Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleAçık Erişim2026Effect of Source Parameter Variability on RVT-Based Site Response Analysis: A Case Study for the Aegean Region of Türkiye
Icen, Abdullah
This study investigates the influence of source parameter variability specifically stress drop and anelastic attenuation on site response analysis using the Random Vibration Theory (RVT) framework. Site amplifications were computed for a representative site in the Aegean region of Türkiye using four different source parameter sets based on regional literature. A single set of randomized Vs profiles was used to account for subsurface variability, while varying source models enabled the evaluation of epistemic uncertainty in site amplification. The epistemic uncertainty associated with source parameters, expressed as τsource, peaks at approximately 0.04 s, reflecting the sensitivity of high-frequency site response to stress drop and attenuation. The study provides a regionally calibrated quantification of source-parameter-driven epistemic uncertainty for the Aegean region. The findings emphasize the need to account for source-related uncertainty in seismic hazard assessment. Unlike most previous RVT-based studies, this work explicitly isolates and quantifies the effect of stress drop and attenuation on site amplification, highlighting a novel contributor to epistemic uncertainty. Future work should incorporate Monte Carlo simulation of source parameters to support PSHA applications.
- MakaleAçık Erişim2026Farklı Deprem Düzeylerinde Doğrusal Olmayan 1B Zemin Tepki Analizi ve TBDY (2018) ile Ampirik Büyütme Fonksiyonu Kıyaslaması
Icen, Abdullah
Bu çalışmada, Türkiye Bina Deprem Yönetmeliği (TBDY, 2018) kapsamında elde edilen DD-1, DD-2 ve DD-3 tasarım spektrumlarına uyumlu yer hareketleri kullanılarak bir boyutlu (1B) doğrusal olmayan zemin tepki analizleri gerçekleştirilmiştir. Analizlerde Hatay–İskenderun 3113 kuvvetli yer hareketi istasyonuna ait VS30 = 240 m/s hız profili kullanılmıştır. Kayıt seçimi, PEER NGA-West2 ve SMD-TR veri tabanlarından seçilmiştir. Her bir deprem düzeyi için doğrusal olmayan (NL) analizler uygulanmış; yüzey spektrumlarıyla taban spektrumlarının oranından periyot-bağımlı büyütme eğrileri elde edilmiştir. Elde edilen büyütme eğrilerinin ortalamaları, TBDY (2018)’de tanımlı Fs–F1 katsayıları ile ve İçen ve Sandıkkaya (2023) ampirik zemin büyütme modeliyle karşılaştırılmıştır. Sonuçlar, kısa periyot bölgesinde (T < 0.3 s) büyütmelerin yaklaşık 1 civarında olduğunu ve TBDY’nin Fs katsayılarının genel olarak konservatif bir yaklaşım sergilediğini göstermektedir. Uzun periyot bölgesinde (T > 0.6 s) ise büyütmelerin İçen ve Sandıkkaya (2023) modeliyle uyumlu olduğu, ancak TBDY’nin F1 katsayılarının bu bölgede daha düşük kaldığı ve dolayısıyla kısmen yetersiz tahminler ürettiği belirlenmiştir. Bu çalışma, farklı deprem şiddet düzeylerinde (DD-1–DD-3) doğrusal olmayan davranışın zemin büyütmesi üzerindeki etkisini nicel olarak ortaya koymakta ve TBDY (2018)’deki zemin büyütme katsayılarının özellikle uzun periyot bölgesinde yeniden kalibrasyon gerektirebileceğini göstermektedir.
- MakaleAçık Erişim2026Bayesian vs. Frequentist Mixed-Effects for Regional Site Amplification
Icen, Abdullah
Accurate treatment of regional site effects is essential for partially non-ergodic Ground-Motion Models (GMMs). This study compares a Bayesian hierarchical regression implemented with brms to a frequentist mixed-effects formulation using lmer for estimating period-dependent site amplification. Both models adopt the same functional form with a global linear term, a nonlinear term, and region-specific random slope deviations. The analysis uses residuals from the updated Türkiye strong-motion database (SMD- TR), spanning four regions and wide ranges of VS30, magnitude, and distance. Results indicate strong agreement in global behavior: linear and nonlinear terms show similar period trends in both frameworks, and the combined regional slopes are essentially identical at all periods. The overall residual standard deviation is also nearly the same, implying comparable fit quality. Differences primarily concern decomposition and uncertainty representation. The Bayesian model resolves sharper period-dependent regional features—most notably a peak near T ≈ 0.8 s consistent with basin/edge effects—while lmer yields smoother, more conservative deviations. For median predictions, either framework is suitable because the combined coefficients and overall standard deviation coincide. For interpretation and uncertainty propagation—especially when period-dependent regional structure matters—the Bayesian approach is preferable. In addition, brms permits weakly informative priors that encode physical expectations, which stabilizes estimates in data-sparse regimes and helps prevent overfitting. Taken together, these results clarify when each framework is most appropriate: brms for physically constrained inference and robust uncertainty quantification, lmer for speed and simplicity when median predictions are the primary goal
- MakaleAçık Erişim2025A comprehensive case study on structural behavior before and after soil improvement
Etli, Serkan; Icen, Abdullah
Addressing the issue of inadequate engineering properties in soil is crucial for enhancing structural behavior and reducing damages, especially during seismic events. This study addresses the critical issue of inadequate engineering properties in soil and their impact on structural behavior, particularly during seismic events. Employing a case study methodology, structural responses are assessed before and after soil improvement, emphasizing the problem's significance. Site response analyses for pre-improvement phases reveal design insufficiencies and areas prone to soil liquefaction. The proposed solution is soil reinforcement through cement injection. Examining six cases under various earthquake scenarios and ground conditions, 132 dynamic analyses are conducted, highlighting substantial improvements post-soil improvement, especially in Interstory Drift Ratios (IDR) and roof drift ratios. These findings underscore the effectiveness of soil reinforcement in mitigating seismic damage, emphasizing its critical role in enhancing structural behavior and contributing to a better understanding of addressing soil inadequacies for improved seismic performance.
AtıfOpenAlex2TR Dizin2
İncele - MakaleYalnız künye2020Experimental Determination of Optimal Improvement Depth in Homogeneous Sand Soils
Aksoy, Suha; Icen, Abdullah
In this study, the depth of the improvement which will be made under a foundation which lies on soft soil is investigated experimentally. If the characteristics of the soil on which a building will be constructed are not sufficient to bear the loads coming from that building, then the ground is improved. Jet grout It is one of the soil improvement methods and is frequently applied in our country. When stabilizing the soil, improvement should generally be made to the underlying stiff soil layer. However, in cases where the solid ground layer is deep, the depth to which the improvement is to be made depends solely on the assumptions made for the solids calculated from the elasticity theory. According to these theories, which consider the ground as elastic and incompressible, the stresses on the subsoil soils are effective up to a depth of 1,5-2,0 times the width (B) of the foundation. Since soil improvement is a costly process, engineers do not make improvements to these depths. In this study, the bearing capacity of the foundations which are improved at different depths was determined experimentally. In order to model the soft soils and foundations in terms of bearing capacity, a continuous steel model foundation resting on loose and medium-firm sandy ground was used. The improved soil under the continuous foundation was modeled by using concrete blocks and experimental results were obtained. It was determined that the superficial improvement to be made on loose soils with insufficient bearing capacity had no significant effect on bearing capacity. However, as the depth of improvement increases, the increase in bearing capacity increases to a