İnşaat Mühendisliği Bölümü Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.11779/1943

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Access Right: Closed AccessAuthor: search.filters.author.Tönük, Gökçe

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Now showing 1 - 8 of 8
  • Article
    Citation - WoS: 10
    Citation - Scopus: 10
    Site Response Analysis in Performance Based Approach
    (Elsevier Sci Ltd, 2024) Ansal, Atilla; Tönük, Gökçe; Sadeghzadeh, Shima; Sadegzadeh, Shima; 02.04. Department of Civil Engineering; 02. Faculty of Engineering; 01. MEF University
    A performance based approach for site response analysis requires a probabilistic approach accounting for the observed variability in soil stratification and engineering properties of the soil layers. The major variability in site-specific response analysis arises from the uncertainties induced by the (a) local seismic hazard assessment, (b) selection and scaling of the hazard compatible input earthquake time histories, (c) soil stratification and engineering properties of encountered soil and rock layers, and (d) method of site response analysis. Even though the uncertainties related to first item, local seismic hazard assessment, has primary importance on the outcome of the site-specific response analyses, the discussion in this article focuses on the possible uncertainties in selection and scaling of the hazard compatible input earthquake time histories, soil stratification, thickness, type and their engineering properties, depth of ground water table and bedrock and properties of the engineering bedrock. One alternative may be to conduct site response analyses for large number of soil profiles generated by Monte Carlo simulations using relatively large number of hazard compatible acceleration time histories to assess probabilistic performance based design acceleration spectra and acceleration time histories calculated on the ground surface with respect to different performance levels. A remaining issue may be considered as the variability induced by 1D, 2D, and 3D site response analysis.
  • Article
    Citation - WoS: 12
    Citation - Scopus: 13
    Damage Accumulation Modelling of Two Reinforced Concrete Buildings Under Seismic Sequences
    (Springer, 2023) Tönük, Gökçe; Tönük, Gökçe; Oyguç, Evrim; Uçak, Doruk; 02.04. Department of Civil Engineering; 02. Faculty of Engineering; 01. MEF University
    The extent of earthquake damage depends solely on the seismicity, site conditions and vulnerability of the building stock in a region. Hence, studies to assess the seismic behavior of building stocks with similar vulnerabilities are important to mitigate seismic risk in earthquake-prone regions. This study aims to simulate the seismic behavior of selected reinforced concrete (RC) school buildings by modelling damage accumulation under multiple earthquakes sequence. The observed data of two RC school buildings heavily damaged after the 2011 Van earthquake sequence in Turkey, namely, the Gedikbulak and Alakoy schools is used. Among these two school buildings, the Gedikbulak school building collapsed immediately after the main excitation, while the Alakoy school building withstood several seismic sequences, suffering heavy damages. In this study, three-dimensional numerical models that can consider the deterioration effects are developed and the capacities of the buildings were evaluated by conducting a force-based adaptive pushover procedure. Additionally, non-linear dynamic analyses were conducted using the concrete plastic damage model. Both degrading and conventional material models were used to examine the structural response under multiple ground motion sequences. The hysteretic behaviors of the studied buildings are presented. Consequently, analytical results are well correlated with the reconnaissance studies and neither of the considered structures are found to satisfy the design performance level.
  • Conference Object
    Site Characterization for Site Response Analysis in Performance Based Approach
    (Sipringer, 2022) Tönük, Gökçe; Ansal, Atilla; 02.04. Department of Civil Engineering; 02. Faculty of Engineering; 01. MEF University
    The local seismic hazard analysis would yield probabilistic uniform hazard acceleration response spectrum on the engineering bedrock outcrop. Thus, site-specific response analyses need to produce a probabilistic uniform hazard acceleration response spectrum on the ground surface. A possible performance based approach for this purpose requires a probabilistic estimation of soil stratification and engineering properties of encountered soil layers in the soil profile. The major uncertainties in site-specific response analysis arise from the variabilities of (a) local seismic hazard assessment, (b) selection and scaling of the hazard compatible input earthquake time histories, (c) soil stratification and engineering properties of encountered soil and rock layers, and (d) method of site response analysis. Even though the uncertainties related to first two items have primary importance on the outcome of the site-specific response analyses, the discussion in this article focuses on the observed variability and level of uncertainty in site conditions, related to soil stratification, thickness and type of encountered soil layers and their engineering properties, depth of ground water table and bedrock and properties of the engineering bedrock. Thus, one option may be conducting site response analyses for large number of soil profiles produced by Monte Carlo simulations for the investigated site to assess probabilistic performance based design acceleration spectra and acceleration time histories calculated on the ground surface based on 1D, 2D, or 3D site response analysis with respect to different performance levels.
  • Conference Object
    Citation - WoS: 3
    Citation - Scopus: 4
    Microzonation With Respect To Ground Shaking Intensity
    (CRC Press/Balkema, 2019) Tönük, Gökçe; Tönük, Gökçe; Kurtuluş, Aslı; Ansal, Atilla; 02.04. Department of Civil Engineering; 02. Faculty of Engineering; 01. MEF University
    Seismic microzonation is conducted to assess the seismic hazard on the ground surface with respect to ground shaking intensity. A probabilistic seismic hazard study is conducted to define earthquake characteristics on the rock outcrop. A grid system is generated to divide the investigation area into cells according to geological and geotechnical data. Site characterizations are based on available information to define soil profiles for each cell with soil stratifications and shear wave velocities extending down to the engineering bedrock. Site-specific 1D site response analyses are carried out for all soil profiles, based on the engineering properties of encountered soil layers, selection and scaling of the sufficient number of input acceleration time histories compatible with the regional seismicity and earthquake source characteristics. The microzonation study carried out for Zeytinburnu town on the European side of Istanbul with respect to ground shaking intensity is presented. The importance of the selection of the microzonation parameters for assessing ground shaking intensity is discussed. © 2019 Associazione Geotecnica Italiana, Rome, Italy.
