A case history and design review of the Kuparuk River Module Crossing and its refrigerated foundation are presented. The Kuparuk Crossing incorporated a presented. The Kuparuk Crossing incorporated a number of design and construction innovations to meet the challenges of bridging a major Alaskan North Slope river. Among these challenges was the need for a foundation system—to be placed in a continuous permafrost bed—which could support a 2,500-ton permafrost bed—which could support a 2,500-ton (2.26 × 10(3) Mg) live load on the bridge deck. A temporary mechanical refrigeration system was provided to refreeze subgrade soil disturbed during provided to refreeze subgrade soil disturbed during construction of this foundation. After the removal of the temporary mechanical refrigeration, a passive thermosyphon system was employed as part of the foundation design to maintain the long-term integrity of the frozen soils. A special procedure was used to install and monitor the passive systems in the foundation piles. The predictions of the thermodynamic design model are compared to five years of post-construction field measurements. General trends of both future performance and foundation stability are discussed performance and foundation stability are discussed and compared to design assumptions. The performance of ground temperature monitoring performance of ground temperature monitoring equipment is also reviewed. Introduction The Kuparuk River Module Crossing is located on Alaska's North Slope, approximately 40 miles (65 km) west of Deadhorse (see Figure 1). The bridge spans the Kuparuk River at a point approximately eight miles (13 km) upstream (south) of the river's confluence- with the Beaufort Sea, and provides the only highway link between the Prudhoe Bay and Kuparuk oil fields. The Kuparuk field, located to the west of the Prudhoe Bay complex, is the second largest producing field on Alaska's North Slope. The Kuparuk River Module Crossing was designed to provide a reliable and heavyload overland transport link between these two world class developments. Spanning the Kuparuk River had concerned oil field developers long before the construction of the Kuparuk Module Crossing. Although summertime flows on the Kuparuk are generally relatively benign (typical daily discharges during the July through September period range from 300 cfs (8.5 m3/s) to 2,000 cfs (56.6 m 3/s), the river can expand to a width of 9,000 feet (2,740 m) within its floodplain, carrying up to 200,000 cfs (5,663 m3/s) during the brief breakup period in late May and early June. In addition to its discharge, the river conveys freshwater ice flows as large as six feet (1.8 m) thick by 100 feet (30.5 m) long. This ice is carried by surface water velocities which approach six feet/second (1.8 m/s). The Kuparuk is braided into three primary channels at the crossing location: the so-called West, Main, and East Channels. A first attempt to span this floodplain with a permanent structure proved unsuccessful. A permanent structure proved unsuccessful. A multi-opening culvert crossing, constructed during the winter of 1979, was destroyed by the following spring's breakup flood. P. 459

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The purpose of this project was to measure the secondary creep rate of 4.5 inch (114 mm) diameter steel piles that were forced into frozen saline silt. The silt contained 30% water with a salt content of 33.4 ppt. The piles, embedded in 19°F (-7°C) silt, were loaded to produce shear stresses of 0.5,1.0,1.5, and 2.0 psi (3.4, 6.9, 10.3 and 13.8 kPa).Resul ts are compared to pUblished data related to frozen soils containing fresh water.