Damping Term Related to Ground Velocity Affects Structural Response Calculated by Displacement Excitation

The structural seismic responses obtained by a displacement excitation approach and an acceleration excitation approach respectively are sometimes significantly different. Regarding the causes of this difference, researchers have not provided a plausible explanation. For the aim of determining the effects of damping terms related to ground velocity on the structural seismic response calculated by the displacement excitation approach, the mode superposition method and Duhamel's integral are applied to solving the dynamic equilibrium equations. The analysis indicates that the difference of structural seismic response caused by the method of displacement excitation, obtained by integral acceleration is small. When calculating the structural seismic response, a time step for displacement excitation and acceleration excitation can be assumed as the same value. (paper)