It is expected to improve the operation and maintenance for the mechanical equipment by using the wearable camera which realizes remote support. In this paper, we describe the expected effects by using the wearable camera for the mechanical equipment in the operation and maintenance stage. Based on the results of the trial by using the wearable camera for the sluice gate of the dam and the drainage pump equipment, we confirm the effects of using the wearable camera, and clarify that the wearable camera is effective for improving the operation and maintenance of the mechanical equipment.

View full abstract

 It is expected that 3D models derived from SfM (Structure from Motion) and MVS (Multi View Stereo) are applied for the efficient maintenance of civil engineering infrastructures. However, it may take a huge amount of time to generate appropriate models because the generation of 3D models requires know-how about shooting images and processing data. Therefore, in this paper, we proposed the method of generating 3D models easily and accurately by images that were taken without too much conscious of SfM. As a result of experiment, high accurate 3D models were obtained by our method about four times faster than by conventional method. Additionally, we presented the procedure and functions of analyzation that are effective for the maintenance of civil engineering infrastructures by time series 3D models and summarized that examples on a prototype system.

View full abstract

 CIM was introduced by MLIT in 2012. However, most of recent efforts for CIM are limited on the contractor side. Though, proactive activities of the owner are indispensable for improving productivity throughout the construction life cycle. In some cases, efforts to improve productivity by the owner have also begun. MLIT has devised the basic-frame as river management CIM. Therefore, with consid-ering the problem of CIM, this paper proposes the data retention as numerical data and improvement of basic-frame. Moreover, based on the proposal, the author considers the owner's CIM of future.

View full abstract

 The Gifu University SIP implementation team (GU-SIP team) is conducting activities to adopt robot technology (RT) into the legal periodical inspection of Kakamigahara Bridge (long-span PC bridge). Based on the guidelines (draft) proposed by a committee of the GU-SIP team, we planned to adopt two-step inspections. In the first step, "preliminary survey" is carried out by using RT. In the second step, "close visual inspection" is conducted on the whole bridge by utilizing the results of the preliminary survey. Performance requirements were established for RT. The performance of RT was then verified. For the RT, we requested that its performance allows us to judge whether or not the soundness class of the structural member under inspection is "II or more". In the "preliminary survey", an RT system combining three drone systems and two robot camera systems was used. We proposed a method in which one drone system detects damage other than concrete cracks on the entire bridge from a short distance and then the RT system with a high-resolution camera detects concrete cracks.

View full abstract

 Investigation and inspection of damage in road and railway bridges after earthquake disaster are oftenly required to take urgent measures to restore the system at an early stage. Also, in mountainous areas, it is difficult for people to access the long span bridges or its high piers after a disaster. It is also difficult to conduct emergent or routine survey for those parts of bridges. Recently, the visual inspection method using general-purpose Unmanned Aerial Vehicle (UAV) is considered as useful for the structural damage detection. In this research, the basic performance for a few type of UAVs were tested by conducting a series of simple flight tests. The inspection performance under wind condition of UAVs were tested by Wind Tunnel tests. A simple wind resistance estimation formula from the wind tunnel test result is proposed. To qualitatively evaluate the performance of UAV for bridge inspection, the Performance Index (PI) for UAV in bridge inspection, considering its Operational, Safety, and Visual-sampling performance, was also proposed. Real bridge inspection verification test using UAV was conducted to examined the effectiveness of this PI.

View full abstract

 After recent large earthquakes, the fast and safety emergency investigation of road and railway bridge systems is realized as one of the most important issue for the disaster mitigation and resilience of urban area in Japan. In this paper, the feasibility of bridge routine and post earthquake emergency inspection using small aerial photography Unmanned Aerial Vehicle (UAV) is verified by a series of onsite flight and investigation tests for 9 bridges. The basic performance of UAV for structure inspection are evaluated by compare the inspection result with the real bridge inspection reports. By using Deep Learning, it is possible to automatically detect damage and speed up image analysis. In this study, as a verification of the usefulness of Deep Learning for damaged images, image classification based on Deep Learning was performed using some images collected by past visual bridge inspection reports.

