Milan Kovarbašić, Roman Salzmann and Nebojša Mojsilović
Milan Kovarbašić, PhD Student, Institute of Structural Engineering, ETH Zurich, Switzerland, kovarbasic@ibk.baug.ethz.ch
Roman Salzmann, Dr Lüchinger+Meyer Bauingeniuere AG, Zurich, Switzerland, rsa@luechingermeyer.ch
Nebojša Mojsilović, Senior Scientist, Institute of Structural Engineering, ETH Zurich, Switzerland, mojsilovic@ibk.baug.ethz.ch
ABSTRACT
Past earthquakes show that unreinforced masonry (URM) walls with door or window openings are among the most vulnerable structures to fail in-plane. In order to improve the understanding of
their load-deformation behavior, two static-cyclic shear tests were performed on a storey-high URM wall with an asymmetric door opening and a shear-span ratio that represents an internal wall in a two-storey building. The wall was constructed using standard perforated Swiss clay blocks and standard cement mortar. The experimental results showed asymmetric response of the wall specimen due to the eccentric door opening. After reaching a certain drift ratio, local increase of normal stresses in the narrower wall pier, next to the door opening, had a detrimental impact on
the propagation of diagonal shear cracks resulting in a brittle failure and limited displacement capacity of the wall. Wall geometry and shear-span ratio exhibited a significant impact on the loaddeformation behavior of the URM wall with a door opening. Furthermore, an empirical model based on Swiss Structural Masonry Code recommendations was used to estimate the deformation capacity of the wall specimen with the boundary conditions applied in the test. This paper presents and discusses the results obtained from the abovementioned experiments as well as from the code empirical prediction.
KEYWORDS: asymmetric wall opening, displacement capacity, shear-span ratio, static-cyclic shear, unreinforced masonry
