ANCHORING THE HINGES AND WATERPROOFING THE CAISSONS
The metal floodgates, which are raised when required to block high tides, are anchored to the reinforced concrete caissons with a hinge mechanism which allows them to be raised and lowered. As Enrico Pellegrini, former Site Manager for Grandi Lavori Fincosit SpA, explained in the interview contained in our magazine, to anchor the hinges to the caissons, a great deal of design work and testing was conducted to identify the most appropriate products and technology to fasten a metal component, in this case the hinge, to concrete.
Mapei specifically developed MAPEFILL MF for this application, an expansive, fluid mortar for anchoring elements in position with great precision. The mortar was applied by injecting it into one side of the hinge and then it flowed to perfectly saturate all the gaps and free spaces to form a single, solid body with the caisson it was anchored to.
The waterproofing system for the caissons, which are then placed on the seabed, also had to be carefully designed and thoroughly tested in order to identify products that would guarantee excellent, long-lasting results. After performing tests on site and in the lab, the external surface of the caissons was treated with MAPELASTIC FOUNDATION, a two-component, flexible cementitious mortar for waterproofing concrete surfaces subjected to both negative and positive hydraulic pressure.
The product chosen for the inside of the caissons, on the other hand, was MAPELASTIC two-component, flexible cementitious mortar. It was applied after treating the substrates with a specially designed version of PRIMER 3296.
This part of the work, as with the challenge of anchoring the hinges, was closely followed by the Mapei Research & Development Laboratory in Milan, which carried out testing on the application of the products for the entire duration of the site.