The increase of costs for maintaining and renewing infrastructure due to deterioration is a long-standing issue. Especially, it is practically important to secure long-term funds, but there exist uncertainties in the deterioration process of infrastructure, so we cannot ignore the difference between the budget for maintenance and renewal and the actual cost that would increase due to unexpected deterioration. Accordingly, it is indispensable to take measures for reducing the uncertainties in the costs for maintenance and renewal caused by the uncertainties in the deterioration process of infrastructure. In this study, the authors discuss the applicability of infrastructure insurance to the maintenance of infrastructure from the viewpoint of risk finance. In detail, we focus on parametric insurance, which has immediacy and can pay insurance premium immediately after a triggering event happens, predict the deterioration of actual bridges based on inspection data, carry out numerical simulation based on the prediction results, and examine the effects of the insurance.

 In the earthwork section of the expressway managed by the NEXCO 3 company (hereinafter referred to as the expressway), there are slopes that are monitored the condition by measurement sensors such as extensometers and borehole inclinometers using the mobile phone network and the Internet. On the other hand, an optical cable network is installed under the expressway so that the communication circuit can function even in the event of a disaster, and it is mainly used for road management facilities such as information boards. But it has not yet been used for monitoring deformation of slopes. In this paper, as an effort to improve the safety and security of the expressway, we tried to regular monitoring the measurement data of the slope between Takatsuki JCT / IC and Kobe JCT on the Shin-Meishin Expressway by a private line. And we showed a method to improve expressway maintenance efficiency based on the analysis results using data observed during rainfall and earthquakes.

 The digital transformation of industries has recently impacted the construction industry, as stakeholders are beginning to consider the application of blockchain and smart contract technologies for construction supply chains. When installing such innovative technologies, the fair and economically rational allocation of development and operation costs of information systems is a fundamental challenge facing public works stakeholders. Without a reasonable understanding of the costs and advantages to be borne across the supply chain, consensus among stakeholders is infeasible. The purpose of this research is to analyze the cost allocation of development and operational cost for a construction management information system that utilizes blockchain and smart contract technology. Based on cooperative game theory, the Weighted Shapley Value and Priority-Ordering Nucleolus were applied to the supply chains of public works projects, and the fairness and economic rationality of arrangements were evaluated. The results show that cost allocation models based on the Weighted Shapley Value can represent an appropriate allocation method for public works stakeholders.

 In this study, a methodology is proposed to select the types of expressway facilities that have the possibility of improving management policies based on a questionnaire survey of on-site engineers. Expressway managers are required to manage a large number of different types of facilities. It is, however, difficult to identify the appropriate management policy for each facility through detailed analysis of the historical failure data. In this study, we define four possible types of management policies, and then conduct a questionnaire survey on the characteristics of facilities to on-site engineers who routinely carry out maintenance work, in order to simply identify the appropriate management policy for each type of facilities. It is then to be confirmed that the proposed methodology enables us to identify appropriate management policies for each type of facilities, and to screen facilities for potential improvements in current management policies based on the results of the questionnaire survey.

 In the selection of project sponsors like in PPP, it is common to be based on the total points of price and quality, which is called comprehensive evaluation method or Most Economically Advantageous Tender (MEAT). In such cases, the quality points are considered to be equivalent to the “price point” of the willingness to pay for additional proposals of services that exceed the required level. Consequently, in principle, “one point” of both price and quality should be monetary equivalent. Therefore, it is necessary to calibrate between price and quality points in the selection based on MEAT. However, this has rarely been pointed out and has not been implemented so far. In this study, three approaches are proposed to calibrate price and quality evaluation points in MEAT and the simulations with a hypothesis case are conducted. The results show the feasibility of the methods in the simulation case and the issues in applying them to real projects are discussed.

 In Japan, the social infrastructure, as well as construction industry, has greatly developed during the postwar period of high economic miracle. At the same time, geological and geotechnical technologies have specialized respectively, and the manualization of various design methods have progressed in each field. On the other side, accidents and troubles related to geotechnical structures have been repeated, leading attempts to practice geological and geotechnical risk management. In this paper, we first review the transition of the design methods of geotechnical structures and clarify the need to reconsider the design basics. We then propose a revised definition of geotechnical structures and finally present the design concept based on the more generalized idea of artificial engineering. The authors believe that this is effective in promoting collaboration with geological and geotechnical engineers, which would contribute to reduce accidents and troubles related to geotechnical structures.

