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.
Keywords
arches, shaking table tests, dynamic analysis, Roman
concrete, dynamics of masonry
Institute for Sustainable Heritage,
Bartlett School of Environment, Energy and Resources
University College London
Central House, 14 Upper Woburn Place
London
WC1H 0NN
United Kingdom