Displacement-based assessment of cantilever masonry elements under out-of-plane actions

Out-of-plane mechanisms induced by earthquakes are typical of many masonry structures and their seismic assessment requires proper methods of analysis and verification. Different displacement based assessment (DBA) procedures have been already adopted in many codes, to take into account the dynamics of rocking mechanisms, but a systematic comparison of their results has not been provided, yet. In this framework, the paper presents a review of the DBA procedures proposed by different national and international codes. In particular, the attention is mainly focused on the out-of-plane mechanisms developed at the upper parts of the buildings; thus, a comparison between the different expressions actually proposed in standards for the floor spectra definition is firstly provided and then a new expression is proposed and validated through experimental results. Finally, the differences and analogies among the different formulations are critically discussed with the support of a reference case study building.