Neville A Parker

LIFE-CYCLE COST ANALYSIS: STATE OF THE PRACTICE VERSUS STATE OF THE ART

Life-cycle cost analysis (LCCA) is increasingly gaining recognition by the transportation community as an indispensable practice if the sustainability of its infrastructure systems is to be realized. The product of a 3-year study that assessed the LCCA practice in state highway agencies (SHAs) is presented. The study examined how LCCA practice changed in two decades, surveyed the way LCCA is practiced currently at SHAs in the United States, and reviewed how this evaluation technique is deliberated by the academics and researchers in the engineering and economics domains. Results of this study prove noteworthy in the inspection of an observed gap between the state of the practice and state of the art of LCCA. After all, that gap set up grounds for the noted mistrust in the credibility of LCCA. In addition to study results, an analysis of the observed gap and its causes is presented as well as recommendations for what can be done to bridge that gap. It is hoped that this will prove valuable for practitioners conducting LCCA, for policy makers, and for researchers carrying out studies on various topics related to LCCA.

Evaluation of Performance of Permanent Pavement Markings

As an implementation strategy of the federal retroreflectivity standards requirement for pavement markings, the New Jersey Department of Transportation (DOT) evaluated its 3-year fixed-schedule restriping strategy, to determine if it is consistent with the actual service life of the pavement markings. The methodology and results of the study are presented. Two types of data were collected: measured retroreflectivity by using LaserLux and subjective ratings from a survey conducted with the participation of the New Jersey driving public along a 32-mi circuit. Multiple regression techniques were used to correlate the average scores reported by the study participants for each specific roadway section with the corresponding measured retroreflectivity. The results suggested that the threshold value of an acceptable versus unacceptable level of retroreflectivity appeared to be between 80 and 130 mcd/m2/lux for New Jersey drivers younger than 55 and between 120 and 165 mcd/m2/lux for drivers older than 55. These results are consistent with conclusions reached by other investigators in similar research, where results generally ranged between 70 and 170 mcd/m2/lux. Interim visibility indices were developed for each age group per pavement-marking type. New Jersey DOT used the indices to determine and prioritize needs and to quantify needed related resources, on the basis of the threshold between acceptable retroreflectivity and unacceptable retroreflectivity, when it developed its pavement-marking management system. This approach also allows for cost-benefit and life-cycle analysis for different pavementmarking materials.

Application of Nondestructive Evaluation to Subway Tunnel Systems

Subway tunnel condition assessment presents significant challenges for engineers and managers and is becoming increasingly important as the systems continue to age. Tunnels are in constant heavy use in an aggressive environment. Tunnel systems are vast, dark, and noisy. The national investment in subway tunnels is enormous, and careful maintenance and management are necessary to protect this investment. Technologies that can rapidly and accurately access the condition of subway tunnels without interfering with the normal operation of the system were studied. First, issues and problems in subway tunnel maintenance were reviewed through the literature and by interviewing transit agency managers and engineers. Next, different nondestructive evaluation (NDE) methods including spectral analysis of surface waves, impact echo, ground-penetrating radar, and impulse response were evaluated to determine the advantages and limitations of these methods on different problems like water leakage, corrosion, and cracks in subway tunnel systems. Issues of data and infrastructure management were also considered. NDE technologies have considerable potential for improving the maintenance and management of transit infrastructure. However, to fully realize that potential, further development is needed. It is necessary to distinguish between methods that require interruption of subway traffic from those that do not. Rapid screening NDE methods must be researched to develop clear signals of delamination, moisture-related damage, and other issues of concern. It is also necessary to develop automated procedures to process the vast amounts of data generated during extensive NDE testing. Case studies and demonstration projects must be developed and documented to convince managers of the utility of this approach.

USING TIME SERIES TO INCORPORATE SEASONAL VARIATIONS IN PAVEMENT DESIGN

Analysis of the seasonal monitoring program data of the long term pavement performance program indicated that some pavement structural properties often follow predictable seasonal patterns. Time series is a statistical technique that may be used to develop periodic functions to predict the values of such properties as a function of time. The application of time series technique in characterizing the seasonal variations of pavement structural properties as simulated functions is presented. In addition, the incorporation of such variations in both empirical and mechanistic-empirical methods of flexible pavement design is demonstrated. To this end, a computer program, seasonal variation in pavement design, was written to carry out the required calculations and to facilitate the comparison between empirical and mechanistic-empirical design methods.

