Journal of Infrastructure Systems

The study reported in this paper has been conducted to shed light on the use of life cycle cost analysis (LCCA) in municipal organizations. The major objectives of the study are to identify the sources of data used in LCCA, examine how cities assign values to the main parameters used in their calculations, explore the possible relationships between LCCA and value engineering, investigate the use of LCCA in the bidding and construction phases of a project, investigate the possible ways of improving the efficiency of LCCA, and define the major factors considered in assessing success in LCCA implementation. The findings indicate, among other things, that major sources of data include archives, computerized databases, and data obtained from other cities. The major criteria that cities consider when assessing the rate of success in LCCA implementation include the extent to which LCCA helps to optimize the total cost of owning and operating the physical assets, achieve lower maintenance costs, allow longer useful life, overcome the problem of limited funds, and achieve lower initial costs. For more successful LCCA implementation, cities are demanding formal guidelines that describe the method of utilization, published values for the different parameters used in LCCA, and the development of standard software.

Acoustic tomography is the art of imaging the internal structure of a specimen through the use of sound waves. In this research, the James Instruments, Inc., Chicago, velocity meter (v-meter) was examined for travel time measurement reliability. To help ensure that data collected for acoustic tomogram production were reliable, gauge potential studies were performed prior to data collection. A gauge potential study is a short-term statistical study that examines the measurement system's potential to be capable in the long term. The case studies indicated that the system does have the potential to be capable in the long term. Based on these results, a standard operating procedure was developed for the v-meter measurement system, and conclusions offered regarding the resolution of the tomograms produced. The U.S. Bureau of Mines 3DTOM software program was used to produce the acoustic tomograms.

The emergence of new technologies is largely dependent on critical examination of the current state of relevant technologies. Accordingly, this paper aims to present the latest advancements in the issues related to deep mixing technology when applied as a countermeasure against liquefaction. Various remedial measures based on the solidification concept are discussed. The basic issues related to various applications of deep mixing for liquefaction, design considerations, and seismic response analysis are examined. A number of case histories is presented, along with the latest progress in new pertinent technologies currently under investigation in Japan. A conceptual framework is proposed for liquefaction mitigation of existing structures. The research needed for further investigation using deep mixing technology for liquefaction is summarized.

Fault tree analysis is a systematic method of analyzing events that lead to an undesirable event. Fault trees can be used to assess the probability of failure of a system (or top event), to compare design alternatives, to identify critical events that will significantly contribute to the occurrence of the top event, and to determine the sensitivity of the probability of failure of the top event to various contributions of basic events. In this paper, fault tree analysis is used to determine the probability of failure of a bridge due to scour and other geomorphic channel instabilities. This analysis permits an examination of a very complex system of interactions and processes that are not well understood. Minimal knowledge regarding the actual processes of scour and channel instability is required for a fault tree analysis. Three examples of analyses for actual bridges are provided showing different combinations of scour (local and contraction) and geomorphic instabilities (channel widening and degradation) at both the abutments and piers. Riprap placed at the abutments for protection is also included in the analyses.