Showing papers in "Journal of Infrastructure Systems in 1997"

Probabilistic Infrastructure Deterioration Models with Panel Data

Abstract: Statistical models of infrastructure facility deterioration are typically estimated using panel data sets of in-service facilities. For example, biannual ratings of bridges have been used to develop discrete models of component deterioration by a number of researchers. Unfortunately, these models have not accounted for the presence of heterogeneity in the panel data, which may lead to biased coefficient estimates. Furthermore, researchers have usually imposed a Markovian specification in the development of such models, implying that the probabilistic deterioration in a given period is independent of history. This assumption may be unrealistic for some types of facilities in which early distress initiation leads to accelerated deterioration in later stages of their lives. In this paper, we adopt a random-effects specification to control for heterogeneity in a probit model of bridge-deck deterioration and extend the model to investigate the presence of state dependence. The proposed model yields improved results in comparison with a simple probit model and provides evidence that is inconsistent with the Markovian assumption in bridge-deck deterioration. An implication of this study is that both heterogeneity and state dependence may need to be accounted for in developing probabilistic infrastructure deterioration models.

Life-Cycle Costs of New Construction Materials

Abstract: New high-performance construction materials are being developed for transportation structures. Economic methods are needed for assessing the life-cycle cost advantages and disadvantages of these new materials relative to conventional materials. This paper provides a step-by-step, project-based approach based on life-cycle costing, minimum performance requirements, and a cost classification scheme that organizes a construction material's life-cycle cost advantages and disadvantages. A case study example of the method analyzes the cost effectiveness of fiber-reinforced-polymer bridge decks relative to reinforced concrete decks.

Fault-tree model of bridge element deterioration due to interaction

Abstract: Bridge engineers and bridge inspectors recognize that deterioration of one element influences the deterioration of another. The effect of this phenomenon may be crititcal if it increases the deterioration rate of the affected elements. The phenomenon is known as element interaction. The consequences of element interaction can help to explain why elements of the same type have varying deterioration rates. No practical model exists for modeling element interaction. This paper presents the use of a fault tree for qualitative and quantitative evaluation of element interaction phenomena. The fault-tree results can be used to better assess the deterioration rate and improve deterioration prediction of an element. An example of the fault-tree model for accelerated deterioration of concrete bridge decks is presented. The fault-tree model is not a deterioration model, but can be used to focus on mitigating accelerated element deterioration by certain maintenance or repair actions. Systematic implementation of the fault-tree approach presented herein must be preceded by field verification.

Fuzzy set-based and performance-oriented pavement network optimization system

Abstract: The objective of the current network optimization system (NOS) model used in Arizona is to minimize annual pavement preservation cost over the planning period. This paper presents an alternative NOS model with the objective of maximizing pavement performance. In addition, fuzzy set representations for different pavement factors are introduced to determine the pavement performance ratings for various pavement condition states, which are necessary to generate the objective function. In this performance-oriented NOS, a uniform annual budget is used as a constraint. This NOS model simulates a possible scenario of a state department of transportation (DOT) for effectively using a given budget in the planning period. The pavement network's performance is maximized for the allocated budget. Necessary minimum annual budgets are analyzed for various pavement performance requirements. A rational annual budget for the needed pavement performance standards can be obtained, which may be used as decision support data for future budget allocations. The research shows that the level of annual budget is very sensitive to variations of the required proportion of pavement in the low roughness requirement, when this proportion is higher than 0.91. A small increase of the proportion of pavement in low roughness significantly increases for annual budget needs. A requirement for low cracking has less effect on the needed annual budget.

Selection Method for Trenchless Technologies

Abstract: Trenchless technologies offer contractors and end users (primarily municipalities) a broad spectrum of tools from which to select when installing or rehabilitating underground infrastructure. Due to the large and expanding number of trenchless methods available, the decision as to which tool to use for any given underground infrastructure problem is no longer trivial. Trenchless methods allow inspection, access, repair, expansion, upgrade, and installation of most underground infrastructure systems with minimum surface disruption. The tools that trenchless technologies offer range from robots to microtunnelling and from closed-circuit television to cured in-place lining. Each tool has its proper application. Inappropriate selection of trenchless tools can lead to inferior performance of the infrastructure system and poor cost-benefit ratios for the investment. This paper presents a paradigm that provides the user an efficient synthesis of needs and methods that can be of use when selecting trenchless cons...

