Tire chain damage on bridge deck wearing surfaces

Master's Project (M.S.) University of Alaska Fairbanks, 2017A light weight, durable, and damage-resistant material is needed as a wearing surface replacement for a two-lane bridge deck that is on a 6% grade. The wearing surface to be replaced is 9.2-m wide and is attached to an orthotropic closed cell steel deck that supported by two 155.9-cm wide by 414.0-cm deep steel box girders. This is a 699.5-m long six span bridge over the Yukon River located near the Arctic Circle on the gravel road section of the Dalton Highway. The bridge is located approximately 80 km north of Fairbanks, Alaska. The structure was designed in the early 1970's with a 127-mm two-layer timber deck wearing surface. Since then, the timber deck wearing surface has been replaced in 1981, 1992, 1999, and 2007. Future decking material may be composites. Factors to be considered in the selection of a new decking material include: thermal cracking, abrasion, durability, flexural strain, traction, weight, and fastening methods to the steel deck. Moreover, the material must retain its structural properties in temperatures that range from -50C to 40C. For a majority of the year, the driving surface is covered with ice and snow. Because of the steep grade, trucks typically use tire chains during the winter. These tire chains damage the current timber wearing surface and are a major factor in its deterioration. Further, the more traffic the less traction. Owing to the damage tire chains cause on the current timber wearing surface, other wearing surface materials are being considered. The purpose of this project was to evaluate possible wearing surface in the laboratory for punching shear, structural strain, modulus, traction, and resistance to tire chains. In this paper, preliminary test results for traction, and wear by tire chains are presented. This is an updated version of a paper that was first presented at ISCORD 2007, Proceedings of the 8th International Symposium on Cold Region Development, Tampere, Finland, September 25-27, 2007, with co-author, J. Leroy Hulsey

Automated beam builder

Requirements for the space fabrication of large space structures are considered with emphasis on the design, development, manufacture, and testing of a machine which automatically produces a basic building block aluminum beam. Particular problems discussed include those associated with beam cap forming; brace storage, dispensing, and transporting; beam component fastening; and beam cut-off. Various critical process tests conducted to develop technology for a machine to produce composite beams are also discussed

The circulation of Prince William Sound

There are no author-identified significant results in this report

Acceleration-Induced Nonlocal Electrodynamics in Minkowski Spacetime

We discuss two nonlocal models of electrodynamics in which the nonlocality is induced by the acceleration of the observer. Such an observer actually measures an electromagnetic field that exhibits persistent memory effects. We compare Mashhoon's model with a new ansatz developed here in the framework of charge & flux electrodynamics with a constitutive law involving the Levi-Civita connection as seen from the observer's local frame and conclude that they are in partial agreement only for the case of constant acceleration.Comment: LaTeX file, 3 figures, 14 page