Journal of Infrastructure Systems

The performance of the surface zone of concrete is acknowledged as a major factor governing the rate of deterioration of reinforced concrete structures because it provides the only barrier to the ingress of water containing dissolved ionic species such as chlorides, which ultimately initiate corrosion of the reinforcement. In situ monitoring of cover-zone concrete is therefore critical in attempting to make realistic predictions as to the in-service performance of the structure. To this end, this paper presents developments in a remote interrogation system to allow for continuous, real-time monitoring of the cover-zone concrete from an office setting. Use is made of a multi electrode array embedded within cover-zone concrete to acquire discretized electrical resistivity and temperature measurements, with both parameters monitored spatially and temporally. On-site instrumentation, which allows for the remote interrogation of concrete samples placed at a marine exposure site, is detailed together with data handling and processing procedures. Site measurements highlight the influence of temperature on electrical resistivity and an Arrhenius-based temperature correction protocol is developed using on-site measurements to standardize resistivity data to a reference temperature; this is an advancement over the use of laboratory-based procedures. The testing methodology and interrogation system represent a robust, low-cost, and high-value technique that could be deployed for intelligent monitoring of reinforced concrete structures.

Pavement rehabilitation is one of the most critical and costly forms of infrastructure asset management. Yet determining the subsequent performance of rehabilitated pavements is a complex task, particularly when multiple performance measures such as roughness, surface deformation, and structural integrity are considered. The complexity arises in part because of the interrelation among these performance measures and the fact that data relating to factors known to affect these measures may not be available. This paper seeks to demonstrate an appropriate methodological approach for studying the postrehabilitation performance of pavements using data from rural interstate roads in Indiana. Specifically, a random parameters seemingly unrelated equations approach is applied to explicitly account for the cross-equation correlation that exists among pavement-performance measures and the underlying heterogeneity across observations caused by imperfect data. The results provide some new insights into the interrelationships among the pavement rehabilitation treatments considered, pavement performance, traffic loads and trucks, weather and soil conditions, and rehabilitation expenditures.

This paper presents an approach to address pavement management decision problems at airports with multiple runways. It relaxes some of the underlying assumptions made in previous studies and explicitly considers time requirements for runway reconstruction, deterioration dependence on traffic levels, and the growth of traffic demand over time. A finite-horizon dynamic program is formulated to investigate the interplays among maintenance and repair (M&R) action time, functional interdependence between runways, and traffic growth. Results from computational studies reveal these interplays, in particular the tradeoff between present M&R action and delay cost and long-term benefits brought by significantly upgrading pavement conditions through reconstructing runways. Sensitivity analyses suggest that baseline demand, demand growth rate, and the parameter differentiating traffic-dependent transition probabilities significantly affect optimal M&R decisions and total expected cost to go.

Many cities in urban and suburban areas are characterized by parking space problems, especially during peak hours and special events. To overcome these problems, some local governments initiate on-street short-term pay programs to limit lengths of stay and generate revenue. The problem lies in determining which data should be collected, how frequently, and for how long to produce significant results. This study applied power analysis in analyzing rate of turnover and utilization levels to develop optimum data collection using license plate surveying methodology. A case involving downtown areas, shopping centers, and beach parks is presented. Analysis evaluated the probability of detecting desired changes, minimum detectable changes (MDC), and coefficient of variation (CV) for different data monitoring frequencies over desired data collection periods. Three critical license plate monitoring intervals for downtown parking were identified to be between 5–20 min, 30–40 min, and 40–60 min, with each group having different characteristics compared with others. There was a slight overlap in transitional monitoring time intervals. Analysis found that, to detect all possible optimal parking characteristics and cost-efficient surveying, license plates should be monitored at intervals less than every 30 min for downtown and 60 min for beach parks.

Presented in this paper are the results of a state-of-the-practice survey on the rehabilitation of water distribution and wastewater collection systems. The survey identified several needs, including the need for rational and common design approaches for rehabilitation systems, quality assurance/quality control procedures and acceptance testing during installation of rehabilitation systems, and decision support tools for choosing rehabilitation/rehabilitation systems versus replacement. Discussed are separate issues for water and wastewater systems in terms of drivers for increased rehabilitation efforts and problems typically encountered. Also examined are the major technologies currently in use and the major issues and key challenges faced in terms of speeding rehabilitation efforts and documenting/improving the performance of the technologies used.

All over the world, limited funding for the development and operation of infrastructure projects propels governments to attract private investment and enter public–private partnerships (PPPs). Different types of PPPs have been practiced in infrastructure development in both developed and developing countries, with diverse results. Although PPPs have many advantages, they involve some complexities in planning, execution, and monitoring and control that vary according to specific project and country conditions. This paper provides a case study of the Tehran–Chalus Toll Road project, one of the largest highway projects in Iran. The authors analyze the contract organization of the PPP project, identify the most important risks, compare the project’s organization with successful and unsuccessful experiences in similar PPP projects, and suggest ways to improve risk allocation to achieve better project performance for this and other PPP projects in developing countries.

In November 2005, the state government of São Paulo, Brazil, announced the intention to bid a 30-year contract to build, operate, and explore passenger services for the Metro Line 4 of the São Paulo Metropolitan Subway System. Given the high risk of the project, to attract private investors the bid documents stipulated that the government would offer risk-mitigation mechanisms such as subsidy payments and a minimum demand guarantee (MDG). Because an MDG has option-like characteristics, the real-options approach is used to analyze the effect of these incentives on the value and the risk of the Metro Line 4 concession project, and their cost and risk to the government. The results indicate that the incentives proposed are effective in reducing the risk, and increase the net value of the project by 36% at a cost to the government of 5% of the total value of the project. Additionally, it is shown that for a given cost, the most effective risk-reduction mechanisms are the ones that include a higher portion of minimum demand guarantees relative to the subsidy payment. The approach developed can assist transportation authorities in designing optimal incentive mechanisms.