Seismic collapse capacity assessment of SDOF systems incorporating duration and instability effects

M. A. Bravo-Haro, M. Liapopoulou, A. Y. Elghazouli

Research output: Journal article publicationJournal articleAcademic researchpeer-review

15 Citations (Scopus)


This paper presents a detailed investigation into the seismic response of non-deteriorating and deteriorating single degree-of-freedom systems controlled by P- Δ effects, with due account for the influence of earthquake duration. In order to isolate the effect of duration from other ground motion characteristics, 77 pairs of records with equivalent spectral shapes are considered in the study. The structural characteristics examined include the structural period, applied gravity loading, post-yield stiffness, viscous damping, material hysteretic behaviour, as well as the level of cyclic deterioration within the pinching systems. Detailed incremental dynamic analyses are carried out, considering an intensity measure corresponding to the spectral acceleration at the structural period of vibration of the system. Based on the incremental dynamic analysis results, predictive relationships are proposed for determining the structural collapse capacity, accounting for the influence of key parameters including instability and duration effects. The median and dispersion of the collapse capacity distribution embedded in the predictive models are also presented. The effect of duration is shown to increase with longer structural periods and to decrease with higher P- Δ levels. The more rapid instigation of dynamic instability in relatively stiff systems is also shown to reduce their comparative sensitivity to variations in ground motion characteristics. Overall, it is indicated that disregarding the influence of duration could lead to over-estimations of up to 50% in the collapse capacity. The paper concludes with a discussion of other sources of structural damage that instigate collapse when using records with equivalent spectral shape but without especial consideration for duration effects.

Original languageEnglish
Pages (from-to)3025-3056
Number of pages32
JournalBulletin of Earthquake Engineering
Issue number7
Publication statusPublished - 1 May 2020


  • Collapse capacity
  • Ground motion duration
  • Hysteretic behaviour
  • P-delta effects
  • Seismic response

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction
  • Geotechnical Engineering and Engineering Geology
  • Geophysics


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