A negative stiffness dynamic base absorber for seismic retrofitting of residential buildings

Abstract

In this study, a negative stiffness-based passive vibration absorber is developed and implemented as a seismic retrofitting measure for typical reinforced concrete (RC) residential buildings. The device, namely, the extended KDamper for retrofitting (EKD-R), is introduced at the base of the structure, between the foundation level and the first story of the building. The design of the EKD-R device and the selection of its properties are undertaken by incorporating a harmony search (HS) algorithm that provides optimized parameters for the mechanism, following constraints and limitations imposed by the examined structural system. Nonlinearities due to the plastic behavior of the structural members and soil–structure interaction (SSI) effects are modeled and taken into consideration during the process. Subsequently, a realistic case study of a benchmark three-story RC building is examined, and the performance of the EKD-R system is assessed. The building superstructure is designed according to Eurocodes. The structure–foundation system, along with the EKD-R, is explicitly modeled using finite elements (FE) that may realistically capture structural nonlinearities and SSI effects. The HS algorithm is employed, and optimized EKD-R components are obtained and implemented in the benchmark structure. Finally, a series of recorded real ground motions are selected, and nonlinear time-history dynamic analyses are conducted aiming to assess the behavior of the controlled system. Results indicate the beneficial role of the novel dynamic absorber, hence rendering the concept a compelling seismic retrofitting technology.