Citigroup Center

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search

Citigroup Center
Citigroup center.jpg
Alternative names601 Lexington Avenue
General information
Location153 East 53rd Street, New York, NY 10022
Coordinates40°45′31″N 73°58′13″W / 40.758533°N 73.970314°W / 40.758533; -73.970314Coordinates: 40°45′31″N 73°58′13″W / 40.758533°N 73.970314°W / 40.758533; -73.970314
Construction startedApril 1974
CompletedOctober 6, 1976[1]
OpeningOctober 12, 1977[2]
Cost$195 million (USD)
(equivalent to $823 million)
OwnerBoston Properties
Architectural915 ft (279 m)[3]
Technical details
Floor count59[3]
Floor area1,578,883 sq ft (146,683.0 m2)
Design and construction
ArchitectHugh Stubbins / KlingStubbins, Emery Roth & Sons
DeveloperBoston Properties
Structural engineerLe Messurier Consultants, James Ruderman

The Citigroup Center (formerly Citicorp Center and also known by its address, 601 Lexington Avenue) is an office skyscraper in New York City, located at 53rd Street between Lexington and Third Avenues in midtown Manhattan. Built in 1977 to house the headquarters of Citibank, it is 915 feet (279 m) tall and has 59 floors with 1.3 million square feet (120,000 m²) of office space.

The building is one of the most distinctive and imposing in New York City’s skyline, thanks to a 45° angled top and a unique stilt-style base. It was designed by architect Hugh Stubbins and structural engineer William LeMessurier. The building is currently owned by Boston Properties, and in 2009, was renamed 601 Lexington Avenue.


Top of the Citigroup Center from the Rockefeller Center

The Citigroup Center is a 59-story, 915-foot-tall (279 m) tower clad in glass and metal facade.[1]:1

Structural engineer William LeMessurier designed the tower to be supported by four massive columns 114 feet (35 meters) high, positioned at the center of each side, rather than at the corners. This design allowed the corners of the building to cantilever 72 feet (22 meters).[1]:1[4] To help accomplish this, LeMessurier employed a system of stacked load-bearing braces, in the form of inverted chevrons. Each chevron is designed to distribute tension loads (due to wind) to their center, then downward into the ground through the uniquely positioned columns.

The roof of Citigroup Center slopes at a 45-degree angle. Designers originally intended it to be terraces for apartments, and later revised it to contain flat-plate solar collectors, to produce hot water which would be used to dehumidify air and reduce cooling energy.[1]:1[5] However, they eventually dropped this idea because the positioning of the angled roof meant that the solar panels would not face the sun directly.

Notable features[edit]

Base of the Citigroup Center. St. Peter's Evangelical Lutheran Church is visible on the left-hand-side below the skyscraper, the location of which necessitated the unusual column locations.

The cantilever exists because the northwest corner of the building site is occupied by St. Peter's Lutheran Church.[1]:1 When Citicorp Center was built in the 1970s, the church allowed Citicorp to demolish the old church building and build the skyscraper under one condition: a new church would have to be built on the same corner, not attached to the Citicorp building and no columns passing through it, because the church wanted to remain on the site of the new development, near one of the intersections. The church, at 619 Lexington Avenue with its entrance from 54th Street, has a theatre in its basement which is mainly used by the York Theatre.[6]

To help stabilize the building, a tuned mass damper was placed in the mechanical space at its top. This substantial piece of stabilizing equipment weighs 400 tons (350 metric tons). The damper is designed to counteract swaying motions due to the effect of wind on the building and reduces the building's movement due to wind by as much as 50%.[7][8] Citigroup Center was the first skyscraper in the United States to feature a tuned mass damper.[9] In addition, in 2002, one of the columns was reinforced with blast-resistant shields of steel and copper as well as steel bracing to protect the building due to the possibility of a terrorist attack.[10]

The building features double-deck elevators, which are separated to serve only odd or even floors. People can travel between odd and even floors using escalators.[11]

Various plazas were included as part of the building's construction.[1]:2 One such plaza exists below the cantilever, where there is an entrance to the New York City Subway station at Lexington Avenue/51st Street, served by the 6, <6>​​, E, and ​M trains.[4]

