Construction has begun on what will become one of the world’s tallest buildings upon its expected completion in 2016—a 530 m tall mixed-use tower near Tianjin, China, that addresses both wind and seismic forces without the use of dampers. © SOM
Designed as a distinctive element of the Tianjin Economic-Technological Development Area, the structure will offer a variety of services.
August 7, 2012—In mid-May ground was broken for the 530 m tall Tianjin Chow Tai Fook Binhai Center, near Tianjin, China, marking the start of construction on what will become one of the world’s tallest buildings upon its expected completion, in 2016. If completed today, the 96-story tower, which features undulating curves and multiple-story wind vents, would be second in height only to the Burj Khalifa, the approximately 828 m tall skyscraper in Dubayy (Dubai), part of the United Arab Emirates. (See “The Burj Khalifa Triumphs,” Civil Engineering, March 2010, pages 44–55.)
The Tianjin Chow Tai Fook Binhai Center is located in the Tianjin Economic-Technological Development Area, one of a number of specially designated zones within China aimed at facilitating foreign investment in manufacturing. The tower’s owner—the New World Development Company, Ltd., of Hong Kong—wanted a supertall building that would serve as a “marker” for the Tianjin Economic-Technological Development Area while offering a variety of services, says Brian Lee, FAIA, LEED AP, a design partner of Skidmore, Owings & Merrill (SOM) LLP, of Chicago, which provided architectural and structural engineering services for the project. SOM collaborated with the project’s engineer of record, the East China Architectural Design & Research Institute Co., Ltd., of Shanghai.
The approximately 251,000 m² tower will comprise mostly office space and 300 apartments, as well as a 350-room hotel near its top. The tower’s four basement levels will provide parking, while an adjacent podium will house restaurants and retail establishments. All told, the complex will have an area of nearly 390,000 m². The varying uses of the building posed a challenge that complicated design efforts. “Each program element had different requirements spatially,” Lee says.
As a result, the structure required different floor plans for the areas devoted to office space, residential apartments, and the hotel. To support the different uses as efficiently as possible, SOM narrowed the building’s reinforced-concrete core as it extends upward and included openings within the core walls to accommodate the various functions and manage transitional forces between the building’s different areas, says Alessandro Beghini, Ph.D., P.E., S.E., M.ASCE, an associate and project engineer for SOM.
High seismic and wind loads figured prominently the building’s design, says William F. Baker, P.E., S.E., F.ASCE, the structural engineering partner of SOM. To address the seismic loads, “we wanted something sufficiently stiff but not too stiff,” Baker says. To this end, the building’s core is mainly of reinforced concrete, although in places it is a composite of concrete and steel plates. At the base, perimeter columns take the form of concrete-filled steel tubes. As they near the top, however, the columns are made of reinforced concrete so that their size can be decreased.
The building’s foundation is formed by a pile-supported mat. Designed to meet specified stiffness criteria, thick core walls begin right below ground level. Extending upward from the base through the building’s lowest section are eight inclined columns that “act like soft braces to stiffen the building at the base,” Baker says. The inclined columns “don’t quite touch in the middle,” he says, and “that enables us to get both stiffness and ductility.” In this way, the design affords the stiffness needed to resist seismic loads while dissipating energy that otherwise would generate significant forces. “That worked well in the lower part” of the building, which is dedicated to office space, Baker says. However, in the residential area, the smaller rooms, with their more regular fenestration, required the use of “more of a moment frame,” he notes, which becomes “more sparse” as it extends upward and seismic forces decrease.
The Tianjin Chow Tai Fook Binhai Center is located in the Tianjin
Economic-Technological Development Area, one of a number of
specially designated zones within China aimed at facilitating
foreign investment in manufacturing. The 251,000 m² tower will
include office space, apartments, and hotel rooms.
The inclined columns also help to address wind loads because they “move the gravity loads to where the wind forces want to go,” Baker says. “We’re able to use the weight of the building to help resist wind and seismic forces—both.” As a result, the building “behaves very, very well” under both wind and seismic loads, he says.
New World Development hired SOM after terminating the services of another architecture firm and structural engineering firm. SOM set out to overcome certain limitations of the design prepared by the original team. “One of the problems with the previous solution was that the wind forces were extremely high,” Baker says. In fact, the original design called for an expensive damping system. Early on, SOM evaluated 18 different design configurations in a wind tunnel, and the findings “informed how we finalized the shape,” he says. “We were able to greatly reduce the wind forces and the wind accelerations to a very low value.” As a result, the tower does not require the use of a damping system.
By developing a design that is stiff yet ductile and cost-effectively addressing wind loads, “we were able to tremendously reduce” the volume of materials needed to build the structure, Baker says, compared with what was called for in the original design. As a result, the building will cost less and take less time to construct than originally planned. Furthermore, the Tianjin Chow Tai Fook Binhai Center is expected to be “very, very quiet,” Baker says. “This is certainly one of the quietest supertall buildings out there from a wind motion point of view.” The approaches used to decrease building movement caused by wind loads included using in-house software to tune the building’s harmonics relative to wind and rounding the structure’s corners.
Despite its undulating appearance, the building’s facade will not use curved glass, Lee says. “The building looks like it’s very voluptuous and curving, and everything is curved glass,” he says. “It’s actually composed of all flat glass panels.”
Work on the foundation pilings for the Tianjin Chow Tai Fook Binhai Center is being carried out by China Construction Third Engineering Joint-Stock Ltd., of Tianjin. As of press time New World Development had not yet hired a primary contractor for the tower’s construction.