The authors established the "Research organization for Development and Application of Deterioration Diagnosis Technology for Concrete Structures" in Kagoshima University in 2002. Purposes of this organization were information provision on infrastructure maintenance, support acquisition of qualifications, technical support, lending service of diagnostic equipment, and enhancement of related technologies on maintenance and management.

 On the other hand, in recent years, the concept of infrastructure maintenance has been further developed, and it is necessary to realize efficient and economical strategic maintenance management by developing innovative technologies with cross-disciplinary and cross-organizational collaboration systems.

 Therefore, in order to reorganize our research organization to satisfy the needs on infrastructure maintenance of today as well, we established "Research Organization for Diagnostic Techniques for Structures (RODTS)" as a general incorporated association in 2018.

 In this paper, we report on activities of RODTS, especially, training of civil engineers, technical support, and industry-academia collaboration in infrastructure maintenance.

 A bridge brief inspection system using tablet computers has been established targeted for small-scale bridges (bridge length of under 15m) which account for almost 80% of municipally managed road bridges. As a result of demonstration experiments carried out by local building constructors before implementation on 384 locally managed bridges of 4 regions, 50～70% of the results completely corresponded, and by providing ranges for the determination outcome of both parties, up to a degree of 90% corresponded.

 when collated with results from periodic inspection implemented by construction consultants. From the previously cited results, it has been considered that upon implementation of this system, overcoming short-age of manpower and substantial cost reducing can be highly anticipated. Therefore, for accuracy enhancement of inspection results, holding training sessions and providing teaching materials for increase of technical capability is requisite in order to compensate for lack of technical knowledge and experience.

 The purpose of this study is to propose a repair system that is directly managed by the manager. The skill level of the staff for the repair effect of problem extraction and patch repair work in the local government was investigated. As a result, it was found that municipalities with low maintenance costs per bridge are considering the introduction of directly managed repairs. In order to carry out directly managed repairs, it is first necessary to eliminate the shortage of engineers and personnel. And after the introduction, there is a problem that there is a lack of intelligence and skills to implement it properly. In addition, the skill level differed depending on the construction direction of patch repair, and the degradation of the adhesive performance on the bottom surface was remarkable compared to the plasterer in any case.

 The concrete lump exfoliation phenomenon to line from the Sanyo Shinkansen tunnel which occurred in June, 1999 was taken up as a big social problem about security of the Bullet train. With this, they established the inspection system of the Department of Transportation railroad engineering works structure, and the way of the maintenance of the structure which a railway company should perform has been arranged. On the other hand, in West Japan Railway Company. (following, JR WEST), we wrestled for the elaborate inspection and repair measures of the tunnel cover mechanic not to make any producing serious exfoliation to line again based on the reflection of this phenomenon. In addition, We clarify the tendency of the exfoliation risk by looking back on enormous inspection records and data accumulated in an approach and we consider and carry out the measures that you should perform.

 In recent years, infrastructures that were intensively constructed during the period of rapid economic growth in Japan have become decrepit. In recent years, these infrastructures, which were intensively developed during the period of rapid economic growth, have been aging.In particular, vulnerable person in evacuation are often mentally and physically fatigued, and many of them have health conditions that require some kind of assistance in their daily lives. Therefore, it is important to maintain and manage infrastructures in such a way that they can cope with sudden earthquakes and reduce the risk to vulnerable person in evacuation.

 Local governments in Nagasaki Prefecture have entered the 2nd round of bridge inspections, in which inspections are being made more advanced and more efficient, and introduction of direct inspection and direct repairs of small-scale bridges has commenced. With a shortage of numbers, technical capability, and resources of maintenance personnel, it is expected that certification of maintenance personnel from Michimori maintenance training courses and the technical support of Michimori can contribute to resolving these issues. As systematic activities by Michimori Training Unit Association composed of people with a certification in road maintenance are enabled, Nagasaki University and the association commence various initiatives in accordance with the needs of local governments. This paper introduces the results of bridge maintenance by local governments using Michimori, and explains new initiatives based on actual examples.

