Palazzo dei Trecento in Treviso: restoration to the crenellations
Sole project manager: ing. Roberta Spigariol
Architect and work manager: arch. Gianluca Sampieri
Safety coordinator: geom. Stefano De Martin
Building firm: Dottor Group Spa, via Italia 131, 31020 San Vendemiano (TV)
Structural calculations: Venice Plan Ingegneria srl, via Rampa Cavalcavia 26A, 30172 Mestre (VE)
Built at the turn of the XII century in the heart of the city, it has undergone numerous conversions and alterations over the years, but it also underwent a spectacular restoration project after the bombing of the Second World War. In fact, after it was hit by an American bomb on 7th April 1944, it was rescued by the pure determination of the townspeople and the Monuments Councillor at that time, Eng. Ferdinando Forlati who, with an admirable work of engineering, managed to straighten the heavy sheer brick walls. Among other damage, the bombing also destroyed all the stone crenellations on the top which were constructed in Ghibelline style during the renovation work at the end of the 19th century . During the restoration between 1947 and 1951, the decision was made to totally reconstruct the crenellations in Guelph style, as depicted in the 1500 painting Madonna con il Bambino e devoto by Pier Maria Pennacchi .
However, just over half a century later the crowning on the palazzo showed serious conservation problems, suffering from erosion, disintegration, flaking and pulverisation of the stone elements with parts even of a considerable size actually falling. Chemical analyses demonstrated that several of the bricks were made by grinding old stones, perhaps those recovered after the bombing. Furthermore the walls were assembled with mortar made from common lime and cement but very lean. Finally, certain crenellations were dangerously inclined and unstable around the entire length of the walls.
with dual component epoxy resin which was injected through a narrow straw. The rest of the hole was then filled with colloidal mortar without cement, which is compatible with the historic walls.
The more unstable merlons which risked causing the collapse of the entire wall, were completely and carefully removed and all the undamaged bricks were recovered. 6 holes were made for each merlon with a diameter of 18 mm, beginning from the foot of the structure with 120 cm depth on the north and south tympanums and 50 cm on the east and west. The same sort of bars were then introduced as for the previous merlons, but in this case horizontal stainless steel binders were added to every four layers of bricks, to render the entire wall much stronger and more stable.
The merlons were all then recomposed with their peak cusps protected by stone tiles and fixed with stainless steel pins and resin to prevent them slipping.
Of the total 63 merlons on the roof, 35 were strengthened with just bars, 24 were removed and reconstructed and the 4 corner ones did not require any structural work.
The stone cornice which forms the base for the crenelated structure was carefully cleaned, stuccoed and strengthened and, again, the small stone elements that cover the join between the stone slabs were more securely fixed with stainless steel pins.
This delicate and complex conservationist and structural restoration project lasted almost six months and forms an important part of the overall plans for the maintenance and improvement to the Palazzo dei Trecento, which are conducted year after year to guarantee the total preservation and safety of the construction.
By Rossella Riscica
Acciaio Arte Architettura 56