Base displacement is one of the typical deteriorations of a transmission tower. So, we have been developing a health monitoring system using inclinometers for monitoring the base displacement. The prototype system developed by the authors has been currently monitoring the inclination of structural members of transmission tower in several fields. The threshold for inclination used in the current system is determined by FEM analysis. The objective of this research is to confirm the validity of the threshold by conducting a real scale experiment of forced base displacement. In this research, the relationship between the base displacement and the inclination of structural members is investigated. The amount of increment in stress due to the base displacement is also studied. These results give us a knowledge for the appropriate sensor arrangements and show the validity of the current threshold.

 On the surface of the steel material (base material) undergoing repeated plastic deformation, a group of surface cracks in which multiple cracks are lined up in stripe patterns is often seen. This group of surface cracks is considered to be the source of ultra-low cycle fatigue cracks starting from the surface of steel material and has a great influence on the ultimate behavior of steel members. This paper clarifies the basic formation mechanism of surface cracks that appear in the process of generation of ultra-low cycle fatigue cracks from the viewpoint of bifurcation theory. Specifically, based on the results of repeated loading experiments and elasto-plastic analyses under large-amplitude strain, the generation and development of plastic wrinkles, caused by the surface instability mode, are microscopically related to the spatial periodicity of surface height. And, the spatial periodicity could already occur at the time of initial yielding of steel surface.

 Although the bridge expansion joint is an important member that directly affects road users, its structure has hardly reviewed so far, probably because it was consider as an accessory the bridge. In this study, we proposed a rationalized structure for steel finger joints and confirmed its validity by performing FEM analysis of the proposed structure. Next, a full-scale fatigue test was conducted to confirm whether the required fatigue durability was secured, and a consideration of fatigue strength was made based on the accumulated damage index for the proposed expansion joint. Finally, in order to establish a design method of the expansion joint, the stress transfer mechanism was elucidated.

 From the viewpoint of maintenance of seismic isolation bridges, seismic isolation rubber bearings for bridges are required to have long-term durability. On the other hand, there are some reports of cracks on the rubber bearings which are caused by ozone deterioration of rubber from the results of investigation of rubber bearings. Understanding the performance and ultimate properties of such damaged rubber bearings is important information for considering the need for maintenance of rubber bearings.

 In this study, we estimated growth of ozone deterioration crack based on the strain distribution and deformation obtained by finite element analysis for high damping rubber bearings (HDR-S).

 Moreover, we fabricated a rubber bearings simulating a ozone deterioration crack for test, and evaluated the basic performance and ultimate properties. From these results we considered the relationship between ultimate properties and the depth of the crack.

 Structural health can be evaluated by modal characteristics, in which regression method such as machine learning is effective. There are cases where training data is generated by numerical analysis to acquire a sufficient amount of data. However, in this approach the accuracy of the model will decrease when using input data obtained from an actual structure. This is due to overfitting caused by the difference between input data in training and in predicting. In this paper, in dealing with thickness estimation on a steel member using local vibration modes which are sensitive to damages, model construction method using data augmentation is proposed to suppress the overfitting. First, finite element analysis and measurement test on a steel member are performed to evaluate the difference between the modal characteristics in training and in predicting. Second, using datasets generated by numerical analysis the performance of the models is evaluated according to the level of the difference of input data. Finally, thickness estimation model constructed by the proposed method is applied to the measurement data. It is proven that the proposed model performs better by more than 40 % compared with the result by the conventional model without data augmentation.

 Evolution of crack depth formed by ozone degradation is studied by laser microscopy that enables the simultaneous measurements of the depth, the number density and the length. The depth evolution depends on the ozone concentration of atmosphere CO₃ and the elongation rate of rubber α. Time dependency of the crack depth is well correlated by a parameter, t∙CO₃ / α², where t is the exposure time to ozone, except for the extreme small elongation rate. The depth can be evaluated from the crack length, that is easily measured at the surface, by a scaling law, while the length is under growing. Even after it stops, the depth is still developed.

 This paper develops a three-dimensional (3D) mesoscale model of reinforced concrete beams with realistically shaped and sized coarse aggregates and simulates the 3D mesoscale fracture behavior similar to the experiments. The mesoscale model reflects the geometry and distribution of coarse aggregates in 3D as well as the 3D geometry of deformed-steel bars. The non-linear finite element analysis with a damage model is applied to simulate the crack propagation behavior in concrete composed of mortar and coarse aggregates. Numerical experiments are presented for reinforced concrete beams with and without shear reinforcements subjected to four-point bending. The results reveal that the 3D complicated fracture behavior can be simulated in mesoscale, and the comparison between the numerical and experimental results shows good agreement.

