Browsing by Author "Tunc, Gokhan"
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Article Citation Count: 0A Close Examination of Ankara's Reinforced Concrete Buildings Designed and Constructed between 1923 and 1938(Mdpi, 2023) Tunç, Gökhan; Tunc, Tanfer Emin; Civil EngineeringThe Republic of Turkey was established in 1923 out of the remains of the Ottoman Empire. Between 1923 and 1938, the Turkish republic underwent fifteen years of rapid expansion and growth, with Ankara as its new capital and Mustafa Kemal Ataturk (1881-1938) as its first president. During this period, reinforced concrete (RC) played a significant role in the construction of Ankara's public-use buildings. This study focuses on 57 of these structures, built either partially, or entirely, out of RC. The buildings are classified with respect to their duration, soil properties, foundation types, structural design details, construction types, materials and overall costs. In order to provide a better picture of the time period in which these buildings were designed and constructed, the technical, financial and political aspects of the projects, and the difficulties and challenges involved in their design and construction, are also discussed. Furthermore, this study outlines the impact of foreign engineers, construction workers, firms and the educational system on the development of civil engineering and use of RC in Turkey.Article Citation Count: 5Constructing Containment: Thompson-Starrett, the cesme Beach Houses, and the Geopolitics of American Engineering in Cold War Turkey(Routledge Journals, Taylor & Francis Ltd, 2020) Tunç, Gökhan; Tunc, Gokhan; Civil EngineeringFor the first half of the twentieth century, Thompson-Starrett and Co., a New York-based American engineering, construction, and contracting firm, dominated the building scene. In operation between 1899 and 1968, it was a leader in skyscraper construction and large-scale projects, and literally built the New York skyline. It designed and constructed the tallest skyscraper of the era, the Woolworth Building, as well as other iconic Manhattan structures such as the Equitable Building, the American Stock Exchange, the New York Municipal Building, and the Claridge, Algonquin, Roosevelt, St. Regis, and Waldorf-Astoria Hotels. A formidable pioneering force in structural engineering a hundred years ago, Thompson-Starrett is, by and large, forgotten today, especially its post-World War II ventures in Turkey, such as the Sariyar Dam and the cesme Beach Houses, a luxury beachfront cooperative located in Ilica, Izmir. However, what would prompt the engineering firm responsible for the Woolworth Building to take on the road and utility construction and project management of a Turkish summer resort? The answer lies in Cold War geopolitics and booming private enterprise, both of which, in the 1950s, converged in Turkey, relied on American engineering, and involved a complex process of Americanization.Article Citation Count: 6Damage Observation of Reinforced Concrete Buildings after 2020 Sivrice (Elazig) Earthquake, Turkey(Asce-amer Soc Civil Engineers, 2021) Tunç, Gökhan; Akış, Tolga; Akis, Tolga; Civil EngineeringAn earthquake with a magnitude of M-w = 6.8 and a depth of approximately 8.06 km occurred on January 24, 2020, with the epicenter near the town of Sivrice in Elazig province, Turkey. The earthquake resulted in numerous collapses and severe structural damage to the buildings located in the downtowns and villages of Elazig and Malatya provinces. A technical team investigated the earthquake-affected areas, and this study presents their observations and findings with respect to reinforced concrete buildings. It was concluded that almost all of the collapsed or severely-damaged reinforced concrete buildings were constructed between 1975 and 1998. The design and construction of these buildings did not comply with the specifications of the Turkish earthquake codes valid at that time. The failures and severe damage of the buildings are associated with poor material quality, inadequate reinforcement configuration, and framing problems related to their lateral load-carrying systems. Therefore, it is recommended that buildings constructed between 1975 and 1998 in the region be structurally re-evaluated to avoid additional loss of life and property in future earthquakes. (C) 2021 American Society of Civil Engineers.Article Citation Count: 1Engineering the public-use reinforced concrete buildings of Ankara during the Early Republic of Turkey, 1923-1938(Pergamon-elsevier Science Ltd, 2022) Tunç, Gökhan; Tunc, Tanfer Emin; Civil EngineeringToday, reinforced concrete (RC) is the most commonly used construction material in Turkey. It first emerged in Europe in the 1850s and was adopted in a number of Late Ottoman period structures, mostly in Istanbul, during the first two decades of the twentieth century. During the Early Turkish Republic (1923-1938), RC appeared in public-use buildings in Ankara, such as the Ethnographic Museum, which was the first in the new capital to feature RC elements, leading the way for many more structures to come. Despite the fact that Turkish and foreign civil engineers faced a series of economic, social, cultural, political, educational and technical challenges during the transition from masonry and timber construction to RC, its adoption was facilitated by the fact that as a European building technology, it became symbolically important to the new republic. Equated with modernity, RC would allow its capital, Ankara, to construct an identity that would contrast with Istanbul, the capital of the Ottoman Empire. This transition would also be catalyzed by the rise of a professional class of Turkish civil engineers who deployed RC to reinforce their authority as trained specialists and agents of modernization.Article Citation Count: 