  In this paper, nonlinear time-history dynamic analyses of selected earthquake
ground motions are conducted on designated wood-frame podium buildings and the
resulting inter-story drifts are analyzed. We aim to construct a reliable
region where performance-based seismic design criteria are met, such that a
two-step analysis procedure can be used with high confidence. We develop a
kriging metamodel with tailored adaptive sampling methods to achieve this goal
in a computationally efficient manner. The input variables we consider are the
normalized stiffness ratio and the normalized mass ratio of the podium
building. We took a six-story wood frame built upon a one-story concrete podium
as a case study for our methodology, where our results indicate that the
two-step analysis procedure may be used with high confidence if its normalized
stiffness ratio is at least 38 and its normalized mass ratio is between 0.5 and
1.5.
