially constant coefficient. However, past studies indicated that the optimal coefficient, namely the depth-underestimation ratio, depends on conditions and its behavior needs to be investigated. In this paper, by computer-graphics-based simulations under various conditions for the water depth, waves and bottom textures, we have shown that the depth-underestimation ratio tend to decrease as the water depth and waves become larger, deviating from the value 1.42 proposed by the past studies. Furthermore, we have examined the underlying mechanism and discussed a countermeasure. We have shown that one of the mechanism is that the cameras with large off-nadir angles of the lines of sight get less used for underwater point estimation as the water depth and waves become larger, due to the increased deviation from epipolar lines and changes in local features.

 In this study, we developed water level prediction model for small-medium river basin using LSTM based deep learning and examined the accuracy under several different conditions of data type and structure of input and output layers. The analyzed results showed that the Nash-Sutcliff coefficient was more 0.9, and error rate of the peak water level was less 10% by the model with multiple points data set of rainfall and hourly water level change for the input layer and the multiple points water level for the output layer. Moreover, the time difference of peak water level occurrence was smaller than in other calculation cases. Therefore, it is shown that water level prediction model developed in this study can be used to predict the water level 3 hours ahead at multiple stations with high accuracy in the small-medium river basin.

 There is a need to develop a new liquefaction countermeasure method that is inexpensive and can be constructed in narrow areas such as residential areas. Against this background, It was attempted to develop a non-cementitious particulate grouting material using blast furnace slag fine powder, aiming at the practical application of a particulate grouting method using inexpensive fine particles made from industrial by-products as the base material. First, focusing on the solidification principle of geopolymer and dolomite, specimens were prepared by the mixing method to confirm the strength characteristics of formulations using multiple fine particles, and uniaxial compression tests were conducted to determine the appropriate formulation. In addition, one-dimensional injection experiments were conducted under different injection conditions, such as injection concentration and injection rate, to understand the penetration of the fine particles and the effect of the improvement. As a result, it was confirmed that the mixture of semi-hydrated gypsum, blast furnace slag fine powder, and magnesium oxide has the necessary strength for liquefaction countermeasures, with no strength loss occurring within one year. From one-dimensional injection experiments using the same formulation, it was confirmed that the improvement effect obtained depends on the concentration and injection rate of the injected material in the proposed formulation.

 Ground improved by permeation grouting method to prevent liquefaction of sandy ground has spatial variability in shear strength compared to naturally deposited ground due to non-uniformity of chemical penetration and spatial variability of soil properties. In such ground with material heterogeneity, it is necessary to ensure that the required quality for liquefaction countermeasures is satisfied with the number of investigation spot that can adequately account for spatial variations. Additionally, unconfined compressive strength in soil properties is more influenced by sample disturbance and is easily underestimated. In this paper, we proposed a strength evaluation method by a combination of in-situ test and laboratory test and demonstrated a field application of proposed method. In addition, we also proposed a configuration method for the number of investigation spot associated with chemical grouting rate.

 Microbially induced carbonate precipitation (MICP) can bind discretized soil particles and improve soil strength and bearing capacity. When microorganisms are added to the actual environment, it is desirable to use indigenous microorganisms in consideration of their impact on the surrounding ecosystem. However, little study has been conducted on stocking indigenous microorganisms useful for soil solidification as microbial resources. Hence, in order to apply MICP technology using indigenous microorganisms to the Okinawa region, this study collected a number of microorganisms from the actual environment and identified useful microorganisms in the Okinawa region through simple solidification experiments and 16S rRNA analysis of the bacterial flora. The results confirmed the presence of useful microorganisms at all sampling sites. Interestingly, the degree of solidification varied between the sampling sites. Additionally, phylogenetic tree analysis revealed that microorganisms useful for soil stabilization had relatively closely related DNA sequences.

