Ten Years of Ice Force Measurements on the St. Regis River, Hogansburg, NY: 1989–1999

Ice loads were measured for ten years on the east pier of the NY Route 37 bridge over the St. Regis River in Hogansburg, NY. This record comprises the longest documented history of ice loads on any bridge in the world. Statistics on the loads for the 10-year period of record are presented along with statistics on ice thickness and strength. The measured ice strength at this site agrees well with other data measured in Canada and Europe. The largest measured ice force on the pier was 356 kN, which is only 15% of the design ice load. Statistical analysis of the data indicates that the return interval on the design load appears to be greater than 1000 years, suggesting the design may be overly conservative. Probabilistic approaches to determining the appropriate design load may help prevent overdesign of future bridges, thereby reducing cost while still maintaining a reliable transportation infrastructure. Field measurements of ice loads on a wide range of river sizes extending over many years will be required to use probabilistic approaches with reasonable levels of uncertainty.