DESCRIPTION
From its inception, the Citicorp Bank building presented a challenge to the the urban disposition. The site was free for development except for the corner, where St. Peter’s Lutheran Church stood. The church reached an agreement whereby it sold its air rights to Citicorp and received, in return, a new church on the same site, separate from the Citicorp building and with open sky above it. These requirements led to a unique engineering solution - the supports carrying the 55-storey office block were positioned in the middle of the façade. This allowed the church to be a free-standing structure and permitted the creation of an open public plaza at street level, receiving plenty of daylight. This striking structural solution gives further emphasis to the strategic location of the Citicorp Center. Moreover, the forty-five degree angle of the Citicorp Center roof makes it instantly recognisable from a distance on the Manhattan skyline. At the same time. a very urbane public space has been created in an attempt to establish direct contact to people via the plaza church and subway in the central base support. Together with the central core, the four 114-feet-high, load-bearing supports carry the entire weight of the skyscraper The tower is divided into six units of eight floors each, defined by diagonal. V-shaped steel buttressing. Within each system of forces, the vertical forces are transferred from the comers into the middle of the sides, where they are then further transferred into the foundations via the four supports. This skyscraper was one of the first tall buildings to be fitted with a tuned-mass-damper (TMD), a 400-ton, computer-controlled concrete block situated on the top of the building and used to equalise the effects of wind sway movements. The central core, located in the center of the tower, also houses a total of Ground floor twenty-two lifts, which, for the most part, have double-floor cabins to transport passengers from two floors simultaneously, thus saving both space and time. The emergency staircases are also located within the centre core as well as in three of the four façade supports.
ARCHITECT:
LOCATION:
Hugh Stubbins & Associates with Emery Roth &Sons
New York, NY, USA
DATE:
ENGINEER:
HEIGHT:
1977
LeMessurier Associates and the Office of James Ruderman
279 m (915 ft) STORYS: STORYS: 59
RESEARCH:
WIDE - SPAN BUILDINGS
JULIAN S E F I R O W ___ A N D R E LINDNER SUPERVISION: PROFESSOR PETER LAND _ IIT Chicago
51. CITICORP CENTER
The façade consists of alternate bands of clear, reflecting glass and shiny aluminium panels. This smooth, gleaming external skin is intended to underline the distinct external appearance of the tower and make it stand out against the surrounding buildings.