Research aimed toward understanding the underlying mechanics and behaviors of curved post-tensioned concrete structures subject to prestressing loads is somewhat limited in the literature. Previous research focused on radial (i.e., out-of-plane normal) stress development has been analytical and, to the research team’s knowledge, there is no experimental research on this topic currently available in the public domain. As a result, this research study is aimed at producing unique experimental data to gain important insights into the effect of localized tensile stresses and concrete delamination behavior in curved post-tensioned structures. Two curved post-tensioned concrete wall assemblies were constructed and tested to delamination failure under monotonically increasing prestressing loads. In an effort to study the size-effect in delamination failure observed in such elements, all dimensions of the second specimen were double those of the first specimen, while maintaining the reinforcement ratio. The test results showed a size-effect related influence on the delamination failures. Furthermore, the compressive stresses at the onset of the first delamination crack were 0.15 fc'~0.23 fc' which are lower than the allowable stress limit for a service load condition in construction, 0.35 fc', specified in the ASME BPVC Section III, Division 2. Finally, the friction losses based on ACI 343R underestimated the actual friction measured during testing by 37 to 44 %. Discussions regarding size effect, indication of delamination failure, stress concentrations around the post-tensioning ducts, and prestressing losses due to a strand bundle effect will be presented.