Seismic behaviour of sheathed cold-formed structures: physical tests

The paper presents the results of an experimental study on the seismic behavior of cold-formed steel stud shear walls, sheathed with wood-based [oriented strand board (OSB)], and gypsum-based (wallboard) panels. Tests were carried out on two, nominally identical, prototypes, which were designed in such a way to contain all the structural elements and components used for this type of structure. The first specimen was tested under monotonic loading conditions. The second one was instead tested under cyclic loading conditions, with a loading history previously derived from an ad hoc numerical study of the deformation histories likely to be imposed by typical Italian earthquakes. The results obtained allow consideration of typical seismic behavior issues (capacity design, connections between horizontal diaphragms and vertical walls, performance criteria) to be drawn. In particular, all the components of this structural system can be designed according to capacity design criteria, imposing collapse in the sheathing connections of the vertical shear wall. In addition, no appreciable deformation of the OSB sheathing-to-floor framing connections was observed in both monotonic and cyclic tests