 Regarding technologies for extending the lifespan of infrastructure, it is important to establish a framework for quantitatively and continuously evaluating the effects of these technologies in order to implement asset management. In this study, the effect of the lifespan-extending technology is evaluated by studying the change in deterioration rate through the adoption of the technology. In order to clarify at which stage of the deterioration process the effect of the lifespan-extending technology is most apparent, the authors propose a mixed Markov deterioration hazard model that takes into account deterioration heterogeneity that changes gradually with each condition state. Using hypothesis testing to evaluate the statistical significance of differences in estimated heterogeneity parameters, the authors quantitatively evaluate the ex-post effects of the lifespan-extending technology. Furthermore, the effect of a waterproof layer on the RC slab of the expressway is evaluated using actual inspection data, verifying the usefulness of the proposed method.

 Compared with main road structures, fittings such as road signs and lighting equipment have shorter lifespans. In road sections where the deterioration of major road structures became apparent, fittings may have been renewed several times, so it is necessary to obtain data on inspection and renewal, in order to predict deterioration with an existing methodology. However, fittings are less prioritized in maintenance, so the accumulated data on renewal for them are insufficient in many cases. Accordingly, in this study, a model of deterioration and renewal of lampposts is formulated while considering the timing and number of times of renewal as potential random variables. Furthermore, the validity of this study is discussed through the empirical analysis of actual inspection data on lampposts, and the appropriateness of renewal plans for lampposts is examined through the collapse risk analysis based on deterioration prediction results.

 In recent years, it has become relatively easy to acquire construction management information on site as digital information through the efforts of i-Construction, especially for earth works. The purpose of this paper is to develop a prototype of a system for ICT earthwork that automates the process from progress assessment to payment using blockchain and smart contracts. Using the developed prototype system, The verification was conducted for the excavation works of the river channel rectification work ordered by the Kanto Regional Development Bureau of the Ministry of Land, Infrastructure, Transport and Tourism (MLIT), and confirm the effectiveness of the system.

 The water supply business in Japan is in a difficult management phase, such as a decrease in profits due to a declining population and changes in the industrial structure, and an increase in renewal costs due to aging facilities. With the revision of the Water Supply Law in 2018, concession contracts can be made even in the water supply business. It is expected that management will be improved by the technical capabilities and management skills of the private sector. In that practice, it is necessary to appropriately evaluate the business risk and profitability, and to consider and apply the contract based on the characteristics as a public service. The purpose of this study is to construct a management simulation model that bundles the three water services of water supply, industrial water, and sewerage, and to quantitatively analyze and evaluate the effects and problems of introducing the concession method.

 For statistical deterioration forecasting, many methods (e.g., Markov deterioration hazard model) have been proposed to estimate Markov transition probabilities using inspection databases with inhomogeneous inspection intervals, and there are many practical applications. These methods, however, require a high level of expertise from analysts, and there are technical obstacles to their use by practitioners. On the other hand, the counting estimation method with inspection database is conceptually understandable, but it is difficult to apply to the case where inspection intervals are inhomogeneous. In this study, an inspection database with inhomogeneous inspection intervals are pseudo-reconstructed so that the inspection intervals are homogeneous, and the counting estimation method is applied to the reconstructed database. Lastly, the usefulness of the proposed method is verified using an inspection database of real bridges, and the relevance of the proposed method to existing methods and the applicability of the proposed method in practice are discussed.

 In rural areas, the number of infrastructure maintenance personnel tends to decrease due to the decrease of the number of government officials and construction industry employees. When planning daily road patrol work, it is necessary to strategically select the road sections to be patrolled from many managed sections. If the number of the patrolmen will decrease, it is more important to select the sections efficiently. In this study, we will develop a method for designing a daily work plan of the road patrol with limited number of patrolmen using mixed linear integer programming problem. Then we demonstrate the model to show its effectiveness empirically.