DEM Analysis of the Mechanical Role of Backfill of Jointed Masonry Fan Vaults: Results of Virtual Experiments

Fan vaulting is a magnificent innovation of English Gothic architecture that has been admired since the 14th century. However, how this breathtaking structural form works under mechanical loads (like self-weight and support displacement) is still poorly understood. One of the many interesting open issues is the mechanical role of backfill. This paper studies how the existence and the height of the backfill affect the horizontal and vertical reactions expressed on the fan vault by the tas-de-charge and the lateral longitudinal wall. In order to analyse this, discrete element models are prepared for small-span and large-span fan vaults constructed of jointed masonry, with Voronoi-shaped elements forming the backfill, and then the structures are submitted to self-weight and gradually increasing quasi-static outwards support displacements. The ratio of horizontal versus vertical reactions is applied to quantify how stable these vaults are in the case of different levels of backfill. The effect of shell thickness is also addressed.