Expo Axis

 
The World Exhibition, also known as the Expo, is one of the most important architectural events in the world. It is held every two or three years and gives the opportunity to many participant countries, especially to the host county, to show their latest achievements in various fields, where architecture plays one of the most important roles. The People’s Republic of China was honored to host the Expo in 2010. After the spectacular Olympic Games in 2008 held in Beijing, this event allowed China to once again demonstrate its growing influence in the world. It is important to mention that there is a longstanding rivalry between Shanghai which hosted the Expo, and Beijing which hosted the Olympics. For this reason, enormous financial recourses were invested in organizing the Expo in Shanghai. Now that it is over we can conclude that this was justified since it significantly improved the reputation of Shanghai and China in the world.

Membrane structures and the World Exhibitions have a long common history. At the Expo in Montreal in 1967 the German Pavilion was covered with a membrane which became the first famous membrane structure in the world. Since then almost every Expo gave the primary or one of the most important places to membrane structures.

One of only four buildings that have not been demolished after the Expo, is the Expo Axis. This structure is really the axis of the area where the Expo was organized. It is located between the three major parts of the exhibition and serves to interconnect them. Expo Axis is a three story building whose main function is to be a pedestrian walkway. The third story allows the pedestrians the view to the whole exhibition from high ground. The stories are made of concrete, and the cover is a unique combination of membrane and space grid structure. The roof structure is 100 meter wide and 1000 meters long. The space grid structure has an inverted cone form, and is divided into a triangular network. The membrane structure has a similar shape, and is structurally independent from the space grid structure, although they make one entity in the visual sense. What is extraordinary about this membrane structure in the structural sense is its huge span. To cover this span the thickest and strongest membrane material was used. In certain parts the material had to be doubled, which results in less light translucency in these areas. Columns with stay cables are used for the supporting structure. One of the requirements that had to be fulfilled is that the failure of one column does not impair the global stability of the structure. This was achieved by adding more safety cables to the structure, which was experimentally proved.

The whole structure is completely open, and the shape of the cover emphasizes this impression. A special feature of this structure are the LED lights placed on the space grid. They make it possible to broadcast shows, making the structure a video screen. This looks fascinating to the spectators, due to the size and the curvature of the “screen”.

Excerpt from: masterbuilder

Vuk Milosevic, Nikola Cekic,
Miomir Vasov , Milos Dacic
Faculty of Civil Engineering and Architecture, University of Nis