 When the estimated strength of improved soil cannot be achieved due to soil condition, time and economic losses may be incurred by re-performing mixing tests and re-considering an applicable construction method. To avoid this situation, it is necessary to develop methods for strength estimation as well for compensation of insufficient strength. This study summarizes the results of unconfined compression tests conducted until now using specimens with embedded micro pore water pressure gauges. In addition, splitting tension test was conducted on the chemically improved soil. The test results confirmed that the strength resulting from the adhesion force between the chemical and soil particles can be calculated from the splitting tension strength. A simple formula for strength estimation, using soil parameters obtained from preliminary investigation, was then proposed and validated with a local soil.

 In a conventional Newmark slope sliding model, a soil block is assumed to slide along a rigid sliding plane in a rigid-perfect plastic manner when input acceleration exceeds a yield value. In reality, a small deformation may well be expected to occur immediately before the sliding starts due to shear deformation in a weak sliding layer underneath the sliding block as indicated from previous model shake table tests. In this research, Spring Supported-Newmark model (SS-Newmark model) is developed combining in sequence a spring for pre-sliding deformation and a slider identical to the Newmark model, and the responses of the model to sinusoidal and earthquake acceleration motions have been calculated and compared with those by the conventional Newmark model. It is found that the SS-Newmark model can evaluate the yield accelerations clearly exceeding those in the conventional Newmark model, and such an exceedance has actually been observed in slope failures in model shaking table tests. According to example calculations on typical slopes of realistic design parameters shaken by earthquake records which triggered a plenty of slope failures, the number of successive sliding and associated sliding distance of failed debris are calculated evidently smaller in this model than in the conventional model by considering small pre-sliding yield displacements. Thus, the newly developed SS-Newmark model can be more realistic in evaluating seismic slope behavior by employing a small pre-sliding slope deformation as a slide-specific design parameter.

 In the evolving smart city projects which is being implemented in various locations, innovative initiatives are being attempted to utilize personal data such as behavioral history to encourage behavioral changes. Concerns about risks such as data leaks and privacy infringements are believed to contribute to a passive attitude towards providing data, which could pose significant obstacles to these innovative initiatives that are expected to be promising new means of problem-solving. In this paper, based on the experience of consensus building in infrastructure development, an analysis of a survey on concerns and countermeasures regarding data utilization, and a discussion on the social acceptance of innovative technologies from the perspective of ELSI (ethical, legal, and social issues) were conducted. It was found that not only the risks of data leaks but also concerns about the impact of data utilization on society are significant factors of anxiety, and the importance of participatory rule formation was identified as a means to alleviate these concerns.

 In recent years, a theory positing a growing ideological conflict between 'Somewheres' (individuals deeply rooted in local communities) and 'Anywheres' (those who value a lifestyle transcending regional and national borders), has been used in social science and commentary, including discussions on urban planning. However, there has been insufficient quantitative analysis on the values of Somewhereness and Anywhereness, their determinants, and their relationship with other psychological tendencies. In this study, we examined the relationship between Somewhereness/Anywhereness (measured by a scale) and personal attributes and moral sentiments, such as 'spiritual vulgarity of the masses' and 'altruism'. Our findings suggest that individuals residing in their current location for longer periods tend to exhibit Somewhereness, while the impact of factors such as income, education, occupation, and residential area is minimal. Additionally, the result indicates that Somewheres may be more morally inclined compared to Anywheres.

 Residential roads are of great interest to residents, and therefore, objective and effective pavement maintenance and management is necessary. In this study, we proposed a network-level pavement evaluation method for residential roads using various types of data on pavement, housing location, and traffic volume covering the target city. The features of this method are the prioritization of repairs based on damaged pavements in the surrounding area, total residential floor space, and traffic volume, and the estimation of repair effects at the city level. A case study of Muroran City was conducted using this method, and a comparison was made with a conventional method. As a result, it was shown that the proposed method can extract sections to be repaired that are more effective in improving the living environment than the conventional method. In addition, scenario analysis allows road managers to develop repair plans adjusted to actual conditions in the city.

