A DISPLACEMENT-BASED ADAPTIVE PUSHOVER FOR SEISMIC ASSESSMENT OF STEEL AND REINFORCED CONCRETE BUILDINGS

A number of recent studies raised doubts on the effectiveness of conventional pushover methods, whereby a constant single-mode incremental force vector is applied to the structure, in estimating the seismic demand/capacity of framed buildings subjected to earthquake action. The latter motivated the recent development and introduction of the so-called Adaptive Pushover methods whereby the loading vector is updated at each analysis step, reflecting the progressive damage accumulation and resulting modification of the modal parameters, that characterise the structural response at increasing loading levels. Within such adaptive framework, the application of a displacement, as opposed to force, incremental loading vector becomes not only feasible, since the latter is updated at each step of the analysis according to the current dynamic characteristics of the structure, but also very appealing, since inline with the present drive for development and code implementation of displacement or, more generally, deformation-based design and assessment methods. Further, such innovative displacement-based pushover algorithm seems to lead to superior response predictions, with little or no additional modelling and computational effort, with respect to conventional pushover procedures.