Experimental Laboratory Procedures for the Construction and Testing of Seismic Resistant Unbonded Post-Tensioned Special Reinforced Concrete Walls

This research investigates the experimental lateral load response of an unbonded post-tensioned cast-in-place concrete special structural wall with bonded longitudinal mild steel reinforcement under the action of quasi-static lateral load. The objective of this report is to describe the procedures for the construction and testing of the wall and to present a summary of testing results. The unbonded post-tensioned cast-in-place concrete special structural wall with bonded longitudinal mild steel reinforcement provides energy dissipation through the yielding of the boundary and web longitudinal steel reinforcement. This steel reinforcement extends from the wall into the foundation block. Additionally, self-centering capabilities are provided by the unbonded post-tensioning strands that extend from the foundation block to the top of the wall. It was found that the limit states that characterize the lateral load response of an unbonded post-tensioned cast-in-place structural wall with longitudinal mild bonded steel reinforcement occurred as presented by Srivastava (2013). Also, yielding of the longitudinal mild steel reinforcement was effective as an energy dissipator. However, self-centering capabilities were greatly diminished after the yielding of the longitudinal bars at a drift of approximately 0.5%. Therefore, self-centering capabilities were greatly limited by the insufficiency of the restoring force provided by post-tensioning. Finally, results showed that initial residual drift of 0.2% occurred as early as the longitudinal bars started to yield which occurred at 0.6%.