Mechanics of Small Utility Cuts in Urban Street Pavements: Implications for Restoration

The results of a three-dimensional finite element analysis of the impacts of small utility cuts in urban street pavements are presented. The analysis was restricted to flexible pavements for cuts of the order of 915 mm (3 ft) square. Using ANSYS Solid 45 Version 5.2 on a one-eighth area, the excavation process was simulated using a stress relief approach, in which the material was assumed to be removed in successive layers. Starting with gravity loading on the uncut model, the element stress results from the previous removal were used to compute the new effective confining stresses of the respective layers. The in situ material properties were typical of flexible pavements in an urban street. The analysis presented a clear picture of the magnitude and extent of the distress induced on the pavement structure below and surrounding the cut. The analysis also showed how the restraining action of the asphalt layer is reflected in its arching up from heave and granular material thrusting, causing tension at the bottom and compression at the top. The results suggested that for unsupported depths of up to 1524 mm (5 ft), material distress may extend approximately 1068 mm (3.5 ft) into the pavement structure. Implications for methodology and economics of restoration are discussed, including determination of optimum cutback and recompaction of the affected area of pavement.

Building a Community Information System for Supporting Disabled Bus Riders and Local Businesses

This paper discusses the implementation of one type of information system for the New York City bus transit service, as a case study to provide value-added transportation services for people with impaired mobility. Information technology is a key tool for finding flexible transportation services, especially for disabled people. Useful information supplies psychological reassurance to these vulnerable people to make them feel more safe and secure. Residents in metropolitan areas increasingly rely on the convenience of public transportation, and they are becoming used to exchanging information relevant to their regional community in on-line settings. The improvement to transit accessibility needs the exact same type of the cooperation between transportation companies, local business, and residents. The widespread use of mobile wheelchairs has a socioeconomic impact. The significance of this research for the longer-term goals lies in its implications for adaptation of this kind of intelligent model into future welfare or assistive activities.

A real-time integrated transport/communication/database architecture to support traffic simulation

This research aims for an establishment of a global center that will advance the knowledge in real-time human and goods transport. The focus of this paper is an approach for addressing the performance and feasibility issues with respect to a reliable and distributed traffic data communication network for optimal and secure routing of traffic. We present communications and database modeling for data acquisition via a high performance system. The proposed architecture is distributed, survivable, and reliable, thus capable of handling stationary and mobile sources of communication systems and integrating databases and dynamic traffic assignment into one comprehensive model. A case study on a visual interactive system for transport algorithms is discussed.

Construction quality effects on pavement asset preservation and valuation: A mechanistic-empirical performance-based LCCA approach

Direct computation of life cycle cost consequences of as-constructed—as opposed to as-designed—quality measures, is presented as a basis for developing the pro-forma financial statements necessary for managing highway pavements as assets. The current and next-generation mechanistic-empirical pavement design and analysis models, combined with the development of easily deployable non-destructive testing technologies, increase the feasibility of estimating the combined effects of variations in the in-situ material properties that influence pavement quality and performance. These models can be deployed to develop the inputs to financial statements. In the process, one can not only develop a framework for monitoring financial health over any given performance period, but also estimate the difference between the life cycle costs associated with the as-designed and as-built pavement, which can in turn, provide a basis for determining contractor penalties or bonuses, suggested here as being an important component of pavement asset management.

Using NDE to Evaluate the Condition of Subway Tunnel Systems

Subway tunnel condition assessment presents significant challenges for engineers, and is becoming increasingly important as the systems continue to age. Technologies are needed that can rapidly and accurately assess the condition of subway tunnels, and identify distress such as delamination, moisture-related damage, without interfering with the normal operation of the system. Towards this goal, different nondestructive evaluation methods including SASW, Impact Echo, GPR, and Impulse Response were evaluated to determine their advantages and limitations for tunnel evaluation. Since tunnels are in constant heavy use in an aggressive environment, it is necessary to distinguish between methods that can be used for high speed screening, and those that require interruption of subway traffic. It is also necessary to develop automated procedures to process the vast amounts of data generated during extensive NDE testing. Introduction and Problem Statement There is an increasing need for better methods to evaluate the integrity of transit infrastructure. Some transit infrastructure, particularly rail transit tunnels and underground structures, is over 100 years old. While the risk of collapse may be remote, there is a possibility of injury to the public and/or significant service interruption caused by falling concrete, loose reinforcing bars, and leakage. Traditional destructive techniques, such as coring, and currently used non-destructive techniques, such as hammer sounding, are time consuming, cover limited area, and have limited effectiveness in identifying possible sites of deterioration. 1 Department of Civil and Environmental Engineering, The University of Alabama at Birmingham, 1075 13 ~ Street South, Suite 120, Birmingham, Alabama 35294-4440 2 Department of Civil Engineering, School of Engineering, The City College of New York NYC 100M 3 Civil Engineering Department, Cleveland State University, Cleveland, Ohio 44115-2440 4 412 S. Peoria, Suite 340, Urban Transportation Center (MC 357), University of Illinois at Chicago 5 Department of Civil & Environmental Engineering, Rhodes 730, PO Box 210071, Cincinnati, OH 45221-0071