Abstract
Block models have been shown to provide a realistic representation of the behavior of many types of masonry structures under static and dynamic loads. When the strength of the units is such that movements along the joints govern the behavior, it is acceptable to make the simplifying assumption that blocks act as rigid bodies. This assumption is particularly useful when dealing with seismic problems, for which the computational times for time domain analysis may be substantial. In this paper, the application of discrete element models for dynamic analysis of masonry structures is addressed. The emphasis is on the seismic behavior of block stone masonry, but the treatment is general to cover other types of masonry. First, the assumptions involved in the choice of a block representation are discussed, stressing in particular the case of rigid block models. Numerical issues are examined, including contact models, calculation of natural frequencies, time stepping algorithms, damping and boundary conditions. A review is presented of modeling examples published in the literature for various types of masonry structures. The choice of numerical representation and its main features are discussed for each case.
Highlights
Earthquakes pose a major threat to unreinforced masonry, in particular historical structures are highly vulnerable
Discrete element models are one of the most powerful options, as reported in surveys ofpublished works [1], which demonstrate the ability of polyhedral block representations to reproduce key aspects of the deformation and failure of masonry
Most of the analyses have considered static loads or statically equivalent seismic loads. [14] performed dynamic analysis of simple structures, such as free-standing circular or pointed arches, under seismic records
Summary
Earthquakes pose a major threat to unreinforced masonry, in particular historical structures are highly vulnerable. Numerical models are presently the best tool to analyze the behavior of these structures under seismic loads or other types of dynamic input. Comparisons with experimental evidence, whether shaking table tests, or structural monitoring data obtained during seismic events, have allowed the progressive validation of the new numerical tools. These may nowadays be used with more confidence in the prediction of dynamic behavior and safety assessment studies. The main applications of discrete block models have dealt with relatively simple stone masonry structures, for example, the column-architrave systems of classical monuments. The particular issues related to dynamic analysis are presented. Several examples taken from published case studies are examined, in order to illustrate the model capabilities and the various issues that may arise in applied studies
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