 In Japan, DMOs are registered by Japan Tourism Agency, and each DMO is required to collect data on the satisfaction of visitors regularly as a Key Performance Indicator so that each agency is able to use data for performance measurement and reflect on its policy. In this research, we collected the level of expectations before visiting an important tourism destination in a region such as a roadside station during the tourism satisfaction survey by a DMO.

 In the survey, we asked visitors to rate both expectations before coming to the Roadside station and satisfaction at the time of visit on 5-point scale, in terms of functions and overall impression of the Roadside station. From the tabulation and analysis, we obtained parking lots, toilets, and product sales as items that visitors to the Roadside station had high expectations. On the other hand, as for meals, traffic information, and tourist’s information, visitors’ expectation was diverse, and satisfaction was similar to the degree of the expectation. The satisfaction model based on multiple regression analysis with the overall satisfaction level of the roadside station as the objective variable, the difference between the satisfaction level and the expectation level of the parking lot was obtained as a significant explanatory variable. This indicates the possibility that visitors strongly pay attention to availability for parking lot in the Roadside station in advance, and this affect overall satisfaction. Therefore, there is a possibility that overall satisfaction can be improved by giving the related information in advance.

 The Cadastral Survey of Japan has been conducted since 1951, yet the area-based progress is 52% of the area of interest. There are 138,361 square kilometers left to survey, and the requiring cost of survey and duration are unknown. Firstly, this research summarizes the background of why such a large-scale cadastral survey is necessary for Japan, as well as its problematic effects to reinforce the importance of the completing the Cadastral Survey as a fundamental national project. Secondary and more importantly, the remaining project cost estimation is conducted based on available GIS and fixed-property tax data, with the common cost estimation method specified in the Cadastral Surveying Cost Estimation Standard book. The results show the estimated requiring cost to be 6.43 trillion yen, and with the current annual budget, it will take next 243 years until the completion. Considering the practicality of the project, this article discusses possibilities of promotion measures.

 In recent years, especially in local cities, there has been a debate on whether residents should participate in road maintenance and management with a sense of ownership against financial challenges. This movement is significant for roads familiar to residents, i.e., community roads. In order to develop a sense of ownership, it is essential to understand the value that residents place on community roads. This study attempts to understand the value consciousness of residents living in a local city toward community roads. We surveyed monitors (n=1,039) of a research company living in three prefectures in the Tokai region to determine the values they seek from community roads. The results showed that residents in local cities place importance on safety, security, ease of use, and passage for vulnerable road users such as the elderly, children, and the disabled as values of community roads. The results also showed that a high level of awareness of these values was not correlated with a high level of awareness of the parties involved in the maintenance and management of the road but rather with a high level of intention that the road should be maintained and managed under the initiative of the government.

 The facilities which serve as local hubs and are attractive enough to be visited as destinations are expected to be assessed from various perspectives. In this study, we propose a method to evaluate the value of facilities themselves, by estimating their utility values to generate visits and their consumer surplus based on the travel cost spent to visit them. At the same time, the proposed method classifies visitors into segments with common utility values, taking into account the heterogeneity of visitors' preferences. We applied the method to visitor data to roadside stations in Ibaraki Prefecture, which were derived from ETC2.0 data. It is found that some roadside stations have a large value despite the small number of visits, and that some functions contribute to improving the attractiveness of the roadside stations. Our method is a novel travel cost method that can take into account the competition with alternative facilities by means of the inverse shortest paths problem model.

 When public agencies design road maintenance policies, if the maintenance cost has a large share of the budget, it is necessary to reduce the expenditures for other items, which decrease the benefits of the other items. These additional costs due to an increase in the public expenditure are called the marginal cost of public funds (MCF). Our study explicitly considers the endogenous MCF, and optimizes the long-term maintenance policy dynamically. Our numerical simulations show that 1）when MCF is low, the ratio of maintenance at condition II is high; when MCF is high, maintenance only at condition III is the optimal policy, 2） when the time discount rate is high, maintenance only at condition III is optimal; when the time discount rate is low, maintenance both at conditions II and III is optimal, 3）when the ratio of degraded bridges is high, maintenance at early stages is necessary. So, the lifetime utility in a future generation is higher than that in the current generation, and 4) the optimal maintenance polity based on the life cycle cost minimization is different than that at MCF>1, so that that policy can yield a large welfare loss.

