The coupled order of the cloister: columns, bases, capitals

edited by Laura Morgante

The preparation of cards to record significant data concerning all aspects of the complex is intended to facilitate the identification of guide-lines for drawing up the conservation project of the cloister. The acquisition of metric, stylistic, structural and conservation data took place after a series of compilation tests on cards planned during the work. The worksite card referred to as S.C.C.B. (Scheda di Cantiere per le Colonnine Binate = Worksite Card for the Coupled Columns) was divided into four sections.

In the first, entitled historical-stylistic, the principal components of the coupled order were split up into: base, shaft, capital and corbel. A selected list was made for each one of them of the variable or invariable elements to examine considered significant for the historical, stylistic and structural analysis and their relative dimensions were all indicated (fig. 1).

The second section, also entitled historical-stylistic, contains the data necessary to recognize the original elements in situ, either reassembled or totally restored and, if possible, the differences verifiable within the various identified groups (fig. 2). It also contains some additional attached information on historical iconography that provides helpful references for recognizing the transformations, reconstructions and extensions that took place, which have certainly left their indelible marks on the cloister (fig. 3).

The third section is dedicated to the structural analysis. Using the vertical line running down the middle of the pulvin as a reference, the deviation from the middle point of the base is recorded, in order to check for eccentricity or off-centering that would indicate rotations and concentrations of forces confirmed in certain cases by losses and flaking (fig. 4).

The fourth part concerns the state of conservation. After a preliminary reconnaissance the subjects were identified on the basis of the NORmal/80 document that has been revised to include the qualities of speed in the manual operations and clarity in the subsequent description of the surfaces to be treated.

Finally an overall editing of all the sections of the card was carried out to unify them both graphically and textually. Having surveyed a column, considered as a type model, a reproduction was made of it, represented on a 1:10 scale with the aim of collecting the data of the first and third sections, and on a 1:5 scale for the fourth section, as the mapping called for a simple-to-carry-out and immediately recognizable topographic representation on the model of the object.

The information collected is in diverse forms: graphic, numerical and textual data are all present. In order to compare them a table has been drawn up that permits the identification of a series of problems. Among the data taken into consideration we have recorded, for example, that the minimum diameter of the scotia of the external base CB26 is 10.70 cm., the minimum diameter of the shaft is that of the upper scape of the external column CB32 equivalent to 8.75 cm., while the minimum section of the base of the internal capital of the coupled column CB34 is 7.2 cm.

The eccentricity of the pulvin with respect to the support slab varies from -1.75 cm. for the coupled column CB25 to +3.75 cm. for CB13. This data must be examined together with data on the state of conservation relating to 'expulsion', or rather losses of stone material. All important sections for this study are the joints between the base and shaft and the shaft and capital. The table below of some of the data and the diagram of the distribution of eccentricity relating to the south side (fig. 5) represent examples of the methodology adopted.

Table of significant data from the south side of the cloister expressed in cm.

Legend:

CB - coupled columns
A - distance between the base slab and corbel.
B - diameter of the scotia of external base.
B' - diameter of the scotia of internal base.
C - diameter of the lower scape, external shaft.
C' - diameter of the lower scape, internal shaft.
D - diameter of the upper scape, external shaft.
D' - diameter of the upper scape, internal shaft.
E - diameter of the base of the external capital.
E' - diameter of the base of the internal capital.
F - eccentricity of the pulvin with respect to the support slab.