Seismic performance of buildings retrofitted with nonlinear viscous dampers and adjacent reaction towers

Abstract

Summary An effective strategy of seismic retrofitting consists of installing nonlinear viscous dampers between the existing building, with insufficient lateral resistance, and some auxiliary towers, specially designed and erected as reaction structures. This allows improving the seismic performance of the existing building without any major alteration to its structural and nonstructural elements, which makes this approach particularly appealing for buildings with heritage value. In this paper, the nonlinear governing equations of the coupled lateral‐torsional seismic motion are derived from first principles for the general case of a multistory building connected at various locations in plan and in elevation to an arbitrary number of multistory towers. This formulation is then used to assess the performance of the proposed retrofitting strategy for a real case study, namely, a 5‐story student hall of residence in the city of Messina, Italy. The results of extensive time‐history analyses highlight the key design considerations associated with the stiffness of the reaction towers and the mechanical parameters of the nonlinear viscous dampers, confirming the validity of this approach.

Optimal design and seismic performance of Multi‐Tuned Mass Damper Inerter (MTMDI) applied to adjacent high‐rise buildings

“…[ 4 ] Their presence can also serve structural purposes, as classical passive dampers connecting the two buildings were studied and proposed for the structural control of adjacent buildings. [ 5–10 ] Under dynamic excitation, that is, wind loads [ 11 ] or earthquake excitations, large displacements and accelerations may be induced due to their high flexibility. [ 12 ] Consequently, these closely spaced structures require an effective structural control system against the large wind forces and earthquake excitation, to prevent them from structural damages.…”

Optimization of Nonlinear Fluid Viscous Dampers for Building Structures: Energy-Based Design Approach Under Stochastic Seismic Excitation

“…Therefore, Eq. (2) has a general significance and can be applied to different damper implementations, such as inter-story dampers [13], adjacent structures with interconnected dampers [14], [15] and dampers installed in between the structure and adjacent reaction towers [16], by suitably adjusting the shape of R according to the problem being investigated. The ground motion acceleration g u is modeled as a random process in the stochastic framework of the proposed optimal design procedure.…”

Modal properties and seismic behaviour of buildings equipped with external dissipative pinned rocking braced frames

“…Eqn. ( 17 ) and ( 18 ) provide closed-form estimates of the changes of the dynamic properties of the system due to the dissipative towers and can be quite useful as very often the external towers are quite rigid. In the next section, the approximation of rigid tower behaviour is evaluated by considering different retrofit configurations.…”

“…In the first arrangement ( Fig. 1 a), the dampers are placed horizontally at floor level, between the frame and an external stiff structure [16]- [18]. This way, the links are activated by the relative displacements between the frame and the external structure.…”