Nonlinear Static and Dynamic Analyses of RC Buildings

Abstract

This study aims to compare pushover and nonlinear time history analyses for existing low- and mid-rise RC buildings to better understand the applicability limits, advantages and disadvantages of nonlinear static and dynamic analyses. The 4- and 7-story buildings designed according to the pre-modern and modern Turkish Earthquake Codes represent the existing low- and mid-rise RC buildings based on inventory results of more than 475 real residential buildings located in Turkey. Eight different ground motion records were used during nonlinear time history analyses selected from destructive earthquakes over past several decades. The outcomes show that the displacement demands obtained from time history analyses differ over a wide range of values, emphasizing the importance of ground motion record selection. The pushover analysis may cause underestimation of the maximum interstory drift ratio for the mid-rise buildings. Besides, it definitely misses the beam damages at the first story. In conclusion, the pushover analysis seems to reflect the nonlinear time history analysis confidently at moderate level earthquakes. However, the results start to deviate as the ground motions get stronger. It is hard to specify a single value for the safe use of pushover analysis considering all parameters in the study. The outcomes of the current study indicate that the pushover analysis provides reasonably well estimates up to 1 and 0.75% roof drift ratios which approximately correspond to 1.5 and 1% interstory drift ratios for low- and mid-rise buildings, respectively. Beyond these limits, the pushover analysis may give misleading demand estimates.