From 1987 to 2009, the bank presented an annual toy train exhibition in the lower lobby.[12]



Public lobby

The northwest corner of the site was originally occupied by St. Peter's Evangelical Lutheran Church, which was founded in 1862 (as the Deutsche Evangelische Lutherische Sanct Petri-Kirche). The original church building was sold and demolished to construct the Grand Central Terminal in 1903. In 1905, the church moved to the location of 54th Street and Lexington Avenue, where it remained until the building was purchased by First National City Bank (later known as Citibank) in 1970.[13]

Engineering crisis of 1978[edit]

View from the street

Due to a design oversight and changes during construction, the building as initially completed was structurally unsound. For his original design, LeMessurier calculated wind load on the building when wind blew perpendicularly against the side of the building—wind from due north, east, south, or west—all that was required by New York building code. Such winds are normally the worst case, and a structural system capable of handling them can easily cope with wind from any other angle. Thus, the engineer did not specifically calculate the effects of diagonally-oriented "quartering winds" (northeast, northwest, southeast, or southwest). In June 1978, prompted by discussion between a civil engineering student at Princeton University, Diane Hartley, and design engineer Joel Weinstein, LeMessurier recalculated the wind loads on the building, this time including quartering winds.[14] This recalculation revealed that with a quartering wind, there was a 40% increase in wind loads, resulting in a 160% increase in the load at the chevron brace connection joints.

LeMessurier's original design for the chevron load braces used welded joints. However, during construction, builder Bethlehem Steel was approved to use bolted joints to save labor and material costs. LeMessurier's firm approved the change, although this was not known to LeMessurier himself. The original welded-joint design had ample strength to withstand the load from straight-on wind, with enough safety margin to withstand the higher loads from quartering wind; however, the load from a 70 miles per hour (110 km/h) hurricane force quartering wind would exceed the strength of the bolted-joint chevrons. The bolts could shear and the building could collapse. Wind tunnel tests with models of Citigroup Center revealed that the wind speed required to bring down the building would occur every 16 years on average.

For occupant comfort, the building has a tuned mass damper, which also negates much of the wind load. The damper is electrically activated, so if power failed, for example during a hurricane, the damper might not turn on,[15] and a much lower-speed wind would suffice; wind of this speed occurs on average once in 16 years. LeMessurier also discovered that his firm had used New York City's truss safety factor of 1:1 instead of the column safety factor of 1:2. These factors, combined, put the building in critical danger. The problems were discovered in June, the beginning of hurricane season, and had to be corrected quickly.[16]

LeMessurier reportedly agonized over how to deal with the problem. If the issues were made known to the public, he risked ruining his professional reputation. He approached the architect (Hugh Stubbins) first, and then Citicorp. He advised them to take swift remedial action. Ultimately, he persuaded Citicorp to repair the building without informing the public, a task made easier by a then-ongoing press strike.[16]

For the next three months, construction crews working at night welded 2" steel plates over each of the skyscraper's 200 bolted joints. They worked during the night, after each work day, almost unknown to the general public. Six weeks into the work, a major storm (Hurricane David) was off Cape Hatteras and heading for New York. With New York City hours away from emergency evacuation, the reinforcement was only half-finished. Ella eventually turned eastward and veered out to sea, buying enough time for workers to permanently correct the problem. As a precaution, Citicorp did work out emergency evacuation plans with local officials for the immediate neighborhood.[16]

Because nothing happened as a result of the engineering gaffe, the danger was kept hidden from the public for almost 20 years. It was publicized in a lengthy article in The New Yorker in 1995.[17]

Ethical questions[edit]

Night view of the Citigroup Center from 30 Rockefeller Plaza

Architect Eugene Kremer has discussed the ethical questions raised in this case.[18]

LeMessurier was criticized for insufficient oversight leading to bolted rather than welded joints, for not informing the endangered neighbors, for actively misleading the public about the extent of the danger during the reinforcement process, and for not informing architects or other structural engineers about the problem and solution for two decades.[18] However, his act of alerting Citicorp to the problem in his design is now used as an example of ethical behavior in several engineering textbooks.