View full abstract

 The purpose of this research is to clarify the issues of the concrete product industry from the viewpoint of industrial organization theory and to propose growth strategies of the concrete product industry.
 Firstly, based on SCP paradigm, analysis about the problem of the concrete industry was carried out by using statistical data. In the market structure where the demand continues to decline, industrial organizations in the concrete product industry were in a state where small and medium enterprises were in a state of muddy. For this reason, it has been found that price competition that reduces profits as market action continues, and it is not possible to produce market results like improvement of labor productivity. On that basis, success factors for the prefabricated housing industry, which is similar to the concrete product industry in terms of assembling factory products on site, were extracted by organizing past studies. Finally, as an action plan of the growth strategy, a technical development project involving other industries in addition to the concrete product industry and the construction industry, and an "ECI method with maintenance" in which the contractor contracts construction and maintenance are suggested.

View full abstract

 In this study, we focus on the causal relationship between failures occurring in concrete bridges of expressway facilities and propose a methodology to analyze the effect of delay of repair action to failure occurrences. Specifically, paying attention to water leakage failures and concrete exfoliation failures in bridges, the mechanism by which concrete exfoliation failure occurs due to water leakage failure is expressed by using Composite Weibull Hazard. Furthermore, we formulate the inflection of the occurrence probability of concrete exfoliation failure due to the deviation between water leakage failure occurrence timing and repair timing against it as a function of repair delay time and deterioration factors. For the estimation, we apply sampling by the MCMC (MH) method after performing the completion operation and estimate the parameters of deterioration factors and delay functions and posterior probabilities of failure occurrence. In addition, we make suggestions about the importance of quickness of water leakage repair through the empirical analysis for actual expressway facilities.

View full abstract

 The purpose of this study is to construct a regression model on crack propagation for concrete girder members of the road bridges in Shikoku region. The model is constructed by a data-driven type machine learning, Gaussian process regression, based the inspection data of 1,344 bridges owned by the government. The data includes the dimensional data of bridges, the environmental conditions, traffic volume, and crack damage ranks. As the result of the factor analysis by the model, it is revealed that the influence of rainfall amount varies at the completion year of construction 1980 and it greatly affects RC girder of the bridges constructed after 1980. It means that the model can extract the local trend.

View full abstract

 The number of deteriorated bridges is increasing. It is expected that the necessity of a repairment and removal strategy of bridges will increase to maintain the service level of a road network. It is important to maintain and manage the bridges with large traffic volume preferentially. Moreover, it is important for network redundancy to maintain and manage bridges that are likely to be used as an alternative route when the capacities of other bridges are decreased. We propose a bridge-linkage table for efficiently grasping the relationship between bridges' traffic volume through a user's route selection. Furthermore, we propose the substitutability importance index to measure the importance of bridges as an alternative route. By applying our method to Uwajima city, Ehime Prefecture, it was shown that some bridges with small traffic volume show higher values of the substitutability importance index.

View full abstract

 MLIT has, in the last few years, established guidelines for the modification of conditions in public works contracts in Japan in order to improve fairness and transparency in the public works sector and secure the quality of the infrastructure in Japan. The author analyzed trends by questionire surveys for the purpose of verifying the effectiveness of these measures. Then, we have presented case studies exemplifying how actual negotiations on design change and modification of contract conditions are handled and picked out some of the existing problems based on the analysis of these case studies.
 To solve thease problems, we proposed 3 measures; (1) Development of the case studies database, (2) Promotion and certification system for these guidelines and (3) Promotion of fairness of contract administration system and operation system by reciprocal check between the owner and the contractor. Then, the auther illustrate the necessity of improvement of thease owner's guidelines and the necessity of providing guidelines geared more towards accommodating the views of the contractor to enable these problems to be solved.

