• Unmanned Aircraft System Assessments of Landslide Safety for Transportation Corridors

      Cunningham, Keith; Olsen, Michael J.; O'Banion, Matt; Wartman, Joseph; Rault, Claire (2016-12)
      An assessment of unmanned aircraft systems (UAS) concluded that current, off-the-shelf UAS aircraft and cameras can be effective for creating the digital surface models used to evaluate rock-slope stability and landslide risk along transportation corridors. The imagery collected with UAS can be processed using a photogrammetry technique called Structure-from-Motion (SfM) which generates a point cloud and surface model, similar to terrestrial laser scanning (TLS). We treated the TLS data as our control, or “truth,” because it is a mature and well-proven technology. The comparisons of the TLS surfaces and the SFM surfaces were impressive – if not comparable is many cases. Thus, the SfM surface models would be suitable for deriving slope morphology to generate rockfall activity indices (RAI) for landslide assessment provided the slopes. This research also revealed that UAS are a safer alternative to the deployment and operation of TLS operating on a road shoulder because UAS can be launched and recovered from a remote location and capable of imaging without flying directly over the road. However both the UAS and TLS approaches still require traditional survey control and photo targets to accurately geo-reference their respective DSM.
    • Use of Geogrids for Limiting Longitudinal Cracking in Roads on Permafrost

      Savage, Bonnie Mae (1991-05)
      Longitudinal cracking of road embankments results from lateral movement of the subbase which creates a subsurface void space. The void spaces propogate to the surface causing cracks and voids. This is hazardous to motorists and expensive to repair. This thesis examines the use of geogrids to limit lateral spreading thereby preserving safe and useable road surfaces. A field experiment, a full-scale laboratory experiment, a soil arching experiment, and behavioral and theoretical analyses are presented. Soil arching forces are quantified and developed using an experiment based on work done by Terzaghi and Kienzl. A theoretical analysis for quantifying the shear force redistribution to be used for geosynthetic embankment systems, was derived from the Soil Arching Experiment. Relationships of load, embankment resistance, deflection and geometric factors are presented. A comparison of geogrid performance to a geotextile performance for the given relationship is presented as well.
    • Wearing Surface Testing and Screening: Yukon River Bridge

      Hulsey, J. L.; Ward, Richard; Anderson, Elliott (2015-09)
      There is a demand and a need for cheaper and alternative surface coverings in environments with high temperature fluctuations. Our design for an alternative surface covering involves a basic twopart component epoxy with the addition of a solvent. The purpose of the solvent is to disrupt the reaction that forms the ordered chains to form a more disordered crystalline structure. The solvent in the finished product is 3% by volume of isopropyl alcohol. This mixture of epoxy and solvent has higher impact strength than epoxy alone, as well as a much lower brittle transition temperature of 27°C compared with 10°C for epoxy. An environmental chamber, tensile tester, Charpy impact tester, and 4- point bending test were used to determine these conclusions. The final product can be tailored with different aggregates to fit a specific need, such as decking surface material to coat the wooden planks on the Yukon River Bridge.
    • Winter Highway Construction

      Bennet, F. Lawrence (1986-10)
      This report focuses on the feasibility of extending the highway construction season further into the winter season than is currently practiced in Alaska. It reviews the literature of research and project experience in accomplishing several elements of succssful highway construction in the winter. It summarizes the cold weather sections of highway construction specification s from 18 states, provinces, and foreign countries. It reports on personal interviews and survey questionnaires with 24 Alaskan contractors who have been engaged in building highway elements in the winter. The report concludes that additional inter highway construction should be permitted in Alaska and urges the Department of Transportation and Public Facilities (DOT&PF) to revise its specifications, on a trial basis, for selected projects in order to permit construction of embankments and asphaltic concrete pavements at below-freezing temperatures. Further research on "cold" concrete, additive materials in embansments and construction productivity is suggested