Reduction of seismic vibration in multistorey structures retrofitted with nonlinear viscous dampers using mode summation method.

• A multi-storey building is considered with nonlinear viscous dampers in each floor. • Structure model is considered as an equivalent multi-degree of freedom mechanical system and equation of motion is found. • Using mode summation method displacement response of building is found for each floor. • It is observed that due to presence of nonlinear viscous dampers the displacement response is decreased remarkably. Viscous dampers are the retrofitted devices used to reduce the vibration energy in mechanical systems. In the present paper an investigation is carried to see the effect of nonlinear viscous dampers (NVDs) in multistory buildings. A model of building consisting of NVDs in each floor is considered and is subjected to base shear excitation. The complete model is considered as an equivalent mechanical system and equation of motion is established for equilibrium condition. Using mode summation method analytical expressions are found for the displacement response of the building's floors due to shear waves. To see the role of NVDs different values of damping coefficients are considered and the result is compared with the response of building without NVDs. Analyzing the result it is found that NVDs present in the building's floors dissipate the vibration energy significantly. [ABSTRACT FROM AUTHOR]