I am relieved to say that construction on the double curving wall project is complete and not only is the wall standing, it performs beyond the level our team had hoped to achieve. That is not to say that we weren’t confident in our ability to complete the task, just that the demands of the project thoroughly challenged the team. From the beginning, we anticipated that constructing such a complex double-curving form was going to take a fair amount of perseverance and creativity, and would push the team’s capacities in determining an innovative solution to this unique problem.
The wall’s design and construction was the result of a collaborative effort, we harnessed our multi-disciplinary team member’s engineering talents, aesthetic sensibilities, and knowledge of construction and materials, we also utilized the equipment of two LTU lab/shop facilities. All recycled Polyboard panels, node connectors, and clips were CNC routed at makeLab, with design, construction and budget oversight also provided by makeLab Director, James Stevens. Steel post fabrication was performed at the metal shop using a manually operated hydraulic tubing bender and MIG welder.
Although it was our original intention to have the free standing wall panels entirely self-supporting the team determined during the process that the material properties of the Polyboard were not sufficient to make this happen. Through prototyping of panel connections, software modeling of internal stresses, manual calculation of shear forces, and observation of the partially assembled panels we realized that a frame of some type would be required. The challenge of this realization proved the basis for what I consider the most innovative part of the wall’s construction.
It is common for complex curving-form structures to utilize a rigid frame with bent panels applied to it as nothing more than cladding. We wanted to avoid constructing our wall in this manner. Our steel posts, like human ribs, are rigid, and as in our skeletal system, bones (posts) work in harmony with muscles and connective tissues (panels, node connectors, and clips) to give the body structural integrity. The Polyboard wall surface supports its own gravity load and provides lateral bracing for the posts. The posts in turn hold the form giving it rigidity. The innovative component in the system is the “clip” that is mechanically fastened to the panel but only slip fit over the post, allowing it to float independently, thus allowing the panels—like muscles—to work against gravity while the posts, like bones, hold the form . Additionally, without the capability of molding the Polyboard material into the curving form we needed to devise a method for making a curved wall from flat panels. The flexibility of the material provided a partial solution. By controlling the width and thickness of the material at the node connector and panel corners we were able to promote curvature in specific locations. This allowed the flat panels to “drape” in a curved form.
by Jason M Colon