Post-tensioned ceramic structures: design, analysis and prototyping

Abstract

This research reports on numerical and experimental methods for the use of post-tensioning with brittle ceramic extrusions. It proposes a novel construction approach, including new joint typologies, and demonstrates the viability of ceramic as a primary structural material in a bending-active context through two pavilion-scale prototypes. The research proceeded in three distinct phases. First, relevant material properties —compressive strength, bending strength, modulus—were determined experimentally. Next, several post-tensioned beam prototypes were tested to examine the interaction between post-tensioning steel and ceramic, understand failure modes, and refine construction details. Finally, two post-tensioned prototypes were designed based on these findings, the Vierendeel Arch and the Hypar Tower. The design process for each prototype involved a novel digital workflow that utilized multiple parametric models to generate and analyze global design geometry, link to structural analysis software, discretize the forms into components based on available stock sizes, accommodate for assembly tolerances, and generate component cut lists. The prototypes behaved as predicted, demonstrating that post-tensioning can successfully control bending stresses in ceramic extrusions, and introducing entirely new applications for the material.