THE WORKSITE

Worksite operations began on August 30th, 2004 with transportation of materials by barge-pontoon equipped with a crane. The unloading began at 5pm at the mouth of of the Grand Canal, (Bacino San Marco) mooring at Consorzio Venezia Nuova’s worksite opposite the Marciana Library. Materials were off-loaded directly into St Mark’s Square by crane thereby passing over the top of the existing worksite at the dockside.

An area of 200 square metres behind the bell tower (Il Campanile) in St Mark’s was set aside as work and storage site for the project. A wooden fence measuring 3 metres 50 was immediately erected using fir match-board painted blue and sustained by wooden trestles. As protection from atmospheric agents, in particular wind and flooding, a system of ballasts was created using a series of basins holding 1mc of water. The weight of materials, previously calculated, against the weight of the enclosure ensured that they did not go over the official 500kg/mq permitted by authorities for St Mark’s Square.

The enclosure, using 15 men, was completed between 8pm of August 30th and 6am of August 31st. Materials were also stockpiled, with the presence of another 12 men, using a system of rubber-wheeled trollies and transpallets. Twenty seven men in all were employed.

The following day saw another off-loading, between 11pm and 5.30am, using the same methods of transportation and employing 14 men.

Nine hundred and fifty quintals of material and equipment were off-loaded providing for the construction of a suspended worksite facing the Clock Tower itself. This suspended worksite is supported by columns bonded to a reinforced concrete base.

Constructing the concrete bed involved removing about 100 square metres of stone blocks (masegni) that make up Venice’s pavement, in the area facing the Clock Tower. Previous to the removal, a photographed map of the area, in 1:50 scale, was taken. Each block was noted and classified with an identifying number in its top right corner. A red water-solubile pastel, fixed with a solution of Paraloid B 72 and diluted with nitrate, was used.

The stones were temporarily stockpiled under the scaffolding surrounding the worksite. As soon as the stockpile behind the Campanile has been cleared, the stones will be arranged on wooden pallets in numerical order. A detailed study has already been carried out on each stone block allowing it to be located at anytime and most importantly at the moment in which the pavement will be relaid.

The earth under the pavement has been dug and levelled at 27cms from the level of the Square with the authorized dumping of about 20 cubic metres of material. The intervention was overseen by an archeologist and technicians belonging to Venice and the Lagoon’s Superintendence for Architecture, Environment, Historical Patrimony, Arts and Demoetnoanthropology.

During the dig, some of the Square’s old masegni were discovered and removed and photographed in detail. Old water and gas pipes were also found and substituted by Venice’s official gas and water companies (VESTA and ITALGAS).

The excavation was protected by a non-woven fabric and nylon spreads cut to an exact outline of the work in course. Three thousand five hundred kilogrammes of iron was used to construct the reinforced concrete bed.

The bed was laid, with the agreement of the afore mentioned public bodies, between the night of the 17th and 18th of September thus avoiding disruption to the public. Work began at 6pm with the construction of a runway from worksite to dockside in the Lagoon. The runway, made up of two layers of plywood nailed together, factilitated the transportation of two wheeled dumpers carrying cement mix from trucks on the pontoon-barge docked behind the Venezia Nuova worksite. Both the runway and the dumpers were carefully studied so as not to exceed the 500kg/mq weight limit permitted in the square to avoid pavement damage.

The whole area was fenced in on both sides with two crosswalks provided and supervised by the city police (vigili urbani). By 6am the construction was dismantled, the square cleaned and removed of all machinery.

The cement, transported to the excavation site was thrown and hand-laid from 9pm to 4.30am. Thirty cubic metres of cement Rck300, S4 was used with the addition of Rheobuild 878 fluidifier. The surface was prepared with a special treatment to recreate the quality of the stone blocks. To make the concrete bed similar to the original stone blocks surrounding it, it was dusted with a specific composition: 40kgs of black ebony, 2.5kgs of red levant, 1.5kgs of terra ombra naturale, 50kgs of quartz sand, 10kgs of black inerte. The mix was freshly worked on site with a trowel and, following the photomap of the original masegni, fissures were cut into the concrete to copy the shape of the old stone blocks. In this way the newly laid bed is hardly recognizable form the surrounding pavement. This phase of the work carried on until midday of September 18th. In total 28 men were involved in the laying of the bed.

From September 20th, work began on flooring and the putting up of walls to form the provisional home of a Bureau de Change which had lost its home owing to the restoration project. The walls and floors were treated with a waterproof seal a spinta negativa (Volteco-Plastivo 250) to avoid leaks during flooding.

The mounting of scaffolding to support the suspended worksite also began. Six zinc-plated steel columns and horizontal beams Ipe 200 and 270 sustain a wooden platform, a metal staircase giving access to the scaffolding and a ceiling cover made from metal tie beams.

The works will continue with the installation of internal and external walls made out of “sandwich” type panels painted light grey. They will be transported by the pontoon-barge on the night between the 23rd and the 24th of September. The number of persons employed in this phase will vary.