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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: 18Creep and Shrinkage Behavior of High-Strength Concrete and Minimum Reinforcement Ratio for Bridge Columns(Precast/prestressed Concrete inst, 2010) Mertol, Halit Cenan; Rizkalla, Sami; Zia, Paul; Mirmiran, AmirThis paper summarizes the findings of an extensive research program that examined the shrinkage and creep behavior of high-strength concrete (HSC) up to a strength of 18 ksi (124 MPa). Creep and shrinkage strains of 60 specimens were monitored for up to two years. The variables considered in this investigation were the concrete compressive strength, specimen size, curing type, age of concrete at loading, and loading stress level. Research findings indicate that the current American Association of State Highway and Transportation Officials' AASHTO LRFD Bridge Design Specifications could be used to estimate the creep coefficient and shrinkage strain of HSC up to 15 ksi (103 MPa). However, the current AASHTO LRFD specifications do not provide appropriate predictions for concrete compressive strength greater than 15 ksi (103 MPa). A revised time-development correction factor is proposed to obtain better predictions for HSC up to 18 ksi (124 MPa). For HSC compression members, the current AASHTO LRFD specifications require an excessive amount of minimum longitudinal reinforcement to account for the long-term effects due to shrinkage and creep. Based on an analysis, a new relationship is proposed for the required minimum reinforcement ratio.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: 2Flexural Behavior of Reinforced Concrete Beams With Various Layers of Conventional and Steel Fiber Reinforced Concrete(Gazi Univ, 2022) Mertol, Halit CenanFlexural behavior of reinforced concrete (RC) beams having various layers of conventional concrete (CC) and steel fiber reinforced concrete (SFRC) were investigated in this study. Two groups of five beams (180x250x3500 mm) were tested under four-point loading to evaluate the flexural behavior. Both of these groups of beams were reinforced with 4 phi 16 reinforcing bars. The main variable in this research was the concrete type of the layers throughout the height of the specimen. The height of the cross-section of the beams was divided into 5 layers, each having 50 mm thicknesses. In group "F" specimens, SFRC layers were added to the layers of a CC beam, starting from the bottom, as replacements of CC layers, i.e. F15P10 represented that the bottom 150 mm was cast using SFRC whereas the top 100 mm was cast using CC. In group "P" specimens, CC layers were added to the layers of a SFRC beam, starting from the bottom, as replacements of SFRC layers, i.e. P10F15 represented that the bottom 100 mm was cast using CC whereas the top 150 mm was cast using SFRC. Experimental load-deflection curves were evaluated based on ultimate load, service/post-peak stiffnesses, and flexural toughness. It can be concluded that reasonable ductility may be achieved by adding SFRC at the tension side no matter how thick the layer is and where it is located.
