A Multi-Disciplinary Approach to Understand Icy Conditions Over Bridges.

More than 450 people are killed each year in the United States due to Icy conditions on roads [3] more than 10% of these deaths are caused by accidents over icy bridges. Many innovation systems were designed and used to prevent bridge icing. Most of these systems either use heat sources to heat the bridges' surfaces or chemical spray to melt the ice over bridges. These systems are usually costly and require regular maintenance. Many researchers contributed bridge icing to the fact that bridges' surfaces freeze before adjacent roads because bridges are suspended above ground, thus bridge decks lose heat from both the top and bottom surfaces while roads gain some heat from their contact with the ground. However, field monitoring and building simulation showed that bridge surfaces' thermal properties are the determining factor of bridge freezing before adjacent roads. Furthermore, Icy bridge surfaces' become dangerous when 1) the bridge's surface reaches freezing point before adjacent roads, 2) there exists water or snow over bridges when adjacent roads are dry (preferential icing). This research presents literature review related to bridges' freezing. The research also used field observation of a 175 mile highway section during a snowstorm to investigate icing conditions over bridges. This research showed that while bridges might freeze before roads during early night hours, dangerous icing formation over bridges occurs when snow is shoveled against the bridges' parapets after snowstorms. Thus, when air temperature rises above freezing, the snow melts and the water runs over bridges' surfaces, and when temperature drops again below freezing later at night, water freezes over bridges, and can create dangerous icy conditions. This research suggests that a combination of applying paint with higher absorptive and lower emissive materials over bridges, along with better snow removal practices ultimately reducing dangerous icy conditions over bridges significantly. [ABSTRACT FROM AUTHOR]

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