Effect of staircases on the seismic performance of reinforced concrete buildings

It is known that, during the structural analysis phase, staircases are not taken into account as structural members but as dead load. Staircases, as secondary structural members, not only serve for connecting separate layers but also provide considerable amount of strength and stiffness to the building which can cause the structure to behave differently rather than it is designed. In this study, in order to examine the effect of staircases on the seismic response of reinforced concrete (RC) buildings, the analytical models were developed for different material properties, number of spans, the existence and location of staircases. Non-Linear Static Pushover Analysis (NSPA) and Non-Linear Time History Analyses (NLTHA) were conducted to compare several engineering demand parameters (EDPs) such as inter-story drift ratio (ISDR), floor accelerations, modal properties, member shear forces and plastic hinge distribution. In addition to these, short column effect, variation in shear forces of columns that are attached to the staircase slab, failure mechanism and nonlinear deformation in staircase models have also been studied. As the result of the performed study, it has been numerically proved that staircases affect the seismic behavior of RC buildings.