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Several architectural configurations of unreinforced masonry residential buildings are designed according to the different methods proposed in the Italian code: rules for the so-called simple mason...

The assessment of the seismic vulnerability of masonry buildings requires reliable and computationally efficient numerical models. Different modelling strategies can be adopted when studying the global response of these structures, such as Continuum Constitutive Laws Models (CCLM) belonging to Finite Element (FE) models, which may be very accurate but whose use in practice presents several issues (high computational burden, requirement of many input data), and Equivalent Frame (EF) Models, that, even if based on strong simplifications, are now widespread in engineering practice, thanks to their computational efficiency and the need of few mechanical parameters for the structural analysis. The paper discusses the consistent use of these modelling techniques for the seismic analysis of masonry structures . To this aim, a comparison of two approaches (CCL and EF models) is presented focusing at first the attention on the calibration of the constitutive laws through analyses on single panels and then moving to the validation of some simplified assumptions made in the EFM through the analysis of a 2D regular URM wall. For the aim of validation, the CCL model is considered as the reference solution making an accurate comparison with the EF model in terms of generalized forces, drift and damage occurred at element scale and of pushover curve at global scale.

The unreinforced masonry (URM) buildings designed to be conforming with the Italian building code, as illustrated in the companion paper, were analyzed by performing time-history analyses on models...

The use of nonlinear static (pushover) analysis in the case of existing irregular masonry buildings is validated through a comparison with results from nonlinear dynamic analyses, assumed as reference because considered as able to represent the actual seismic behavior. After the selection of a regular prototype case study building, different irregular configurations are defined (in terms of plan irregularity and finite stiffness of horizontal diaphragms). Specific proposals are considered for the selection of load patterns to be used in pushover analysis and the definition of limit states on the capacity curve. A general overview of possible approaches for modelling and analysis of masonry buildings is presented in the introduction.

This paper presents the comparison of the results of nonlinear static analyses performed on a simple masonry building with different computer programs that work within the Equivalent Frame Modelling approach. The activity described in this paper is part of a wider research program carried out within the ReLUIS 2014-2018 project (founded by the Italian Department of Civil Protection) whose main objectives are: to support the professional engineers in acquiring a proper awareness in the use of software packages available for the seismic assessment; to provide them analytical tools and a methodological approach for the critical analysis of the obtained results. Within this context, the paper is focused to one of the benchmark case studies conceived in this project that consists in a single-unit two-story masonry building with rigid diaphragms. Seven different configurations have been designed varying the layout of the openings on the four bearing walls and the structural details. The modelling process of the building has been faced by adopting, when possible, common assumptions in order to facilitate the interpretation of the differences in the results obtained by the different software. Comparison of the results involves different aspects: the global scale response in terms of pushover curve; the damage pattern predicted; checks at local scale in terms of generalized forces. In general, the achieved results show a very good agreement when configurations are close to the shear-type idealization while increasing scattered results arise in case of configurations characterized by weak spandrels (i.e. without tensile resistant elements coupled).