Punta della Dogana
www.restauropuntadelladogana.it
The ultimate challenge in site management
Looking towards Punta della Dogana from St. Mark’s Square, the building seems a triangle floating on the water. This building dating back to the 13th century, always owned by the state, and recently in abandon and disrepair, was originally a series of salt warehouses, and later ''Dogana da Mar'', strategically built at the junction of the Giudecca and Grand Canals. François Pinault, already owner of the Palazzo Grassi Contemporary museum, made arrangements with the city to lease and renovate this spectacular symbol of Venice to house his permanent art collection. Palazzo Grassi SpA called on Tadao Ando Architect & Associates of Osaka to design the project for the restoration while the Dottor Group was appointed general contractor. The building was beautifully shrouded in white and in absolute secrecy for the thirteen month restoration. Brick by brick and tile by tile the building was completely restored, reinforced, reconstructed but also architecturally and artistically renewed. At the heart of the building based on Tadao Ando’s vision and design, Dottor Group constructed a cube: magnificent 7 meter high cement walls, smooth as silk. The detailed and carefully planned phases of the project were carried out paying particular attention to take advantage of the opening of the 2009 Venice Biennale Art Exhibition.
The Ando cement walls
Of particular note are the signature cement walls designed by Tadao Ando to delineate the new space for the contemporary art museum. The existing structure was restored to its original architectural form and few modern elements were added. The walls, one of these key elements, symbolize a crossroad for a building that once represented trade during the reign of the Venetian empire, and now where past, present and future meet in the context of contemporary art.
The Ando walls are bare cement, smooth as silk and shiny, evoking a typically Japanese materialness and formal perfection. The walls form a cube inside the main gallery: each side is 16 meters long, 30 cm thick and 7 meters high.
Their construction represented one of the greatest challenges during the restoration: never before had the Ando walls been constructed on a site floating on a heavily navigated waterway. Initially, the Dottor Group simulated and studied the time needed to perform the operation on dry land. The caisson was designed and built using 90 x 180 cm panels brought on barges to the site, then assembled with a tolerance of no more than 3 mm to guarantee a flawless result. The assembly and setting of the caisson was handled with use of two cranes, an extremely delicate operation due to the need to pass the panels between the existing 17th century trusses. The casting was then completed in 8 different castings over a period of two months. Although the briefest operation during the construction of the walls, it was the most difficult. The engineers identified the optimal cement mix after months of testing the granule composition, the ratio of water to cement and the type fluidificants and retardants. Barges transported the cement trucks and pumps; work was carried out at dawn or during the night to avoid waves by passing boats. Even a small oscillation caused the crane to sway some meters. The cement was pumped gradually while technicians with 8 vibrating needles eliminated air bubbles. 48 hours later, the caisson was dismantled to reveal a perfect single surface, and an illusion of lightness and elegance.
