The optimal shape of a plinth

The base of a plinth is traditionally shaped in the form of an inverted mushroom whose stalk (the pillar) transmits a vertical axial load to the hood (the platform) which rests on the ground and distributes the load. Insertion of a stone cushion at the base of columns in monumental buildings is a device that, although practised for many centuries, lacks sound theoretical understanding of the relative dimensions to be employed. A simple method is here proposed to determine the shape of a platform's central cross-section. Our approach replaces the pillar by a long wall and then adapts a plane elastic solution due to Neuber (1985, Section 4.10).