Ultra-Thin-Layered 3D Printed Hollow-Core Sections for Concrete Casting (2024-08)¶

Lightweight concrete shells with anticlastic curvature are among the most efficient structural systems. But the difficulty and cost of current construction methods present a challenge. This research employs additive manufacturing techniques to generate 3D-printed (3DP) hollow-core formwork for concrete casting. The additive manufacturing technique enables material to be put exactly where required; thus, less material is used, and material waste is significantly reduced. We propose utilizing a hollow-core section for the double-layered thin concrete shell to reduce the amount of concrete and increase the material efficiency. In the case study presented the first step is to tessellate the designed shell into smaller parts. This is done by considering the limitations of current robotic arms, available infrastructure, the transportation and moveability of a crane, and labor at the construction site. Also, the height of the parts and the wall thickness must be optimized based on the hydrostatic pressure of the wet concrete and formwork material properties. A trussed section is used to maximize mold stiffness with less material. Next, we use robotic 3DP to fabricate the formwork and cast and cure the concrete. Finally, since the shell is designed to act in pure compression, these parts can be assembled by friction-fit, without any glue or mortar, and with limited additional scaffolding. Additive manufacturing enables the production of custom formwork quickly and more accurately than traditional construction techniques.