Transportation Infrastructure Financing: Evaluation of Alternatives

Abstract: As part of the transportation infrastructure modernization program, a 24-km Colombo-Katunayake Expressway (CKE), is being envisaged between the Colombo International Airport (CIA) and the city center. The Road Development Authority (RDA) has identified an alignment for the facility, which would become the nation’s first access controlled road toll. However, the RDA, whose total annual budget is $100,000,000, must seek funds from nontraditional sources to initiate this estimated $90,000,000 project. This paper presents the findings of a financial viability and investment risk analysis of CKE under different financing options. Four of the financing options available to the RDA are discussed in light of experience with privately financed roads elsewhere. The sensitivity of the project’s financial returns and risk to variables governing cash flows under the four options are tested using the Monte Carlo simulation. It is shown that expected demand and project cost have a profound effect on return and risk. Thus, it is concluded that the project can only materialize either as a joint venture with a large equity stake from the government or as a public facility.

Particle transport in soils: review of significant processes in infrastructure systems

Abstract: Fine-particle transport in porous media affects performance of civil infrastructure in a number of diverse disciplines. The particle transport processes that are important in infrastructure systems are (1) wastewater filtration; (2) clogging of soil and geotextile filters used as liners for protection of subsurface and aboveground structures; (3) erosion and piping in earth dams; and (4) facilitated transport of contaminants in the subsurface. While particle release from soils is the primary focus in some areas, their transport and subsequent entrapment are important in others. In this paper, research developments on particle transport are reviewed in each of these areas and the cross-cutting nature of the fine-particle transport problem is demonstrated. The need for synthesis of research developments in the individual areas is assessed considering the emerging developments in geoenvironmental engineering. The challenges associated with integrating the research developments are pointed out.

Network-Level Bridge Life-Cycle Management System

Abstract: In existing bridge management systems, the information on one stage in the life cycle of a bridge is not efficiently used in other stages, which results in much waste in time and effort. In this paper, a new type of bridge life-cycle management system is developed to overcome this problem. The system integrates geographic information, design data, inspection and maintenance data, earthquake data, and image data in a user-friendly environment. These improvements make it possible to use the system during the entire bridge life cycle, from the planning stage to the demolition stage, as discussed here. Several applications of this system are discussed, which include location selection, condition assessment, maintenance plan optimization, and spatial retrieval.

Multistage heuristic approach for solving infrastructure investment decision problems

Abstract: The solution of an infrastructure investment decision problem is highly complex. The mathematical model developed in this paper represents the investment decision as a 0-1, nonlinear, multiobjective knapsack selection problem that discourages straightforward, exhaustive solving approaches because of high computational complexity. This paper introduces a staged heuristic approach to tackle this problem. The practical significance of the proposed approach is twofold, including (1) the inclusion of the gray relation concept for determining the rank order among alternatives; and (2) the introduction of a set of heuristics for alternative selection for removing the nonlinearity in the investment problem. Based on experience of implementing this approach in real-life problems, both the computational effort required and the quality of the results are satisfactory. It is suggested that the proposed approach be implemented by public agencies responsible for routine infrastructure investment decisions.

Designing Network Partitions to Improve Maintenance Routing

Abstract: The problem of designing districts for winter maintenance operations for a state department of transportation (DOT) is considered in this study. Many maintenance activities, including snow removal, are routed to serve demands at the edges of the road network. Requirements of the routing operations must be taken into consideration while designing service districts. The problem of maintenance district design was formulated as a mixed integer linear program structured to integrate a simple yet effective route design strategy with the location allocation components associated with district design. Compared with earlier models, this model estimates deadhead (travel with no service provided) and required number of routes more accurately. Existing service districts are redesigned using this model, and the effectiveness of this methodology in designing maintenance districts that better support route design is demonstrated.