 This study formulates a dynamic stochastic general equilibrium model that explicitly considers the role of the construction sector. Then, this study analyzes the relationship between national disaster risk and the optimal size of the construction sector in terms of capital stock and number of employees. This study obtains the following findings with the analysis. The risk aversion tendency of the households affects whether the disaster risk increases the optimal size of the construction sector in the normal period, when disasters have not hit for a long time. When the risk aversion is high, the optimal size of the construction sector in the normal period increases, and vice versa. Considering the high risk premium of disaster insurance in Japan, the presence of disaster risk will increase the optimal size of the construction sector in the normal period. The size of the construction sector should be expanded to the optimum level as soon as possible when the increase in disaster risk becomes apparent.

 In order to control cathodic protection depend on corrosion rate, it is necessary to establish a method to evaluate the corrosion rate of steel in concrete under cathodic protection. We have proposed the RAP method (Reciprocating Anode Polarization Curve Measurement Method) for evaluating the corrosion rate of steel in concrete under cathodic protection in the moist environment. However, the evaluation accuracy of the RAP method under the atmospheric environment has not been investigated. Laboratory tests on mortar specimens confirmed the accuracy of the RAP method under the atmospheric conditions. The RAP method is more accurate than the Tafel slope method for both natural corrosion and cathodic protection.

 This study focuses on the effect of repairing crack with silane type water repellent on water absorption of concrete. Experimental results showed that the silane type water repellent applied to the cracked concrete reduced of water absorption. By examination using the numerical simulation of moisture transfer of concrete that the effect of repairing crack with silane type water repellent is inhibit water absorption and reduce the moisture transfer at impregnated area.

 This study aims to evaluate the effects of water immersion and freezing and thawing on asphalt mixtures. Laboratory tests were conducted and it was found that water immersion and freezing and thawing can cause performance deterioration to asphalt mixtures such as stripping and cracking. Furthermore, as a result of quantitatively evaluation, it was evaluated that the effect of freezing and thawing was greater than that of water immersion alone. In addition, new findings were also obtained that, the freeze-thaw action increases the voids in the asphalt mixture, but it not only increases the voids inside the asphalt mortar, but also progresses the voids along with the interface between the aggregate and the asphalt. The aggregate gradation and asphalt binder type of asphalt mixture affects freeze-thaw resistance, the effect of polymer additive was recognized as positive to freeze-thaw resistance.

 It is important to secure and increase the amount of orders received by Japanese companies in promoting overseas development of infrastructure systems. Considering the recent situation of assistance from competing infrastructure exporting countries in international cooperation, it is difficult to say that Japan's yen loan policies, such as STEP and high-quality infrastructure development, have responded well to changes in the surrounding environment. In this study, the status of orders received by Japanese companies for yen loan projects are examined. After surveying the breakdown of projects for bridges, it is summarized the application of STEP and discuss measures to increase the performance of infrastructure exports.

 The objective of this study was to evaluate the performance of a large commercial-scale soil washing plant in a full-scale demonstration for remediation of agent orange/dioxin-contaminated soils (1,200 to 20,000 pg-TEQ/g, 900 tons total) in southern Vietnam. Although there are difficulties in obtaining proper material balances for large commercial-scale plants, dioxin balance analysis was taken into consideration first, before evaluating soil washing performance such as dioxin removal efficiency and volume reduction rate. During this study, observations were made, as follows: 1) dioxin balance of the full-scale demonstration ranged from 88% to 108%, with an average of 93%, values which are sufficient for verifying that the soil washing testing procedure was properly conducted; 2) dioxin removal efficiencies ranged from 67 to 87%, with an average of 79.2%, for the hydrocyclone system alone, and were greatly improved to a range of 91 to 97%, with an average of 94.0%, by the subsequent flotation system; 3) soil washing system clearly demonstrated effective soil cleanup, satisfying the dioxin criteria in Vietnam for residential areas (300) from contaminated soil of up to 6,000 pg-TEQ/g, for recreational areas (600) from contaminated soil of 6,000 to 11,000 pg-TEQ/g, and for commercial/industrial areas (1, 200) from contaminated soils of 11,000 to 16,000 pg-TEQ/g; 4) volume reduction rates of feed soils were also sufficient, ranging from 59 to 74%, with an average of 65%; and 5) dioxin concentration rates of sludge cakes ranged from 1.3 to 3.8 times, with an average of 2.4 times, of feed soils. These results indicate that the soil washing system, combined with flotation, is characterized by both high dioxin removal efficiency and high volume-reduction rate; and that this process can be practically used in southern Vietnam for the effective remediation of dioxin contaminated soils.