In-plane response of perforated unreinforced masonry walls under cyclic loading: experimental study

This paper presents the results of an experimental study into the behavior of perforated (containing openings) unreinforced masonry (URM) walls subjected to cyclic in-plane lateral loading. Damage to perforated URM walls during previous earthquakes has revealed that the in-plane response is mainly influenced by the pier and spandrel geometry, as well as the level of axial compressive stress on the walls due to gravity loading. The study focused on masonry typologies representative of historical URM buildings in the Australian context. To investigate this behavior, eight full-scale URM walls with semicircular arched openings, double wythe thickness, and materials representing masonry construction from the mid-19th to mid-20th century were constructed for pseudostatic cyclic in-plane testing. The experimental program considered varying spandrel depths and pier widths and the imposed vertical loading on the piers was also varied to observe the lateral load capacity and the variation of pier-spandrel failure modes. The test results showed that the in-plane capacity and the failure modes were significantly affected by changes of wall geometry and the imposed vertical precompression loading. Predictions of wall strengths, in-plane stiffnesses, and failure modes according to ASCE guidelines show that the guidelines agree well with the test observations.