Seismic Behaviour Improvement of Steel-Concrete Composite Frames Based on Steel Spiral-Confined Slabs

The use of continuous spiral reinforcements can be an efficient solution for the seismic performance improvement of reinforced concrete members. Several literature studies confirm their positive confinement effects especially for concrete columns, where typical benefits take the form of enhanced ductility and energy dissipation capacity. In this paper, the attention is focused on steel-concrete composite frames, where the study of both joint and slab detailing can involve several design challenges. Steel spirals are thus introduced for the seismic reinforcement of concrete slabs. Based on literature documents and a set of parametric Finite Element (FE) numerical analyses, selected configurations of technical interest are explored. As a first key step, the compressive response of concrete slabs with confining steel spirals is discussed, with a focus on local and global effects.