Optimal Seismic Design of Controlled Coupled Multiple Rocking Systems with Viscous Dampers in Irregular Buildings

The reduced damage and residual deformations of rocking systems make them efficient for designing resilient buildings for earthquakes. This paper presents a design approach for multiple-rocking coupled self-centering concentrically braced frames (SC-CBFs) with linear fluid viscous dampers (FVDs) utilizing an efficient gradient-based optimization procedure. The optimization problem is formulated such that the framing system, the post-tensioning layout, and the location of the rocking sections are simultaneously designed with the FVDs. The constraints of the optimization problem are formulated following performance-based seismic design. These constraints are evaluated based on results obtained from nonlinear time history analyses of the system when subjected to an ensemble of ground motion records. For the first time, a design method suitable for irregular buildings with multiple-rocking coupled SC-CBFs is proposed. A nine-story irregular building was designed using the proposed method. The results show that an efficient design can be achieved with reasonable computational effort. In addition, the results show that the design of these buildings is not intuitive. A multiple-rocking solution was obtained to reduce force demands in the framing elements.