Probability-based assessment of number of equivalent uniform stress cycles

Çetin, Kemal Önder
Bilge, H. Tolga
For seismic soil liquefaction triggering and performance assessments, durational effects in field-based evaluations are mostly represented by the magnitude of the seismic event. However, in the laboratory, the equivalent number of uniform shear stress cycle concept is used. Benefitting from the findings of both case history- and laboratory-based research streams requires the conversion of earthquake-induced transient shear stresses to equivalent uniform (harmonic) stress cycles, or vice versa. A critical review of currently existing studies has revealed that; i) significantly extended earthquake catalogs are now available, which enable improved assessment of the conversion scheme, ii) based on the findings of Cetin and Bilge, weighting factors (m values) of stress conversions are now known to be stress, strain and density state dependent, and iii) these weighting factors extend to ranges that exceed the limits of earlier studies. Inspired by these, a semi-empirical probability-based model for the estimation of equivalent number of uniform stress cycles as functions of earthquake, site and performance (either strain or pore pressure-based) parameters is proposed. The proposed predictive relationship is shown to be more accurate and precise, evident by higher R-2 and smaller model error standard deviations. However, despite significant improvement to an R-2 value of 0.30, it is concluded to be still low, which addresses the uncertainties involved in duration assessments of earthquake shaking, and the need for further research. The probabilistic use of the proposed model is illustrated for a sandy soil layer at a soil site, which is expected to be shaken by a scenario earthquake event.


Evaluation and selection of ground motion intensity measures for nonlinear seismic demand and fragility analysis of MDOF systems
Kadaş, Koray; Yakut, Ahmet; Department of Civil Engineering (2021-5-21)
In performance-based seismic design methodology, intensity measures are thought to be key parameters of ground motion records that relate the seismic hazard levels with the structural response or damage. Therefore, it is important to identify efficient intensity measures that are capable of reducing the variability in seismic demand predictions. There exist several simple-to-advanced scalar and vector ground motion intensity measures; however, the literature is limited in the number of comparative studies i...
Spatial sensitivity of seismic hazard results to different background seismic activity and temporal earthquake occurrence models
Yilmaz, Nazan; Yücemen, Mehmet Semih (Elsevier BV, 2011-07-01)
Spatial sensitivity of seismic hazard results to different models with respect to background seismic activity and earthquake occurrence in time is investigated. For the contribution of background seismic activity to seismic hazard, background area source with uniform seismicity and spatially smoothed seismicity models are taken into consideration. For the contribution of faults, through characteristic earthquakes, both the memoryless Poisson and the time dependent renewal models are utilized. A case study, ...
Spatial sensitivity of seismic hazard results to background seismic activity models
Yilmaz, N.; Yücemen, Mehmet Semih (2011-08-04)
In the probabilistic seismic hazard analysis, the past earthquake records that can not be associated with any one of the specific faults are treated as background seismic activity. Contribution of background seismic activity to seismic hazard is generally calculated by using two different models, namely: background area source with uniform seismicity and spatially smoothed seismicity model. In this study, two case studies are carried out for a large (a country) and a small region (a province) in order to in...
Statistical evaluation of the damage potential of earthquake ground motions
Sucuoğlu, Haluk; Gezer, A; Erberik, Murat Altuğ (1998-01-01)
This study focuses on the damage potential of earthquake ground motions based on the inelastic dynamic response of equivalent single degree of freedom structures. Their yield resistances are selected in accordance with seismic design codes. An index accounting for the accumulation of damage due to inelastic excursions is used to represent structural damage. A set of 94 ground motions are employed for this analysis, which are all scaled to the same peak ground acceleration of 0.4 g. Earthquake ground motions...
Experimental evaluation of geomembrane / geotextile interface as base isolating system
Taheri Bonab, Amin; Gülerce, Zeynep; Kalpakcı, Volkan; Department of Civil Engineering (2016)
The objective of this study is to evaluate the effect of the composite liner seismic isolation system on the seismic response of small-to-moderate height structures. For this purpose, a building model with the natural frequency of 3.13 Hz (representing 3-4 story structures) was tested with and without the addition of composite liner system using the shaking table test set-up by employing harmonic and modified/ scaled ground motions. Experiment results showed that the composite liner seismic isolation system...
Citation Formats
K. Ö. Çetin and H. T. Bilge, “Probability-based assessment of number of equivalent uniform stress cycles,” SOIL DYNAMICS AND EARTHQUAKE ENGINEERING, pp. 0–0, 2021, Accessed: 00, 2021. [Online]. Available: