Uncoupled rocking and shear base-mechanisms for resilient reinforced concrete high-rise buildings

High-rise buildings are an efficient solution to meet the housing challenges of global urbanization that is happening at an incredible pace. Code-based seismic design philosophies are aimed at achieving collapse-prevention under major earthquakes, implying extensive structural damage associated with important losses. A number of high-performance systems have been investigated for enhancing the resilience of high-rise buildings whose design is especially challenging due to higher-mode effects even when a flexural mechanism is formed at the base of the structure. To this end, this paper proposes a new concept consisting of a three-dimensional uncoupled rocking and shear mechanism system for high-rise buildings where reinforced concrete (RC) core walls are used as the lateral-force-resisting system. The proposed system provides a dual-mechanism at the base that independently limits both overturning moments (OTMs) and shear forces and thus more effectively mitigates higher-mode effects. The characteristic mechanics of the proposed system are first studied through an idealized model. A physical embodiment is then designed, detailed, and validated through advanced models and extensive nonlinear dynamic analyses. A 42-story RC core-wall building that is located in Los Angeles and was studied as part of the PEER Tall Buildings Initiative is used as a reference structure in this study. Results confirmed that the proposed system eliminates damage at the base of the walls and minimizes the inelastic demands over the height of the building. In a general sense, the proposed concept provides a framework in which the intended dual mechanism can be implemented to a wider range of high-rise structures.