Kremer discusses six key points:[19]

  1. Analysis of wind loads. Check all calculations and not rely just on building codes; these set minimum requirements and not the state of the art.
  2. Design changes. In this case change from welded to bolted connections. Changes are considered in the overall design context and by everyone involved and not a spur of the moment decision.
  3. Professional responsibility. To follow the codes of conduct for every chartered institution. LeMessurier did not consider the public safety first.
  4. Public statements. In this case the public statements issued by LeMessurier and Citigroup set out to mislead the public deliberately.
  5. Public safety. The public statement denied the public the right to ensure their own safety and to make their own critical decisions.
  6. Advancement of professional knowledge. Concealing this problem for almost 20 years prevented ethical and engineering learning that could have taken place.

Sale and name/address changes[edit]

Former Citicorp Chairman Walter B. Wriston was reportedly behind the decision to acquire several low- and mid-rise buildings in the area, supposedly to buy out massage parlors and mom-and-pop stores in Midtown.[20] In 1987, Citigroup sold two-thirds of its interest in the building, along with one-third of its interest in 399 Park Avenue, to Dai-Ichi Mutual Life Insurance Company for $670 million (total cost of building adjusted for inflation: $365,584,843).[21] In 2001, Citicorp sold its controlling stake in the building for $755 million (cost of building adjusted for inflation: $569,794,069) to Boston Properties. Citigroup relocated its headquarters to 399 Park Avenue.[22][23]

In 2008, building owner Boston Properties began the process of renaming the tower "601 Lexington Avenue".[24] Renovation of the lobby resulted in relocation of the tower's entrance from 53rd Street to Lexington Avenue.[25] All signage for Citigroup was removed from the building and surrounding block. The name change became effective in 2009.[26][27] The company is also considering selling naming rights to the building.[28]

Renovation plans[edit]

In March 2017, Gensler revealed designs for a major renovation around the base of the tower. The renovation will include a redesigned entry plaza and a new atrium space.[29]

In popular culture[edit]

  • The building's architectural design and history were the feature of episode 110, "Structural Integrity", of the podcast 99% Invisible.[30]
  • The silhouette of the sloped top of the building appears on the label of Chock full o'Nuts coffee.[31]
  • The sloped top of the building is referenced in the Manhattan Mini Storage logo, as the top of the first letter "t" is similarly sloped.[32] In an older version of the logo, the top left corner of the letter M was sloped like the Citigroup Center.[33]
  • According to Business Insider, the New York Mets have at times used a logo since 2014 that has included the Citigroup Center, as Citigroup is the sponsor of their home stadium, Citi Field.[34]

See also[edit]



