Seismic Behaviour of an Innovative Hybrid Coupled Wall System Investigated Through Cyclic Tests

This article presents the experimental results obtained from the cyclic testing of an innovative hybrid coupled wall (HCW) system – a fixed-base reinforced concrete (RC) wall coupled with two steel side-columns via steel coupling links, where the wall carries almost all the horizontal shear force and the overturning moments are partially resisted by an axial tension-compression couple developed by the two steel columns rather than by the individual flexural action of the wall alone. The initial stiffness properties were primarily identified through the first cycle, estimating the yield force and displacement of the HCW system. Incremental cyclic tests were then conducted according to the ECCS 1986 provisions, targeting specific performance levels: (i) “reparability” of the HCW, i.e. the yield displacement, where the steel links yield with negligible damages in the wall and the self-centering capacity of the system is active, so that the actual replacement capacity of the elements can be validated; and (ii) a displacement level corresponding to a major earthquake with very low probability, which activates the wall as an additional dissipative element, eventually leading to a non-reparable damage state. Relevant results have been discussed through graphical and real-life illustrations. Finally, the constructional aspects are also discussed from a real-life application viewpoint.