  • Conference Object
    Citation - WoS: 10
    Citation - Scopus: 12
    Implications of Site Specific Response Analysis
    (Springer, 2018) Tönük, Gökçe; Tönük, Gökçe; Ansal, Atilla; 02.04. Department of Civil Engineering; 02. Faculty of Engineering; 01. MEF University
    Definition of design earthquake characteristics, more specifically uniform hazard acceleration response spectrum, on the ground surface is the primary component for performance based design of structures and assessment of seismic vulnerabilities in urban environments. The adopted approach for this purpose requires a probabilistic local seismic hazard assessment, definition of representative site profiles down to the engineering bedrock, and 1D or 2D quivalent or nonlinear, total or effective stress site response analyses depending on the complexity and importance of the structures to be built. Thus, a site-specific response analysis starts with the probabilistic estimation of regional seismicity and earthquake source characteristics, soil stratification, engineering properties of encountered soil layers in the soil profile. The local seismic hazard analysis would yield probabilistic uniform hazard acceleration response spectrum on the bedrock outcrop. Thus, site specific response analyses also need to produce a probabilistic uniform hazard acceleration response spectrum on the ground surface. A general review will be presented based on the previous studies conducted by the author and his co-workers in comparison to major observations and methodologies to demonstrate the implications of site-specific response analysis.
  • Conference Object
    Citation - WoS: 1
    Citation - Scopus: 1
    A Simplified Approach for Site-Specific Design Spectrum
    (Springer, 2017) Tönük, Gökçe; Tönük, Gökçe; Ansal, Atilla; 02.04. Department of Civil Engineering; 02. Faculty of Engineering; 01. MEF University
    The design acceleration spectrum requires site investigations and site-response analyses in accordance with the local seismic hazard. The variability in earthquake source and path effects may be considered using a large number of acceleration records compatible with the earthquake hazard. An important step is the selection and scaling of input acceleration records. Likewise, a large number of soil profiles need to be considered to account for the variability of site conditions. One option is to use Monte Carlo simulations with respect to layer thickness and shear wave velocity profiles to account for the variability of the site factors. The local seismic hazard analysis yields a uniform hazard acceleration spectrum on the bedrock outcrop. Site-specific response analyses also need to produce a uniform hazard acceleration spectrum on the ground surface. A simplified approach is proposed to define acceleration design spectrum on the ground surface that may be considered a uniform hazard spectrum.
  • Conference Object
    Observations From Geotechnical Arrays in Istanbul
    (Springer, 2015) Tönük, Gökçe; Tönük, Gökçe; Cetiner, Barbaros; Ansal, Atilla; Çtiner, Barbaros; 02.04. Department of Civil Engineering; 02. Faculty of Engineering; 01. MEF University
    Few small earthquakes with local magnitude slightly larger than M-L = 4 were recorded by geotechnical downhole arrays that have been recently deployed in the west side of Istanbul. Same events were also recorded by Istanbul Rapid Response Network (IRRN) which comprises of 55 surface strong motion stations in the European side of Istanbul. The strongest one of these earthquakes took place on 12/3/2008 in Cinarcik with local magnitude of M-L = 4.8. Even though the observed PGAs were not exceeding 0.01 g, an effort is made to model the recorded response at the downhole array sites as well as the at the IRRN stations using the acceleration records obtained by the deepest sensors, i.e. on the engineering bedrock, at the downhole array sites as input bedrock motions. 1D equivalent linear site response analysis that is generally adopted for site-specific response analysis is used for modelling. Observations from the recorded response and results from 1D modelling of ground response have yielded in general good agreement between the observed and recorded soil response at the station sites.
  • Article
    Citation - WoS: 6
    Citation - Scopus: 6
    Case Study on Seismic Behavior of Aseismically Designed Reinforced Concrete Frame Structures
    (Springer, 2017) Oyguc, Evrim; Tönük, Gökçe; Tönük, Gökçe; 02.04. Department of Civil Engineering; 02. Faculty of Engineering; 01. MEF University
    In this study, the seismic performances of two aseismically designed plan-irregular reinforced concrete frame (RCF) households damaged during the October 23, 2011 Van earthquake are assessed. Since no strong ground motion recordings from the main shock were available, first, strong ground motion parameters of the event are evaluated and then compatible with these parameters suits of real records are selected and scaled to match with the event's simulated acceleration spectrum to be used in the analytical investigations. The results of previous reconnaissance studies, in which one of the present authors was involved, are then discussed. Capacities of the considered RCF's are determined applying a 3D single-run adaptive pushover procedure that is capable of considering the effect of plan irregularities. The performance assessment procedure based on the current 2007 Turkish Earthquake Code is then applied to these investigated buildings. Additionally, nonlinear dynamic time history analyses are carried out using the previously selected time histories. The hysteretic behavior of the considered buildings is examined as the consequence of the conducted analyses and considering the different suits of selected ground motions, the seismic response of the buildings is evaluated in terms of interstorey drifts. None of the buildings are found to satisfy the expected performance level. Moreover, the numerical results are found to have good correlation with the field observation results.