Membranes

Since the 80’s Octatube has been realizing membrane structures  for a wide variety of projects.
Tensioned membrane structures or “tents” in their architectonic  and  sculptural  manifestations  have been familiar since the 1960s work of Frei Otto of Stuttgart. The main use of the tent in the Netherlands has been as an “urban umbrella”, where  the  tent  functions  as  a  canopy,  a  shelter  from  the  rain/sun  or  a freestanding roof, for example over a shopping centre. The most common form is a roof surface combining convex and concave curves. This arrangement allows  the  fibers  in  the  reinforcement  woven  into  the  cloth  to  support  one another  as  the  wind  loading fluctuates.  Tensioned  cables  running  with  a concave or convex curve through the roof material, stiff compression members in steel tube or laminated timber, or steel masts to lift the membrane, reinforced if necessary with guy ropes, serve to maintain the so-called “anticlastic” form of the membrane with its opposing curves. The  successful  design  of  membrane  structure  calls  for  close  collaboration between the project architect and construction contractor on the one hand and the product designer and the product manufacturer on the other, with a joint approach to the design right from the outset. Tensioned membranes are always special  products.  The  direct  influence  of  the  dimensions  of  supporting  and other structures in the vicinity mean that one design rarely duplicates another. In the Netherlands the smaller membranes generally use polyester-reinforced PVC fabric with a lifespan of fifteen to twenty years.
In addition, there are applications with the Teflon-based PTFE and ETFE. Almost transparent materials which often are applied with air pressured cushions  as a building skin. Compared to glass they are less transparent and more prone to punctures, but they are recyclable and especially many times lighter.