The footbridge was realized as an experimental building in 2005. Its simple vegetable-technical structure shows demonstrates the conceptual as well as the constructive approach of the Baubotanik.
The structure is made out of 64 vertically and 16 diagonally in steady distances arranged bundle struts, each composed of 12 up to 15 plants. This supporting structure is the base for a walkable area in 2,5 meter hight made out of a totalled 22 meters length steel-grating. It also contains a stainless steel tube that is used as a handrail. This thus built wakable space can be entered through two cross paths by means of ladders.
The living supporting structure is engeneered from the willow genus Salix viminalis, which possesses a high ability to regenerate and to root into the ground independently. Therefore the footbridge does not possess a foundation in the usual sense of the word. The vegetable supporting structure absorbs all the load exclusively and redirects it into the ground where the structure is anchored by the roots.
The site with its continuous moist reed meadow offers excellent conditions for the vital growth of the structure. Only a few weeks after the constructional completion first leafs sprouted and proved therewith the vitality of the structure. Due to the rampant sprouting of the supporting structure a dense green wall emerged already in the first growing season. During this state of temporary wildness merely the steel elements and the geometrical shape point out the artificial character of the structur. And in autumn when the structure sheds its leaves it is again clearly evident, that the building sure is a plant but a rational constructed supporting structure at the same time.
Meanwhile the footbridge formed a rampant crown and is thereby even in wintertime recognizable as a treelike structure. Over the years the individual plants became thicker and the at first delicate green bark turned gnarly. The nodal points where the plant struts are joint with the stainless steel handrail make visible how the stability of the structure increases through the growth. On several spots the tubes are totally merged with the structure.
The bundle struts were dimensioned in a way to warrant a high stability already immediately after the constructional completion. Consequential however the result is a high plant density. This implicates a competition between the individual plants resp. struts about light, their very vital resource. Thereby stronger grown plants suppress the weaker ones. Steady care is necessary to keep the system in the aspired balance.
One main consequence of these longtime observations is that already during the design of a Baubotanik building the architect has to mind the coerciveness of botanical development processes: It is important to concede enough space in the implementation for vital processes. Since every living module is a plant, it needs space to perform i.e. photosynthesis.
Experimental building/ study project
- Planning team:
Stipendienprogramm of the DBU, sponsors
- Structural completion:
Neue Kunst am Ried