Recent experimental and analytical research has shown the benefits of using unbonded post-tensional to improve the seismic behavior of precast beam-to-column joint subassemblages. Compared with current industry practice, the use of unbonded post-tensional in a seismic structural system is a significant innovation. The seismic behavior of unbonded post-tensioned precast concrete walls with horizontal connections has been investigate analytically. However, the experimental evidence needed to verify the wall analytical model is not currently available. This project is to experimentally evaluate the lateral load behavior of multi-story unbonded post-tensioned precast concrete walls. The research has two specific objectives: (1) to verify the wall analytical model that has been developed to predict the flexural wall behavior under seismic loading; and (2) to qualify the shear capability of the horizontal connections of these walls. Cyclic and monotonic lateral load tests will be performed on half-scale models of eight walls. Two lateral load profiles, based on nonlinear dynamic analyses, will be used. The first lateral load profile produces a large base-moment-to-base shear ratio. Five walls will be tested under this load profile. The second lateral load profile produces a small base-moment-to-base-shear ratio. Three walls will be tested under this load profile. Experimental results will be compared with predicted behavior to identify improvements that need to be made in the models and methods for predicting flexural and shear slip behavior.
