On The Spot Damage Detection Methodology for Highway Bridges, July 2010

Vibration-based damage identification (VBDI) techniques have been developed in part to address the problems associated with an aging civil infrastructure. To assess the potential of VBDI as it applies to highway bridges in Iowa, three applications of VBDI techniques were considered in this study: numerical simulation, laboratory structures, and field structures. VBDI techniques were found to be highly capable of locating and quantifying damage in numerical simulations. These same techniques were found to be accurate in locating various types of damage in a laboratory setting with actual structures. Although there is the potential for these techniques to quantify damage in a laboratory setting, the ability of the methods to quantify low-level damage in the laboratory is not robust. When applying these techniques to an actual bridge, it was found that some traditional applications of VBDI methods are capable of describing the global behavior of the structure but are most likely not suited for the identification of typical damage scenarios found in civil infrastructure. Measurement noise, boundary conditions, complications due to substructures and multiple material types, and transducer sensitivity make it very difficult for present VBDI techniques to identify, much less quantify, highly localized damage (such as small cracks and minor changes in thickness). However, while investigating VBDI techniques in the field, it was found that if the frequency-domain response of the structure can be generated from operating traffic load, the structural response can be animated and used to develop a holistic view of the bridge’s response to various automobile loadings. By animating the response of a field bridge, concrete cracking (in the abutment and deck) was correlated with structural motion and problem frequencies (i.e., those that cause significant torsion or tension-compression at beam ends) were identified. Furthermore, a frequency-domain study of operational traffic was used to identify both common and extreme frequencies for a given structure and loading. Common traffic frequencies can be compared to problem frequencies so that cost-effective, preventative solutions (either structural or usage-based) can be developed for a wide range of IDOT bridges. Further work should (1) perfect the process of collecting high-quality operational frequency response data; (2) expand and simplify the process of correlating frequency response animations with damage; and (3) develop efficient, economical, preemptive solutions to common damage types.

The Economics of Reducing the County Road System: Three Case Studies in Iowa - Executive Summary, HR-242, 1986

This Executive Summary presents a brief summary of the main research report, "The Economics of Reducing the County Road System: Three Case Studies in Iowa" (DOT/OST/P-34/86-035). The case studies are described, as well as the analytic methodology and research findings.

Communicating Highway Safety: What Works, 2002

Few topics in transportation are of greater significance, now and in the future, than making today’s roads safe for those who use them. This study aims to assist the formulation of policy by examining the empirical evidence currently available on the ability of several forms of communication efforts and activities to increase knowledge about and affect attitudes and behavior toward highway safety practices. The objective of this effort is to provide a comparative synthesis of what works and what does not in highway safety campaigns across a large number of topical areas that have a mass media component. This was accomplished by conducting an extensive literature review to determine the current state of knowledge concerning what works and what has significant potential for wide use in future highway safety campaigns. An analytic framework for investigating highway safety campaigns was created. The framework includes (1) the types of media components, (2) the types of collaborations, (3) the context in which the campaign is intended to have impact, (4) the structure or procedural steps into which campaigns are organized, (5) the principles for what works in a campaign, and (6) the desired impact of a campaign on its target audience. The report reveals 25 characteristics of successful communication campaigns, strategies that stand a chance of achieving changes in knowledge, attitude, and behavior. The actual impact of mass communication remains unproven because of a perceived lag in the development of adequate evaluation techniques. Education by itself has not generally resulted in significant changes in the behaviors targeted, but education of the public and advocacy groups has often helped enact necessary legislation, transmit knowledge about the provisions and penalties of laws in ways that increase their deterrent effect, and generate public support for law enforcement programs. Even in such cases, however, when enforcement is inconsistent, public compliance frequently decreases with time. Approaches to traffic safety that emphasize the need for long-term individual- and community-based measures are found to be especially crucial for addressing complex problems like drinking and driving that are determined by a myriad of lifestyle and psychosocial factors.