Reconsidering the Historical Cap Ceiling (2024-08)¶

Traditional cap ceilings, self-supporting vaulted structures once prevalent in historical masonry construction, are experiencing renewed interest due to their potential for material efficiency and reduced waste. This resurgence comes amidst a pressing need to reduce material consumption in construction. However, the contemporary fabrication of such vaulted structures presents practical challenges. Leveraging advancements in 3D printing, this research seeks to revive cap ceilings by integrating historical techniques with computational structural design and extrusion-based additive manufacturing. Our approach aims to develop a fabrication-aware method for designing formwork-free, self-supporting cap ceiling structures suitable for in situ 3D printing using earthen materials. Using graphic statics, we propose an iterative method for simultaneously form-finding and analyzing the cap ceiling on a global (entire structure) and local (during fabrication) scale. Based on the generated print path, a method for robotic motion planning for cylindrically equivalent target objectives is developed. Physical prototypes using a mobile robot for earth extrusion are fabricated to validate and assess the feasibility of the proposed design and fabrication approach. This interdisciplinary investigation aims to bridge the gap between historical craft and contemporary design and fabrication methods, offering sustainable approaches for future construction practices.