Reducing Displacements in Thermoset 3D-Printed Formwork by Optimizing Ribs and Tie-rod Placement

3D-printed formwork shows great potential for concrete casting, as it can be used for complex shapes while reducing costs, labor, waste, and material usage. However, a significant challenge arises when the formwork exhibits excessive displacement under load. In this study, an optimization framework specifically tailored for 3D-printed thermoset formwork is presented in order to address displacement issues. The Ground Structure Method is integrated to propose an optimized rib design and strategic tie-rod placement, significantly minimizing displacement while maintaining material efficiency. This approach significantly differs from conventional formwork reinforcement strategies, with a focus on thermoset materials for their high stiffness, thermal resistance, and superior performance under the hydrostatic pressures encountered during concrete casting. The optimized designs are developed through numerical modeling, and to validate their effectiveness, experimental techniques employing 3D Digital Image Correlation are utilized. Water pressure testing verifies the influence of hydrostatic pressure and thermal response on displacement, while example applications using Self-Compacting Concrete demonstrate the practical effectiveness of the optimized design. Results demonstrate the efficacy of the optimized design, particularly the combined use of ribs and tie-rods, in achieving a significant 81% reduction in maximum displacement with a minimal 10.7% increase in material compared to a non-ribbed plate. This research provides valuable insights for the construction industry, establishing a robust framework for optimizing 3D-printed formwork for superior performance and minimized displacements in formwork structures.