The palace, located on Corso Ercole I d’Este, opposite the Palazzo dei Diamanti in Ferrara, is a historic and protected property of significant importance. The Soprintendenza paid extremely close attention to the type of reinforcements to be designed: for each of these, reversibility and compatibility with the building’s prestige had to be demonstrated. This circumstance required extraordinary attention from SB+ to study many different types of consolidation, each suited to its specific location and the deficiency present there. Such a meticulous and articulated study, aimed at finding the best possible solution for the problem at hand and verifying its effectiveness with internal studies and literature, constitutes an experiential asset that SB+ has adopted and continues to apply in the consolidation of masonry structures with wooden or hollow-core concrete slab floors.
Both traditional technical solutions (tie rods, stitch and un-stitch, chains, etc.) and innovative ones (UHTSS galvanized steel micro-strands, glass fibers, and frayed fibers, etc.) were planned and dimensioned.
Once the necessary knowledge of the building was acquired, modeling began to seismically and statically verify structural deficiencies. These emerged in ways typical of masonry buildings, for example, concerning local overturning mechanisms; others, however, were linked to the maintenance status of certain elements. Particular attention was paid to the study of overturning mechanisms, which are notoriously the first to activate and pose the greatest danger to users’ lives. As a protected asset, considerable attention was given to “refining the calculation models” based on the material investigations that had been carried out.
As anticipated, the design utilized both traditional techniques and the most modern intervention technologies:
- stitch and un-stitch (reinforced and unreinforced);
- repair of lesions;
- consolidation of lesions on decorated walls after applying a supporting tissue paper to protect valuable elements and subsequent removal of the bandage/tissue paper;
- tie rods, to be inserted at masonry intersections;
- curbing with fiberglass strips and connection flakes, planned for hollow-core concrete slab floors not effectively anchored to the masonry;
- curbing with steel strips made of ultra-high strength galvanized steel micro-strands (UHTSS);
- reinforced courses with pultruded laminates made on the external, non-frescoed faces of the Monumental Staircase;
- steel curbing planned for vulnerable roofs and in the attic of the monumental staircase;
- stiffening of the roof plane, with the application of double wooden boarding and bracing steel strips;
- reconstitution of the masonry texture (closing niches) to recreate the structural integrity of the walls;
- cladding with composite material mesh provided only for the pilasters present at attic level in the North wing;
- consolidation of the wooden structure of cane-and-plaster vaults from both the extrados and intrados, through the employment of a restorer;
- flexural and shear consolidation of prefabricated beam and hollow-core concrete slab floors;
- construction of a new roof truss.
Particular attention was paid to those floors that showed static deficiencies regarding flexural and/or shear stresses; for those on the first and second floors of the central portion, connections of the beam ends with the external wall were planned using a splayed fiber rope on the wall itself, where a fiberglass strip on lime mortar will run along the entire length of the facade.
The design of the interventions, carried out in compliance with ministerial guidelines for historic buildings, allowed for a significant improvement of many tens of percentage points. The modeling was performed using STADATA’s 3Muri calculation program.
Based on the provided survey, the BIM model of the entire building was developed, and the designed interventions were incorporated into it, achieving a LOD C level of detail.
