Ground motion selection for the evaluation of residual inter-story drifts in moment-resisting reinforced concrete frame buildings

An evaluation of some structural parameters affecting the amplitude and height-wise distribution of peak and residual drift demands of reinforced concrete frame buildings modeled as 3D complex MDOF systems is presented. In addition, the influence of different ground motion selection methods on the uncertainty in the estimation of both peak and residual drifts is assessed. For this purpose, buildings with different characteristics were subjected to record sets selected: a) randomly, b) considering the magnitude and epicentral distance, and c) to match an objective spectral shape. Results indicate that parameters like the post-yielding stiffness ratio and the structural overstrength importantly affect the magnitude and height-wise distribution of residual drift demands on buildings. The estimation of residual drifts involves a higher level of uncertainty than that of peak drift demands. Selecting records based on a target spectral shape is very effective in reducing the uncertainty on the estimation of both peak and residual inter-story drift demands. Residual drifts may be underestimated if the design/assessment of buildings is conducted by using seismic records that were selected randomly or according to their magnitude and epicentral distance only.