EXPERIMENTAL AND NUMERICAL STUDY OF THE DYNAMIC BEHAVIOUR OF MASONRY CIRCULAR ARCHES WITH NON-NEGLIGIBLE TENSILE CAPACITY

摘要

Continuous arches and vaults made of cohesive materials with low but nonzero tensile strength, such as Roman concrete, are a common feature in historic and monumental structures, many of them sited in earthquake-prone regions. The effect of tension capacity on the dynamic behaviour of masonry vaulted structures has scarcely been studied. We describe a series of shaking table tests on model-scale, continuous circular arches of 1m span, with the aims of assessing the effect of tensile capacity on mechanism formation, evaluating the structures' lateral acceleration capacity and comparing their performance to that of voussoir arches. While tested arches fail by forming a four-link mechanism like the no-tension voussoir arch, significant differences in behaviour between continuous and voussoir arches are observed, including: differences in hinge positions; higher accelerations required to initiate rocking; cracking of material required to form hinges; inability of hinges, once formed, to close and move to a different location (travelling hinges). Conventional limit analysis, whose basis includes an assumption of zero tensile strength, is a suitable analytical tool for voussoir arches, but is shown to be inaccurate when applied to arches having a modest tensile capacity. The experimental observations are modelled using nonlinear finite elements Abaqus/Explicit dynamic analysis algorithm, from commercial software Abaqus 2017. By applying the concrete damage plasticity numerical material law, good agreement is obtained between the tests and the numerical predictions, supporting the formation of collapse mechanisms that significantly differ from the mechanisms observed for no-tension arches. Finally, the numerical model is upscaled to study full-size arches with a span of 4m, obtaining results that align with the experimental observations and do not agree with observations and models for the no-tension voussoir arch, evidencing the need to account for tensile capacity of vaulted structures when assessing their dynamic capacity.