 There are bridges throughout Japan not covered by the country’s Road Act, with most not subjected to periodic inspection. While municipalities conduct inspection of bridges in accordance with the Road Act, the resultant repair may not always proceed as planned, due to declining tax revenues and other local conditions. Amid such circumstances, the authors intend to configure a scheme to implement routine maintenance of bridges by four-way cooperation among the private and public sectors, academia, and local community. In this study, students’ knowledge about bridge inspection was enhanced by formulating techniques of education, while inspection and simple repair were carried out using a simple check sheet, which was developed by the four-way cooperation, at not only bridges under management of municipalities but also those not covered by the Road Act and managed by the local community. As a result, the knowledge and awareness of bridge maintenance among residents who participated in inspection and repair were found to increase, with the inspection results by residents demonstrating strong correlation with the results by academics.

 In 2012, a collaborative concrete road paving project with citizens and students in Hirata Village, Fukushima Prefecture was conducted by the authors, and also in 2013, the project for naming bridges by elementary school students was begun. Through these projects, it was decided to build a system for citizens to maintain local bridges in the future. Since 2015, the "bridge self-maintenance model" in which mainly local residents can inspect bridges using a simple bridge inspection check sheet, check a bridge map that visualizes bridge contamination, and clean up dirty bridges, has been developed. As a result, the number of participants in the self-maintenance activities increased, and the authors created a set of " Specification for Activities" so that the activities could be carried out spontaneously and safely without the authors’ presence. In this research, a questionnaire survey was conducted to evaluate whether the participants understood the content and the purpose of the rules, and whether any foreseeable hazards were overlooked, and the content of the specification was reviewed.

 Collaborative activities which based on cooperation by private company, public office, academic institution and local area residents, is becoming more important problem as a new concept for infrasuructure maintenance. Improveing both user mind of local area residents and the public relations strategy on infrastructures will be paied attention as essentical and difficult problem in this concept.

 In this paper, Hashi-mori activity by CATS-B (Civillian Activity Team in Shunan for Bridges) including civic collaboration and many public relations for bridge maintenance are introduced from the viewpoint of mentioned above. Also, public and educational effects and start-up concept on Hashi-mori activity were reviewed from the questionnaire results for participants. Especially, Shunan city office has admited officially importance of Hashi-mori actvity, and promotiong collaborative infrastructure maintenace was cleary builted in bridge repair planning for realizing long service life in May, 2020.

 In maintenance of local roads, there are the challenges of reduced demands on budgets and time and the shortage of engineers. In order to solve these problems, it is necessary to check road conditions immediately when damage or complaints occur, to check defects and damage frequently between regular inspections, and to transfer operational knowledge and train personnel.

 In order to support the proper inspection, maintenance, and repair of road pavement surfaces and road structures, we developed a road maintenance management system. In this study, a commercially available video camera was attached to the front of the car to capture images of the road surface and surrounding road structures. In the system, the images with their location information are displayed using three-dimensional visualization software. Road administrators can use the system to check the status of complaint areas, register damaged areas, and point out areas that need attention, in order to transfer knowledge.

 Metropolitan Expressway has a high proportion of structures such as bridges and tunnels. Therefore, meticulous maintenance is required. Furthremore, it is expected that the number of engineers involved in maintenance and operation will decrease as the working-age population declines, in addition to the increase in damage due to the aging structures. Thus, it is necessary to consider and implement more efficient maintenance methods for ensuring the safety and security of structures. Moreover, in order to quickly grasp the damage status of structures, it is essential to invesitgate and introduce methods of collecting information more quickly in terms of dizaster response. This paper reports overview and effects of introduced new technology including ICT and various new maintenance technology which realize efficient maintenance.

 Since most of the members of port structures are located in underwater, visual inspection is generally conducted by divers. The safety of performing the inspection is influenced by many factors, among them tidal and wave conditions, mooring and the cargo workings of the facility. The effective inspection devices to improve safety have been required for appropriate maintenance and management of port structures.

 Underwater drones that can observe underwater conditions in real-time have become widespread in recent years. In this study, the scope of application and points to notice for conducting the visual inspection of port structures using underwater drones were described. Moreover, visual inspection by the underwater drone quipped with original simple devices was carried out in accordance with the proposed operation plan. It was consequently confirmed that the use of underwater drones would be effective in improving the safety and efficiency of visual inspection of port structures.

 In the downstream portion of the Tenryu River, erosion of low-water riverbank has occurred, meanwhile, the overgrowth of trees in the river channel and vast high waterbeds. Therefore, they have become a challenge to secure the frequency of confirmation of the status grasp and to ensure promptness and comprehensiveness.

