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- MakaleYalnız künye2026Scopus SJRQ1Effects of earthquake frequency content and isolation thickness on seismic behavior of a structure system resting on geotechnical seismic isolation layer
Ozturk, Kasif Furkan; Cakir, Tufan; Araz, Onur
Geotechnical seismic isolation (GSI) systems aim to partially dissipate the energy before it reaches the foundation of the structure system and are therefore regarded as an important alternative to structural seismic isolation systems. In addition, the use of petroleum-derived waste materials in the GSI systems fills a significant gap in the field of waste recovery. The present study investigates the changes in the dynamic responses of a 5-story building system with and without GSI, using a set of earthquakes classified according to their frequency content. For this purpose, parametric analyses were performed using analytical methods, considering three different earthquake frequency contents and six different GSI thicknesses. Furthermore, an approach for selecting the GSI thickness was suggested. The results generally show that, for structures founded on both natural soil (NS) and GSI systems, the earthquakes with low frequency content produce responses greater than the average responses calculated for all the investigated earthquakes. Although increasing the GSI thickness has a significant effect on attenuating structural responses, increasing this thickness beyond 3 m does not lead to a relatively significant reduction in the dynamic responses of the investigated structural system. Therefore, considering the structural system, NS, rubber-soil mixtures and earthquakes examined in this study, selecting a GSI thickness in the range of 2–3 m (inclusive) may be regarded as a practical approach for mitigating the dynamic responses of the structure since further increments in thickness beyond this range provide only progressively limited improvements in structural responses. Consequently, this research may provide meaningful data for the development of vibration control strategies to improve seismic resilience of structures, and the results are expected to be useful for better understanding of the GSI applications.
- MakaleAçık Erişim2025Scopus SJRQ1Investigation of the effects of mainshock-aftershock sequences on the dynamic responses of pipeline considering soil-pipeline interaction
Ozturk, Kasif Furkan
Pipelines are important structural elements that are frequently used today to meet many infrastructures needs such as drainage, natural gas or water transmission. In this context, the usability of such structures, which are important elements of infrastructure systems, especially after disasters such as earthquakes, is of great importance. For this reason, within the scope of this study, a parametric investigation of the seismic behaviors of a natural gas pipeline system under mainshock-aftershock sequences have been carried out, specifically taking into account the soil-natural gas pipeline interaction (SNGPI) in the help of finite element model (FEM) proposed. Before developing the model of SNGPI system proposed using solid element, the fundamental mode frequencies of the pipeline system modeled using the solid element for the verification have been compared with those of obtained from the pipeline system modeled using the beam element and the analytical solutions. After verification of proposed model is demonstrated, SNGPI system has been modeled and its fundamental modes have been compared with mode frequencies of soil stratum obtained from well-known simple analytic solutions. After this stage, the dynamic analyses of natural gas pipeline (NGP) system in the time domain have been carried out using four different soil systems and four different mainshock-aftershock sequences. The results of the nonlinear time-history analyses have been investigated in terms of the stress and the displacement responses. Parametric evaluations show that the greatest displacements and the stresses occurring at the considered nodes of NGP system may be importantly affected from mainshock-aftershock sequences and soil stiffness changes. As the soil stiffness decreases, both the peak stresses and displacements increased significantly. On the other hand, the same responses obtained under mainshock loadings, which have relatively lower peak ground acceleration (PGA)/peak ground velocity (PGV) ratio compared to aftershock loadings, are generally larger than those obtained under aftershock loadings.
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İncele - MakaleYalnız künye2025Scopus SJRQ1Influence of PGA/PGV ratio on the seismic performance of buildings with different slenderness ratios considering soil-structure interaction
Araz, Onur
In this study, the seismic performance of buildings equipped with tuned mass damper (TMD) having different slenderness ratios, subjected to ground motions with varying a wide range of PGA/PGV ratios is investigated, considering soil-structure interaction (SSI). A methodology based on hybrid Genetic Algorithm-Particle Swarm Optimization (GA-PSO) algorithm is proposed to determine the optimal parameters of TMD. For this purpose, three buildings (i.e., 3-story, 6-story, and 12-story buildings) are considered and the dynamic properties of these buildings are determined according to the provisions specified in ASCE-7. These buildings, which are frequently encountered in the traditional building stock, represent low, medium, and high-rise buildings, respectively. In the numerical analysis, three different soil types (i.e., SC, SD, and SE) and 80 ground motions are also considered. These records are divided into three different classes: high, intermediate, and low frequency content. The Newmark integration method is used to determine the dynamic responses of the structures in the time domain analysis. Numerical results show that the frequency content of ground motion and the slenderness ratio have a significant effect in reducing the peak displacement and acceleration responses of structures. The findings also demonstrate that when the PGA/PGV ratio is greater than 2, TMD shows mostly sufficient control performance for all buildings and all support conditions.
