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Article Citation - WoS: 10Citation - Scopus: 10Evaluation of Masonry Buildings and Mosques After Sivrice Earthquake(Croatian Soc Civil Engineers-hsgi, 2021) Mertol, Halit Cenan; Tunc, Gokhan; Akis, TolgaThe evaluation of masonry and mosque type structures after the Sivrice Earthquake is presented in this study. Stone masonry buildings exhibited damage such as vertical cracks and splitting at corners, wedge shaped corner failures, diagonal cracking on walls, out-of-plane splitting of walls, and separation of walls from flooring/roofing systems. On the other hand, the separation of flags and caps of minarets was a common example of damage in mosques. Future earthquake damage can be prevented by following design codes and providing adequate supervision for new structures, while strengthening measures are recommended for the existing buildings.Article Farklı Geleneksel ve Çelik Lifli Beton Katmanlarına Sahip Betonarme Kirişlerin Eğilme Davranışı(2022) Mertol, Halit CenanBu çalışmada, farklı geleneksel ve çelik lifli beton katmanlarına sahip betonarme kirişlerin eğilme davranışı incelenmiştir. Boyutları 180×250×3500 mm olan toplamda 10 kiriş, iki grupa bölünerek dört nokta yüklemesi altında eğilme davranışı değerlendirmesi için test edilmiştir. Tüm kirişlerde çekme bölgesinde 416 donatısı kullanılmıştır. Bu araştırmadaki ana değişken kiriş yüksekliğince oluşturulan katmanlardaki beton tipidir. Kirişin yüksekliği her biri 50 mm olan 5 katmana ayrılmıştır. “F” grubunda bulunan geleneksel beton kullanılan kirişlerde, çelik lifli beton katmanları aşağıdan başlayarak geleneksel beton katmanlarının yerlerine yerleştirilmiştir. Örnek olarak, F15P10 kirişinin yüksekliği boyunca aşağıdan 150 mm’si çelik lifli betondan, yukarıda kalan 100 mm’si ise geleneksel betondan imal edilmiştir. “P” grubunda bulunan çelik lifli beton kullanılan kirişlerde ise, geleneksel beton katmanları aşağıdan başlayarak çelik lifli beton katmanlarının yerlerine yerleştirilmiştir. Örnek olarak, P10F15 kirişinin yüksekliği boyunca aşağıdan 100 mm’si geleneksel betondan, yukarıda kalan 150 mm’si ise çelik lifli betondan imal edilmiştir. Kirişlerin yük-sehim eğrileri elde edilmiş ve bu eğriler azami yük, kullanım rijitliği, tepe sonrası rijitlik ve eğilme tokluğu açısından değerlendirilmiştir. Araştırma sonucunda göre, yeterli sünekliğin çekme bölgesinde bulunan çelik lifli beton katmanı ile sağlanabileceği belirlenmiştir. Bu katmanın, çekme bölgesinde olduğu sürece yüksekliğinin ve yerinin davranışı önemli bir şekilde etkilemediği görülmüştür.Article Citation - WoS: 4Citation - Scopus: 4A Site Survey of Damaged Rc Buildings in Izmir After the Aegean Sea Earthquake on October 30, 2020(Croatian Soc Civil Engineers-hsgi, 2023) Mertol, Halit Cenan; Tunc, Gokhan; Akis, TolgaAn earthquake with a magnitude of Mw = 6.6 and a depth of approximately 16.5 km occurred on 30 October 2020 off the cost of Samos, a Greek island 35 km southwest of Seferihisar, a town in Izmir. The earthquake caused several collapses and severe structural damage in approximately 6,000 buildings, specifically in the Bayrakli District in Izmir Bay. This paper presents the observations and findings of a technical team that visited the earthquake -affected areas immediately after the earthquake. Eleven partially or fully collapsed and several severely damaged reinforced concrete buildings were investigated. Based on the site investigations, we observed that almost all of the collapsed or severely damaged reinforced concrete buildings in the region were built between 1975 and 2000. Site observations also confirmed that the construction of these collapsed or damaged buildings did not conform to the requirements outlined in the Turkish Earthquake Codes used at the time. The failures and severe damage to buildings in earthquake-affected areas are primarily related to inadequate reinforcement configuration, poor material quality, the absence of geotechnical studies, and framing problems related to their lateral load-carrying systems. Therefore, it is recommended that all the buildings located in and around Izmir Bay, particularly those built between 1975 and 2000, be structurally evaluated to prevent any further loss of life and property during future earthquakes.Article Citation - WoS: 6Citation - Scopus: 7Finite Element Analysis of Frames With Reinforced Concrete Encased Steel Composite Columns(Mdpi, 2022) Tunc, Gokhan; Othman, Mohammed Moatasem; Mertol, Halit CenanStructural frame systems that consists of concrete-encased-steel-embedded composite columns and reinforced concrete beams are typically used in mid-rise to tall buildings. In order to understand their overall structural behavior, a total of 12 frame models with high and low ductility features were constructed and analyzed using LS-DYNA software. Two of these models were validated using the results of previously tested frames. The remaining 10 models were studied to predict the behavior of frames with varying concrete strengths, reinforcement configurations, and structural steel sections under vertical and lateral loads. The results were investigated in terms of cracks and failure patterns, load-deflection relationships, energy dissipation, and stiffness degradation. The analytical results indicated that the high ductile frame models showed slightly better lateral load carrying performances compared to low ductility frame models. Moreover, the analytical studies demonstrated that the existence of structural steel in a column, regardless of its cross-sectional shape, was the most important parameter in improving the lateral load carrying capacity of a frame.Article Citation - WoS: 5Citation - Scopus: 7Lessons Learned From Four Recent Turkish Earthquakes: Sivrice-Elazığ, Aegean Sea, and