Pushover analysis of full-scale innovative hybrid coupled wall systems

This article presents the design detailing and the seismic behaviour of two innovative hybrid coupled wall (HCW) systems, essentially consisting of a single 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. Encouraging numerical results have already been obtained regarding the HCWs’ seismic behaviour through comprehensive parametric studies using two-dimensional frame models. However, experimental evidences are necessary for practical implementation, addressing issues and develop advancements in the analysis, design, and detailing. Therefore, two types of 4-storey full-scale HCW systems have been designed and constructed for pseudo-dynamic testing – (i) HCW system with a fixed base wall and (ii) HCW system with a rocking-base wall and vertical links. The design outcomes are discussed in details regarding each individual component of the HCW system. Engineering drawings are presented for the experimental specimens. Both configurations are investigated through nonlinear pushover analyses using two-dimensional frame models and three-dimensional solid models to characterize their seismic behaviour. Specific performance levels have been identified and discussed with respect to their force-displacement behaviour: (i) the “reparability” of the HCW system, i.e. yielding of the steel links/dissipative devices with negligible damages in the RC wall – where the self-centering capacity of the system is active and the actual replacement capacity of the elements can be validated; (ii) yielding of the longitudinal rebars in the RC wall and (iii) structural collapse, i.e. significant damages in the concrete wall, eventually leading to a non-reparable damage state. Different damage criteria have been considered for a sensitivity analysis of the proposed HCW systems. Relevant results have been discussed through graphical and contour plots. Finally, from a sustainable construction point of view, the assembling and disassembling of the system has also been stated to highlight the possibility to re-use different elements in a new construction.