 In this study, regarding the contents of river inspection using UAVs (Unmanned Aerial Vehicles) that can be carried out within the range, which does not require advanced operation technology, equipment, and legal procedures, it was verified the portion, photo shooting method that the inspection utilizing UAVs is effective with considering the river features of the downstream portion of the Tenryu River, further the possibility of improvement of river inspection by utilizing UAVs was considered.

 In addition, as a technology for quantitatively and efficiently grasping sediment accumulation and changes over time in river channels, the tool that discriminates vegetation areas, water areas, and sandbars automatically by generating orthoimages from UAV imaging data and performing AI analysis was verified.

 An internal loading method is proposed as a method to evaluate the cross-sectional stiffness of agricultural pipelines. This method is still in the research stage and has been evaluated mainly at the laboratory level. However, in order to apply this method to agricultural pipelines, 76% of which have a diameter of less than 800 mm, automation is necessary. In this study, we developed an automatic system for the field and verified the consistency of the data of load and deformation obtained for sound RC, PVC and FRPM pipes. As a result, it was found that the data obtained for PVC and FRPM pipes were appropriate. However, for the RC pipe, the reliability of the data decreased as the load increased, and it is supposed to be caused by insufficient torque of the motor for loading. Although the automatic machine still needs improvement, it has good potential for field application.

 In the Infrastructure Maintenance Renovation and Management Program of SIP (the Cross-Ministerial Strategic Innovation Promotion Program), many advanced technologies have been researched and developed for new maintenance and management works for an infrastructure since 2014. In order to spread these cutting-edge technologies into the local governments, 12 regional implementation support teams based on regional universities have been organized nationwide. One of them, the Tottori University team, verified the applicability of 4 robot technologies in the series of the demonstration test at the Eshima Ohashi Bridge. Those 4 robot technologies were evaluated successfully, and basic performance data for practical use were obtained from those verifications, to develop the specifications.

 In recent years, Japan is assisting techniques and capacity development of bridge maintenance and management for developing countries all over the world. And the activities of these projects aimed at formulation of maintenance and management plans, including bridge inspection and repair techniques, are being carried out. However, the current condition of the bridge to be managed is not understood and there is no effective data for the formulation of bridge maintenance plans when it is at the start of technical cooperation project because bridge inspection activities have not been carried out in many developing countries.

 In this paper, the method of a bridge database development and bridge management issues of the Ministry of Transport of Tajikistan located in Central Asia, during the JICA technical cooperation project period will be described.

 The project of a total replacement of bridge RC slabs has started as a part of the expressway renewal work. In the Hokuriku expressway located in a cold and snowy region, there may be the combined deterioration caused by ASR and steel corrosion accelerated by de-icing salts on the road. Therefore, it is very important to identify and determine the main cause of deterioration in the plannning of maintenance work for each bridge. In this study, the survey on the amount of chloride penetration into cpncrete and the degree of ASR of concrete was investigated using cores taken from RC slabs in the bridge in the Kanazawa city area. As a result of this survey, a new type of cathodic protection method was applied for them, and its effectiveness was monitored by titanium wite sensors . It was found out that a new-type cathodic protection method was effective in controlling the steel corrosion of steel bars of RC slabs in a saline environment using the de-icing salts.

 With the increase in the number of deteriorated RC slabs, it is necessary to quantitatively grasp the stiffness and load bearing capacity of each slab and to perform efficient maintenance with the highest priority. In this study, the stiffness and load bearing capacity of RC slabs deteriorated by salt damage due to antifreeze in the Hokuriku region were evaluated by measuring the deflection of the slabs using a test truck and general trucks whose loads were measured by Bridge Weigh-In-Motion (BWIM). As a result of comparing the experimental values of the slab deflection obtained from the vehicle tests and the analytical values obtained from the models simulating various degrees of deterioration, it was confirmed that the stiffness of the subject slab was lower than that of the sound condition. In addition, although the load bearing capacity of the slab calculated by FEA is much higher than the maximum vehicle load estimated by BWIM, it is indicated analytically that the load bearing capacity of the slab was reduced by 20-50% compared to the sound condition.

 For concrete decks that have been in service for 40 to 50 years after construction, the upper surface of the deck is scraped by a cutting machine when the pavement is replaced, making it easier for rainwater and salt to enter the inside of the deck..

 For repairs, a method of thickening the upper surface of the floor slab using SFRC is adopted, but it is difficult to reserve a mobile car required for construction, and SFRC is delaminated from the floor slab.

