Ice on Suspension Bridge Cables

In this report we study mathematical models for predicting when ice may form and fall from vertical steel hangers of suspension bridges down onto the road below. This is an important problem to study, not only because of the economic costs related to closing a bridge due to the risk of falling ice, but also the human cost if the bridge is still open to traffic when ice falls down. In the report we present two main categories of models for predicting falling times: 1) models based on heat transfer from the surrounding air, and 2) models based on heating due to radiation from the sun. A flow chart is furthermore presented together with tables for determining which model to use and quickly estimating time of failure based on a set of simple conditions.