PSI - Issue 29

Michele Paradiso et al. / Procedia Structural Integrity 29 (2020) 63–70 Paradiso, Conte and Prosperini / Structural Integrity Procedia 00 (2019) 000 – 000

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The current structure of the Church derives, in fact, above a ll from the la tter, as well as more significant, transformation. This radical modification eliminates the first two trusses, replaced by two false struts resting on the third truss. Iron chains were insertedwith a key that harnessed stakes in correspondence with the corners of the main facade and in the rear. The volume of the entire Church was divided into three parts by two wooden floors, supported by nine septum partitions arrangeda t constant center distance corresponding to twice the center distance of the trusses. The septa, on the ground and first floors, were made up of four pillars, the terminal ones of which leaned against the longitudinal wa lls and connectedby roundarches suitably chainedwith square-section iron chains andvertical linear key for each order. The thickness of the partitions is 0.80 m. up to the arches, and then reduced to 0.60m. up to the support of the second floor. The construction techniqueadopted to create thepillars is the mixed masonry whichprovides two rows of dia tonic bricks a lternatingwith a row of rounded stone and bricks, while the arches are made of common bricks. On the second floor the septa did not perform a load-bearing but only served as elements for the distribution of the spaces makingup the soldiers' dormitories. Newopenings were a lso createdon the internal and externalwa lls, taking into account the new distribution structure of the complex.Therefore, a ll the old windows and doors that were no longer adequate were buffered and three orders of twelve windows were made that follow one another a t regular interva ls. In correspondence with the apse area, the entrances to the three chapels are buffered, creating an internal counter-façadewhich thus separated the main hall from thenewrear rooms. The la tterwas securedby additional iron cha ins at thefirst, seconddeckandattic. Thevolumeof the mainchapel and the chapel of the HolyTrinity was divided into three parts by two floors placed a t the same level as the floors of the hall, while the space obtained from the demolition of the bell tower and the San Giovanni chapel was used to build the stairs connecting to the new floors. The vaulted structures that make up the load-bearingelement of the internal elevation system are madewith a single layer of bricks positioned sideways with the shorter side of the exposed brick and are part of the category of self supportingvault madewith minimumorwithout use of ribs. The load-bearing structureof the shelves was made from a ha lf-vaulted roof, while the ramps from a half -vaulted ramp, with a slight curvature in the longitudinal direction. In the Iberianworld and then in the La tin Americanone, they are called bóvedas tabicadas in the first case, bóvedas de rosca in the second. Also in the Iberianworld, they also take names referring to the specific geographical loca tionof origin ormaximumdiffusion. For example, the former are also knownasbóvedas catalanas and the la tter, originating in the Extremadura region, bóvedasextremeñas. The technical litera ture in this regard is vast, even if the constructive knowledge of bothhas been lost, starting from the70s of the century. last. Some authors even trace its origin back to the Arab influence in Spa in (9thcentury).With this construction technique, any typeof vaulted surface was created, including domes, and, as in this case, a lso the load-bearing part of traditional elevation structures: las escaleras de cáscara. For lightness, resistive efficacy and cost-effectiveness, the technique, in genera l and specifically referred to the sta irs, was soonadoptedby militaryengineeringwhich, as is known, since the Rena issance has always dia logued between Spainand Italy, up to assume, specifically ofmilitaryconstructivewisdom, character of universality.

Fig. 2. (a) Photo of the attic; (b) Photo of the load-bearing structure of the stairwell where the use of a single layer of brick with the short side visible is evident.