Abstract
Probabilistically controlled design values of the nonlinear seismic response of reinforced concrete frames are obtained using a method previously proposed by the authors. The method allows to calculate conservative design values characterized by a predefined nonโexceedance probability, using a limited number of spectrumโfitting generated accelerograms. Herein the method is applied to elasticโstrain hardening single degree of freedom systems representative of RC framed structures and is then assessed with reference to four reinforced concrete model frames designed according to EC8. The frames are characterized by different natural periods and aspect ratios. The results, compared with those obtained applying current EC8 recommendations, show the effectiveness of the proposed method. EC8 provides for design values of the seismic response of a structure with a nonlinear behavior computed as the mean value of the responses to seven accelerograms or as the maximum value of the responses to three accelerograms. These two criteria lead to design values characterized by very different and uncontrolled nonโexceedance probability levels, while the proposed method allows the analyst to directly control the nonโexceedance probability level of the calculated design values. Copyright ยฉ 2009 John Wiley & Sons, Ltd.