Predicting ice accretion from freezing rain on bridge stay cables

Abstract

An morphogenetic model that simulates ice accretion on arbitrarily oriented cables exposed to freezing rain has been developed at the National Research Council Canada (NRC). This predictive numerical model has been validated experimentally for a limited number of conditions in the NRC Climatic Testing Facility. The facility is 6 m wide, 6 m high and 30 m long, and can generate a range of freezing precipitation environments. Inclined stay cable models with a diameter of 0.218 m and a length of 2.4 m were exposed to simulated freezing rain. The final experimental ice accretion shapes were scanned and digitized using a handheld laser scanner. These three-dimensional experimental ice shapes were used to partially validate the NRC morphogenetic model. The successfully validated model was used to examine ice accretion on stay cable geometry in an environment representative of freezing rain conditions in Eastern Canada. Prediction of wet snow accretion on already ice covered stay cables has also been undertaken.