FaiMec: an app for fast seismic assessment of local mechanisms in unreinforced masonry building aggregates

Unreinforced masonry (URM) buildings without box-like behavior are highly vulnerable to out-of-plane (OOP) failure modes in earthquake-prone areas. Local failure mechanisms may involve large portions of URM buildings with serious civil protection implications in terms of danger to people, structures and road networks in the surrounding area. In this framework, a fast application, named FaiMec (Failure Mechanisms), has been recently developed for a large-scale seismic assessment of multi-story URM buildings in aggregate, in terms of predic-tive OOP failure mechanisms. It exploits an advanced macro-block model and the FaMIVE (Failure Mechanism Identification and Vulnerability Evaluation) procedure, previously devel-oped by the authors. The input data are derived using the CARTIS Building form, promoted by the Italian Civil Protection Department for qualitative inspections; these are then trans-formed by FaiMec into simplified assessments, whose conceptual basis is consistent with Ital-ian Technical Standards. The advanced model, based on the application of the linear kine-matic approach of limit analysis and taking into account the interlocking between walls, is adopted to calculate the load factors at the onset of the failure modes. Two classes of OOP mechanisms are considered here, namely the rocking-sliding and the flexure mechanisms, with the aim of identifying the most likely mechanism providing the minimum seismic capaci-ty/demand ratio for each building and the corresponding vulnerability class. Floor spectra are also used to evaluate the seismic demand at the different levels of buildings