RESPONSE IN THE INELASTIC RANGE OF STAIRCASE FRAMES BELONGING TO R.C. STRUCTURES IN SEISMIC ZONES

In this paper the inelastic response of staircase frames belonging to RC. frame building subjected to seismic excitations is investigated. In particular it is shown how the stair structures, namely the flight-beam system which leads ۱۰ a greater frame stiffness is compared to that determined by the stair slab system, affect the structural response mainly in the inelastic range where, owing to the high sheas and axial forces, failure mechanisms having a brittle nature develop, in contrast with the objective of earthquake resistant design. Results obtained froni static and dynamic analyses are compared. Influence of vertical acceleration component is pointed out.