Comprehensive Level of Service: Needed Approach for Civil Infrastructure Systems

Abstract: Levels of Service for infrastructure systems should be defined in terms of both capacity (Level of Availability) and maintenance (Level of Operation). Levels of Service for a highway system consider capacity, but assume good pavement conditions. This neglects the effect that deferred maintenance could have on a reduction of capacity. Likewise, maintenance Levels of Service definitions, although serving as trigger points for accomplishing maintenance activities, do not consider the impact that deferring or failing to accomplish maintenance has on highway capacity. A Comprehensive Level of Service is thus defined and modeled to account for both the impact of deferred maintenance and highway obsolescence, which is defined as the inability of a highway system to carry traffic volume as designed. A system dynamics approach is taken because of the complex nature of the problem and the feedback loops that are developed with the interrelationships between the Comprehensive Level of Service and the effect on the socioeconomic system. The model variables and parameters form the basis for a targeted data collection effort for defining a management information system that will aid future decision making concerning transportation system maintenance and construction programs.

Condition Assessment of Water Supply Infrastructure

Abstract: A capacity-weighted reliability surface is suggested as a tool to assess the condition of deteriorating water supply infrastructure. A method is developed for calculating the spatial variation in reliability throughout a water distribution network. The method considers the reliability to meet demands at nodes to depend on the reliability and hydraulic capacity of all the network elements leading from the sources. Using a measure of network connectivity, point values of the reliability of water supply at demand nodes are calculated. An efficient algorithm is developed to adjust these point values in order to account for the carrying capacities of the components linking the source of water to the demand points. The adjusted values are then contoured to define the reliability surface. The surface may be used as an aid for prioritizing the maintenance and rehabilitation of the water distribution network.

Vehicle size and weight regulations and highway infrastructure management

Abstract: The relevance and important implications of regulations governing the sizes and weights of heavy vehicles in highway infrastructure management are presented. A procedure for evaluating the infrastructure impacts, trucking productivity, and highway cost-allocation implications of alternative truck weight limits and enforcement options is presented. The procedure uses a weight-prediction methodology that resolves some major uncertainties from the regulatory standpoint respecting input variables required to provide the technical basis to support policy regulatory and infrastructure management decisions. The regulations represent the core of transport policies relating to trucking productivity, infrastructure provision, and management. Any revisions in the size and weight limits are reflected in truck fleet, operating weights, and volumes, which in turn affect the infrastructure geometric requirements, loadings, maintenance, and rehabilitation intervention levels. The proposed evaluation approach allows regulatory and weight-control policies that are compatible with the existing infrastructure capabilities to be developed.

Infrastructure and economic development : Airport capacity in Chicago region, 2001-18

Abstract: An attempt is made to establish a relationship between airport capacity and economic development in the Chicago metropolitan area. Formulating a quantitative link between infrastructure and development has proven difficult. In the analysis adopted in this paper, an association between employment growth and airport enplanements is used to provide the link. The employment data are then fed into an econometric input-output model of the region's economy to assess the impact of future capacity limitations on employment, growth, income, and gross output in the Chicago region over the period 2001-2018. The capacity is assumed to be disembodied (there is no prior assumption about expansion of existing facilities or the creation of a new, third airport). The results indicate that without additional capacity, employment losses (jobs that would otherwise have been expected to be located in the region) would amount to 84,000 in 2001 (2.24% of estimated jobs for that year) rising to 522,000 in 2018 (11% of total jobs). In income terms, the losses amount to 13.6% of total income in 2018, while gross output (the volume of goods and services produced) would be reduced by 16% in the same year.

Installation Status Report

Abstract: The U.S. Army maintains more than 200 installations within the 50 states and another 95 overseas. However, money has been shifted from maintenance of facilities on these installations to training and the support of operations such as those currently under way in Bosnia. Some estimates are that there will be in excess of $5.1 billion in backlogged repair and maintenance projects on U.S. Army installations by the end of fiscal year 1997. Thus, the Installation Status Report (ISR) was developed to categorize installation facilities that were deficient, develop funding requests for Congress, and to allow the installations to better articulate their needs to the Department of the Army (DA). ISR results are used to provide a nontechnical evaluation of current installation readiness. This is significant in that it was developed to help policymakers to understand the status of the installations. The ISR has proven to be a major success. The DA has been able to use ISR to articulate the needs and costs to Congress...

