20% cheaper and build 50% faster

Prefabricated shell for Fibonacci in Amsterdam

With Fibonacci, developer VORM 2050 and its construction partners are adding 243 sustainable social and middle rental apartments to the scarce affordable segment in Amsterdam. Special features of the residential building include its striking appearance and wide variety of residential floor plans, combined with the prefabricated construction method. "The ambition of VORM 2050 is to build 20% cheaper and 50% faster. To make this possible, the main supporting structure as well as the interior walls, floors, bathrooms, installations and concrete facades will be prefabricated," says Peter Duits, board member of Stable Management. "We support this approach because it also leads to higher quality, less transport, lower nitrogen emissions and a safer working environment."

As a partner of VORM 2050, Stable Management came to the table as early as the tender phase, to work out a smart and economic precast structure for Fibonacci. "We then engineered, delivered and assembled the complete precast shell," says Duits, who handled both the shell design and project management. "The shell consists mainly of concrete walls in thicknesses of 150, 200 and 250 mm, combined with prestressed and non-prestressed floor slabs. In addition, we supplied and assembled the stairs and landings. Sandwich elements with a concrete inner leaf and a concrete outer leaf with masonry were chosen for the facade, the assembly of which we provided."

Fibonacci's stability is derived from a sophisticated collaboration between the apartments' residential separating concrete walls and the sandwich facades, explains Duits. "Because the sandwich facades were supplied by another party, precise coordination was necessary in the design and engineering phase. This also involved consultant Snijders Ingenieursgroep and chief structural engineer IMd Raadgevende Ingenieurs." Due to the limited construction site, all precast elements had to be delivered just-in-time and processed immediately. "A challenge, because the construction cranes had to be available at that time. Moreover, all work had to flow smoothly into one another in order to meet the short construction time. In order to perfectly coordinate all prefab components, we expressly looked beyond the boundaries of our own package. This is how we arrived at the best solutions for the project and all parties involved."