Study of RC Structures with Different Floor in Progressive Collapse

Short column phenomenon was one of effective cause in the structures with different floor at past earthquakes that floors of stories in this structures created in two or several heights. 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 whit Sensitivity Index (SI), displacement, plastic hinge pattern in columns and beams and capacity spectrum and… studied linear and nonlinear behavior of Progressive collapse whit rupture of one member happens rupture of next member and frequently collapse in 4 and 8 story structures with story level difference. The result show that the short structures with story level difference have more stiffness and load capacity and if the height difference was less,the sensitivity index is more.