7Evaluation of masonry buildings and mosques after Sivrice earthquake(Croatian Soc Civil Engineers-hsgi, 2021) Mertol, Halit Cenan; Tunç, Gökhan; Akış, Tolga; Civil EngineeringThe 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 Citation Count: 3Experimental Analysis of the Behavior of Composite Column-Reinforced Concrete Beam Joints(Springer Heidelberg, 2021) Tunç, Gökhan; Mertol, Halit Cenan; Mertol, Halit Cenan; Civil EngineeringThis study assesses the seismic performance of steel-reinforced concrete (SRC) composite columns connected to reinforced concrete (RC) beam joints, and their ability to dissipate seismic energy through inelastic deformations. In this article, experimental aspects regarding the seismic performance of high-ductility and low-ductility steel-concrete composite frame were investigated. The principle design parameter in this study was ductility, which is considered a conceptual framework in Efficiency-Based Seismic Engineering. Thus, attention was focused on assuring various ductility ranges of joints obtained through a detailed study of the Turkish Earthquake Code (TEC 18) [Ministry of Public Works and Housing.: Turkiye Bina Deprem Yonetmeligi (Turkey's Earthquake Code for Buildings). Official Gazette (2018) (in Turkish).]. After identifying deficiencies and the energy dissipation capacity in the newly proposed joints, two half-scaled frames with specific ductility-related designs were constructed, instrumented, tested, and analyzed. The specimens were tested under displacement-controlled lateral cyclic loading that incorporated constant axial loading to create cyclic tension and compression facets across the joint areas. The test results proved that the SRC column-RC beam frames employing an extra column reinforcement ratio exhibit slightly better seismic performance. Due to the presence of structural steel, the shear failure of the joint was effectively prevented, even after the formation of the plastic hinge on the interface of the beam. During the testing, the column rebars, to some extent, made a minor contribution to the joint strength of the specimen compared to the structural steel that absorbed almost all of the load applied to the frame.Article Citation Count: 4Finite Element Analysis of Frames with Reinforced Concrete Encased Steel Composite Columns(Mdpi, 2022) Tunç, Gökhan; Mertol, Halit Cenan; Mertol, Halit Cenan; Civil EngineeringStructural 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 Count: 11Investigation of RC Buildings after 6 February 2023, Kahramanmaras, Turkiye Earthquakes(Mdpi, 2023) Mertol, Halit Cenan; Tunç, Gökhan; Akış, Tolga; Kantekin, Yunus; Kantekin, Yunus; Aydın, İshak Can; Civil Engineering; Department of Civil EngineeringTwo 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 Citation Count: 2A Light Bulb in Every House The Istanbul General Electric Factory and American Technology Transfer to Turkey(Johns Hopkins Univ Press, 2022) Tunç, Gökhan; Tunc, Gokhan; Civil EngineeringIn 1946, Turkish entrepreneur Vehbi Koc signed an agreement with the U.S. firm General Electric to build and operate its first light bulb factory in the Near/Middle East, in Istanbul. This private joint venture introduced new manufacturing techniques, business practices, and consumer habits to Turkey, opening channels of postwar technological exchange. Closer examination of the GE-Koc partnership reveals that during the early Cold War, the transfer and embedding of American technologies in Turkey was a politically complicated process of innovation that required constant adaptation. Fraught with unforeseeable obstacles, it also required cautious negotiation with multiple transnational actors. The story of the GE-Koc partnership thus adds a new dimension to historical understandings of the Turkish Cold War experience and the Americanization of the region. It illustrates how transferring a nonmilitary, soft-power, domestic technologythe light bulb-played a significant role in Turkish-American relations and therefore contributes to studies of U.S. Cold War diplomacy through transnational investment in innovation.Article Citation Count: 2A 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; Tunç, Gökhan; Akış, Tolga; Civil EngineeringAn 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 Count: 5Transferring Technical Knowledge to Turkey: American Engineers, Scientific Experts, and the Erzincan Earthquake of 1939(Royal Soc, 2022) Tunç, Gökhan; Tunc, Gokhan; Civil EngineeringOn 27 December 1939, a 7.8 magnitude earthquake struck Erzincan, Turkey, claiming close to 33 000 lives, and leaving 100 000 injured and 250 000 homeless. World War II was in its initial stages, and the USA was particularly concerned about the vulnerable situation in Turkey, since there was a possibility that it would join forces with Germany, as the Ottoman Empire had done in World War I. Consequently, the Turkish request for information on 'a type of quake resistant concrete construction understood to have been developed in California', resulted in a flurry of correspondence between numerous Turkish and American actors, including the US State Department, which supplied this material with notable attentiveness. As this article will argue, this request not only represents an early critical juncture in the transfer of earthquake engineering knowledge from the USA to Turkey, but also illustrates how diplomacy and engineering can intersect at pivotal points in time. Engineers and other scientific experts strengthened the Turkish-American relationship during this period, thereby laying the foundation of the technical cooperation that would flourish during the Cold War. This watershed moment also resulted in immediate developments in Turkey, such as the development of a comprehensive national disaster management programme, a seismic zone map, and earthquake building codes.