Decision-making models provide highway agencies with a plan for optimal decisions about mainte-nance and repair activities. The objective of these models is to minimize the total expected cost of maintaining a system of facilities incurred by an agency and the users over a given planning horizon. Recent models take into account measurement error in the inspection process and optimize the inspection schedule. Other state-of-the-art models include uncertainty in performance forecasting. Our research develops a model that jointly determines when to inspect and what maintenance activity to. perform, while taking into account both uncertainty in the measurements and feedback in the estimation of the deterioration rate. A computational implementation is performed in order to study empirically the relative significance of uncertainties in the deterioration rate and the state of the system.

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This paper overviews traditional approaches in engineering economics and reliability engineering to maintenance and replacement and examines their applicability to infrastructure management. Problem of infrastructure management is formalized as a general stochastic impulse control (SIC) model and then a way for solving it is instructed. As a special case of the problem, the discrete stochastic dynamic programming (SDP) is illustrated with its application to replacement of an infrastructure. Finally, the research agendas for the methodological development of infrastructure management, particularly topics in project accounting system, mechanism design are discussed in perspective view.

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This paper proposes deterioration prediction methods based upon actual inspection data in order to carry out strategic maintenance and to rationalize life cycle cost analysis. Firstly, using deterioration rates, the methodology of predicting the deterioration is discussed to model the averaged deterioration of structures. In the second place, for the prediction of the individual structure, a probabilistic approach using the distribution of deterioration rates and its own historical inspection data is proposed. The validity of these methods is verified through the actual visual inspection data of bridges.

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This paper focuses upon the optimal repair and inspection policies of public facilities under uncertainty. The deterioration processes of the facilities are supposed to be partially observable by inspection. The optimal impulse control problem is formulated to find out the optimal timming for ispection and repairing so as to minimize the expected life cycle costs. The state dependent rules are presented to determine the optimal timing for inspection and reparing based upon the observation of deterioration levels. The paper is concluded by illustrating numerical examples.

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This paper aims to propose the optimal control policy for the maintenance of the multiple runway system, in particular, concern the influence of the flight demand on the runway condition. First, the mathematical formulation for this problem is discussed and the necessary conditions for the optimization are obtained by applying the traditional Pontryagin's Maximum Principle. Second, through the numerical examples, it is understood that for the effective maintenance policy for the multiple runway system the long interval for maintenance is required in spite of the thickness of the resurfacing. Moreover, the maintenance schedule that has a short interval gives the concentration to one runway, while the schedule that has a long interval gives the “even share” to each runway.

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Pavement deterioration models provide useful predictions of distress initiation, for purposes of pavement design and management. A common problem in modeling the initiation is the inappropriate treatment of data censoring. If the censoring is not accounted for properly, the model may suffer from statistical biases. In this paper, an analysis of pavement crack initiation data based on the duration modeling techniques is presented. Duration models enable the stochastic nature of pavement crack initiation to be represented as well as censored data to be incorporated in the statistical estimation of the model parameters. The results show that the model predictions are more accurate than those obtained with the original AASHO model.

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Infrastructure deterioration is influenced by a multitude of factors including design and construction quality. This paper focuses on quantifying the impacts of such initial condition variables on life-cycle performance. Although in previous research an analysis framework for investigating such impacts was developed, quantitative results were inconclusive due to data and model limitations. In this study a rutting progression model that explicitly captures design and material quality variables is used whereby the effects of these variables on rut depth evolution over time are analyzed in quantitative terms. The results are in turn used to motivate future research in understanding significant temporal tradeoffs in infrastructure provision.

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This paper provides a joint-production model, based on a hybrid rectangular input-output framework, to estimate direct and indirect by-products embodied in the domestic economy. The model enables us to investigate a supply and demand structure of the by-products from industries and households. The empirical analysis between 1990 and 1995 reveals that there exists some sectors such as “metal products for construction and architecture” whose direct and indirect effects were positive and negative, respectively, because of technological changes. This is obviously inconsistent with the spirit of the well-known zero-emission. Furthermore, the results show that the historical changes in private and public capital formation largely influenced not only the embodied scrap iron and slag related to the construction sector but also to other by-products such as scrap papers.

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This paper explains a way of the landscape design on a historical region, Maruyama Park., Kyoto. It has been a set of fine sites on the mountain foot since before the foundation, as well as in Edo era when each sites fostered unique architectures and gardens employing their terrain movements. In modem era, once these sites were divided into fragments, but the design operated by Jihei Ogawa in early Taisho era revived this region paying attention to the middle area. The design using the characteristics of their micro terrain movements, such as water streams, plantings, flexible path works, and restaurants surrounding garden., brought about continuity and accessibility of whole region, ambiguity of flames, and the traditional way to place people into the broad landscape with some caters has been kept.

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As an attempt to express the essential characteristics of inter-regional trade, we propose a demand forecasting model based on the analytical frameworks of inter-regional and inter-industry linkage analysis and the spatial price equilibrium model. This model seems to be useful in predicting inter-regional freight demands in conditions of semi-open and middle-term equilibrium. At the same time, we explain the kind of data to be considered for practical use, using a complementary model and an estimation of a model. Furthermore, we show an application results to motorway improvement project in Japan and we verify the applicability of our model.

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Effective segmentation for trip makers is indispensable for future transportation planning. This study aims to revise the designation of common segmentation that was proposed in 1999, and to show the real transformation of personal duration pattern in urban area. Based on the National Person Trip Surveys that have been executed in 1987, 1992 and 1999, trip makers are classified into 11 groups throughout 46 cities. The pattern of personal durations is strongly shifting to the car-dependent groups. It is also investigated that the land-use control is not direct, but one of the most effective methods to improve transportation environments.

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It is necessary to use a suitable model that represents induced traffic generated by new road in benefit estimation of road investment. In this paper we forecast the traffic flow and estimate the user benefits of a new road with combined network equilibrium model that can represent the induced traffic. This model gives consistent framework of demand forecasting and benefit estimation based upon economic theory. The model shows that the induced traffic by the new road is small in view of the overall area, but it affects heavily the traffic situation of new road and estimation of user benefit by comparison of traditional fixed demand model; traditional model overestimates the user benefit of road in-vestment in our application.

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Iron piles with screws (screw piles) had been developed from the middle of 19th century in European countries including Ireland and Great Britain applying to the foundations of bridges, lighthouses and jetties. Screw pile is iron or steel pile with cast iron screw at the bottom end to be propelled into ground due to torque introduced at the head. Screw pile was introduced into Japan at the beginning of Meiji Era and had been applied to bridge piers, foundation of lighthouse and jetties etc. In this paper the process of the development of screw piles in Modern Japan had been clarified and studied by examining the practical applications in Japan as well as European countries.

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The purpose of this study is to discuss relationships between spatial speed change characteristics, which are one of the traffic jam occurrence causes, and motorway alignments and/or facilities in sag sections. Running car experiments were carried out in section of about 45km of Chuo Expressway. In the running car experiments, speed, accelerator opening, and ruining position were collected. One of the results showed that speed drop in sag sections over long distance in upgrade section in which the traffic jam occurs frequently. The sag detection performance of a driver was high as sag with large algebraic difference in grades. Authors also discussed that a sag section might newly actualize to be a bottleneck after lane increase construction completion in this motorway section.

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