Neapolitan open-staircases vaulted system

The vaulted open-staircases system in Naples (Italy) is one of the most interesting expressions of the building art. Therein, the functions of the arch and vault aren’t only related to the covering requirements and support, but they form a single whole with the definition of a path, where it shows the combination between the harmonic architectural function and the structural function. Springs from a dynamic architecture linked to the succession of ever-changing visual achieved through scenographic artifices and from the structural function. This allows to interpret the staircase entire system in relation to the form-stress ratio. This allows to interpret the entire system of the staircase in relation to shape-stress ratio. Generally, the arches and vaults that compose the Neapolitan open-staircases do not differ in con-struction, in materials used or in construction techniques from those which constitute the building where the staircase is at service, but for plane impost geometric arrangement that must cover (and at the same time, support) the ramps of staircases. The rampants (generally called 'gooseneck') can be realized by arches or vaults. The vaults, however, in addition to the characteristic of lay down plane at staggered levels, have geometric characteristics of shape and construction due to the particular type of the dismount or relax walkway. Through the survey operations and consequent staircases plant geometric analysis, have been classified the dif-ferent configurations from the vaults to cover the different staircase spaces. The geomet-ric-configurative analysis, accompanied by the realization of three-dimensional models, has led to a typological characterization about the structure of rampant and the staircase type, where the most frequent type is closed on three sides and open on the courtyard intended as scenic background. From this geometric analysis came out the following main correspondences depending on the ramps structure: mid rampant barrel used in the staircases with free shaft; sail vault in support of the dis-mount or relax walkway; cross rampant present in walling staircases or in pillared shaft system.