Re-evaluation of ice loads on the Molikpaq structure measured during the 1985–86 season

• Published in: Canadian Journal of Civil Engineering
• Main Authors: Jordaan, Ian, Hewitt, Kevin, Frederking, Robert
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 2018
• Subjects: General Environmental Science; Civil and Structural Engineering; Buttons; Beaufort Sea
• Online Access: http://dx.doi.org/10.1139/cjce-2016-0444; http://www.nrcresearchpress.com/doi/full-xml/10.1139/cjce-2016-0444; http://www.nrcresearchpress.com/doi/pdf/10.1139/cjce-2016-0444

The Molikpaq drilling platform, a steel annulus filled with sand, 90 m wide, was deployed at the Amauligak I-65 location in the Beaufort Sea during the 1985–1986 winter. It was heavily instrumented for measurement of ice loads, using strain gauges, extensometers, and Medof panels. The original calibrations of the Medof panels were used to estimate loads. Calibration was carried out using uniform pressures up to 1.86 MPa. The actual loading in the field of the Medof panels was extremely non-uniform spatially, particularly during ice crushing, and is very different from that in the original calibration. The resulting high pressures led to softening of the polyurethane buttons in the panels, including the Mullins effect. The panels were consequently reading too high. Extensometer readings, geotechnical measurements, and those pertaining to a decelerating floe impacting the structure, support the conclusion that actual ice loads were about half those obtained using the original Medof panel calibrations.