A MINDLIN SHELL FINITE ELEMENT FOR STONE MASONRY BRIDGES WITH BACKFILL

Stone masonry bridges are difficult to analyse with commercial finite element (FE) packages for their specific heterogeneous composition. The stone arch is best modelled as a thick shell where there are predestined directions of tension failure, normal to the bed joints. A dedicated, very simple, Mindlin shell finite element is developed with five translational degrees of freedom per node. It features compatibility with linear isoparametric or constant strain elements for the backfill. Most bridges can be analysed with a sufficient accuracy assuming plain strain conditions. The element then simplifies to a Timoshenko beam element with three translational degrees of freedom per node. An application of the latter one to the bridge at Ponikla is presented.