Architecture students of Ball State University, along with their professors Gernot Riether and Andrew Wit, have created an eye-catching parametric tensegrity structure: the Underwood Pavilion. In definition, tensegrity structures are ‘lightweight structures composed of cables in tension and struts in compression.’ The Pavilion, which is located in Muncie, Indiana at the moment, is created from 56 lightweight structures of Elastan fabric. The composition creates a dynamic shaded space for visitors to enjoy while viewing the surrounding landscape through frames created within the structure itself. 
The Underwood Pavilion stands out as a new art destination. With its composition, mobility, and the new essence it brings, the pavilion attracts many of the city’s residents and tourists to new places. With its current location in one of Indiana’s post-industrial landscapes, the pavilion draws people to experience Art Events in an innovative way. The Structure is made of two main components: the lightweight structure and the self-shading envelop. The lightweight structure is composed of multiple variations of a three-strut tensegrity module. The modules vary in their proportions causing them to have different curvatures and rotations. As for the self-shading envelop Elastan, an eco-friendly polymer, was used. The design of the Underwood Pavilion frames nature around it as precious art pieces, while standing out as a beautiful structure within the landscape. Find more details from the architect after the jump. 
Lightweight structure: The Underwood pavilion’s modules were developed from different variations of a 3strut tensegrity module. Varying the distance between the upper face and the lower face and varying the scale between the upper face and the lower face of the module informed the curvature of the envelope. These variations also generated a different rotation within each module causing the envelope to twist in different directions. The structural simulation engines Rhino Membrane and Kangaroo were essential tools in the form finding process of the pavilion’s structure. The final tensegrity state of a module could only be reached with all cables in tension and all bars in compression. The entire system remained loose with all members being connected except one. This allowed for the modules to be stacked and transported efficiently as a loose low–volume bundle of bars and cables (3” x 3” x 6’). At the site of construction only one cable per module had to be joined. Using a turnbuckle to connect the final node allowed regulating the stress in the module until it snapped into the predicted tensegrity geometry. Each of the 56 modules describes a volume of 3’ x 3’ x 3’ to 4’ x 4’ x 4’. 
Self-shading envelope: To respond to a specific context the modules were arranged in a tensegrity pattern. Skipping every second module in every second row created smaller and larger openings that were placed to frame the environment. Elastan, an eco-friendly polymer originally used for sportswear was adapted to create the pavilion’s self-shading envelope. Elastan is created from filaments that are more durable than non-synthetic materials such as rubber. It can be produced from 100% renewably sourced raw material such as recycled polyester. Once all modules were connected each module was dressed with an elastic fabric to form a minimal volume that was defined by the location of the struts and the elastic quality of the fabric. Tensegrity structures have large advantages compared to other structural systems. Using predominantly tension members they are lighter and stronger than conventional systems. As temporary lightweight structure the Underwood pavilion additionally takes advantage of the self-erecting behavior of tensegrity systems. Using physics engines as a design tool shows how tensegrity systems can be parameterized to adapt to site and program.
Project info and credits:
Project Name: Underwood Pavilion – Ball State University – 2014
Location: Muncie, IN, USA
Design And Realization: Gernot Riether, Prof. Dipl.-Ing., M.S. Architect, Andrew Wit, Prof. M.S.
Student Team: Noor Al-Noori, Andrew Heilman, Chris Hinders, Charles Koers, Huy Nguyen, Nick Peterson, Steven Putt, Ashley Urbanowich
Community Partner: Muncie Makers Lab
Photographs: Gernot Riether
By : Ala’ Abbuhasan
