Structural design and testing of material optimized ribbed RC slabs with 3D printed formwork

Most of the concrete volume in multistorey buildings is cast solid slabs, which are frequently flat slabs supported on columns. By using two-way spanning ribbed consumption could be significantly reduced. However, due to high costs associated with formwork, such a complex rib configuration rarely used nowadays. With advent technologies for automated formwork fabrication, material-saving potential inherent this structural system again exploited. This paper investigates feasibility material-efficient building scale conventional and steel reinforcing bars inside three-dimensional-printed plastic-based formwork. To that end, code-compliant design first discussed, followed by introduction concept an design-to-production workflow. The sustainability slab compared solution case study consisting multibay office 8 m both directions, revealing use 40% less than slabs. Several representative elements (ribs, slab-column transition) were produced at full-scale tested until failure investigate production performance. Three T-beams various shapes (straight, kinked diaphragms, curved) three-point bending configuration, showing ductile behavior longitudinal reinforcement yielding indicating relevance torsional effects curved ribs. Punching tests two connections (ribbed, solid) revealed optimized prevent brittle punching failures achieve ultimate load 105% higher reference slab. All specimens' load-bearing predicted established formulas, producing applied technology.