Long-Term Performance of Three Bridges on Permafrost

摘要

In 1964 the Alaska Department of Transportation and the U.S. Army Cold Regions Research and Engineering Laboratory initiated a cooperative study which in the long-term generated a significant amount of ground temperature and settlement data at three bridge sites near Fairbanks, Alaska. The purpose of the study was to evaluate the long-term bridge performance in order to improve bridge design techniques in areas where permafrost is present. Data over the past 20 years has been reduced and evaluated revealing some drastic changes in the thermal regime. At the Goldstream Creek Bridge, settlements of approximately 6 in (15 cm) over a 10-year period were observed. At the Moose Creek Bridge, annual heave and subsidence with long term net uplifting has been measured. Differential settlements of more than 8 in (20 cm) and slight annual heaving have been measured at the Spinach Creek Bridge. The bridge analysis has demonstrated the hazards of relying on permafrost adfreeze bonding for support of piles located in streambeds in warm permafrost regions.