ABSTRACT
Abstract A rational procedure for the determining the cr-factor for one and mult i-story frames is presented based on the non - linear dynamic (time-history) analysis, using DRAIN-2D computer program. The collapse load is determined corresponding to the attainment of ultimate plastic rotation in beams or columns, obtained through of DUCTROT-93 computer program. The different parameters, as accelerogram type, natural vibration period,. axial forces, story number, degradation etc., are analized. For the interaction q--0some simple relationship are proposed depending on the position of plastic hinge in structure. Keywords: Global ductility, Structural behaviour factor, Accelogram, Natural vibration period, Ultimate plastic rotation.
