Ashlar Staircases with Warped Vaults in Sixteenth- to Eighteenth-Century Spain

[EN] During the sixteenth to eighteenth centuries, three-section cantilevered stone stairways supported by vaults of complex warped shapes were built along Spain's Mediterranean coast. Presented here are five case studies. The geometric analyses and the comparative study with the relevant treatise illustrate the existence of a geometric construction method. The process involves handling elevation and plan projections simultaneously to obtain the geometric center of the curves that delimit these vaults. The simplicity of the geometric formula applied relies on the use of dimensional references obtained from the stairwell measurements.