Role of viscous damping in nonlinear vibration of buildings exposed to intense ground motion

It is the purpose of this paper to present how important the role of viscous damping is in preventing buildings from story collapse during intense earthquake ground motion. The paper first covers an earthquake response analysis of a single-degree-of-freedom model with various types of damping. The study shows that only the viscous damping can decrease the displacement of the model subject to large plastic deformation. Then, with the use of some ten-degree-of-freedom shear models, it is found that the viscous damping is capable of making up for a deficient strength of any story of a building, preventing the structural damage from concentrating into that story. Finally, installation of visco-elastic dampers into RC buildings is found to be a better means of improving their ultimate seismic stability than other conventional means of seismic strengthening.