Flexframe

The pilot structure of the ETH House of Natural Resources on the Hönggerberg in Zurich won two prestigious awards hot on the heels of its completion – the Schweighofer Prize innovation award and the Prix Lignum hard-wood award.

 

These accolades are more than a grand honour for Häring – they also confirm the practicality of this pre-tensioned structure. Children’s push puppets show very well how pre-tensioned structures work. The strings inside the figure and the spring tension always act together to return the multi-jointed elements of the wooden figure to their original form.

The basic framework of the ETH House of Natural Resources consists of a coarse mesh skeleton made from native-wood glulam. The ash supports, which are placed every 6.5 metres, are connected by ash-reinforced spruce beams. In the same manner as the push puppet, the structure is stiffened by means of tension and will revert to its original shape even in the event of an earthquake. Instead of strings, though, the ETH House con-tains pre-tensioned cable with a tensile force of 70 tons. Häring developed this pioneering project together with the ETH and injects financial and material support into the research work. The building’s first occupants moved in during June 2015.