Abstract : Thermal stress concentration factors were determined for rectangular flat plates, some of which were penetrated by holes and some which had filleted width changes. The experimental data indicate that the thermal stress concentration factors would be less than tension stress concentration factors for the same bars. Additionally, the peak thermal stress was found to be smaller in magnitude than the nominal applied thermal stress, except for one case in which the peak stress at the hole was 1.2 times the applied stress. (Author)