Numerical Evaluation of Applying Geothermal Bridge Deck Deicing Systems to Mitigate Concrete Deterioration from Temperature Fluctuations

Abstract

This paper uses numerical modeling to evaluate the ability of a geothermal bridge deck deicing system to mitigate concrete deterioration. A model of an experimental bridge deck with embedded heat exchanger tubing was created using COMSOL (version 5.6) Multiphysics software. The model accounts for heat transfer and structural behavior and was validated against temperature and strain data from physical experiments. Inlet fluid temperatures of 10°C and 50°C, reflecting average ground temperatures in Montana, were tested to evaluate the system's effect on deicing, frost action, and thermal stresses. A sensitivity analysis was also completed to investigate the influence of ambient temperature, inlet fluid temperature, and tube spacing in the efficiency of the geothermal deicing system. The results suggest that higher fluid temperatures and reduced pipe spacing improved the effectiveness for deicing and mitigating frost action and strain due to thermal movements, but also increased temperature gradients in the bridge deck. The deicing system shows promise in reducing some mechanisms of concrete deterioration, while staying within allowable limits for others. Numerical modeling provides insights into designing deicing systems to mitigate frost action and thermal stresses in bridge decks.