Issue 29

J. Toti et alii, Frattura ed Integrità Strutturale, 29 (2014) 166-177; DOI: 10.3221/IGF-ESIS.29.15 166 Focussed on: Computational Mechanics and Mechanics of Materials in Italy Damage propagation in a masonry arch subjected to slow cyclic and dynamic loadings J. Toti, V. Gattulli Department of Civil, Construction-Architectural and Environmental Engineering, University of L'Aquila, Italy jessica.toti@unicas.it , vincenzo.gattulli@univaq.it E. Sacco Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Italy sacco@unicas.it A BSTRACT . In the present work, the damage propagation of a masonry arch induced by slow cyclic and dynamic loadings is studied. A two-dimensional model of the arch is proposed. A nonlocal damage-plastic constitutive law is adopted to reproduce the hysteretic characteristics of the masonry material, subjected to cyclic static loadings or to harmonic dynamic excitations. In particular, the adopted cohesive model is able to take into account different softening laws in tension and in compression, plastic strains, stiffness recovery and loss due to crack closure and reopening. The latter effect is an unavoidable feature for realistically reproducing hysteretic cycles. In the studied case, an inverse procedure is used to calibrate the model parameters. Then, nonlinear static and dynamic responses of the masonry arch are described together with damage propagation paths. K EYWORDS . Cyclic and dynamic analysis; Masonry arch; Nonlocal damage; Finite element method. I NTRODUCTION ecent seismic events have led to an increased demand for the development of effective methods able to discern on the safety of existing masonry structures under dynamic loadings; in this context, arches and vaults have confirmed to be vulnerable with respect to the earthquakes showing the occurrence of extensive damage [1]. In this respect, while the static analysis of arches is widely investigated, a better understanding of the response of masonry vaults and arches under dynamic loading conditions is necessary for the evaluation of the behavior of these structural elements when located in seismically active areas. The seismic capacity of masonry arches is usually studied considering the well-known Heyman’s hypotheses [2], who assumed infinite compressive strength and no tensile resistance. This modeling approach is often adopted in the framework of limit analysis [3]. The method provides analytical solutions and can lead to approximated estimates of the seismic capacity of arches. The results of the limit analysis have also been used to validate numerical simulations performed using the Distinct Element Method (DEM), which describes the structure as an assemblage of rigid blocks and nonlinear interfaces [4]. Although, the DEM method allows an accurate description of the dynamic behavior of masonry arches composed by blocks, it could be however inadequate for studying three-dimensional structures made out of a large number of elements. R