Dual Kahramanmaraş(Springer, 2024) Tunc, Goekhan; Mertol, Halit Cenan; Akis, TolgaT & uuml;rkiye is located in an earthquake-prone region where almost all of its population resides in risky areas. In the past 100 years, there has been a strong earthquake every two years and a major one every 3 years. This study investigates the impact of four recent earthquakes, that occurred between 2020 and 2023, on reinforced concrete (RC) buildings. The first, Sivrice-Elaz & imath;& gbreve;, struck the eastern part of T & uuml;rkiye on January 24, 2020, with a moment magnitude of Mw = 6.8. The second, the Aegean Sea, hit the western part of the country on October 30, 2020, with an Mw of 6.6. The third and fourth are the February 6, 2023 dual Kahramanmara & scedil; earthquakes with Mws of 7.7 and 7.6, which struck the eastern part of T & uuml;rkiye approximately 9 h apart. Immediately following these earthquakes, a technical team investigated each of the damaged areas. This study summarizes their findings on RC buildings. It was discovered that the majority of the collapsed or severely damaged RC buildings were constructed before 2000. The main reasons for this included technological limitations, specifically on producing high-quality concrete, as well as a lack of public policies and enforced laws in the construction sector to maintain an acceptable international standard. Furthermore, the damage patterns of buildings from these four earthquakes indicated poor workmanship, low material quality, improper structural framing, a common appearance of soft and weak stories, the inadequate use of shear walls, and defective reinforcement configuration. The significance of soil studies and the enforcement of building inspections are also discussed, along with the earthquake codes. The study concludes that the maximum peak ground accelerations from the dual Kahramanmara & scedil; earthquakes were almost triple the code-prescribed values. Therefore, it is recommended that the current mapped spectral acceleration values be revised and that buildings constructed before 2000 should be prioritized while determining their structural performances.Article Citation - WoS: 53Citation - Scopus: 58Investigation of Rc Buildings After 6 February 2023, Kahramanmaras, Turkiye Earthquakes(Mdpi, 2023) Mertol, Halit Cenan; Tunc, Gokhan; Akis, Tolga; Kantekin, Yunus; Aydin, Ishak CanTwo major earthquakes struck Pazarcik and Elbistan, towns in Kahramanmaras, Turkiye, on 6 February 2023, approximately 9 h apart. The first earthquake, recorded at 04:17 local time, had a M-w = 7.7, with a focal depth of 8.6 km. At 13:24 local time, a second earthquake occurred with M-w = 7.6 at a focal depth of 7 km, approximately 90 km north of the first one. A total of 11 provinces were severely affected by these earthquakes. As of 15 April 2023, they caused close to 51,000 deaths and almost 215,000 completely destroyed/severely damaged buildings. At some locations, the largest horizontal peak ground acceleration (PGA) values of the first and second earthquakes exceeded the code-generated PGAs by almost 3 and 1.75 times, respectively. A technical team visited these areas within 15 h of the first earthquake. The purpose of this article is to present their observations, findings, and the characteristics of the two earthquakes, with comprehensive site survey results supported by photographs. This study concludes that most of the collapsed and severely/moderately damaged buildings in the region were built between 1975 and 2000, when site inspections were rare or non-existent. In addition to the high PGAs recorded in these earthquakes, it was verified that the design and construction of these buildings did not fully comply with the earthquake codes valid at the time. The collapsed buildings and their damage patterns confirm inadequate development length, violation of bending stirrup ends at 135 & DEG;, deficiencies in construction materials and reinforcement configuration, noncompliance with confinement zones, violation of the strong beam-stronger column analogy, and issues related to building inspection. Based on the extent of the damage, it is strongly recommended that the structural performance inspection of all other buildings located near major fault lines, specifically those constructed between 1975 and 2000, should be completed. Since these earthquakes generated much higher PGAs, which is believed to be one of the main reasons for the extensive damage, a re-evaluation of all other PGAs along major fault lines is also recommended.Article 23 Ekim 2011 Van, Türkiye Depremi Sırasında Gedikbulak Okul Binasının Yıkılması(2023) Mertol, Halit Cenan23 Ekim 2011 tarihinde Türkiye'nin doğusunda Mw = 7,2 (ML = 6,7) büyüklüğünde bir deprem meydana gelmiştir. Yer hareketinin en yüksek yer ivmesi 0.18×g olarak ölçülmüştür. Deprem, yığma ve betonarme yapılarda küçük çatlaklardan tamamen göçmeye kadar değişen hasarlara neden olmuştur. Bu depremde, Gedikbulak Köyü'ndeki 4 katlı betonarme okul binası tamamen yıkılmıştır. Bu okul binası Türkiye Cumhuriyeti Milli Eğitim Bakanlığı tarafından hazırlanan tipik bir projedir (No: 10370) ve bu tipik proje Türkiye'nin çeşitli yerlerinde okul binalarının yapımında yaygın olarak kullanılmıştır. Bu makalede, Atılım Üniversitesi Keşif Takımının ana şoktan birkaç gün sonra okul binasının yıkıldığı yerde yaptığı saha gözlemleri ve okul binasının yıkılma nedenleri üzerinde durularak detaylı analizleri anlatılmaktadır. Analiz sonuçları göçmenin, düz donatı çubuklarının yetersiz kenetlenme ve bindirme boyu nedeniyle perde duvarların tabanının (hem x- hem de y- yönlerinde) temelden ayrılmasından kaynaklandığını göstermiştir. Yapılan inceleme ve analizler sonucunda benzer mevcut okul binalarının gelecekteki depremlerde yıkılmaması için önerilerde bulunulmuştur.
