Characterizing the In-Plane Rocking Response of Masonry Walls with Unbonded Posttensioning

Unlike the use of bonded reinforcement to anchor a masonry wall to its foundation, the use of unbonded posttensioning may result in a controlled rocking response of the wall. Considering that conventional analysis techniques routinely employed for monolithic structures are inadequate to describe a controlled rocking response, this paper introduces analysis methods that are able to predict the monotonic force-displacement responses of masonry walls with unbonded posttensioning. These methods include (1) an iterative procedure that employs sectional analysis and accounts for the confinement effects attributable to lateral friction at the wall-to-foundation interface and (2) a simplified procedure that is based on equivalent stress block analysis. The two methods are compared against experimental data from three past research studies, and high-fidelity finite-element models are used to verify predictions of the wall responses, including the neutral axis depth (NAD) at the wall-to-foundation interface. Comparisons show the proposed analysis methods to adequately capture the experimental force-displacement responses and produce NAD variations that agree well with the finite-element models.