Field tests on the prediction of heating power requirements for deicing in Jiangyin, China

Abstract

Hydronic heating systems with geothermal heat exchangers are one of the innovative methods for bridge deck deicing in winter, which avoids infrastructure corrosion and environmental pollution caused by chemical methods. This paper focused on field tests on the temperature process of a bridge deck with a hydronic heating system to predict the heat exchange rate needed to keep the bridge deck temperature above 0 °C before snowing. The heating power in the test was kept constant, and three different heating powers of 125 W/m2, 187 W/m2, and 250 W/m2 were considered. The heat exchange rates remained constant under constant heating powers. The slab temperature and thermally induced stress were analyzed, and the heat exchange rate prediction was discussed. The required heat exchange rate is determined by the air temperature and the wind velocity. The minimum temperature in situ is approximately -5 °C in winter. The heat exchange rate should be greater than 178 W/m2 to keep the slab surface temperature above 0 °C under the condition that the wind velocity is less than 3 m/s. The thermally induced compressive stresses caused by operating the system were <5% of the compressive strength of concrete. Operation of the system does not structurally damage the bridge deck and can protect the bridge deck from being damaged by excessive tensile stress caused by low temperatures in winter.