Hanking Center Tower is a commercial office building noted for its tall, thin and irregular shape; and at 1,150 feet, 73-story in height, it is the world’s tallest detached core building. The external mega-braced frame structural system accommodated the distinct architectural form, which features a service core offset 33 feet from the rest of the floor plate and a structural form capable of resisting typhoon-level winds.
Design work for the 1.2 million-square-foot tower began in January 2013, and the building topped out in December 2016. The building is now structurally completed, and occupancy is slated for 2019. It is the third tallest skyscraper in Shenzhen and the 51st tallest building in the world.
The Chicago buildings group was the structural designer of the Hanking Center Tower in Shenzhen, China. The skyscraper is essentially composed of two towers that are too slender to stand on their own, but wrapped together into one structure that can resist overturning forces. Our scope of work included schematic design, design development, participation in the expert panel review process through approval, and review of the construction documents prepared by the local design institute. WSP also served as the mechanical-electrical-plumbing-fire protection engineer and the vertical transportation engineer for the project.
Our structural engineering team worked closely with Morphosis to stay true to the design intent – a challenge given some aspects of the tower’s design. Chief among these, the core of the building is shifted outside of and separated 32.8 feet from the office floor plate. Only narrow walkways were envisioned to link the core to the remaining tower mass. This could have created two incredibly slender towers, with insufficient lateral strength and stiffness.
To address this and other design challenges, our team designed an innovative ‘mega-braced’ tube structure. Composite columns were linked by steel diagonal bracing organized over multistory modules around and through the tower. The result is a closed tube structure that achieves a high degree of efficiency by engaging the entire tower depth in resisting overturning forces. By using this bracing in lieu of more common concrete systems, the structure could be designed to the higher drift limits allowed for steel systems by Chinese code. This approach offered significant savings to the structure and helped keep it relatively light, particularly given its height.
The structural concept was fully integrated with the architectural design. This included fitting bracing through floor plans without compromising lease spaces, and also maintaining the minimal floor links, envisioned by Morphosis, between the tower and core through the use of light steel bracing at selected levels.
The structure is designed in accordance with the latest performance-based seismic design approaches using non-linear time history analyses, and received expert panel approval.
With its striking design, Hanking Center Tower – which won the 2017 National Council of Structural Engineers Associations (NCSEA) Excellence in Structural Engineering award, and the Progressive Architecture Award in 2016 from Architect magazine – stands out among the many supertall skyscrapers that have emerged on the Shenzhen skyline over the past 20 years.
