Journal of Infrastructure Systems

Research is a conscious and directed effort to increase understanding and discover new and better ways to achieve goals. Leading economists attribute a major share of the nation's economic growth since World War II to the results of scientific and engineering research and development (R & D) activities. Available evidence indicates that U.S. R & D spending for infrastructure is low, compared to the benefits that might be gained from improved infrastructure technology, as well as to spending rates in other sectors of the economy and in other industrialized nations. Several recent studies have proposed high-priority topics where greater R & D effort could yield substantial dividends. Some federal agencies and private-sector initiatives indicate that infrastructure R & D spending on these topics could increase. However, transfer of research results into practice is essential to justify such spending.

As documented in the World Development Report 1994 , infrastructure's links to economic development work through its contributions to economic growth, poverty alleviation, and environmental sustainability. These benefits are realized through the services infrastructure delivers. Widespread failures to provide reliable services that users demand stem from inadequate maintenance, misallocated investment, and inefficient operation, which in turn are largely rooted in institutional factors including the following: lack of competition in infrastructure service provision; lack of managerial autonomy for service providers; pricing practices that involve heavy public subsidies; and few incentives for service providers to be responsive to the needs of users. An opportunity to improve infrastructure's performance in developing countries is being created by technology change in some sectors, by successful experiments in many countries with new ways of providing services, and by a new willingness of many governments to involve the private sector in infrastructure provision. Improvements in infrastructure's performance has the potential to produce for developing countries $50 billion per year in efficiency gains and $123 billion dollars per year in fiscal revenue savings. Such amounts are large fractions of the $200 billion per year these countries currently invest in new infrastructure facilities.

An infrastructure-performance-deterioration model predicts the performance of infrastructure facilities such as bridges, railroad, and highways as a function of explanatory variables such as inherent infrastructure characteristics (material properties, construction quality), ambient climate, usage of the facility, etc. However, there is no unambiguous approach to measuring directly the performance of the facility, and hence we consider performance to be unobservable (latent). The problem of developing performance-deterioration models includes the definition of the aforementioned unobservable performance in terms of the measurable distress measures of the facility, and simultaneously relating the performance to the explanatory variables. In this paper, we extend previous research to include user costs (costs accruing to the users of the infrastructure facility) in the modeling framework. Hence, an integrated performance and user-cost model system is developed, and a case study is conducted on a highway example using data from Brazil compiled by the World Bank. Although, the case study is on highways, the methodology is general and applicable to any deteriorating facility with measurable distress measures and explanatory variables.

The present paper addresses the problem of assessing infrastructure condition using detailed spatial distress data. A new understanding of the spatial behavior of infrastructure distress is presented, and a condition assessment methodology commensurate with the identified behavior is developed. Two deterioration mechanisms are identified. The environmental mechanism describes deterioration as a consequence of causal factors and exhibits both macroscopic and microscopic scales. The interactive mechanism describes deterioration as a result of distress at a location influencing the deterioration of neighboring locations and exhibits a microscopic scale. A nonstationary stochastic spatial model that captures both mechanisms is proposed. Based on this model, a methodology founded on nonparametric cluster analysis and dynamic programming is developed to identify uniformly behaving regions (referred to as fields) within which condition can be estimated accurately. The results of the application of the methodology to a 15-km-long highway facility demonstrate the validity of the spatial model and emphasize the need for correctly identifying the uniform fields.

The efficient use of scarce resources for domestic water supply and sanitation is particularly vital in low-income countries. Conventional cost–benefit analysis gives an indication of the appropriateness of projects but often fails to reflect factors that cannot be assigned monetary values. A form of linear programming, data envelopment analysis, is used to measure a single-efficiency score for 10 water supply and sanitation projects in Ghana, relating noncommensurate technical, financial, economic, institutional, social, and environmental inputs to output factors of reliability, utilization, and convenience. Following the experiences of the Water Decade, the desired public-health benefits were deemed to follow from the utilization of reliable and convenient facilities. Results suggest that capital- and management-intensive projects for water supply in major cities are as efficient as community-based rural sanitation schemes based on pit latrines. Within these two extremes, many projects are failing to reach potential levels of efficiency; most significantly, rural boreholes fitted with handpumps, sewerage, and overengineered latrines.

The remediation of infrastructure systems represents a massive public-works effort that probably rivals past activities such as dam/canal building in the 1930s and the construction of the interstate system more recently. Every facet of construction (including materials, design, testing, installation, and inspection) will be brought into this effort and will even be challenged so as to expand the horizons of the respective technologies. Existing and newly developed technologies will both be included, and geosynthetics will have a role. Just how large of a role is yet to be seen as the total remediation effort unfolds. This paper presents the manner in which geosynthetics might be considered for various aspects of infrastructure remediation based upon the primary function that is being served. Once decided, some of the many applications involving geosynthetics in infrastructure remediation are presented. Obviously, not all applications can be included, but it is felt that the major ones currently available are described here. Hopefully, the paper will convey to the reader the wide range of infrastructure remediation applications that utilize geosynthetics and the important role that these materials can perform either by themselves or in a complimentary manner with other construction materials.