Speaker:

Eray Baran, Graduate Research Assistant, Department of Civil Engineering

Description:

Each year a large number of concrete bridges in the United States are hit by over-height vehicles or vehicles carrying over-height objects, not only damaging the structure but in many cases causing injuries and even fatalities. The available literature indicates that highway bridges in such collisions are able to redistribute and transfer the locally-applied impact loads to other parts of the bridge. Pedestrian bridges, however, are of lighter construction and do not have the high degree of redundancy exhibited by highway bridges. These characteristics make pedestrian bridges more vulnerable to collapse under lateral impact.

University of Minnesota researchers recently investigated the safety of a different construction approach for pedestrian bridges: prestressed concrete through-girders. The study consisted of an experimental and analytical investigation of the vulnerability of the prestressed concrete through-girder pedestrian bridge construction used in Minnesota. A series of laboratory tests were performed on representative details and subassemblages to determine the stiffness, strength, and ductility characteristics of critical elements of a typical pedestrian bridge system under representative load configurations. The load-deformation characteristics obtained from the laboratory tests of the individual bridge components and connection regions were incorporated into detailed finite element models to assess the bridge system performance under statically applied lateral loads.

Speakers:

Robert Johns, Director, Center for Transportation Studies

David Levinson, Associate Professor, Department of Civil Engineering

Description:

A metropolitan area that works for all its residents and visitors provides easy access to many regional places. In the Twin Cities area, one such place is the University of Minnesota's Twin Cities campus, a major regional destination for students, employees, and many others. Transportation, however, means more than access: it is also a vital component of an area's identity. The people and goods that move from place to place—and how they do it—all contribute to an area's character.

Please join us for a presentation of the Center for Transportation Studies' Access to Destinations research program, a new initiative that will analyze accessibility to places within the Twin Cities region. The event will also include an informal discussion of how well the regional transportation system provides access to the University and to other destinations.

Speaker:

David Levinson, Assistant Professor, Department of Civil Engineering, University of Minnesota

Description:

If Minnesota leaves its current construction policies in place, would the network we get meet our future needs? In this project, Associate Professor David Levinson is comparing networks forecast under alternative budget scenarios with networks constructed according to a set of decision rules developed with Mn/DOT and Met Council staff. Using a set of performance measures, Levinson then evaluates the alternative futures to determine whether the network we would get in the absence of a change in policies outperforms or underperforms the networks developed by applying the suggested decision rules. This evaluation framework enables new decision rules for network construction to be tested, suggesting a path beyond "business as usual." The presentation will report on work in progress for this ongoing project, which extends the Mn/DOT "If They Come, Will You Build It" project.

Speaker:

Demoz Gebre-Egziabher, Assistant Professor, Aerospace Engineering & Mechanics, University of Minnesota

Description:

Recently there has been considerable interest in using miniature aerial vehicles for traffic management and highway infrastructure security applications. The motivations for using these vehicles are compelling. For example, rapid incident response or year-round highway infrastructure inspection requires the installation of intelligent transportation system sensor networks in and around highways. In rural areas, however, it is neither cost-effective nor physically possible to provide wide-area coverage using fixed sensor networks; it is impractical to build the power, communications, and other infrastructure required to support such networks. Appropriately instrumented aerial vehicles can provide an easily configurable complementary network that augments existing terrestrial sensor networks. The use of remotely piloted aerial vehicles in this manner assumes that these vehicles can be safely and legally operated over populated areas and alongside other passenger-carrying aircraft in the National Airspace System. In this presentation, the researchers will discuss the sensing, regulatory, and operational challenges that have to be addressed before remotely piloted aerial vehicles can be routinely used in these applications. University of Minnesota research addressing these challenges will also be discussed, and prototype sensing systems, aerial platforms, and operational procedure developed as part of this research will be demonstrated.