nederlands / english

Fortisbank / Blaak 555

Blaak Office Tower is the name of the high-rise for Fortis Bank Blaak. It is a true American skyscraper, designed by the German /American high rise specialist Helmut Jahn. The relatively slender building has a special construction, which uses "outriggers".



Opposite the Schielandhuis a former building of Gerzon from 1935 had survived the WWII-bombing. After the departure of Gerzon the building was used by the Dutch Credit Bank. The site was developed in 1991 by the developer as Alvesta Blaak Office Tower. In 1993, the location was chosen as the headquarters of Credit Lyonnais, that was taken over by Generale Bank during the build, and later part of Fortis Bank. The limited space demanded a slender building. The building was designed by architect Helmut Jahn of Murphy / Jahn from Chicago.For the development and implementation the Dutch Architects Inbo and the Dutch design office D3BN were enabled.




The building is 106 meters high and has an area of about 38,000 square meters. Underneath the building is a parking garage of three layers. The building has a curved wall on the side of Blaak and Rottenburg street. On the side of the Hoogstraat there is an upward sloping lower portion of eleven stories like a "backpack". The lower part remains an open construction to give the Schielandshuis enough visibility. On the side of the Soetensteeg the building slopes gradually on, so the houses have sufficient daylight. The upper floors of the high-rise feature a steel crown.




The building has necessarily been made using a special construction. Common at a building height of 106 meters and for stability and rigidity a concrete core of ten meters in diameter is needed. The remaining office floors would however be too small for a profitable use. In the longitudinal direction the core houses the lifts, stair risers and ducts. In the transverse direction a number of steel wall mounted columns, which are suported by V-shaped steel yokes in two places and are secured to the core. This construction method is called a transfer or outrigger construction system and is usually used for buildings of about 200 meters high. The backpack is mostly made of concrete, only the sloped wall is a steel construction. The support structure on the lower level is a steel truss structure. With its asymmetrical design, varying facades and typical crown the skyscraper provides a different silhouette from every standpoint. In that sense it is a typically American building that differs from the nearby located more geometric towers like the Robeco Tower by architect Quist and Schieland Tower by architect De Bruijn.


  • Bouw 1992-20
  • Archis 1993-1
  • Cement 1996-1
  • Bouwen met Staal 1996-11/12

Murphy/Jahn Architects

Construction year
1990 - 1995

Blaak 555
3011 GB Rotterdam
verwijder van mijn route
voeg toe aan route


Bookmark and Share


view all routes