Flexural Behavior of Concrete Slabs Reinforced with Embedded 3D Steel Trusses

This paper presents a proposal for slabs reinforced with 3D steel reinforcements. Two configurations of 3D steel reinforcement, manually fabricated using 4 mm diameter rods, were investigated: cubic and square pyramid truss lattices. Two control groups were produced: a non-reinforced slab and a linear steel rod-reinforced slab. Three-point bending tests were conducted to assess the flexural behavior of the slabs. The results were analyzed in terms of flexural strength, peak load, mid-span displacement, energy absorption, crack formation, and ductility. The digital image correlation (DIC) technique was employed to capture the full-field principal strain and determine the mid-span displacement at the point of crack initiation. Furthermore, the compression capacity of each slab was evaluated. The results were compared with those of the non-reinforced and linear reinforced slabs, revealing that the slab with the cubic truss lattice configuration exhibited the highest bending moment capacity. While the square pyramid truss slab demonstrated relatively low bending strength, it exhibited exceptional energy absorption characteristics. In terms of ductility, the cubic truss-reinforced slab showed superior performance. When compared to the slabs with linear rod reinforcement, the 3D-reinforced slabs with cubic and square pyramid configurations enhanced the bending strength by approximately 51.19% and 47.32%, respectively. Overall, this study shows that the oblique connectors in the pyramidal reinforcement, compared to the vertical connectors in the cubic reinforcement, provide greater ductility and promote a more uniform distribution of smaller cracks, thereby enhancing energy absorption.