Abstract
The measured stresses at the existing dam spillway roller gates were compared with the stresses calculated under the same load conditions with the measurements. The uncertainties in the several types of stress calculations were quantified as the statistical characters of the stress ratio between the measurements and the calculations. The result showed that the uncertainties varied with the types of the calculations. These differences of the uncertainties in the stress calculations should be concerned in establishing the structural safety assessment formula based on the structural reliability theory.