A constructible solution for a complex curvilinear skylight
Xuzhou Suning Plaza is an award-winning complex of ultra-modern buildings. It is located in the business district of Xuzhou, a major city in Jiangsu Province, China.
The focal point of this multi–use commercial development is a 266m-tall tower that contains office space and a luxury hotel. Four residential blocks flank this landmark construction, which is Xuzhou’s tallest building. Inspired by an uplifting ethereal design concept, these curvilinear structures are configured in a traditional ‘lucky cloud’ pattern above a six-storey retail podium. An expansive feature skylight covers the central atrium of this lower mall area.
To realise their ambitious vision, the client engaged BuroHappold Engineering to provide specialist steel structure expertise for the skylight along with facade consultancy.
The central skylight is an elliptical, three-dimensional surface with a circular opening at its apex. This structure rises 10m and spans 59m x 37m at the widest point. A key challenge with such a sizeable and geometrically complex piece was developing a constructible solution while using slender steel components to maximise ingress of natural light. This all had to be accomplished on budget and to style while avoiding the need for a second layer of structure.
Further testing our ingenuity, economic constraints made it necessary to render the curved lines of the building’s facade in such a way that delivered the desired eye-catching effect at minimal cost.
Another client aim was to meet national energy targets to attain a Green Building 2-star rating.
BuroHappold structural engineers specialising in lightweight steel devised the design of the long-span atrium skylight. Using advanced 3D analysis, our team conceived a compliant solution that served the architectural motif. Addressing the complex geometry and large span, we devised a single-layer latticed shell steel structure that supports both gravity and wind loading. We also developed steel connection details that minimise unsightly plates and bolts to enhance visual appeal without restricting fabrication and construction.
Considering the requirement to reduce facade costs, it was determined that fewer curved panels could be used if they were partly replaced by less expensive flat panels. We undertook simulations that determined the optimal arrangement of flat and curved panels across rounded planes, which cut outlay without compromising the overall aesthetic.
Our engineers worked with the wider design team to meet sustainability goals. We studied the performance of the major facade systems and optimised the shading strategy to make the final scheme as effective as possible. The building subsequently met stated national energy targets.
The Xuzhou Suning Plaza opened in 2017 and proved to be an immediate success. More than 500,000 people visited the mall on its first business day.
Our solution for the skylight created an impressive roof structure that met the project’s architectural, economic and sustainability requirements.
Close collaboration between our team, the client and the architect throughout the project ensured that we produced effective engineering solutions that support the integrity of the design.
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