Due to frequent heavy rains in recent years, disasters caused by flooding occur almost every year on railway river bridges in Japan. In this paper, we proposed methods for improved maintenance for pier foundation of river bridges, based on the experience of disasters so far, in order to prevent trains from serious events such as the inclination of piers caused by scouring around the foundation due to flooding. First, we proposed a method to set the highest water level in the past as an approximate water level for timely inspection after floods, and confirmed its effectiveness through actual flood cases. Furthermore, regarding the impact vibration test, which is generally performed as a detailed inspection for bridge piers, we examined advanced method that also focuses on the damping constant in addition to the natural frequency. We have confirmed through the impact vibration test of railway bridges crossing river, that it is possible to grasp more detailed situation of scouring of the pier foundation for the railway river bridge with this method.

 The Koumi Line is running at the highest altitude among other JR Lines (highest point:1375m asl).

 The temperature in this area drops to less than minus 20 degrees Celsius in a severe winter and the frost heave of the roadbed occurs every winter.

 The frost heave causes track irregularity that threatens safe and stable transportation.

 We report on our attempts of countermeasures to it since 2010 and their results when the railway track was heavily affected by frost heave

 Scaling and cross-section defects due to frost damage have occurred in the Shinkansen viaduct 40 years after its construction. Although the Shinkansen viaduct has been constructed using AE concrete in consideration of frost damage, deterioration due to frost damage is increasing year by year. Therefore, for the purpose of grasping the current situation of the existing viaduct, core samples were collected from a part of the viaduct and the actual condition of the air content was investigated. From the survey results, it was confirmed that the air content was lower than the design value as a whole, and it was confirmed that many frost damage deformations occurred in places where the air content was below a certain value. In addition, one of the factors that caused the air content to be less than the design value was considered to be a decrease in the air content during the construction process, so we examined changes in the air content during the construction process. Based on the above survey results and verification results, we revised the internal standards as a concrete measure to ensure frost damage resistance.

 It is important to know the condition of viaducts in the future in order to keep them in service in a sound condition for a long time. Deterioration prediction is the estimation of the state of a structure over time. The deterioration of reinforced concrete structures is often caused by the corrosion of steel bars, and the rate of deterioration is correlated with factors such as the carbonation depth, chloride ion concentration, depth of concrete cover and moisture content in concrete. Using the investigation results on actual structures, Monte Carlo simulations were conducted to predict deterioration for each structure, taking into account the variability. The degradation prediction results were able to reproduce the actual repair results, so it was considered that the future condition was estimated.

 A bridge inspection needs a lot of costs. It causes a lack of engineers and budget. So some local governments couldn’t complete the bridge’s aggressive preventive maintenance in Japan. We focus on the image-based bridge inspection technique. It enables us to reduce bridge inspection costs. Some previous studies proposed a deep learning-based method for crack detection. These methods detect cracks on a concrete surface image of the bridge and show high accuracy. However, the evaluation of the robustness of such a method to the real bridge surface images is not enough yet.

 In this paper, we proposed a multi-model method to detect cracks on various bridges. This method uses several models trained with different fake images. We evaluated three different crack detection models with three different bridge images. The evaluation result shows the effectiveness of multi-model trained by different fake images.

 The railway bridge bearings are an important part that transmits the load of the superstructure to the substructure, and as the times have changed, the optimum structure and method have been adopted at that time. However the deterioration of bearings is increasing with the passage of time.More than 30 years have already passed since the “Guidance for Bearing Measures for Steel Railway Bridge” written during the JNR era. The cases described are old and needed to be consistent with the latest technical standards. Therefore, the contents of the Guidance were completely reviewed, we have written a new “Reference Material for Repairing Railway Bridge Bearings” that describes the process of investigating the cause of the deterioration occurring in the railway bridge bearings to repair measures. This Reference Material has made it easier for engineers engaged in the maintenance of railway in JR East to understand the process from investigation to repair measures.Based on this, we aimed to implement appropriate measures.

 River engineering structures such as levees play a major role in preventing flooding due to heavy rain. The forms of such facilities must be constantly monitored for alteration due to rain and running water, and limited human resources and budgets make it necessary to efficiently maintain river administration facilities. During maintenance, inspection results are commonly recorded on paper documents. Continuous inspection and repair using information systems are an on-going challenge.

 In this study, a maintenance management system using three-dimensional data was developed to improve the efficiency of river maintenance management. The three-dimensional data was constructed by UAV photogramettry and terrestrial laser scanning. The system designed and developed using three-dimensional GIS software, which has the function of registration and reference to the inspection results at any position in three-dimensional data by linking them using a smart devices. This study proposed the possibility of solving the problems of river administrators through river maintenance management using three-dimensional data.

 In order to clarify the influence of bridge environment on the durability, a macroscopic analysis was conducted using the most recent inspection data (18, 300 bridges in total) for bridges with concrete super-structures that were inspected by fiscal 2019. The results were compared with previous environmental surveys. It was found that salt attack tends to occur in areas up to 500 m from the coastline, frost damage in areas on the Sea of Japan side of northern Japan, especially where the minimum temperature was below - 5°C, and ASR in northern Kyushu and Okinawa prefecture. In addition, we proposed an index that allows relative comparison of the difference in the degree of damage to the durability of bridges managed by each prefecture.