 In this research, we have developed a construction method that applies a dry spraying method that enables construction to thicken the top surface without using a mobile vehicle, and an ultrafast hard polymer cement mortar material that does not peel off from the existing floor slab.

 As the service life increases on the expressway, a larger number of repair work sites are required to work on not only a binder course but also an upper base course. Based on this situation, we conducted a nationwide field survey. As a result, it was clarified that the asphalt pavement was damaged such as fatigue cracks and permanent deformation, and that the weakening of the lower base course and the interlayer debonding. To extend the service life of asphalt pavement, it is important and the simplest method to increase the adhesive strength of interlayer. However, a method that can appropriately evaluate these methods has not yet been established. Therefore, we developed a new testing apparatus and method simulating the real damage phenomenon in fields. Regarding the vertical cold joints, different characteristics were confirmed depending on the material. On the other hand, for the interlayer of asphalt pavement, we used this test that reproduced the breakage of adhesion due to water seen on the actual road and evaluated several types of tack coats. In this report, we report on the technical standardization of the application of materials with excellent adhesiveness and water-stopping properties for the vertical cold joint. In addition, we clarified the problem that any of the tack coats currently applied can not maintain the necessary bonding property in summer condition.

 In 1999, the lifting of the concrete cover became conspicuous in San-yo Shinkansen viaducts, and the early deterioration of concrete structures became a social problem as the "The ploblem of San-yo Shinkan-sen viaducts”. Taking this opportunity, we have prepared and utilized a guide that summarizes the points to be noted for each repair method, with the aim of organizing the concept of applying the repair methods necessary to maintain the structures in a sound condition in the future and utilizing the guide to improve the quality of repair work. In this paper, the performance confirmation and verification of repair effects for the concrete surface coating materials and patch repair materials applied to San-yo Shinkansen viaducts were confirmed by long-term exposure tests.

 Concrete structures of sewage facilities have begun to exceed its standard service life of 50 years, and it is expected that the demands for renovation will increase in the future. In addition, concrete in the facilities often suffers from severe corrosion due to sulfuric acid produced by microorganisms and needs early repairs. In order to continue sewage services under the limited condition of financial sources and personnel, sulfuric acid-resistant concrete, which dramatically increases resistance to sulfuric acid and contributes to maintenance-free and longer service life, is effective. Sulfuric acid-resistant concrete that decreases corrosion rate to 1/10 or less of ordinary concrete, has been developed. Construction techniques and design method are also developed to optimize its quality, and we started application. This concrete is expected to contribute to the reduction of burden related to personnel and financial sources by making the concrete structures maintenance-free and extending service life.

 For the labor saving, robotics and digital technologies have begun to be actively used in the inspection of civil structures. In this study, the authors developed an infrastructure inspection/evaluation system that generates 3D models from measurement data, automatically converts them into FEM models, and evaluates their performance through computer simulation, with the aim of improving the diagnosis of infrastructures. In order to confirm the feasibility of the proposed system, the verification test were conducted on the RC beam specimen. A highly accurate point cloud model was generated by the SfM algorithm combined with a stereo camera and a LiDAR, and the point cloud was converted into a 3D model with geometryc shapes. Finally, the FEM model was generated by converting the geometric 3D model, and it was confirmed that the structure performance could be evaluated.

 Within the jurisdiction of the JR East, short-circuit running of maintenance machines was started in FY 2003 as a measure to prevent collisions of trains and maintenance machines. However, in order to short-circuit on the conventional lines, it is necessary to consider the effect on railroad crossings. We have developed a short-circuit filter for maintenance machines (hereinafter referred to as LPF), and have gradually introduced to maintenance machines of low-frequency track circuit and line section of Autonomous decentralized Transport Operation System. However, railroad crossing ringing events have occurred despite LPF running, and the cause has not been identified.

 Therefore, for the purpose of clarifying the cause of railroad crossing ringing when the maintenance machine is running on the LPF, we have conducted a reproduction test by short-circuit running on the base line and the business line, and in the factory to confirm the performance of the LPF. The test was carried out. However, even in these tests, the cause could not be identified, so when a railroad crossing rang during LPF driving, we developed a monitoring device to see if the electrical performance changed in the LPF, and installed it to maintenance machines.

