ABSTRACT
Sometimes, the dynamic load may not be known in the form of Force Vs time, but as random vibration (such as earthquake) in the form of frequency Vs acceleration. This frequency spectrum is treated as a linear combination of individual acceleration (amplitude) Vs time of specific frequencies. Each acceleration Vs time is equivalent to applying force Fy(t) at node I in Jth DOF given by Fy = mass at node I x acceleration in Ith DOF. This analysis is called response spectrum analysis.
