Wilding, Bastian Valentin1; Dolatshahi, Kiarash2 and Beyer, Katrin3
1 PhD Student, Earthquake Engineering and Structural Dynamics Laboratory (EESD), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Vaud, Switzerland, bastian.wilding@epfl.ch
2 Assistant Professor, Civil Engineering Department, Sharif University of Technology, Visiting Professor of the EESD-laboratory at EPFL, Lausanne, Vaud, Switzerland, dolatshahi@sharif.edu
3 Assistant Professor and Head of the Earthquake Engineering and Structural Dynamics Laboratory (EESD), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Vaud, Switzerland, katrin.beyer@epfl.ch
ABSTRACT
Quasi-static cyclic in-plane shear tests on unreinforced masonry (URM) walls are carried out to experimentally determine parameters that are of interest in the design process, e.g. effective stiffness, force capacity, drift capacity. Yet, the structural capacities can be a function of the demand and therefore dependent on the applied loading history. Although the effect of loading histories on URM wall capacities has not been investigated systematically, the comparison of few pairs of tests where monotonic and cyclic tests were performed indicated that in particular the drift capacities can be rather sensitive to the applied loading history. Structural design codes provide estimates of drift capacities that have been derived from sets of tests in which different loading protocols have been applied. Hence, an improved understanding of the influence that loading protocols can have on stiffness, shear force and drift capacities of URM walls would be important and would help reduce the uncertainties that are currently associated with the seismic assessment of URM buildings. This paper assesses the influence of the in-plane loading protocol on the forcedisplacement behaviour of unreinforced masonry walls by means of a numerical investigation. Four representative walls (two shear and two flexure controlled) from literature are modeled and subjected to several loading protocols. The occurring differences in effective stiffness, peak shear strength, energy dissipation as well as ultimate drift capacity are presented and discussed.
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