To predict thermal stress independent of uncertain material properties of early age concrete, a new
thermal stress device was developed by Kim et al. in [1]. Several experiments and numerical analyses
were performed to verify its validity. However, the application of the device in a real structure has yet
to be attempted. Thus in this paper, the application of a stress device for predicting hydration-induced
thermal stress in an actual structure is investigated. For this purpose, a series of experiments were performed
by varying the amount of restraint in the thermal stress device. The reasonably good agreement
between the restraint strains from the site and the stress device indicates that variation of the thermal
stress at any position in concrete structures can be measured during the design stage even when the
properties of the concrete are uncertain. The application of various degrees of constraint at a site can
be achieved by the thermal stress device by varying the thermal expansion coefficient and the cross
sectional area of the restraining frame.