This is a post Loma Prieta earthquake (Oct. 1989) investigation project in learning from this damaging event. The objective of this project is to utilize the strong- motion records to validate and improve the current analytical methods for predicting the drift response of flat-plate buildings. It has been demonstrated repeatedly that discrepancies exist between the analytically predicted response and the actual response of flat-plate buildings. Because of their inherent flexibility, the survivability of flat- plate buildings very much depends upon controlled drift. A realistic estimate of lateral drift is therefore essential for a safe design. A number of flat-plate and flat-slab buildings, ranging in height from six to twenty stories, have yielded over twenty seconds of strong-motion data. Records from a selected number of these buildings will be collected for evaluation of drift response. Each building will be analyzed for lateral drift using the code defined lateral forces and the currently accepted analytical models. The analyses will then be repeated for time-history response using the ground motion recorded at the base of the buildings. By comparing the predicted and the measured response and using the system identification techniques, the reliability of the existing models for predicting the drift response of flat-plate buildings for an earthquake type of loading could be improved.