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  • Article
    Citation - WoS: 3
    On the Yielding of Two-Layer Composite Spherical Pressure Vessels
    (Gazi Univ, 2017) Akis, Tolga
    The yielding of two-layer composite spherical pressure vessels under either internal or external pressure is investigated analytically in the framework of small deformations and von Mises yield criterion. It is shown for both pressure cases that depending on the material properties and sphere dimensions, different modes of plasticization may take place. Unlike the deformation behavior of a single layer spherical pressure vessel, yielding may commence at the inner layer or at the outer layer or simultaneously at both layers of the assembly.
  • Article
    Citation - WoS: 4
    Citation - Scopus: 4
    A 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, Tolga
    An 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: 2
    Yielding of Radially Pressurized Functionally Graded Long Tubes Based on Von Mises Criterion
    (Gazi Univ, 2015) Akis, Tolga; Eren, Omur
    The elastic behaviour of functionally graded long tubes with axially constrained ends subject to either internal or external pressure is investigated analytically. The modulus of elasticity and the yield limit of the tube material are assumed to vary radially in nonlinear forms. Making use of von Mises yield criterion, the effect of grading parameters on the yielding behavior of the tube is investigated and it is observed that for both pressure cases, the plastic flow may commence at the inner surface, at the outer surface or simultaneously at both surfaces depending on the functionally grading parameters.
  • Article
    Citation - WoS: 10
    Citation - Scopus: 10
    Evaluation of Masonry Buildings and Mosques After Sivrice Earthquake
    (Croatian Soc Civil Engineers-hsgi, 2021) Mertol, Halit Cenan; Tunc, Gokhan; Akis, Tolga
    The 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.