Forecasts of funding needs for infrastructure renewal

Abstract: The objective of the work from which this paper was derived included the development of a construction estimating technique for preparing long term cost and timing forecasts of funding needs for renewal of constructed infrastructure. The work was undertaken with the aim of improving a rational preparation technique for adequate user fee policies and providing justification for their use. In addition, as opposed to preparation by other types of professionals, this technique was primarily focused on the particular contributions that experienced construction estimators could make to this process. The paper describes procedures for conversion of construction cost estimates to renewal cost estimates, in a form that can be correlated with data on the service life of components; a tool that accounts for multiple cyclic occurrences of renewal event costs; the generation of time serial forecasts for yearly renewal costs; and forecasts of needed revenue recovery rates for renewal construction. This estimating technique is meant to improve the financial effectiveness, performance, and reliability of the many different types of civil and private facilities to which it could be applied.

Performance testing of trenchless wastewater line spot repairs

Abstract: The University of Texas at Austin conducted a study for the City of Austin to evaluate the performance of commercially available trenchless spot-repair methods in the City's wastewater pipelines. This paper reports short-term testing procedures and results for two epoxy resin repair methods that were a part of the study. Both methods of repair were proposed by the City of Austin Department of Water and Wastewater, and were field demonstrated in Austin on 200-mm (8-in.) unreinforced concrete wastewater lines. Each process uses remote control, cured-in-place techniques: one method employs a robot to prepare substrate surfaces and to inject epoxy into pipe defects; the other employs an inflatable rubber packer to form a continuous epoxy collar up to 0.6 m in length at the defect. The objective of the study was to evaluate and compare, by field sampling and laboratory testing, the structural integrity and watertightness of the repair processes. A small number of repair samples were obtained by excavation of a...

Resource Allocation for Army Installation Management

Abstract: Given the recent decreases in the defense budget, unfunded contingency operations, aging military infrastructure, and restationing of overseas troops to within the continental United States, milita...

Issues in Building the European High-Speed Train Network

Abstract: A European high-speed train network is profitable from a collective point of view. But the schemes devised by the European Union seem to be much too ambitious, and should be carefully fine-tuned. The project encounters difficulties on the grounds of interoperability between countries and funding, as the financial rates of return of the projects are lower than their collective rates of return. Anyway, a major issue will be to foster competition to increase the creation of new services. A means to go in that direction would be to decrease the scale of franchised services, and to attribute paths through systematic auction bidding. A unique European regulator is desirable, but it is not clear whether new tracks should be built and managed by the incumbent infrastructure operators through some kind of private financing and bidding process.

Airline planning and marketing in a changing environment. viewpoint

Abstract: Airlines are very competitive and dynamic, and maintaining a profit in this environment can be extremely challenging. Airlines have forged ahead of other industries, though, in embracing operations research and information technology. Changes in the air traffic control environment and in planning and marketing can have pronounced or subtle impacts on the airline industry. The authors view the changes ahead for the airline industry based on national route program (NRP) expansion, collaborative decision making (CDM), and free flight. The authors explain how airline planning and marketing define an airline's products and the selling process. The impact of air traffic control changes on airline planning and marketing is discussed also. Free flight, as well as NRP and CDM, should improve airline efficiency and reduce flight times.

Optimal Design for Automatic Control of On-Demand Canal Systems

Abstract: A methodology is developed for the design of an automatic gate controller for an on-demand canal system. The design is based on the EL-FLO plus RESET control concept developed previously by the U.S. Bureau of Reclamation. Two additional design parameters are included in this study to ensure a smooth upstream gate operation. The basic design parameters are optimized to achieve a stable flow condition in the entire canal system where multiple gates are operated to supply water to meet unexpected turnout demands along the canal. Due to the complexity involved in canal hydraulics, the optimization model is highly nonlinear. Decomposition allied with successive approximations is used for solution. The proposed design methodology, when applied to a section of the Caraibas Project in northeastern Brazil, showed that the proposed methodology is successful in minimizing hydraulic transients in a multipool canal system. A sensitivity analysis of the optimal design is conducted with respect to maximum demand level and the two new design parameters.