View full abstract

 In Japan, it is an urgent issue to manage proper wage level and holidays as well as enhance the labor productivity. The purpose of this research is to grasp the system and the role of the orderer which relates regulating work hours and securing wage levels in the U.S.A. based on documents and field research. It should also consider the difference of current system in Japan, and acquiring knowledge for future development in Japan. We acknowledged that there is no limit for total hours spent at work in working hour regulations in the U.S.A., however there is a system to pay 50% on top of their regular rate of pay for all hours worked over 40 hours in a workweek. The Davis-Bacon Act has a big influence on managing wage levels of skilled construction workers, and the role of the orderer is well established in the system in order to follow the regulations of the Davis-Bacon Act.

View full abstract

 The purpose of the study is to show a few outstanding examples of the collaboration of disaster relief volunteers and local construction businesses. These examples will lead the discussion that the local constructors, who are the bodies of public works in each region, have the potential to fulfill CSR (corporate social responsibility) achievement by the collaboration. First of all, the author confirms the inherent definition of CSR born in Europe and consider that the term means "integration between social problems and core business" in the construction industry.
 Secondly, the author describes a high affinity between disaster volunteer activities and local construction businesses. This type of new collaboration offers a social contribution different from contribution by implementing restoration work based on the "disaster agreement" done by the construction industry.
 Finally, the author will state that there is a possibility of obtaining citizens' trust more directly through active cooperation with non-profit organizations, and show support groups and social welfare councils etc. that carry out disaster area support activities.

View full abstract

 Some social problems consist of sub-problems in various fields. Disaster prevention is one of the typical problems because so many issues such as social support for elder person, regional restoration planning and cost-effective analysis from economical point of view are included. To solve such problems, the researchers in various fields must collaborate to seek for comprehensive solution. However it is hard to build the team for interdisciplinary collaboration with suitable researchers because the interest of each researcher cannot be known exactly. Also it is difficult to know who can bridge the researchers with different field. In this study, we develop several decision support methods for interdisciplinary collaboration in disaster prevention. There methods are based on text analysis which is applied to examine the interest of researchers.

View full abstract

 Through the restoration and reconstruction activities after the Great East Japan Earthquake, the significance of local civil engineering consultant company was recognized greatly. However, their profit had become worse due to intensified competition and changes of contract system. In 2013, the government recognized it as a severe problem and began to consider solutions.
 This paper considered the actual situation of order acceptance by local consultant companies, using the latest database on bid information of the Ministry of Land, Infrastructure, transport and tourism. As a result, it was confirmed that the order volume per engineer of the local consultant company was remarkably lower than that of the large consultant company, but the trend was improving. Furthermore, it became clear that the proportion of the contract system could affect the number of local consultant companies.

View full abstract

 Japan faces great risk of natural disasters and it is concerned that there will be other large-scale disasters which may cause fatal damage to important functions for maintaining administration as well as social and economic systems. In order to avoid such kind of situations, recently it is said to be important to make resilient national land. However, estimations of damage such as economic loss caused by large-scale floods have not been done yet, even though these are quite important to assess the validity of measures to promote National Resilience. Therefore, this study conducted estimations of economic loss due to inundation caused by large-scale floods in Tokyo, Osaka, and Tokai areas according to the expected floods scenarios by a spatial computable general equilibrium (SCGE) model. As a result of that, serious damage to the economy triggered by inundation in Tokyo, Osaka, and Tokai areas was estimated. The result suggests the great need of mitigation measures against large-scale floods.

