This illuminated, webbed steel structure at the 2011 Xi’an International Horticultural Expo in China is the second project to be featured on Dezeen this week by London architects Plasma Studio.

The structure is named the The Guangyun Entrance, as it frames the main visitor entrance to the expo site.

It is anticipated that climbing plants will grow over the trellis frame and create a green roof.

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The following details are from the architects:

The Guangyun Entrance

The Guangyun Entrance operates as infrastructure and fulfils the role of bridging the main road that dissects the site. It channels visitors from the plaza at the entrance where they congregate and orient themselves, plotting their direction. Their path over the bridge rises 7m and offers vantage points to gain an overview of the different zones of the Expo displayed ahead.
Bridge design often has two lanes: one for incoming and another for outgoing traffic. However in this case, the flows are uneven and change throughout the day.

With inspiration taken from rush hour escalator traffic in the London Underground stations, the bridge has been devised with three lanes, so the middle lane can switch direction from incoming in the morning to outgoing later in the day.
 These three bands read as interwoven braids, and together with a surrounding trellis roofed structure, they give the appearance of bands of landscape peeling off and rejoining the mass at the end of the journey. Between the three bands are green areas and a water feature for visitors to stop, rest and enjoy the view.

Above, an open trellis steel structure forms the shading device that is intended to become naturally overgrown with climbing plants, thus forming a green roof, and suggests the theme of the Expo to distant onlookers.
The lightweight roof has been developed together with Arup engineers as an innovative integral structure that appears as beams seemingly free-floating in space.

The Guangyun Entrance has been conceived as a landbridge with a tensegrity trellice structure that will gradually become overgrown by greenery.

International Competition: 1. Prize, 2009
Project: 2009-2011
Opening: April 28th 2011
Completion: March 2011
Client: Chan-Ba Ecological District
Architecture: Plasma Studio, BIAD
Landscape Design: GroundLab, LAUR Studio, Beijing Forestry
University 
Engineers: John Martin and Associates, Arup