Browsing by Author "Shamekhi, Shima"

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    Master ThesisPublicationMetadata only
    A comparison study between 1D and 2D site response analyses based on observed earthquake acceleration records
    Shamekhi, Shima; Ansal, Mustafa Atilla; Ansal, Mustafa Atilla; Çinicioğlu, Safiye Feyza; Tönük, G.; Department of Civil Engineering; Shamekhi, Shima
    Dynamic site response analysis is a technique that uses site characteristics and dynamic movements to attempt to predict the response of the specific site to ground motions in the form of response spectra. The main objective of the present work is to evaluate the difference between the one-dimensional and two-dimensional site response analysis, based on the comparison among the peak ground and spectral accelerations recorded by Istanbul Rapid Response Network (IRRN) and three Istanbul vertical array stations (IGVA) including Ataköy, Fatih and Zeytinburnu stations, during the Mw=6.5, 24.5.2014 Gökçeada and Mw=5.9, 19.5.2011 Kütahya earthquakes with the calculated accelerations by the 1D and 2D site response analyses. In this study, shear wave velocity profiles were determined based on insitu geophysical, geotechnical measurements, and laboratory tests within the Istanbul Microzonation Project. The shear wave velocity values, which are subject to some uncertainties due to some measurement methods or environmental conditions, are re-evaluated using a revision scheme to obtain the best matches between the recorded and calculated spectral accelerations by 1D site response analysis. These modified shear wave velocity profiles are later used for 1D and 2D site response analyses which in North-South and East-West directions to model peak ground and spectral accelerations on the ground surface. The results show the improvement of the calculated PGA and SA values. Finally, as another focus of this study, by modelling different symmetric spacing around the main boreholes separately in two main directions of some IRRN stations, the influence of horizontal distance on site response was investigated for 2D analyses. The results show that, in general, no unique relationship can be defined between the horizontal distance and the site response. There is an optimal spacing for each soil profile to obtain the best agreement between the calculated SA and the recorded value.
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    Conference paperPublicationMetadata only
    A comparison study between 1D and 2D site response analyses based on observed earthquake acceleration records
    (Springer, 2023) Shamekhi, Shima; Ansal, Mustafa Atilla; Kurtuluş, Aslı; Civil Engineering; ANSAL, Mustafa Atilla; KURTULUŞ, Asli; Shamekhi, Shima
    The objective of the present work is to evaluate the necessity of 2D site response analysis based on the comparison among the peak ground and spectral accelerations recorded by Istanbul Rapid Response Network and Istanbul vertical array stations during the Mw = 6.5 24/5/2014 Gökçeada and Mw = 5.9 19/5/2011 Kütahya earthquakes with the calculated accelerations by 1D and 2D site response analyses. The shear wave velocity profiles determined based on in-situ geophysical and geotechnical measurements and laboratory tests within the Istanbul Microzonation Project are revaluated adopting a revision scheme to obtain the best fits between the recorded and calculated spectral accelerations by 1D site response analysis. These modified shear wave velocity profiles are later used for 1D and 2D site response analyses performed in North–South and East–West directions to model peak ground and spectral accelerations on the ground surface. Finally, by modelling different distances around boreholes the influence of variation of the soil profile in horizontal direction is investigated by 2D analyses.
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    Conference paperPublicationMetadata only
    A comparison study between 1D and 3D site response analyses based on observed earthquake acceleration records…
    (National Technical University of Athens, 2023) Shamekhi, Shima; Ansal, Mustafa Atilla; Civil Engineering; ANSAL, Mustafa Atilla; Shamekhi, Shima
    The characteristics of the site conditions have a very significant influence on the variation of building damage during earthquakes, thus, it is essential to evaluate and analyse the effects of site conditions. One option is to conduct site-specific response analysis to calculate the response of the soil layers by using estimated acceleration records on rock outcrop, shear wave velocity profiles, shear modulus reduction, and damping ratio curves as inputs for the encountered soil layers. The objective of the present work is to evaluate the necessity of 3D site response analysis based on the comparison among the peak ground and spectral accelerations recorded by Istanbul Rapid Response Network and Istanbul vertical array stations during the Mw=6.5 24/05/2014 Gökçeada and Ml=5.7 26/09/2019 Silivri earthquakes with the calculated accelerations by 1D and 3D site response analyses. The shear wave velocity profiles determined based on in-situ geophysical and geotechnical measurements and laboratory tests within the Istanbul Microzonation Project are revaluated adopting an optimization scheme to obtain the best fits between the recorded and calculated accelerations by 1D site response analysis. These modified shear wave velocity profiles are later used for 3D site response analyses performed taking into consideration the three components of the recorded acceleration time histories in all three directions at the bedrock level to model peak ground and spectral accelerations on the ground surface.