View full abstract

 Many large-scale earthquake disasters attacked throughout in Japan. In a mountainous region, many estates for housing which developed embankments were suffered a lot of serious damage. These damages were caused by subsurface structure which a foundation inclined. As the cause, embankment developed in the 20-50 years before didn't become united with a ground foundation and wade up a small landslide occurred by a ground motion from earthquake. Such situation has happened by many seismic hazards in the past disaster. Therefore, these ground foundations were revealed as well as the strength of the houses were also important. This study focused these facts that building, and housing damage rate varies depending on the subsurface structure in Sendai City due to the 2011 off the Pacific coast of Tohoku Earthquake. And analysis of the technique of the geographical information system (GIS), which was proved that those were right. Finally, Seismic risk in Sendai area is analyzed.

View full abstract

 As shown the Action Plan to promote PPP/PFI projects, promotion to small municipalities which have few experiences of them is required. However, the one of inhibitory factors is complication of administrative affairs. One of methods reducing the difficulties is to simplify affairs about reply to tender candidates' questions. The purpose of the current research is to clarify features of replies in the open documents of existed PPP/PFI projects during 5 years. The text mining which is introduced as a method can find the tendency of key words which appear many times in questions by tender candidates. The results indicate suggestions to reduce difficulties of administrative affairs about PPP/PFI projects.

View full abstract

 In Japan, when the national or a local government orders public works, a contract official is mandated to set a threshold price, which is the upper limit of the bidding price, and a contractor who bids exceeding the price is disqualified in the bidding. This system is required by Public Accounting Act established in 1889 and was abolished in other developed countries. And it is pointed out that this system causes opportunity loss by rebidding and increase in administrative costs.
 In recent years, Ministry of Land, Infrastructure, Transport and Tourism (MLIT) has been promoting the comprehensive bidding method to secure quality of the public construction. According to this method, the limitation condition for the remarkable rise of the bidding price is added even if the upper limit system of the threshold price is abolished, because a successful bidder is decided by the bidding price and its technical evaluation point.
 In this study, a simulation model which incorporates the decision process of bidding price in the comprehensive bidding evaluation method was developed and the paper quantitatively investigated the situations in budget management and a change of the technical level of the successful bid company providing the upper limit restriction of the planned price is abolished.

View full abstract

 The purpose of this study is to improve in the procedure for technical proposal and negotiation method based on the result of application in accrual MLIT projects. The results of this study revealed the idea on applicable condition, selection of contract type, period for contractor involvement, theme for technical proposal, risk allocation, process of design and negotiation, accountability for payment transparency etc., for technical proposal and negotion method. Based on the proposed idea, different from existing methods such as design-bid-build and design-build, the guideline on technical proposal and negotiation method for MLIT projects was revised in Dec, 2017.

View full abstract

 The social infrastructure built during the period of high economic growth is aging rapidly. For this reason, the social infrastructure is being repaired based on periodic inspections and inspection results. Maintenance for the purpose of long life of the bridges has become a urgent issue.
 In this study, we aim to develop the permanent magnet moving robot that can inspect crack of concrete floor slab in steel bridge. We also report on the results of field trials at the bridge. Furthermore, it shows the effectiveness of the moving robot into bridge inspection work.

View full abstract

 The aging of infrastructures in Japan is in a serious condition. At the same time, the decline of maintenance engineers due to the low birthrate and longevity and shortage of maintenance budget are serious. Especially in Shikoku region, the population decrease and the budget decrease are progressing much faster than the national average. Under such bad conditions, it is necessary to train engineers in order to stop the deterioration of infrastructures. In particular, engineers that have a comprehensive and panoramic viewpoint and can contribute to efforts throughout the region are required. This paper describes about the development of "infrastructure maintenance experts (ME) education program" by Ehime University to solve above mentioned infrastructure problems.

View full abstract

 The aim of this study is to examine the estimation model of construction period in Gunma prefecture against the background of ensuring appropriate construction period and efforts to expand holiday in civil engineering works. Firstly, construction costs and construction period data used for analysis were collected and basic characteristics were grasped. Next, we examined the estimation model of construction period in Gumma Prefecture. Finally, we proposed an improved model. This model considers securing a two-day weekly holidy system and reflects the characteristics of construction.

View full abstract