Improving the seismic torsional behavior of plan-asymmetric,single-storey,concrete moment resisting buildings with fluid viscous dampers

The optimal distribution of fluid viscous dampers (FVD) in controlling the seismic response of eccentric, single-storey, moment resisting concrete structures is investigated using the previously defined center of damping constant (CDC). For this purpose, a number of structural models with different one-way stiffness and strength eccentricities are considered. Extensive nonlinear time history analyses are carried out for various arrangements of FVDs. It is shown that the arrangement of FVDs for controlling the torsional behavior due to asymmetry in the concrete structures is very dependent on the intensity of the peak ground acceleration (PGA) and the extent of the structural stiffness and strength eccentricities. The results indicate that, in the linear range of structural behavior the stiffness eccentricity es which is the main parameter in determining the location of optimal CDC, is found to be less or smaller than the optimal damping constant eccentricity e*_d, i.e., |e*_d| > |e_s|. But, in the nonlinear range of structural behavior where the strength eccentricity er is the dominant factor in determining the location of optimal CDC, |e*_d| > |e_r|. It is also concluded that for the majority of the plan-asymmetric, concrete structures considered in this study with e_r ≠ 0, the optimal CDC approaches the center of mass as e_r decreases.