Displacement-based adaptive pushover

Abstract eng:
A number of recent studies raised doubts on the effectiveness of conventional pushover methods, whereby a constant 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 of the so-called adaptive pushover methods whereby the loading vector is updated at each analysis step, considering one or more response modes, reflecting in this way the effects that damage progression have on the response characteristics of structures subjected to increasing loading levels. Within such adaptive framework, the application of a displacement incremental loading vector becomes not only feasible but also advantageous since it leads to superior response predictions, with little or no additional modelling/analysis effort, in comparisons with conventional pushover procedures. In addition, such single-run Displacement-based Adaptive Pushover (DAP) method features also the advantage, with respect to recently proposed multiple-run alternatives (e.g. MPA, AMCP), of leading to structural response estimates that correspond to equilibrated structural stress-states. The improvements in accuracy gained by the employment of DAP have been scrutinised and confirmed through extensive comparisons with the results of nonlinear dynamic analysis, commonly considered as the most accurate tool to estimate seismic demand/capacity of structures. A multitude of case-studies were considered, including non-seismically and seismically designed buildings and bridges, reinforced concrete and steel constructions, 2D and 3D modelling scenarios, all of which subjected to tens of earthquake records. In addition, and in order to enable the incorporation of this innovative pushover algorithm within design/assessment codes and guidelines, a complete Nonlinear Static Procedure (NSP), involving thus also the calculation of target displacement, that capitalises fully on the potential of the DAP algorithm has been developed and proposed; Adaptive Capacity Spectrum Method (ACSM). The results obtained with the latter, and its comparison with other NSPs (CSM, N2, MPA, AMCP), are also referred to in this work.

• Export as: BibTeX | MARC | MARCXML | DC | EndNote | NLM | RefWorks
• Add to your basket