A simplified analysis method for characterizing unbonded post-tensioned precast wall systems

In recent years, a significant effort has been placed towards understanding the lateral load behavior of unbonded post-tensioned precast wall systems because they are easier to construct and they exhibit desirable response characteristics, including self centering feature and minimal damage when subjected to large lateral displacements. However, the conventional section analysis cannot be applied to these walls because of the nonexistence of strain compatibility condition between the unbonded post-tensioning steel and concrete at the section level. This paper presents a simplified analysis method to characterize the monotonic response of unbonded post-tensioned precast wall systems and provides verification for the method using available test data. It is shown that the proposed simplified analysis method not only captures the lateral load behavior of walls, but also accurately quantifies the neutral axis depth, elongation in the post-tension steel, and deformation of the connector used in jointed wall systems as a function of lateral drift.