Abstract
Considering the seismic behaviour of cultural heritage buildings, an influential role is played by
masonry vaults, often representing the most vulnerable part of the construction. Despite their
long-lasting history and the damage observation following the Italian earthquakes of the recent
past, research in this area is still limited. In this regard, the present thesis is devoted to the study
of the seismic behaviour of masonry groin vaults, considered as one of the most diffused vault
type in European seismic prone areas in cloisters, palaces and churches. Groin vaults are resulting
from the intersection at a right angle of two semi-cylindrical shells on a square bay, and can be
addressed as the simplest form of cross vaults, defined as a combination (compound) of curved
shells whose thrust converges along the diagonals to isolated abutments. The goal of this work is
met via an integration of laboratory tests and numerical analyses.
The first part of the thesis reviews the historical developments of the cross vault, the structural
methods adopted by the scientific community and the damage evidences after laboratory
experiments and post-seismic observation. The subsequent part deals with shaking table tests on
a scaled arch built with dry-joint 3D printed voussoirs. The experimental campaign had a twofold
purpose. On the one hand it gave insight into the seismic behaviour of masonry arches and, on
the other hand, thanks to the tracking motion system employed to record the tests, it provided
valuable information to calibrate a three-dimensional numerical model.
The physical model was studied using a commercially available FEM software, namely DIANA
(from TNO Delft), assuming rigid-infinitely resistant blocks and Coulomb friction interfaces. The
nonlinear analyses regarded both the static and dynamic behaviour, shading light on the influence
of interface stiffness and damping. The numerical model was subsequently extended to the study
of the three-dimensional behaviour of groin vaults. In particular, the analyses focused on the
results available in literature following a recent experimental campaign on a 1:5 scaled vault. The
model was able to properly catch the maximum strength and the failure mechanism recorded in
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SEISMIC PERFORMANCE OF MASONRY CROSS VAULTS
the quasi-static tests. Analogies between the nonlinear behaviour of the vault and the free-standing
rigid block undergoing incremental horizontal force are also discussed.
The last part of the thesis is dedicated to a sensitivity analysis aimed at evaluating the influence
of the main geometrical and mechanical parameters on the seismic capacity and failure
mechanisms of groin vaults. A non-commercial code implemented in Matlab, based on the upper
bound approach of standard limit analysis, was used. The results were finally processed through
a multiple linear regression analysis in order to get simplified analytical equations for expedite
seismic evaluation of existing groin vaults.
Keywords: cross vault, groin vault, dry-joint arch, shaking table, seismic capacity, time history
analysis, limit analysis
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