Improving Static Pushover Analysis by Optimal Bilinear Fitting of Capacity Curves

Flavia De Luca, Dimitrios Vamvatsikos, Iunio Iervolino

Research output: Chapter in Book/Report/Conference proceedingChapter in a book

2 Citations (Scopus)
111 Downloads (Pure)


An improvement of codes’ bilinear fit for static pushover (SPO) curves is put for-ward aimed at decreasing the error introduced in the conventional SPO analysis by the piecewise linear fitting of the capacity curve. In the approach proposed herein, the error introduced by the bilinear fit of the force-deformation relationship is quantified by studying it at the single degree of freedom (SDOF) system level, away from any interference from multiple degree of freedom (MDOF) effects. Incremental Dynamic Analysis (IDA) is employed to enable a di-rect comparison of the actual curved backbones versus their piecewise linear ap-proximations in terms of the spectral acceleration capacity for a continuum of limit-states, allowing an accurate interpretation of the results in terms of performance. A near-optimal elastic-plastic bilinear fit can be an enhanced solution to decrease systematically the error introduced in the SPO analysis if compared to the fit approaches provided by most codes. The main differences are (a) closely fitting the initial stiffness of the capacity curve and (b) matching the maximum strength value, rather than disregarding them in favor of balancing areas or energies. Employed together with selective area discrepancy minimization, this approach reduces the conservative bias observed for systems with highly curved force-deformation backbones.
Original languageEnglish
Title of host publicationComputational Methods in Earthquake Engineering
EditorsManolis Papadrakakis, Michalis Fragiadakis, Vagelis Plevris
Number of pages13
ISBN (Electronic)9789400765733
ISBN (Print)9789400765726
Publication statusPublished - 1 Jan 2013

Publication series

NameComputational Methods in Applied Sciences
PublisherSpringer Netherlands
ISSN (Print)1871-3033


  • Incremental dSingle-degree-of-freedomzynamic analysis
  • Piecewise linear fit
  • Pushover curve
  • Single-degree-of-freedom


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