Kalliontzis, Dimitrios1; Schultz, Arturo2 and Sri Sritharan3
1 Ph. D. Student, Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Twin Cities, Minneapolis, MN, United States, 55455, kalli072@umn.edu
2 Professor, Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Twin Cities, Minneapolis, MN, United States, 55455, schul088@umn.edu
3 Wilkinson Chair Professor in Engineering, Iowa State University, Ames, IA, 50011-3232, sri@iastate.edu
ABSTRACT
There is a growing interest in understanding the in-plane behavior of unbonded-posttensioned walls to develop wall systems that can re-center with small residual deformations and little damage when subjected to horizontal seismic loads. However, conventional analysis methods cannot reproduce the response characteristics of unbonded-posttensioned masonry walls accurately, as a) there is strain incompatibility between masonry and the unbonded bars; and b) these walls respond primarily by rocking, which concentrates the wall deformations at the base. Due to the walls’ rocking response, the neutral axis depth at the base of the wall tends to decrease with increasing posttensioning force and wall lateral displacement, while the wall toe region experiences confinement from lateral friction at the wall-to-foundation interface. This paper presents an approach to address the response characteristics pertaining to these wall systems by using an analysis method that enables the walls to respond in a mixed mechanism of rocking, flexure, and shear responses. The analysis method is shown to improve correlation to experimental results compared to analyses that assume only a rocking response.
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