In recent years, under the policy of i-Construction, the adaptation of information technology to construction sites has been progressing, and improvement in productivity is expected. Information obtained from construction sites is being utilized not only for construction management but also for as-build inspection. However, the process of on-site inspection conducted by a inspector to ensure immutability has not been streamlined yet. In this research, a new as-build inspection system using blockchain is proposed through the design of a system that guarantees the immutability of construction management information, the development of a prototype, and the proof of concept test.
For the construction of infrastructure in developing countries, technical standards of design, construction and maintenance are important to secure the quality of their infrastructure. It is expected that the transfer of Japanese technical standards to developing countries could promote exports of Japanese infrastructure system. Aiming to promote Japanese technical standards for port facilities overseas especially developing countries, this study summarizes the overseas promotion strategies of major international technical standards, and discusses the overseas promotion strategy of Japanese technical standards for port facilities. It is effective to customize the technical standards based on Japanese ones to conform with natural and construction conditions of the partner country. In Vietnam, a series of new design, construction and maintenance standards for port facilities has been developed to conform with Vietnamese local conditions based on Japanese technical standards. In addition, this study presents the basic concept of customization of technical standards for port facilities in Japan to conform with local conditions, the generalized customization methodology to apply to other developing countries, and the summary of important notices on the customization.
Initiation and propagation of a large number of fatigue cracks on a steel slab of an expressway viaduct would reduce its fatigue durability considerably. For such failures and damages which cannot be repaired radically with usual repair methods, it is necessary to establish management plans considering large scale repair methods based on the initiation status and the propagation process of failures and damages. In this study, a method is proposed to estimate initiation and propagation processes of fatigue cracks on steel slabs with high accuracy, considering initiation timings, which cannot be directly observed by visual inspections, as latent variables. Then a methodology is proposed to select between normal repair and large scale repair for each repair unit based on life cycle costs calculated with the estimated initiation and propagation processes of fatigue cracks. Lastly, the proposed methodology is demonstrated with actual steel slabs of expressway viaducts.
The Eddie Current Test (ETC) is capable of detecting cracks from the surface of paint film and has excellent efficiency and economical advantage to Magnetic Particle Testing. But when it is applied to a round weld part where the shape and direction of weld bead changes frequently, it is said that ETC likely fails to detect small crack or miss judge as crack exist where it doesn’t. The newly developed eddy current flaw detection imaging system performs C-Scope imaging by displaying the estimated crack shape at the scan position. We attempted to improve the accuracy of fatigue crack detection of the crack in the early stage of propagation by removing signal noise, which shows spatial distribution around a round weld. Furthermore, accuracy of the C-Scope images were evaluated using real fatigue crack specimens produced in the beachmark loading fatigue test.
The purpose of this study is to propose a way of risk management for infrastructure projects by ODA in developing countries based on case analysis of highway projects in India. The results of analysis revealed the importance of partnership with local contractor and participation using technology of Japanese contractors. For ODA construction projects, more positive involvement in additional survey for risk reduction and quality improvement by using technology and experience of Japanese government, consultants and contractors are required from the early stage of the projects.