The out-of-plane collapse of large masonry façades subjected to earthquake excitation is modeled by a special rigid body and spring model (RBSM) that takes specifically into account the effect of the material internal texture at the macro-scale level. The model allows to performed full non linear dynamic analyses of realistic church facades by adopting a limited number of degrees of freedom. At the meso-scale –first step- two multi leaf textures are analyzed, relying the first into a quasi periodic arrangement of large blocks with different length and a weak transversal interconnection, the second into a better interconnected three leaf masonry with external leaves constituted by two head walls. Three different models are proposed at the meso scale to estimate moment-curvature diagrams in the elastic, peak and post peak range at increasing levels of vertical pre-compression. The first is a FE homogenization procedure performed on a sufficiently large test window (RVE or representative volume element) subjected to increasing bending and torsion. The second is an analytical approach based on the assumption of a simplified kinematic on the RVE. Finally, the third is a non-linear heuristic model where non linearity is concentrated on springs with suitable mechanical properties. First and second model are assumed as valuable reference solutions to compare with. On the contrary, the implementation of the heuristic model at a structural level is very straightforward, because the actual masonry behavior at different pre-compression level may be automatically estimated without a previous onerous collection of a numerical database of moment-curvature diagrams. A structural validation of the third meso-mechanical model on both RVEs considered is provided evaluating the seismic response of a masonry church façade through a rigid body and spring model (RBSM), using four artificial accelerograms representing different seismic zones.

HOMOGENIZED MODELS FOR THE NON LINEAR DYNAMIC ANALYSIS OFMULTI-LEAF MASONRY WALLS OUT-OF-PLANE LOADED

CASOLO, SIRO;MILANI, GABRIELE
2011

Abstract

The out-of-plane collapse of large masonry façades subjected to earthquake excitation is modeled by a special rigid body and spring model (RBSM) that takes specifically into account the effect of the material internal texture at the macro-scale level. The model allows to performed full non linear dynamic analyses of realistic church facades by adopting a limited number of degrees of freedom. At the meso-scale –first step- two multi leaf textures are analyzed, relying the first into a quasi periodic arrangement of large blocks with different length and a weak transversal interconnection, the second into a better interconnected three leaf masonry with external leaves constituted by two head walls. Three different models are proposed at the meso scale to estimate moment-curvature diagrams in the elastic, peak and post peak range at increasing levels of vertical pre-compression. The first is a FE homogenization procedure performed on a sufficiently large test window (RVE or representative volume element) subjected to increasing bending and torsion. The second is an analytical approach based on the assumption of a simplified kinematic on the RVE. Finally, the third is a non-linear heuristic model where non linearity is concentrated on springs with suitable mechanical properties. First and second model are assumed as valuable reference solutions to compare with. On the contrary, the implementation of the heuristic model at a structural level is very straightforward, because the actual masonry behavior at different pre-compression level may be automatically estimated without a previous onerous collection of a numerical database of moment-curvature diagrams. A structural validation of the third meso-mechanical model on both RVEs considered is provided evaluating the seismic response of a masonry church façade through a rigid body and spring model (RBSM), using four artificial accelerograms representing different seismic zones.
Atti del XIV Convegno Anidis
9788875220402
masonry; RBSM model; meso-scale approach; texture; non-linear dynamic analysis
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11311/605315
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