Torsion as a design driver for structures and architecture
Dr. Serenay Elmas
Supervisor: Prof. Günther H. Filz
ended 2024
Abstract. Twisted forms, with origins dating back to ancient times, have a prominent presence in architectural history, embodying both aesthetic appeal and structural complexity. This thesis bridges architecture and engineering disciplines to examine a beam element assembled from four thin plywood strips under large rotational and translational deformations, resulting in a unique twisted form. The central question guiding our exploration is whether such flexibly twisted members can enhance structural performance, while embracing their aesthetic values. This research touches on many related viewpoints, including the architectural, artistic, engineering, and pedagogical perspectives, as documented by publications, and showcased by several experimental full-scale structures and exhibitions. The geometry of the twisted beam is derived from the intentional deformation of a thin-walled square tube, where each strip of the tube is hinged-joined along its longitudinal edges. The equilibrium geometry of the beam emerges through a delicate interplay between material, its properties, and physical rules within defined boundary conditions, as a case for self-organized form. The resulting geometry has been presented as a novel cantilever beam, utilizing elastic torsion for structures and architecture [Pub. I], and as a structural element compared with standardized profiles [Pub. II]. Given the observed large deformations, it was crucial to ascertain the residual stress state before proceeding with any subsequent architectural application. In this light, the plywood strip has investigated in detail by considering each individual ply. Furthermore, a parametric model has employed that highlights the potential significant effects of minor changes in the strip's geometric parameters on its overall performance, underlining the geometrically nonlinear behaviour of actively twisted and bent plywood [Pub. III]. Full-scale prototypes provide insights into practical challenges and advantages of the chosen methods, processes, and material, demonstrating its lightness in its applications in a kinematic pavilion [Pub. V], its rapid assembly from identical strips, and utilising standard stock material, while minimizing material waste by applying a simple cutting pattern. Built pavilions showcase how the presented lightweight beam element can be applied to ephemeral architectural scale structures [Pub. IV], as well as elevating it from a mere object to an integral part of a holistic, experimental architectural narrative. They highlight the non-tangible aspects of architecture. Through the presentation of concepts such as harnessing unconventional structural materials like plywood, the reduction of material consumption through an exploration of equilibrium geometries, and the emphasis on the significance of assembly logic, we aspire to influence the current mindset, with a view to positively shaping the future of the building sector, society, and the environment.