Development and mechanical evaluation of stress-line inspired ribbed timber slabs with stay-in-place formwork

While stress-line inspired ribbed slabs have been proposed and studied in concrete, their application in timber remains limited, hindered by the complexity associated with designing and constructing the intricate rib patterns. Current design tools and fabrication approach often fall short when applied to timber structures. To bridge this gap, this study introduces an integrated computational design and fabrication method for producing stress-line inspired ribbed timber slabs. A weighted Voronoi diagram-based algorithm is employed to generate rib patterns that align with stress-line distributions through radial and looped curves, adaptable to diverse slab geometries and boundary conditions. The resulting rib system—comprising radial and looped components—enables the bending of continuous radial laminae against looped, stay-in-place formwork, achieving mold-free fabrication. A preliminary numerical-experimental comparison of a single triangular slab unit was used to check the deformation trend of the finite element model. Numerically, under a set of idealized modelling assumptions, the stress-line slab showed improved deformation control compared with the conventional unreinforced and equal-volume thickened reference slabs. At the slab-edge measurement point, the calculated initial vertical stiffness improved more than 10 times compared with the unreinforced case. Besides, the estimated material-utilization improvement could reach 50.0%–51.3%. By integrating computational design with digital fabrication, this work provides a scalable solution for fabricating geometrically complex timber structures, offering a promising pathway toward more sustainable constructions.