Ice Force Measurements on the Pembina River, Alberta, Canada

Book excerpt: Just before spring breakup in 1972, 23 in situ tests were conducted on the Pembina River, in Alberta, Canada, to measure ice forces. These tests simulated an ice sheet pushing against a bridge pier. The apparatus utilized a hydraulic ram to push a 5 1/2-in. (14.0-cm)-wide vertical pile section horizontally against the ice sheet, which varied from 11.5 to 19.5 in. (29.2 to 49.5 cm) in thickness. The velocity of the pile was varied from 0.07 to 21 in./sec (0.18 to 53.3 cm/sec) by hydraulic flow control valves. Both flat and round piles were used to represent the pier. Some tests began with the piles a few inches away from the ice sheet, whose edge was cut flat. Other tests began with the pile in contact with the ice sheet. For some of the round pile tests, augered holes were used to provide better initial contact. These in situ test results were compared with the ice force measurements made by other workers on a nearby bridge pier during ice breakup. The in situ test ice forces were about 50% higher than the bridge pier test results. This disagreement was caused by a difference between the sizes of the piles and the size of the pier and a three-day warming of the ice before the ice impacted against the pier. (Author).