trump_nightTrump Tower Chicago is a multi-use building with a height of 1,134 feet (1,362 feet including the spire) above grade and was completed in 2009. The building is located on the site of the forner Sun-Times Building, bounded by the Chicago River to the south, Rush Street to the east, and Wabash Street to the west. Designed by Skidmore, Owings & Merrill LLP (SOM) the 92-story Trump Tower is the tallest concrete building in the United States, and the tallest building built in North America since the completion of Sears Tower in 1974. The 2.6 million square foot building includes condominium, service apartments, health club, parking, and retail functions. Two below-grade levels, lower level one and two, are located between the elevations of Upper and Lower Wabash Street. A third below-grade level, lower level four, is located below the elevation of Lower Wabash Street generally within the footprint of the tower.

The tower superstructure is generally reinforced concrete. New ground was broken through a series of high performance concrete mixes designed by Prairie Material Sales, Inc. and employed by SOM on the project. It is believed to be the first application of 16,000 psi self-consolidating concrete pumped and placed to an elevation up to 650 feet above grade. The dense limestone ½-inch topsize aggregate was supplied from the Material Service Corporation. The Thornton quarry in Northern Illinois was specified for the high strength concrete on the project.

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Trump Tower - View from east

The building has major setbacks at levels 16, 29 and 51 that correspond to the top elevations of prominent neighboring buildings, providing visual continuity with the building’s surroundings. These buildings include the historic Wrigley Building on the east, Bertrand Goldberg’s Marina City to the west, and Mies van der Rohe’s IBM Building located directly across Wabash Avenue. Transfer walls occur at the setback levels to distribute discontinuous column forces to other structural elements. A central reinforced concrete core wall system, with wall webs generally spaced 30 feet on center, extends from the foundation level to the top of the tower. The core wall elements are connected by reinforced concrete link beams. The core wall dimensions in the north-south direction remain constant. Individual core wall elements terminate at select setback levels such that the configuration of the core wall system is similar to that of the building massing.

The major columns are reinforced concrete. Columns along the north and south faces are spaced at 30 feet on center while the distance between columns on the east and west faces varies. Interior columns below level 16 are generally spaced at 30 feet in the east-west direction and 45 feet in the north-south direction. Interior columns above level 16 are generally spaced at 30 feet in the east-west direction and 20 feet in the north-south direction.

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Construction of upper residential floors

Floor structures are generally flat plates or flat slabs. Special thick, heavily reinforced slabs are required at and above the mechanical levels. Floor slab thicknesses are increased at many levels to limit acoustic and vibration transmission. Typical residential floors are 9-inch thick flat plates spanning up to a maximum of 30 feet without perimeter spandrel elements. This construction minimizes the structural depth of the floor, allowing higher ceiling heights. Tower columns are typically 2-by-4-feet rectangular sections at the top of the building and 6-foot diameter circular sections at the base.

The tower lateral load resisting system is made up of the core wall system, outrigger system, and north/south face exterior columns. The outrigger system is composed of (a) outrigger walls that connect the core and exterior columns and (b) perimeter walls connected to the outrigger walls that engage exterior columns. The transfer walls referenced above are generally integrated with the outrigger system.

The tower foundation system consists of reinforced concrete caissons. A total of 57 rock caissons support the tower. The tower columns are supported by 33 of these rock caissons up to 8 feet in diameter and stabilized by a series of caisson caps and grade beams. A 10-foot thick concrete mat under the core walls transfers their enormous loads into a grid of the twenty-four, 10 feet diameter drilled shaft rock caissons that extend about 80 feet down where they are socketed 6 feet into solid Chicago limestone bedrock. The design team specified an Osterberg load cell test be performed on one of the first production rock caissons to verify an increase in allowable bearing pressure above the Chicago Building Code allowable 200 tons per square foot (TSF). The resulting successful Osterberg load cell test and the subsequent code variance, allowed the design team to utilize allowable bearing pressures up to 270 TSF. The increase in allowable bearing pressures, coupled with the utilization of high strength (10,000 psi) concrete in the caisson shafts, resulted in significant reduction in rock caisson quantities for the project.

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Utililization of rebar terminators

Because of the magnitude of the applied loads and the scale of the outrigger elements, the structural engineering design for these elements was unique and extremely challenging. Large tie forces are resisted by top and bottom longitudinal reinforcing and vertical ties. The heavy longitudinal reinforcing steel must pass from the thicker outrigger through the thinner core wall web to transfer forces between the columns and core. To reduce congestion, all primary reinforcing bars in the outrigger levels are United States Grade 75. Further, in three especially-tight locations, high strength structural steel plates with welded shear studs are used in lieu of reinforcing bars to transfer the necessary forces through the core wall web.

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Concrete delivery

A series of high performance concrete mixtures, specified by SOM and designed by Prairie Material Sales, Inc., are advancing the state-of-the-art. Concrete strengths of 12,000 psi at 90 days have been specified for all vertical column and wall elements up to Level 51. Local areas in the outrigger zones, however, require 16,000 psi concrete at 90 days. Because the 16,000 psi concrete is located in areas with high reinforcement congestion, self-consolidating concrete (SCC) with a minimum flow table spread of 24 inches has been specified. Further, to reduce the heat gain in the massive elements, the high performance SCC incorporates slag cement, fly ash, and silica fume as well as portland cement.

Project completion was in 2009; however, based upon the phased-occupancy plan, the 339 room Hotel opened January 30, 2008, and the 16th floor restaurant opened February 2008; well before the topping out of the structure.

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Original Sun-Times Building
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Slab shoring

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Column and slab rebar placement
  
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View inside core wall formwork

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Construction photo - September 21, 2006

Photos by Lawrence Novak


References:
Baker, W.; Korista, S.; Sinn, R.; Pennings, K.; & Rankin, D., “Trump International Hotel and Tower,”Concrete International, July 2006, 28-32. Marketing article, February, 2007.

Baker, W.; Korista, S.; Rankin, D.; Sinn, R., “Specifying High Performance Concrete for the Trump Chicago,” Proceedings of the ASCE/SEI Structures Congress 2008.


Credits

Developer:
401 North Wabash Venture LLC (The Trump Organization), New York, New York

Structural Engineer: 
Skidmore, Owings & Merrill LLP, Chicago, Illinois

Architect
Skidmore, Owings & Merrill LLP, Chicago, Illinois

Geotechnical Consultant:
STS Consultants Ltd., Chicago, Illinois

Construction Manager:
Bovis Lend Lease LMB, Inc., New York, New York

Concrete Contractor:
James McHugh Construction Co., Chicago, Illinois

Concrete Supplier:
Prairie Material Sales, Inc., Bridgeview, Illinois

SCC Admix. Supplier:
Degussa Admixtures, Inc., Beachwood, Ohio

Year:
2009