AtıfScopus21WoS20OpenAlex17İncele - MakaleYalnız künye2025Scopus SJRQ1Optimal design of inerter-assisted series tuned mass dampers for seismic vibration control of multi-story buildings
Araz, Onur
This work introduces a framework for the optimal design of inerter-assisted series tuned mass dampers (STMDI) placed at the top story of a multi-story building under ground motion and performs comparative research to assess its effectiveness against conventional TMDI. The identical inertance ratio and total mass ratio are taken into consideration for the optimization of both control systems. In the frequency-domain analysis, the five design variables of the STMDI are optimized based on the minimization of the peak amplitude of the displacement transfer function at the top story of the building using the genetic algorithm (GA). The optimized variables are damping ratios (ξ1and ξ2), tuning frequency ratios (f1and f2), and mass ratio of the first to second TMD mass (µh). The proposed control system is applied to a 4-story, an 8-story, and a 16-story case-studies, and the optimal parameters are verified using eighty-five historical benchmark earthquakes in time domain analysis. These records are divided into three different groups according to their frequency content, i.e. PGA/PGV ratio: high, intermediate, and low. The results demonstrate that the STMDI performs better than the TMDI at the same mass and inertance ratio, especially at excitation frequencies close to resonance. The most important advantage of STMDI compared to TMDI is that it provides this performance in a wider frequency range and in an almost similar way. Finally, the seismic performances of STMDI and TMDI are compared considering ground motions with different frequency content.
AtıfScopus24WoS25OpenAlex26İncele - MakaleYalnız künye2025Scopus SJRQ1Effect of frequency content of ground motion on seismic response of buildings with variable aspect ratio including soil-structure interaction
Kaya, Dilek; Cakir, Tufan; Ozturk, Kasif Furkan; Araz, Onur
Soil-structure interaction (SSI) may lead to reduction, amplification or negligible change in structural responses depending on the relationship between the nature of excitations and subsoil conditions. Since neglecting SSI effects may cause uncertainties in seismic design, it is crucial to consider them during the design process. Another important factor affecting the dynamic behavior of structures interacting with the ground is the dynamic properties of the structures. To consider this effect, three buildings with 4, 8, and 12 stories designed in accordance with the Turkish Building Earthquake Code (TBEC-2018) are analyzed. The aspect ratios of these structures are 2, 4, and 6, corresponding to squat, ordinary, and slender structures, respectively. The primary objective of this study is to simulate the combined effects of these key parameters on the dynamic response of reinforced concrete structures. In the time history analyses, six ground motions classified by three different frequency contents are considered. 3D finite element models of SSI systems are established using ANSYS software. The usability of the numerical models is demonstrated for both SSI and fixed-base cases through three different analytical approaches. The displacement, acceleration, and stress responses are examined through time history analyses. The results indicate that the SSI is not negligible and neglecting the SSI is an oversimplification that does not lead to always-conservative predictions. Moreover, both the frequency content of the excitation and the structural aspect ratio are found to be decisive parameters in seismic response.
AtıfScopus12WoS12OpenAlex11İncele - MakaleYalnız künye2023Scopus SJRQ1Seismic-induced vibration control of a multi-story building with double tuned mass dampers considering soil-structure interaction
Araz, Onur; Elias, Said; Kablan, Feyza
This paper presents a methodology for the optimization of double tuned mass dampers (TMDs) positioned on the top floor of a multi-story building subjected to ground motions considering soil-structure interaction (SSI). In the optimization process, it is considered that double TMDs are connected both in series and in parallel. STMD and PTMD are used to denote the series TMDs and parallel TMDs, respectively. The equations of motion for an n-story shear building controlled by STMD and PTMD are derived by considering the SSI effect and the optimum parameters of both devices are obtained by minimizing the amplitude of the displacement transfer function for the top floor of the building in the frequency domain analysis. The effectiveness of the PTMD and STMD designed using the Jaya algorithm (JA) is verified by numerical examples of a ten-story shear building under twelve earthquake records with different frequency content and the comparison with the traditional TMD is also performed. In order to investigate the effect of earthquake frequency content on the control performance of the TMDs, earthquakes considered are divided into three different groups as low, intermediate, and high-frequency contents. In addition, the influence of the soil stiffness on the optimum parameters and effectiveness of the PTMD and STMD is discussed. Numerical results show that the optimally designed PTMD and STMD effectively suppressed the maximum floor displacements and accelerations of the building. It is also shown that SSI effects can be ignored when the building is built on stiff soil. In addition, it is concluded that the SSI and earthquake frequency content have a significant effect on the control performance of TMDs and the seismic response of the building.
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