Seismic Behavior of Short Column in RC Structures with Different Floor Level

Engineering structures as well as office or apartment buildings are affected by earthquakes. A common cause of failure seems to be shear stresses. The earthquake tremor developed at different floor levels need to be brought down along the height to the ground by the shortest path. Short column phenomenon is one of the frquent causes of buildings failure in the past earthquakes. This destructive phenomenon is due to the column height difference in a story level that is predominantly owing to the location of building on sloppy ground. These buildings have unequal height columns along the slope, which causes poor effects like twisting and damage in shorter columns. In some buildings, few or no walls are provided at the first story (pilot). In the structures with difference in the story levels, major problems is due to the discontinuity of floors diaphragm that causes significant changes in natural period, stiffness and distribution of earthquake forces. In this study, at first, seismic behavior of short column phenomenon is determined, then, nonlinear behavior of RC short columns in the 4, 8 and 10 story buildings with story level difference is investigated. Short columns and mentioned structures are analyzed under the earthquake records of Elcentro and Tabas with different peak ground acceleration using IDARC software which is nonlinear dynamic analysis program. In this investigation, the results of maximum response, base shear, global damage index and displacement time history and effect of short column in structural failure are evaluated.