 The section between Higashi-Oume and Oume on the Oume Line is a single-line section with large number of trains, which passing tonnage is 26 million tons. In the same section, heavy railing work to replace 50N rails with 60kg rails and accompanying work were carried out from FY 2016 to FY 2020 with the aim of improving the durability of the track. There are two crossing with an articulated track structure and four crossing with a Soken-type paving plate structure in the construction section. Especially, the two points of the articulated track structure are wide crossing that intervene in a sharp curve, and it was difficult to make the rail of the crossing part and the articulated block into 60 kg rails at the same time. There were many issues such as the need to replace it with a block of 60kg rails. we will introduce our achivements and our construction methods, focusing on the articulated track part.

 Seven times of standard value excess occurs in 2019 on inspections of shaking of a vehicle. The main repair method is overall tamping of ballast when it is exceeded. However, this is not a good repair method because the standard value excess is tend to be occurred soon after repair work again at the same place. In this paper, we tested the hypothesis that sleeper replacement from a prestressed concrete sleeper to that with elastic rubber materials makes rail track better and decreases the number of the standard value excess of the inspections. As a result, we found that sleepers with elastic rubber materials are effective to suppress shaking of a vehicle and reduce maintenance cost in long term.

 The TC-type labor-saving track has a structure that integrates sleepers and ballast, and was developed for the purpose of not requiring repair work such as tamping. The laying is in progress. Most of them maintain good track conditions, but some of them are laid on soft roadbeds, and the adjustment amount of rail surface height adjustment may be larger than the limit value, so maintenance is difficult. Therefore, we implemented a post-filling method for the purpose of improving the roadbed, and confirmed the workability and basic performance.

 This paper illustrates fundamental policies and ideas useful for municipalities to promote the utilization of new technologies (local implementation) in the field of infrastructure maintenance based on the authors’ experience of activities to support local implementation of “SIP Infrastructure”. Support from university researchers has proven effective in overcoming the inherent difficulty in direct cooperation between private and governmental groups in the local implementation of new technologies. Based on such experience, university researchers interviewed railway administrators and overpass inspectors, summarizing the current state and problems of overpass inspection, which is carried out within a limited time window at night. In this light, this paper provides instances of ideas to enhance the efficiency of overpass inspection and images of new technology development, while introducing the technology of panorama walkthrough. Instances of efforts envisioned in the future based on the research results and new technology images are presented as well.

 A reinforcement, which is one of the most important part of mechanically stabilized earth wall (MSEW), is generally buried in soil so that it is difficult to inspect damage, fracture or excessive tension of reinforcement from extemal side of the wall, and this is a major issue for maintaining MSEW. In order to diagnos reinforcements, unique panels which enable reinforcements to penetrate Multi-Anchored Reinforcement Wall (MARW) were developed. These panels were applied for MARW on site and the existance of fractuire and tension force of the reinforcements which were functioning as mein parts of wall stracture were measured by impact-elastic test, ultrasonic flaw detection and pull-out test. Concequently, it is revealed that it is possible to diagnos reinforcements from extemal side of wall though each diagnosis method has limitations and needs to be applied appropriately.

 The rationalization of maintenance for the superstructure of jetty at the thermal power plant was achieved where salt damage deterioration has become apparent. First, static analysis and dynamic analysis by 3D finite element method were applied as the original design review, and the ability of more accurate structural performance was verified. Then, the structural performance degradation of each member was estimated and the future structural performance was evaluated. To estimate the structural performance degradation, the estimation method for the amount of rebar corrosion was proposed by combining statistical estimation by Markov chain model until the end of the progression period and theoretical estimation of salt damage after the acceleration period. This makes it possible to determine the repair location and timing by structural performance, which is a quantitative index, instead of the degree of deterioration, which is a conventional qualitative index.

 In recent years, due to the aging of dams and climate change, sedimentation in reservoirs has been progressing, threatening the normal flood control and water utilization functions of dams. Surveys and observations of reservoirs are indispensable for appropriate dam maintenance. The most basic survey is to obtain the amount, shape and planar distribution of sedimentation. The main method of sedimentation survey is the single and multi-beam acoustic bathymetry. However, errors are inevitable in depth and shallow surveying of reservoirs with complex shapes in the water, and the negative sediment volume is evidence of this. In this paper, the principle of negative sediment content is described along with the principle of acoustic depth surveying. Then the principle of negative sedimentation is described as well as the principle of acoustic depth sounding. Data on sedimentation rates of dams under the jurisdiction of the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) and the Japan Water Agency (JWA) are analyzed to summarize the occurrence of negative sedimentation. In addition, the method of surveying with high accuracy and the method of correcting the measurement data are discussed.

