Civil Engineering Association

ANALYSIS OF BUILDING STRUCTURES WITH SOFT STORIES

Past earthquakes in Turkey and around the World have shown that soft story irregularity in building structures pose a serious threat to their integrity and stability. Heavy damaging or collapse of numerous buildings with soft story irregularity during the recent earthquakes have prompted a concentrated research;effort into linear and nonlinear analysis methods to evaluate the behaviour and capacity of such buildings under seismic actions.The objective of this thesis is to determine the nonlinear behaviour of the building structures having soft first stories by nonlinear static pushover and time-history analyses and to evaluate the accuracy and effectiveness of these methods. Several two dimensional analytical models with various number of stories and spans are,investigated with nonlinear static pushover and nonlinear time history analysis methods by considering various first story heights and deformation levels. The investigation procedure as a summary consists of (a) creating finite element models representative of the building stock in Turkey, (b) determining the nonlinear member behaviours, © performing the nonlinear analysis procedures on these models, and finally (d) evaluating the results obtained from these nonlinear analyses methods. In view of these analysis results, the soft story behaviour is investigated and the facts, reasons and results of this irregularity are explained in detail. In addition, various codes are evaluated considering the soft story irregularity and the provisions of these codes are summarised.