Refined Element Discontinuous Numerical Analysis of Dry-Contact Masonry Arches

Abstract

The behavior of buried masonry arches is studied in this article using the Discontinuous Deformation Analysis (DDA), a numerical method that allows for the physical simulation of the intrinsic structure dis- continuities since it is based on contact and friction among pseudo-rigid blocks. Two types of arches (or vaults) are studied with a specially developed computer program, one of semicircular and another of ovoidal shape. The loads are self-weight, lateral filling, embankment thrusts and concentrated (through a short distribution) forces close to the peak. These loads are transformed into point forces applied to the center of gravity of each block with simple formulae from classical mechanics. Equilibrium is reached in the whole structure through contact forces calculated with a standard contact algorithm: penalty plus Coulomb friction. DDA-macroblocks composed of linked (through penalty contact springs) pseudo-rigid blocks are for- mulated. This linkage allows for the simulation of collapse by instability or by stress compressive failure more accurately than traditional DDA analyses, for instance funicular polygons. The numerical results are compared with those of the experiments taken from the literature with, for most cases, very good agreement given the uncertainties on geometry and material properties and given the intrinsic quality dispersion of masonry structures. Collapse loads as function of number of joints, safety factors and limit point forces from the numerical and experimental results are compared. The hinges that appear prior to collapse are also compared, obtaining again for most cases very good agreement.