 It is important to build new structure for considering the lack of resource about finances and human resources in order to run sustainably maintenance and repair regarding bridge deck joints. Especially, bridge deck joints of bridge accessories which is installed on harsh environment bridge(influence of corrosion and heavy-duty etc.) is important to suppress deterioration of bridge and bridge bearing.This report shows adopt-standard which is taken into account bridge deck joints’ required performance and quantitative evaluation basis so that Staff of Toyama city will be able to choose optimal the bridge deck joints standardly when they will run maintenance. As a result, their productivity will be able to be improved. Toyama city’s bridge deck joints will be able to be prevent from re-deterioration and to non-affect the influence of the other bridge equipment.

 The authors are proposing a bridge seismic technology that installs a "die and rod type friction damper" with the rigid-plastic hysteretic characteristic at the upper and lower joints of a bridge structure. This technology performed the ability to fix support bearings at level 1 earthquake motions and exerts damping effects during level 2 earthquake motions to improve the seismic resistance of piers.

 In this paper, after giving an overview of the technology, we will show an example of applying this technology to actual bridge seismic retrofitting work. In this construction, the reinforcement effect was obtained, such as the response curvature of the base of the pier during Level 2 earthquake motion was reduced by about 60% compared to before reinforcement. Furthermore, the high-speed loading experiment for the 1,000kN class friction damper applied in the construction is described. As a result of the experiment, it was confirmed that the friction damper exhibits the rigid-plastic hysteretic characteristic and energy absorption performance as expected at the design.

 In 2005, we developed a seismic retrofit technique using post-installed plate anchored shear reinforcing bars to increase the shear capacity of reinforced concrete structures, which can be applied even when site conditions are restricted. Since then, we have continued to expand the applicable scope of the technology in response to the needs of users, and have carried out the necessary experiments to verify the effectiveness of the technology without fail. As a result, this method has been applied to a number of infrastructure facilities. We are also actively engaged in research and development for new applications. In addition, to keep the construction reliability, which is of particular importance, we have established a construction method committee and are systematically educating personnel.

 Girder replacement has been considered to be an appropriate countermeasure for fatigue cracks in I-beam end. However, it requires a large amount of labor and cost, and sometimes it is difficult to apply this method due to the constraints of construction conditions. Therefore, countermeasures other than girder replacement are required. In this study, the cause of fatigue cracks in I-beam end was confirmed, and effective and simple countermeasures other than girder replacement were studied by FEM analysis and test construction in an actual bridge. In addition, the fatigue durability of the stop-hole repair was shown, and resin injection into the gap between bearing and bridge seat was adoped as a simple method of erasing vertical displacement at I-beam end. And the countermeasures for fatigue cracks in I-beam end was organized.

 In the maintenance of steel structures, it is very important to grasp the remaining plate thickness of each member in planning the repair, reinforcement and renewal for the present state and future of the structure. However, when an ultrasonic thickness meter or a micrometer which is a conventional plate thickness measurement method is used, removal of rust parts is required as a preliminary preparation, and measurement in an underwater part becomes difficult, and it is restricted by work labor and environmental conditions. As a new nondestructive inspection technique to solve such a problem, this paper tries to measure the remaining thickness of corroded part of steel structures in service for a long time by an extremely low frequency eddy current testing (ELECT) which detects plate thickness from eddy currents penetrated to the inside of steel materials. As a result, it was confirmed that a drastic shortening of measurement time can be realized by utilizing the advantage that removal of corrosive substances such as rust is not necessary, while measurement accuracy equivalent to the conventional measurement method is obtained.

 In this paper, for the detection of corrosion in embedded parts of steel bridge piers, the detection of cross-sectional defects 12 mm and 19 mm thickness with cross-sectional defects by using high-sensitivity magnetic non-destructive inspection (ELECT) was investigated. As a result, the differential intensity measured in the 12 mm and 19 mm steel plates largely decreased due to corrosion 10 mm under the ground when the remaining thickness was less than 50 %. When the thickness of the remaining plate was 75 %, the decrease in the differential intensity at 10 mm under the ground was small, however, it was possible to detect the corrosion in embedded parts of the steel pier by measuring several points in the axial direction of the steel pier from the ground and using the differential intensity given at low frequencies. In the case of a defect on the backside of the ELECT measurement, the change in the differential intensity showed that corrosion could be detected when the remaining plate thickness was less than 50 %.

