Evolutionary seismic design optimization of mega‐brace damper architectures in three‐dimensional structures

Abstract

AbstractNovel seismic protection systems are widely used to improve building performance or collapse prevention under extreme events. However, a systematic approach for the distribution of dampers in structures expected to operate inelastically under extreme seismic loading does not exist in modern seismic codes. Furthermore, optimal designs are achieved typically performing only forward analysis with no direction on how device topologies and properties distribution affect the response and the plastic action distribution throughout structures for different types of passive devices. To address the above, this study utilizes an evolutionary framework for optimization of the topology and properties of passive dampers in three‐dimensional buildings subject to seismic loading. The framework incorporates a self‐organizing evolutionary algorithm, a novel concept of mega‐brace damper architecture scheme, and an active ground motion subset scheme to efficiently find optimal designs that satisfy predefined performance targets. Three‐dimensional buildings considered include eight‐story irregular, eight‐story regular, and 14‐story regular structures, while passive devices included yielding, friction, and viscous dampers. The seismic environment consisted of twenty‐five synthetic ground motions with 5% of probability of exceedance in 50 years. The study included design examples with realistic three‐dimensional buildings, and the proposed framework yielded optimal designs that exhibited uniform ductility demand along the height when compared to the base buildings. Novel three‐dimensional multiscale mega‐brace architectures not seen in practice were identified, while their corresponding plastic action distribution throughout the buildings was assessed for each case.