 In this study, time-series changes in the resident population within a 500m mesh including stations during two planned suspensions of railway operations in the Tokyo metropolitan area in September and October 2019 were examined using mobile space statistics. As a result, it was found that the number of visitors increased from 9:00 to 12:00 at many grids during the planned suspension in September, and that there was no significant change in the number of visitors during each time period during the planned suspension in October. The results of an analysis of the relationship between the above population trends and the provision of information on the resumption of operation and the actual resumption of operation are as follows. The planned suspension in September was on weekdays and there was a lot of commuting demand, so it was suggested that the delay in resuming operations might have affected the population increase. On the other hand, the planned suspension in October may have suppressed private demand due to holidays, so verification of information provision is a future issue.

 Japan’s railways are equipped with avalanche prevention forests to prevent disruptions in operation or train accidents that may be caused by avalanches. In this study, the avalanche prevention effect of these forests along the Joetsu and the Yonesaka Lines has been eveluated according to records of avalanches, snowfall depth and snowcover depth, and planting of these forests. The number of avalanches on both lines occurred discontinuously change (jump) to decrease side in the early 1960s, although it was not until the mid or late 1980s that annual snowfall depth and annual maximum snowcover depth jumped to decrease side. These avalanche prevention forests have been established since the 1930s after opening of the respective lines, and many of them began to demonstrate their initial functions in the early 1960s when the number of avalanche jumped to the decreasing side. Also, there is a strong correlation between the number of avalanches and annual snowfall depth and/or annual maximum snowcover depth before the jump in the number of avalanches. From this, the jump to decrease side in the number of avalanches in the early 1960s can be evaluated as an effect of the avalanche prevention forests.

 To avoid damage from natural disasters to vulnerable people who cannot evacuate by themselves, it is essential to avoid locating nursing care facilities in high-risk areas. This study analyzes the disaster risk of nursing care facilities nationwide and evaluates the risk reduction effect of relocating facilities located in high-risk areas. The primary data used were the location of nursing care facilities, the number of persons requiring nursing care, the year of commencement of operations, and overlapping hazard maps. Results revealed that the percentage of facilities at risk of flooding was higher than other risks. In recent years, a high percentage of facilities have been located in high-risk areas, and the number of staff to assist in evacuating those in need of care may be inadequate. Furthermore, it found that encouraging the relocation of facilities that started operations before 2000 and are located in high-risk areas could ensure the safety of those in need of care.

 Using Sentinel-1 SAR data, the estimation method of snow depth was studied and its accuracy was verified at snow depth observation sites in the upper reaches of the Tone River in Gunma Prefecture, Japan. The estimation of snow depth was confirmed to be possible based on the variation of backscattering coefficients of VV and VH polarization with snow depth in the forested area in this region. The estimation accuracy of the snow depth below 400 cm based on the backscatter coefficients for a 500 m meshed slope covered with trees was about 20 to 50 cm, indicating that this method can be used to evaluate the snow cover situation over a wide watershed area for estimating snowmelt.

 The long-term climate mitigation scenarios are not estimated in the context of their validity and feasibility, despite their essential role in climate policymaking. In this study, we focused on the distribution of rate and amount of annual change in indicators from the scenarios, presented an evaluation method comparing the future and historical change, and applied the method to the three indicators consisting of energy intensity, carbon intensity, and electrification rate. The change rate distribution in energy intensity is within the range of historical experience, but 40 to 50% of the change rate distribution is out of the range of historical experience in carbon intensity and electrification rate required in some scenarios with severe climate targets.

 There are few empirical studies on energy conservation and decarbonization measures for reefer containers (RCs), which account for a particularly large share of energy consumption in ports, and the gap between research and practical application is a challenge for port decision makers. In this paper, a simulation model to evaluate the effect of installing roof shades in RC areas at the Hakata Port was used to estimate the energy saving effect, which was then used to evaluate the economic benefits and the possibility of applying the model to other areas was evaluated. The results show that the energy conservation rate could be larger in winter than in summer, and in cold regions than in warm regions, because the effect of solar radiation is relatively small in summer and in warm regions. The results of this paper are expected to contribute to the energy conservation and decarbonization of ports around the world, as they provide a powerful tool for port decision makers to make a preliminary assessment of roof shade installation.