Organic forms: Chaoyang Park Plaza, Beijing

Draped across the Beijing skyline like a flowing black curtain, or the blots of ink from a calligrapher’s brush, the twin towers of Chaoyang Park Plaza were inspired by nature, but built using the latest facade technology.

The obsidian black office buildings, designed by MAD architects, the Chinese firm led by Ma Yansong, appear to rise like mountain peaks on the edge of a lake in the largest park in the central business district.

They form part of a major 220,000m² complex, a total of 10 buildings conceived as an extension of the park into the urban realm. The site layout was informed by Chinese art and landscape painting, and mirrors traditional Eastern cities where architecture and nature are designed in unison, each with the other in mind.   

Ma Yansong says: ‘The complex unfolds as a Shanshui landscape painting on a city-scale. We wanted to bring elements of traditional Chinese artworks into the city context as a way of extending the green space of the neighbouring park into the urban context. So the ­design remodels the relationship of large-scale architecture in our urban centres by introducing natural forms and spaces – the brook, creek, forest, mountain, rocks and valley – into the city.’

The two asymmetrical skyscrapers – the tallest rises to 120m – positioned at the northern edge of the site maintain the sightlines of existing buildings. Notable local architecture includes the doughnut-shaped headquarters of Chinese broadcaster Phoenix Television and OMA’s angular CCTV building.

A series of seemingly random-placed low-rise commercial buildings at the south end of the site resemble eroded rocks to form a ‘creek’ flowing towards the ‘valley’ – represented by the space between the two towers.

The layout, shape and height of all the buildings was informed by views from neighbouring structures, the position of the sun at different times of day and the sun’s relationship to the site.

Landscaping weaves between all the buildings and integrates pine trees, bamboo, rocks and ponds to create a tranquil space where people can commune with nature in the city. Efforts to connect the urban with the natural extend to the 17m-high glass lobby set between the two towers, where the sound of flowing water is played to make it feel like a natural scene in a real mountain valley.

Ma comments: ‘Many of the towers found in our cities stand as symbols of power and capitalism. I want to do something different. I want to build architecture that brings nature into the city context, and makes inhabitants rethink the way we approach urban developments.’

Ridges and valleys define the shape of the exterior glass facades, as if the forces of nature have eroded the towers into stratified layers. Ridges run up the sides and over the top of the roof in an apparently seamless curve. Curved glass in the facades appears to stretch between the fins and gives the impression that the building’s skin is being pushed out from the inside.

According to Ma, a key challenge was how to realise these organically-shaped objects as a continuous smooth surface, while dealing effectively with the edges of the concrete slab.

Initial hand drawings were rationalised into buildable geometric shapes and lines: limiting factors included the size of glass available from the factory, the construction method and the available budget. The facade package, supplied and installed by Beijing Jiangho Group, cost around RMB100 million (£11.1 million).

The envelope is a hybrid, comprising a thermal break unitised system on the vertical facade and a prefabricated semi-unitised system on the rooftop. Around 7,000 facade panels were installed across both towers in total. Panels between the ridges contain cold-bent single-curved glass, rather than faceted flat glass, to create a smooth, uninterrupted appearance.

‘A customized and cost-efficient unitised system was developed specifically for this project – the biggest challenge was how to adapt it to changing angles and vector axis,’ says Ma. ‘The finished result gives the impression the building does not look as if it has been built, but as if it is naturally growing out of the ground.’

Although both towers have different heights, this was primarily an aesthetic conceit based on the idea that in nature no two objects are exactly the same. The  ‘functional’ height of both buildings is in fact the same, 100m – only the roofline changes.

Chaoyang Park Plaza was awarded LEED Gold by the US Green Building Council, one of the highest US sustainability ratings, based on its use of natural lighting, intelligent building and air purification. The facade is thermally efficient with a U-value of 1.9W/­m²K and comprises a layer of insulated glass with a thermal break aluminium extrusion.

The dark, reflective glass is both aesthetic and functional. On the one hand it evokes traditional Chinese ink painting and reflects the surroundings, including the water, the cityscape and the park. ‘Mysterious reflections’ are created in the curved surfaces between the fins. The glass material was synthesised specifically to filter out the sun and reduce solar gain.

‘The materials were informed by the overall design, and what we wanted to achieve, both visually and emotionally,’ says Ma.

The vertical ridges double up as a natural ventilation system for the towers. Fresh air is drawn up through the shafts, filtered, and pushed into the interiors through apertures on each floor. During the summer, ventilation air passes through a pond at the base of the towers before it enters the fins to reduce the overall temperature inside.

Ma has spoken in the past of his belief that Chinese architects should be more visionary, forming movements capable of influencing society, and being less collusive with the commercial world. He has said architects have a role to play in solving major problems facing the planet, including climate change and the future of cities. The darkly majestic forms of Chaoyang Park Plaza, inspired by nature and Chinese tradition and drawing on the latest technology and sustainable best practice, could be seen as his mission statement for 21st century Chinese office building.