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Seismic retrofitting of braced frame buildings by RC rocking walls and viscous dampers
Author(s) -
Barbagallo Francesca,
Bosco Melina,
Marino Edoardo M.,
Rossi Pier Paolo
Publication year - 2018
Publication title -
earthquake engineering and structural dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.218
H-Index - 127
eISSN - 1096-9845
pISSN - 0098-8847
DOI - 10.1002/eqe.3105
Subject(s) - structural engineering , braced frame , seismic retrofit , damper , retrofitting , displacement (psychology) , seismic analysis , engineering , vibration , dissipation , dissipative system , ductility (earth science) , damping ratio , frame (networking) , reinforced concrete , materials science , physics , creep , mechanical engineering , psychotherapist , thermodynamics , psychology , quantum mechanics , composite material
Summary A design procedure for seismic retrofitting of concentrically and eccentrically braced frame buildings is proposed and validated in this paper. Rocking walls are added to the existing system to ensure an almost uniform distribution of the interstorey displacement in elevation. To achieve direct and efficient control over the seismic performance, the design procedure is founded on the displacement‐based approach and makes use of overdamped elastic response spectra. The top displacement capacity of the building is evaluated based on a rigid lateral deformed configuration of the structure and on the ductility capacity of the dissipative members of the braced frames. The equivalent viscous damping ratio of the braced structure with rocking walls is calculated based on semi‐empirical relationships specifically calibrated in this paper for concentrically and eccentrically braced frames. If the equivalent viscous damping ratio of the structure is lower than the required equivalent viscous damping ratio, viscous dampers are added and arranged between the rocking walls and adjacent reaction columns. The design internal forces of the rocking walls are evaluated considering the contributions of more than one mode of vibration. The proposed design procedure is applied to a large set of archetype braced frame buildings and its effectiveness verified by nonlinear dynamic analysis.