Experimental investigation of energy pile response for bridge deck deicing applications

Abstract

Using energy piles is becoming an increasingly popular method for economically and efficiently accessing shallow geothermal energy for heating and cooling buildings. Energy piles are deep foundation elements integrated with fluid circulation tubes, which allow them to serve as heat exchangers in addition to their traditional role of structural support. In this study, the use of energy piles for deicing of bridge decks was investigated. Temperature-induced stresses that develop as a result of soil-pile interaction during heat exchange operations need to be evaluated for adequate design of energy piles. This paper presents the results from a series of full-scale field tests on an energy pile during bridge deck deicing operations. The resulting axial strains and stresses in the pile are presented and discussed within the context of soil-pile interaction under thermal loads. Conclusions are drawn about the behavior of energy piles and recommendations are given for their use as heat exchangers.