Seismic Vulnerability of RC Structures with Different Floor under Earthquake (Technical Note)

Civil engineering structures as well as office or apartment building are affected by earthquakes. In some buildings, few or no walls are provided at the first story (pilot). In the structures with difference in story level, major problems is due to discontinuity of floor diaphragm that causes significant changes in period, stiffness and distribution of earthquake force. In this paper, using IDARC software which is nonlinear dynamic analysis program, time history and location of first crack and plastic hinge, time history and location of plastic hinge in short columns, local and global damage index in 4, 8 and 10 story structures with story level difference under the two earthquake records of Elcentro and Tabas with different peak ground accelerations of 0.3g, 0.5g and 0.7g are evaluated. The results show that in both earthquakes, top stories of all structures have the most damage in 0.3g. Global damage index of 8 story structure is more than 4 and 10 story structures in 0.7g of Tabas earthquake, but in Elcentro earthquake some result comes true about 0.5g. In both earthquakes, crack pattern and plastic hinge of beams happen in common part of two structure that have height difference and the damage of beams and columns happen in the frame shorter part of 4 and 8 story structures and in the frame tall part of 10 story structure.