Icon Yunduan Tower is a 192-metre-high hybrid building located in a high-tech zone on the outskirts of the city of Chengdu, China. The aim of the project was to create a landmark visible on entering the city as well as a focal point for the earlier building phases of the area. The project is based on a winning entry in an invited architecture competition in 2009.
Project name: Icon Yunduan Tower
Project address: Chengdu High Tech Zone, Tianfu Road, Chengdu, China    goo.gl/maps/HPFWNNqWYmQ2
Architects: PES-Architects www.pesark.com
Architectural and interior design / PES-Architects: Tuomas Silvennoinen (chief designer), Pekka Salminen, Tristan Hughes, Emanuel Lopes, Toivo Moustgaard, Fang Hai, Satu Ristola, Miguel Santos, Kati Norta,  Beatriz Redondo, Marcelo Diez, Teija Anttila, Tiina Juntunen, Uros Kostic, Teemu Kekkonen,  Masahide Nakane
Local architectsChina South West Architecture and Design Institute (CSWADI): Qian Fang, Qiu Xiaoyong, Wang Yongwei, Feng Tailin, Zhu Yanqing
Structural engineering: Bi Qiong, Liao Rongquan, Lei Yu
Other collaborators:
Main contractor: China State Construction Engineering Corp. Ltd.
Technical design: China Southwest Architectural Design and Research Institute, CSWADI
Lighting design: a+g Licht, Germany
Client/contractor: Chengdu Hi-Tech Investment Group Co. Ltd.
FunctionMixed-use (commercial and cultural)
Location: Chengdu High Tech Zone, Tianfu Road, Chengdu, China
Year: 2017
Built area: approx. 190,000 m2
Total floor area: 103,650 m² (tower), total including underground areas approx. 160,000 m²
Finish materials: Glass/ceramic facades
Structure: Concrete/steel
Attached photos: Marc Goodwin, Archmospheres; Zhewei Shu (as indicated by file name)

The assignment comprised the design of an office and residential area, which was developed further in collaboration with the client and a local design office, China Southwest Architectural Design & Research Institute (CSWADI).  During the design process, what was originally planned as an office tower evolved into a versatile, mixed-use building complex. A shopping centre occupies the first two levels of the 47-storey building, while the third and fourth floors feature restaurants. A conference centre spans the fifth floor, followed by 23 floors of offices and 13 floors reserved for an apartment hotel. The top three floors contain dining, reception and meeting areas. The roof features a helipad.

The underground spaces were originally planned to accommodate a spa and gym, but the client later decided to replace these with a concert hall seating 900. This was designed by CSWADI partly under and partly adjacent to the building.

The underground premises also provide parking for 3,000 cars and a connection to the metro station.
The tower has an L-shaped plan at ground level that grows into a square towards the top. This form creates a sweeping façade that overlooks the Tianfu River and a straight edge that defines the corner of the site along Tianfu Avenue, the main road to the centre. The curved elevations to the south and east are defined by green terraces up to the 30th floor. Glass and glazed ceramic elements form a checquered pattern on the other facades. The recessed glass surfaces alternate with infills formed of 200 mm high and 900 mm wide vertically stacked glazed ceramic panels.

Chengdu is located in an area highly susceptible to earthquakes, and the building lies on soft land masses. The effects of a potential earthquake were taken into account in the building’s massive structures. The concrete-braced core of the building comprises the shafts and vertical connections, while the rest of the building frame is of steel. The columns in the five-storey-high lobby are 1.5 m thick. The walls of the central lift and building technology shaft are 1.2 m thick, and the foundation slab, which covers an area of several hectares, is over 2 m thick.

PES-Architect also created the master plan and concept-level landscaping plans for the site. The draft designs also included detailed interior design plans for all the building’s public spaces; however, these were subsequently adapted to local preferences and the tenants’ requirements. The spatial highlight of the building is the 30-metre high lobby that opens to the east and towards the river and around which the commercial spaces, restaurants and conference centre converge.

The main tenant of the building is the European Union, which plans to use it as a base for European organisations and companies in Western China.

The curved, terraced form of the building, rising from a water element, was perceived to resemble a white mountain with garden terraces reaching towards the sky. Hence, the building was named Yunduan, “Above the clouds”.

Tuomas Silvennoinen (b. 1969), Design Director, Partner, PES-Architects.
Architect SAFA (MSc, Helsinki University of Technology 2000).
After working at PES-Architects in 1995-1999, Tuomas Silvennoinen joined the firm again as partner in 2002. He previously had a private practice and worked in several architectural offices and teams in Finland and abroad. Silvennoinen also worked as a part-time teacher at the Helsinki University of Technology in 2002-2004.
Tuomas Silvennoinen’s awards as chief designer include the Steel Structure of the Year Award in 2017 for West Terminal 2 in Helsinki West Harbour. His other main works include the non-Schengen expansion of Helsinki Airport, the Icon Yunduan Tower in Chengdu, the Vanke Deep Blue Club building and villa in Shanghai, as well as ongoing arena projects in the Finnish cities of Helsinki, Jyväskylä and Turku.
PES-Architects Founded in 1968, Helsinki-based PES-Architects is one of the most international architecture and design firms in Finland. Today, the office employs over 70 staff and continues to work towards an architecture that embraces a cross-disciplinary approach. The practice is known for its complex and wide-ranging building types, including airports and transport terminals, theatres and concert halls, sports facilities and mixed-used developments, as well as demanding refurbishment projects. PES-Architects’ Shanghai studio was established in 2010, although the architects have been working in China since 2003.
PES-Architects main works in China include the Wuxi Grand Theatre (2012), the Icon Yunduan Tower in Chengdu (2017) and the Fuzhou Strait Culture and Art Centre (2018). Important projects in Finland and Europe include Helsinki Airport terminals; West Terminal 2 ferry terminal in Helsinki; Ring Rail Train Stations in Vantaa, Finland; and the Marienkirche Concert Hall in Germany.