Shake-table response simulation of a URM building specimen using discrete micro-models with varying degrees of detail

Abstract

Recent technological advances have enabled earthquake engineering researchers to develop numerical models of increasing complexity, capable of duly reproducing even the smallest structural detail. In the case of unreinforced masonry (URM) structures, however, because of their discrete and heterogeneous nature, computational performance tends to decrease exponentially as a function of the adopted refinement level, thus confining the applicability of advanced micro-models, according to which each masonry unit is typically modelled separately, to reduced-scale problems. To enable their use at a building scale, and benefit from considering simultaneously out-of-plane failures, local wall-diaphragm interaction and collapses, researchers often need to decrease the level of detail of specific members or sub-structures. In the current literature, however, the influence of the abovementioned simplifications on the quality of micro-modelling predictions has been only marginally investigated so far, while code-based guidelines are missing. To start addressing such knowledge gap, the dynamic response of a shake-table-tested full-scale URM building specimen has been simulated in this work using a very detailed micro-model, and the results obtained were then compared with those of nominally identical models in which, however, the idealisation of some specific structural elements has been purposely simplified. Aimed at further extending the impact of this study, pushover analyses were also performed using the same models. Preliminary outcomes, which may serve as a reference to develop more informed, effective and targeted multi-scale micro-modelling strategies in the future, indicate that: (i) maximum base shear predictions tend to be less impacted by the introduction of modelling simplifications, (ii) despite requiring more labour, the explicit representation of the brickwork pattern generally led to better results in terms of predicted damage propagation, failure mechanisms and displacement capacity, (iii) using equivalent membranes, as opposed to modelling each component of timber diaphragms, provided acceptable results, making it a plausible alternative for practical applications of micro-modelling approaches.

FRIBAS database for better characterization of RC and URM buildings: Towards specific T-H relationships

“…For URM buildings, the analysis of expected seismic response, in particular the fundamental period, has historically been based on simpli ed methods (Block et al 2006;Snoj et al 2020), and is still a common approach (i.e. Portioli et al 2021;Calò et al, 2021;de Felice et al 2021). At the European scale, URM buildings represent a high share of the residential building stock (Crowley et al 2020).…”

Seismic analysis of failure mechanisms in adjacent interacting stone masonry buildings via rigid block modeling

“…Differently from other discontinuous models such as the distinct element method and the applied element method, see e.g. (Calò et al 2021;Hart et al 1988;Malomo et al 2020a, b), the rigid block modelling approach adopted here relies on a variational formulation of the problems associated to the limit (Cascini et al 2020), non-linear pushover (Portioli et al 2021) and time-history analysis (Portioli 2020). The optimization problems were here reformulated following a unified approach, based on the equivalence with the complementarity problems corresponding to the set of equations governing the behavior of the rigid block models.…”

Simulated seismic testing of two pitched roofs constructed using timber trusses extracted from vintage unreinforced masonry buildings

“…However, it is high-lighted that with few exceptions (e.g., refs. [8][9][10], most studies have focused on timber floors rather than timber roof diaphragms. The availability of research data including analytical formulations for floors provides the opportunity to study the response of building roofs when recognizing some similarities in the construction forms.…”