Experimental behavior and seismic performance assessment of Unbonded Post-tensioned Precast Concrete Walls for low-rise buildings

The current growth of the urban population has led to an increment in the housing demand, increasing the seismic exposure, especially in developing countries that struggle to provide efficient and safe housing solutions. To address this issue, it is necessary to develop structural systems that provide sufficient seismic performance while allowing reduced building time and cost. This paper presents the structural identification and seismic performance assessment of a structural system based on unbonded post-tensioned precast concrete walls. These structural walls are composed of precast concrete panels connected through shear connectors and post-tensioned using unbonded steel bars. Three unbonded post-tensioned precast concrete wall specimens were subjected to a cyclic loading test, obtaining several structural parameters from the analysis of the experimental campaign results. In addition, the seismic response of the proposed system was identified by characterizing its hysteretic behavior and by defining several experimental damage limit states. Based on these results, a numerical model was calibrated using the Pinching4 material of the OpenSees software. Finally, a numerical seismic performance assessment of the in-plane response was carried out by proposing an archetype building and using the FEMA P695 far-field ground motion set as seismic input. These analyses allowed the development of fragility functions of the diverse damage states observed on the tested specimens. The results show that the proposed structural system based on unbonded post-tensioned precast concrete walls is a feasible option for its implementation as a lateral load structural system on low-rise buildings, providing sufficient seismic capacity and allowing further improvements in its implementation.