 The acquisition of water level data during heavy rainfall is important in order to conduct flood prevention activities and evacuation actions at the appropriate time against river flooding and inundation inside the levee caused by heavy rainfall. It is desirable to obtain water level data at several different locations, especially when conducting analysis for inundation inside the levee. A measurement system that is easy to install is required when conducting measurements at multiple points. In this study, water level measurements using non-contact sensors (laser sensor and ultrasonic sensor) were carried out and their characteristics were discussed. The non-contact sensors can contribute to the improvement of the workability by eliminating the need to enter the river. The water level measurements were carried out in the situation where the water was stationary and in the situation where the water was flowing. The results showed the possibility that both sensors can measure water level changes in the river, although there were differences in the variability of the measurement data.

 East Japan Railway Company (JR East) is taking on the challenge of creating a system to cope with the future decline in the working population, and is working on technological innovation using ICT and other advanced technologies. As part of these efforts, we have developed a track monitoring system that can remotely monitor the condition of the tracks, and have deployed. With the deployment of this system, a CBM (Condition Based Maintenance) type maintenance method has been adopted in the track maintenance, and various effects have been obtained, such as early detection of abnormalities in track, more efficient inspection, and optimization of maintenance plans based on data analysis.

 This paper presents the development, deployment and future plans for this system.

 This study have been monitoring for a four-span continuous PC rigid frame bridge with the Gerber hinges from 2015 under an industry-academia-government collaboration system. In this paper, the tendency of crack growth due to ASR, and the behaviors of the displacement and the tilt angle of the hinges were investigated based on the monitoring data. As the results of the investigation, it was clarified that the function of the hinges were sufficiently maintained and that the tendency of the tilt angle did not change significantly, and there is no significant progress in the crack in the girder.

 This study examined the applicability of monitoring by using the long basis optical stand sensors to the evaluation of deterioration of the RC deck slabs. The wheel load test adopted a new loading method, loading the close to amount to an actual traffic load. The measurement was to use strain amplitude of the long basis optical stand sensors and the resonance frequency that can grasp the deflection, the crack density and the decrease in rigidity inside deck in order to evaluate the relationship between the strain amplitude and other deterioration indicators.As a result of the test, the strain amplitude can capture the deterioration of the deck to punching shear failure and correlates with the deflection, the crack density and the resonance frequency to indicate the possibility of detecting decrease in the rigidity inside the deck. Rain flow analysis showed the possibility of the evaluating of deterioration when random loads acts to decks at real bridges.

 In recent years, due to factors such as the aging of bridges, it has become an issue to secure a budget for regular inspections and planned repairs by local governments. In this paper, for the purpose of reducing the inspection cost and safe management of Nanao City, the examination of the change of the inspection method by the AI bridge diagnosis support system (introduction of AI simple inspection, Digital transformation) is shown. As a result of conducting a demonstration experiment, AI confirmed a correct answer rate of 86.4%. This was equal to or higher than the correct answer rate (80%) for engineers. In addition, with the introduction of AI simple inspection, it was estimated that the inspection unit price would be 65% of the conventional one. On the other hand, since concerns were confirmed due to the simplification of the inspection contents, measures such as selection of bridges to be targeted for simple inspection by AI and creation of a manual were taken. Based on this result, as a result of operating a simple inspection by AI from the next fiscal year, we confirmed a correct answer rate of 92.9% for soundness and 96.4% for deterioration factors. Based on these results, the evaluation of AI simple inspection and future issues were organized.

 Municipal roads account for about 84% of the total length of roads in Japan, and they extend to every corner of the country. Municipalities are facing a shortage of technical staff and financial resources, and are required to save labor in many fields. On the other hand, understanding the current traffic volume is an important basic data collection for road maintenance and management. In this paper, we use Tamana City Hall as a case study, which is a local public organization with insufficient financial resources and technical staff, to analyze the problems of traffic volume surveys conducted directly by the city, and to implement a simple traffic volume survey using a trail in order to improve operations under the constraints of limited resources (staff and budget). Based on the results of this practice, further problems are extracted, and a simple traffic volume survey that combines low and high technologies is described, which aims to save labor by using artificial intelligence.

 Although the stock of pipeline facilities is increasing with the spread of sewerage, there are severe social issues such as a decrease in sewerage revenue due to population decline and a decrease in the number of local government employees engaged in sewerage maintenance.