  1. ^ a b c d e f Postal, Matthew A (December 6, 2016). "Citicorp Center" (PDF). New York City Landmarks Preservation Commission. Retrieved December 10, 2018.
  2. ^ "Citicorp's Center Reflects Synthesis of Architecture". The New York Times. October 12, 1977. Retrieved June 24, 2018.
  3. ^ a b c "Citigroup Center – The Skyscraper Center". Council on Tall Buildings and Urban Habitat. Archived from the original on June 15, 2012.
  4. ^ a b Morrone, F. (2009). Architectural Guidebook to New York City. Gibbs Smith. p. 169. ISBN 978-1-4236-1116-5. Retrieved December 13, 2018.
  5. ^ Loring-Meckler Associates, Inc.; Massachusetts Institute of Technology (June 1977), Solar Energy Dehumidification Experiment on the Citicorp Center Building (PDF), National Science Foundation
  6. ^ Our Venue, York Theatre
  7. ^ Greer, William R. (October 24, 1982). "Rx for Swaying Skyscrapers". The New York Times. Retrieved July 25, 2009.
  8. ^ Brady, Sean (December 8, 2015). "Citicorp Center Tower: how failure was averted". Engineers Journal. Retrieved December 10, 2018.
  9. ^ "BUILDING BIG: Databank: Citicorp Center". PBS. Retrieved December 10, 2018.
  10. ^ O'Driscoll, Patrick (September 25, 2002). "High-rises remain vulnerable after 9/11". USA Today. Retrieved April 11, 2010.
  11. ^ Mackay, D.A. (2010). The Building of Manhattan. Dover Architecture. Dover Publications. p. 137. ISBN 978-0-486-47317-8. Retrieved December 10, 2018.
  12. ^ Citi Derails Holiday Toy-Train Show in Credit Crunch Bloomberg News, December 9, 2008[dead link]
  13. ^ "St. Peter Lutheran Church". NYC Ago. Retrieved June 23, 2017.
  14. ^ "OEC – Addendum: The Diane Hartley Case". Online Ethics Center. National Academy of Engineering. February 11, 2014. Retrieved March 13, 2019.
  15. ^ Connor, Jerome J. (2003). "Chapter 4: Tuned Mass Damper Systems" (PDF). Introduction to Structural Motion Control. Prentice Hall Pearson Education. p. 223. ISBN 978-0130091383.
  16. ^ a b c Werner, Joel. "The Design Flaw That Almost Wiped Out an NYC Skyscraper". Slate. Retrieved April 17, 2014.
  17. ^ Joseph Morgenstern (1995), "The Fifty-Nine-Story Crisis", The New Yorker, May 29, 1995. Pages 45–53.
  18. ^ a b Eugene Kremer (2002). "(Re)Examining the Citicorp Case: Ethical Paragon or Chimera", Cross Currents, Fall 2002, Vol. 52, No 3.
  19. ^ Delatte, Norbert J. (January 1, 2009). Beyond Failure: Forensic Case Studies for Civil Engineers. ACSE Press. p. 340. ISBN 978-0784472286. Retrieved March 13, 2019.
  20. ^ Stern, Robert A.M.; Fishman, David; Tilove, Jacob. 'New York 2000: Architecture and Urbanism Between the Bicentennial and the Millennium. ISBN 978-1580931779.
  21. ^ Berg, Eric N. (October 3, 1987). "Citicorp Selling Part Offers Headquarter". The New York Times. Retrieved September 4, 2009.
  22. ^ "Citi Doesn't Live Here Anymore as Name Comes Off NYC Skyscraper". Business Standard. New Delhi. Bloomberg News. January 29, 2013.
  23. ^ "Boston Properties Completes Citigroup Center Buy". The Weekly. April 26, 2001. Retrieved March 13, 2019.
  24. ^ Dana Rubinstein (2008), 'Citigroup Center' to Become Scintillating '601 Lexington Ave' Archived August 10, 2011, at the Wayback Machine, The New York Observer, December 12, 2008.
  25. ^ "JLL to Lease Renamed 601 Lexington Avenue" (Press release). Jones Lang Lasalle. June 24, 2009. Retrieved March 13, 2019.
  26. ^ "Boston Properties Announces Second Quarter 2009 Results" (Press release). Boston Properties, Inc. July 21, 2009. Archived from the original on October 6, 2018. Retrieved November 14, 2011.
  27. ^ "Frank Stella at the Atrium Shops and Cafes at Lexington Avenue and 53rd Street, New York, NY (Formerly Citigroup Center)" (Press release). Boston Properties, Inc. November 23, 2009. Archived from the original on October 6, 2018. Retrieved March 13, 2019.
  28. ^ BNET Boston Properties to rename 601 Lexington Avenue. Archived September 22, 2010, at the Wayback Machine
  29. ^ Lynch, Patrick (March 28, 2017). "Gensler to Complete 200,000-Square-Foot Renovation of New York's Citicorp Center". ArchDaily. Retrieved March 13, 2019.
  30. ^ Mars, Roman (April 15, 2014). "Structural Integrity". 99% Invisible. Retrieved April 23, 2014.
  31. ^ Barron, James (June 19, 2004). "Lost Towers, Reflected in a Can". The New York Times. ISSN 0362-4331. Retrieved July 24, 2017.
  32. ^ "Manhattan Mini Storage (logo)". Retrieved March 13, 2019.
  33. ^ "Original Manhattan Mini Storage Logo". Archived from the original on October 16, 2017. Retrieved October 16, 2017.
  34. ^ Gaines, Cork (September 16, 2014). "The Mets Have Been Using A New Logo With An Interesting Corporate Twist". Business Insider. Retrieved March 13, 2019.


External links[edit]