MULTISTORY BASE-ISOLATED BUILDINGS UNDER A HARMONIC GROUND MOTION .2. SENSITIVITY ANALYSIS

A series of sensitivity analyses for multi-story base-isolated structures subject to a harmonic ground excitation is carried out. Several base isolation and energy dissipation devices are considered. The effects of variations in properties of structures and base-isolation systems on the peak responses are studied. For a range of natural frequency, friction coefficient, and damping of the isolator, the peak responses are evaluated. The sensitivity of the base-isolated structure to variations in the amplitude and the frequency of ground excitation is also studied. Particular attention is given to the effects of long-period excitations. The study shows that the peak structural responses for base isolators with a frictional element are less sensitive to variations in intensity and frequency of ground excitation when compared with non-frictional systems. Furthermore, the performances of frictional isolators are insensitive to small variations in friction coefficient and its velocity-dependence. © 1990.