Kraanspoor (translated as crane way) is a light-weight transparent office building of three floors built on top of a concrete crane way on the grounds of the former NDSM (Nederlandsche Dok en Scheepsbouw Maatschappij) shipyard, a relic of Amsterdam’s shipping industry. This industrial monument, built in 1950 by architect J.D. postma, has a length of 270 meters, a height of 13,5 meters and a width of 8,7 meters, a street length and width, and was saved from demolition in 1997. The challenge of the design for OTH was to realize a maximum surface area without having to make radical adjustments to the existing concrete structure, utilizing its maximum allowable load-carrying capacity. To help minimize the weight, a light-weight building of steel structure in combination with an infra+ floor system (now referred to as Slimline-floor concept) was chosen for the new development, reducing the total building weight nearly by half. The new construction assembled on top of this old concrete base accentuates the length of Kraanspoor and the phenomenal expansive view of the river IJ and the old city–centre of Amsterdam.