Congressional response to fragile foundations: analysis of congressional infrastructure legislation introduced since 1988

Abstract: In 1988, the National Council on Public Works Improvement (NCPWI) issued a report, which made various recommendations with respect to national infrastructure policy. The recommendations included a commitment to double current spending, rational capital budgeting at the federal level, and incentives for better financing and management of public works investments. NCPWI's report was especially notable because Con­ gress created the commission and asked for its views. The present paper analyzes Congressional legislation submitted since the issuance of the report and assesses the degree to which Congress responded to the guidance contained within the report. The analysis shows that there were many bills submitted that picked up the rec­ ommendations, but none of these bills passed, indicating a lack of national consensus around these issues. The only major bill that did pass and that did contain some of the ideas pondered by NCPWI was the Intermodal Surface Transportation Efficiency Act (ISTEA), indicating that while transportation has coherence as a national concern, infrastructure does not yet have that full-blown identity at the Congressional level.

Infrastructure obsolescence and design service life. discussion and closure

Abstract: A discussion of a paper with the aforementioned title by A.C. Lemer, published in this journal (Volume 2, Number 4, December 1996), is presented. The discussion maintains that the full costs or disbenefits of final disposition of resources used in infrastructure are not accounted for in society's infrastructure planning and management decision making and suggests that infrastructure obsolescence and replacement strategies should also be considered from the viewpoint of sustainable development. Discussion is followed by closure from the author.

VIEWPOINT: Infrastructure Renewal Requires More Than Money, Political Will, and Commitment

Abstract: Dr. Ralph Haas is The Nonnan W. McLeod Engineering Professor at the University of Waterloo, Ontario, Canada, and past chainnan of its Department of Civil Engineering. He is also a founding partner and honorary chainnan of the ITX Stanley Inc. group of infrastructure consultants. Haas has been elected to the Canadian Academy of Engineering and is a Fellow of the Canadian Society of Civil Engineering. He has also been honored as a Distinguished Alumnus of the University of Alberta's Faculty of Engineering. He is a member of ASCE and serves on the editorial board of the Journal of Infrastructure Systems. In addition to an extensive consulting and lecturing career in many countries around the world, Haas has chaired the Pavement Management Committee of the Transportation Research Board and the Pavements Technical Committee of the Transportation Association of Canada. Currently, he is chainnan of the International Society for Asphalt Pavements, and serves on a number of other professional bodies, councils, and committees. In 1994 he chaired the Third International Conference on Managing Pavements in San Antonio, Tex., and will cochair the Fourth Conference in Durban, South Africa, in 1988. Haas has published extensively, including 10 coauthored books and monographs, about 300 technical papers, and more than 150 major technical reports.

Loads for Fatigue Life Assessment of Gates at Navigation Locks

Abstract: The U.S. inland navigation infrastructure is deteriorating primarily due to the aging of its components and the operation at near to full capacity of the system’s structures. Gates at navigation locks play an integral part in keeping navigation traffic continuously moving, and their reliability is essential to the navigation infrastructure. Assessments of fatigue reliability as a function of time for existing gates at navigation locks require knowledge of loading cycles. This assessment can contribute to the economic evaluation of the remaining fatigue life of critical fatigue details in gates. The accuracy of this assessment depends in part on the accuracy of the loading cycles used in the reliability analysis. Water elevations from hydraulic records were used to compute water-head differentials on the miter gates. Loading or hardware cycles were obtained from the U.S. Army Corps of Engineers (USACE) lock performance monitoring system (LPMS) and were then combined with head differential to obtain loading histograms for the gates. These histograms are needed to successfully perform fatigue reliability analyses. A probabilistic model was also developed for predicting the number of loading or hardware cycles for the gates. This paper includes an example to demonstrate the suggested methods and models for fatigue reliability assessment.