Browsing by Author "Iyisan, R."

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    2D non-linear seismic response of the Dinar basin,TURKEY
    (Elsevier, 2016-10) Khanbabazadeh, H.; Iyisan, R.; Ansal, Mustafa Atilla; Hasal, M. E.; Civil Engineering; ANSAL, Mustafa Atilla
    Local geological conditions generate significant amplification of ground motion and concentrated damage during earthquakes. The highly concentrated damages at the edges of the Dinar basin during occurred earthquakes at regions close to rock outcrop bring up the effect of the inclined bedrock effect on the dynamic behavior of the basin with 2D geometry. In this study, first the idealized 2D model of the basin based on the results of the underground explorations and geologic investigations is proposed. Results show that Dinar basin has an asymmetric 2D geometry with two different bedrock angles at edges. Then, a numerical study using finite difference based nonlinear code which utilizes appropriate static and dynamic boundary conditions, and includes hysteresis damping formulation based on the user defined degradation curves is conducted using real earthquake motions of different strength and frequency content. The constructed model is subjected to the collection of 16 earthquakes with different PGA's of 0.1, 0.2, 0.3 and 0.4 g, four motions for each PGA. It was seen that the dynamic behavior of the basin is broadly affected by the two dimensional bedrock. The results indicates the higher effect of the 6° bedrock inclination at east part on the amplification with respect to the steeper 20° bedrock slope at the west. Also, the results show the insignificant effect of the bedrock at the depth more than 150 m on the amplification of the east edge. While the effect of the 6° bedrock angle at the east part continues until 1500 m from the outcrop, it affects the amplification until 700 m from the outcrop at the west part with 20° bedrock angle.
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    Nonlinear dynamic behavior of the basins with 2D bedrock
    (Elsevier, 2018-04) Khanbabazadeh, H.; Iyisan, R.; Ansal, Mustafa Atilla; Zulfikar, C.; Civil Engineering; ANSAL, Mustafa Atilla
    Resonance due to impedance contrast, focusing due to subsurface topography, conversion of the body waves to surface waves and subsurface topography are among the factors influencing the amplification specification of the sites, which can only be considered by the application of suitable nonlinear analysis method. In this study, using the fully nonlinear analysis method, along with a hysteretic-type model and no extra damping, the effects of the basin edge on the dynamic behavior of the basins is investigated in more accurate manner. To make the results useful at engineering affaires, the investigated basins are classified into sandy, clayey and layered basins. Special degradation curves for each of the (soft, medium plasticity and stiff) clay and (loose, medium dense and dense) sand types have been extracted and fitted to the continuous functions which is used by the nonlinear method's hysteretic-type damping scheme. The results exhibit the differences in the amplification behavior of the basins with different soil types under the different excitation levels. Also, the sensitivity of the different parts of the basin surface with 2D geometry to different period levels is investigated. This finding can be used at dynamic structural design of the buildings on basins with 2D bedrock inclination.