Out-of-plane response of three-leaf stone masonry walls taking account of soil-structure interaction: an experimental study

This paper studies the out-of-plane seismic response of stone masonry walls, typically encountered in historic and monumental structures, with due consideration to soil foundation structure interaction (SFSI). The problem is investigated experimentally, through a series of pushover tests, performed on reduced scale (1:3) specimens. Each specimen consisted of a three-leaf stone masonry wall built on top of a rectangular footing. The walls were subjected to out-of-plane displacement, imposed at mid-height. The specimens were tested as built, with the exception of one specimen tested in strengthened condition. In a first phase, a set of experiments were conducted ignoring SFSI. Then, in a second phase, the masonry wall foundation specimens were founded on a sand substratum to investigate the role of SFSI. The effect of soil resilience was examined by modelling two idealized soil deposits: (a) dense sand of relative density D-r = 92%, and (b) loose sand of relative density D-r = 33%. The observed failure modes are discussed with due emphasis on the cracking patterns of the walls and post-test soil deformation. As shown by the obtained test results, the out-of-plane seismic performance of the walls was substantially affected by SFSI effects, as well as by the boundary conditions.