 Therefore, we developed software that makes expanded imaging method inspections by television camera more efficient. This software utilizes AI to automatically detect pipe joints and connection pipes with 90% or more performance, and it is possible to complete the process of creating an expanded image, damage discrimination, and creating a report, which can significantly reduce business hours.

 In safety management of dams in their maintenance works, visual inspection and monitoring of various measurement data such as water leakage and deformation are basic and important means for anomaly detection. However, the number of dams in long-term service increases, while the number of experienced and skilled staff is decreasing. In order to deal with such a situation, it is necessary to make more effective use of various measurement data so that the manager can more accurately judge whether or not there is a safety problem in the dam.

 In this study, the possibility of using AI technology for supporting dam managers’ judgement was discussed on a trial basis focusing on time-series deformation data obtainded in concrete dams. As a result, it was shown that LSTM (Long Short Term Memory), which is a kind of recurrent neural network, can be expected to be used for predicting the behavior of dams for anomaly detection.

 With the formulation of the bridge periodic inspection procedure, periodic inspection of bridges by close visual inspection has been legalized. However, there are about 700,000 bridges nationwide, and there are problems such as a shortage of engineers and raising inspection costs. Research is being conducted to introduce a bridge 3D model for the purpose of labor saving in maintenance, and the method using VR (Virtual Reality) provides a simulated experience of inspection without being affected by the on-site environment such as traffic and weather. In addition, we believe that inspection can be supported by highlighting damage such as cracks that are difficult for the human eye to observe on the model. Therefore, in this research, we have developed a system for observing a bridge 3D model in VR space by reflecting the highlighting of cracks by AI on the bridge 3D model and facilitating the confirmation of damaged parts.

 Many mortar-sprayed slopes were constructed during the period of high economic growth, and they are aging at the same time. It is difficult to visually check for floats among the abnormalities of mortar-sprayed slopes, so percussion inspections are used to check for them. However, due to the shortage of inspection engineers and the financial difficulties of the national and local governments, there is a limit to the amount of time that can be spent on a continuous diagnosis of floats using only percussion inspections. This study, developed two models for the automatic detection of floating areas by deep learning using infrared images. The results show that model-2, which can take into account the features around the floating area, can detect the floating area properly and its performance does not depend on the mesh size.

 The government amended the Road Act in 2013, prompting the 2014 Ministerial Ordinance which obligates road administrators to conduct a close visual inspection once every 5 years. Municipalities with a weak financial base have been imposed heavy burdens by this revision of the law. Therefore, labor-saving and efficiency improvement of visual inspection is required.

 Maintaining and managing social infrastructure, saving labor, and improving efficiency in visual inspections is one of the urgent issues in recent years. Therefore, in this study, in order to solve this problem, we apply the segmentation method using deep learning to images acquired by a digital camera and examined a method that automatically detects the deformation and classifies the degree of damage.

 It is inevitable that a decrease in the working population will lead to a shortage of skilled infrastructure inspection engineers due to the declining population, low birthrate, and aging population. Furthermore, the aging of structures is accelerating in inverse proportion to the decrease in the number of inspection technicians. In order to promote efficient and optimal maintenance management with limited budgets and engineers, it is important to improve and quantify the quality of inspection and survey data, which is the basis for understanding the condition of structures.

 Although percussion inspection has been widely used as a diagnostic technique for social infrastructure, the method and judgment of percussion inspection are based on the subjectivity and experience of inspectors. The purpose of this study is to develop a technology that can accurately identify damage without being affected by the experience and skills of the inspector. We conducted a demonstration test of percussion inspection and classified and organized the judgment results obtained according to the number of years of experience and work procedures. The results were classified and organized according to the number of years of experience and work procedures. The requirements and issues regarding the adaptability to new technologies were also identified.

 In late years, both local heavy rain and long-term rainfall become intense, and the rain disaster occurs almost every year. Under such severe circumstance, both hard and soft measures must be considered in order to ensure safe and stable of the railway transportation. Particularly, for the disaster from the outside site of railroad, the hard measures by the track are limited, and soft measures are main. We introduced three train operating control regulations for the purpose of more ensuring safety to our conventional line, in June, 2020. The first is "the soil precipitation" that is an index showing sediment-related disasters well. The second is the radar precipitation that can observe continuously the torrential rain in detail. The third is the evaluation system of debris flows risk that are occurred to a place away from a railroad track.