Field Measurements and Predictions of Concrete Temperatures in Large Diameter Drilled Shafts in Hawaii

Large diameter, non-redundant drilled shaft foundations are becoming more popular in engineering and construction practice. When the drilled shaft diameters become large (generally 1.8-meter (6-foot) diameter or greater), mass concrete considerations need to be taken into account in the design and construction of these foundations. Mass concrete considerations due to the high heat of hydration are more acute in Hawaii because the local concrete mixes are very rich in cement content due to the angularity of the local crushed aggregates and the lack of cost-effective secondary cementitious materials (slag or structural quality fly ash are not readily available in Hawaii). Temperature measurements from several large diameter drilled shafts were taken in an effort to better understand the distribution of the temperatures in the constructed drilled shafts. In this paper, the temperatures at the center and edges of the drilled shafts and at various depths for several large-diameter drilled shafts are presented. The predicted temperatures from the finite element program compared well with the measured temperatures. Therefore, a discussion of the parameters used in the temperature predictions is presented.