 In this paper, the infrastructure management method based on the hierarchical evaluation by coordinating network evaluation and road diagnosis is proposed in order to effectively maintain the municipal roads. The importance of roads is evaluated by network analysis using our developing Public Asset Simulator (PAS). By feasibility study in Muroran-city, it is demonstrated that the comprehensive importance can be derived from various influencing factors and the cost effect due to introduction of the hierarchical evaluation can be evaluated. Anew British road management technology is applied to the priority evaluation of roads, and its applicability in Japan is investigated by survey in Yokosuka-city. The application of road diagnosis results to road management planning is also discussed as the identification of road treatment methods and lifecycle analysis.

 Close visual inspection of road infrastructure is obligatory. It has been considered in each local government for the application of the database system. In this paper, this study explained the outline of the infrastructure integrated database system operated in the Fukui Prefectural Government, and investigated the situation and the deterioration factor of the infrastructure structure managed by the Fukui Prefectural Government from the statistical processing using the database. In addition, this study proposed a new database system with the real-time performance that enables monitoring of measuring data on a database map.

 In order to properly maintain and manage road structures, it is necessary to collect and accumulate daily and periodic inspection data. However, since inspection registers are often stored and accumulated without being digitized, it is not efficient to spend a lot of time referring to past data. It is necessary to make effective use of the accumulated past data and conduct inspections efficiently before delays in repair and reinforcement due to aging facilities lead to fatal situations. In this study, we developed a system to share information between road managers and inspectors, and to achieve more efficient road maintenance and management by utilizing the data accumulated in daily inspections. In this system, the results of the existing daily inspections can be checked in the field, and alerts can be issued for inspection points of high importance and follow-up observations can be made. The operability and usefulness of the system were evaluated by experts on the Shiraito Highland Way in Nagano Prefecture.

 Since municipal roads account for about 84% of the total length of roads in service nationwide, it is important to establish a pavement maintenance cycle for municipal roads. Local governments have been conducting pavement inspections and making progress in pavement repairs based on the national pavement inspection guidelines, but there are very few cases in which detailed management methods have been established for community roads. In this paper, we present a direct management analysis of the current status of pavement repair and the systematic issues for pavements managed by Tamana City Hall, which is one of the local governments where the maintenance and management of roads for daily use is an issue. In addition, to reflect the needs of the residents on the huge length of the road, we analyzed the residents' requests and, by using the understanding of the condition of the site accumulated by ICT, we developed a system for pavement maintenance that incorporates the residents' requests. This paper describes the creation of a pavement maintenance cycle system that incorporates the needs of the residents of living roads.

 In Ota city, we formulated a bridge long life extension repair plan in 2009, and established a system to operate a maintenance cycle by us. By practicing the maintenance cycle as before, we can reduce the life cycle cost and sustain the maintenance level during the targeted in-service period. But we need to cope with occasional challenges such as the ideal way of social infrastructure, the decrease in the working population, financial constraints due to the increase in social security costs, and the succession of technology. So we need to make sure the plan into practice, longer life than planned and further reducing life cycle costs. Therefore, we included following elements in the plan so that the plan correspond to next generation in the revision of 2019. (1) human resource development and how the organization shoud be, (2) technical issues to be solved in future, (3) attempt to grasp technical issues in advance (4) ideal way of repairing specialized in preventive maintenance.

 East Japan Railway Company maintains and manages railway tunnels, a number of about 1, 200 and an extension of about 950 km. Since the charactristic of each tunnel has various kinds of components such as construction era, tunnel lining material, ground condition and environmental condition arround tunnel, etc., it is difficult to systematize the tunnel maintenance management, developed and applied to the bridge maintenance. So, the efficiency of maintenance management for JR East’s tunnel is requiered to be improved. As a result of analyzing observed deformations of all of the tunnels, it was confirmed that there was no clear correlation between tunnel properties such as strucuture, construction method, geology arround tunnels, and circumstances, and tendency of deformations. Therefore, it was thought to be rational that the condision of each tunnel is evaluated besed on enginner’s evaluation, and the tunel are managed properly according to thier strategic management policy. In this paper, we report on the development of maintenance management technique for tunnel in East Japan Railway Company. Furthermore, we descirbe the advantage of the system to improve the accuracy and efficeincy of tunnel maintenance and engineer’s ability to maintain tunnels.

 Performance based road maintenance contract (PBC) has been introduced and established through JICA technical cooperation projects in the Republic of Kenya since 2010, in order to strengthen the supervisory capacity for outsourcing. As the result, the capacity of road authorities and private contractors has been developed, and also the roads maintained under PBC are increasing and kept good condition. However, as the projects ended in 2019, it is essential to carry out PBC works by themselves. This paper outlines the project activities and achievements, and also presents some strategies for sustainable operation of PBC.

 As a case of improving local knowledge and skills in developing countries through the introduction of Japanese infrastructure maintenance technologies using the framework of Public-Private-Academia collaboration in ODA project, this paper summarizes the implementation structure and project activities of the Project for Capacity Development in Laos. And through adaptation of Japanese infrastructure maintenance technologies in the project, this paper analyses their effectiveness and sustainability in developing countries and provides lessons learnt to promote the Public-Private-Academia collaboration.

 The tracks maintenance section of JR East has realized until now various efficiency for the mass retirement of the expert employee of the Japanese National Railways adoption to come in the near future. On the other hand, it is necessary to deal with the special track works and maintenance management technique in order to continue railway business for the future. Therefore the Track Maintenance Technical Management Center (TMTMC) was established in head office in 2018 to plan the maintenance succession and the development of the maintenance of tracks technology. In this paper, It is described about the outline of the TMTMC such as missions and rolls, technical support for the site engineers, support for solving the problem of the difficult place of track maintenance and innovation of technical regulations and structures of the future track.