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Author: Akis, TolgaWoS Q: Q1

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    Letter
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    Letter
    Amendments on "application of Mises Yield Criterion To Rotating Solid Disk Problem" by N. Aleksandrova [int. J. Eng. Sci. 51 (2012) 333-337]
    (Pergamon-elsevier Science Ltd, 2012) Eraslan, Ahmet N.; Akis, Tolga
    [No Abstract Available]
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    Article
    Citation - WoS: 50
    Citation - Scopus: 55
    Plane Strain Analytical Solutions for a Functionally Graded Elastic-Plastic Pressurized Tube
    (Elsevier Sci Ltd, 2006) Eraslan, Ahmet N.; Akis, Tolga
    Plane strain analytical solutions to functionally graded elastic and elastic-plastic pressurized tube problems are obtained in the framework of small deformation theory. The modulus of elasticity and the uniaxial yield limit of the tube material are assumed to vary radially according to two parametric parabolic forms. The analytical plastic model is based on Tresca's yield criterion, its associated flow rule and ideally plastic material behaviour. Elastic, partially plastic and fully plastic stress states are investigated. It is shown that the elastoplastic response of the functionally graded pressurized tube is affected significantly by the material nonhomogeneity. Different modes of plasticization may take place unlike the homogeneous case. It is also shown mathematically that the nonhomogeneous elastoplastic solution presented here reduces to that of a homogeneous one by appropriate choice of the material parameters. (c) 2006 Elsevier Ltd. All rights reserved.
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    Article
    Citation - WoS: 5
    Citation - Scopus: 7
    Lessons Learned From Four Recent Turkish Earthquakes: Sivrice-Elazığ, Aegean Sea, and Dual Kahramanmaraş
    (Springer, 2024) Tunc, Goekhan; Mertol, Halit Cenan; Akis, Tolga
    T & 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.
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    Article
    Citation - WoS: 53
    Citation - Scopus: 58
    Pull-Out Behavior of Prestressing Strands in Steel Fiber Reinforced Concrete
    (Elsevier Sci Ltd, 2012) Baran, Eray; Akis, Tolga; Yesilmen, Seda
    This paper presents the results of an experimental study investigating the effects of steel fibers on the mechanical properties of concrete and the enhancement of bond strength of prestressing strands in steel fiber reinforced concrete (SFRC). The first part of the experimental program consisted of compression, tension and flexural tests on SFRC. Two types of steel fibers with 30 mm and 60 mm fiber lengths were used with five different fiber contents. The second part of the study consisted of simple pull-out tests on 12.7 mm and 15.2 mm diameter seven-wire untensioned prestressing strands embedded in concrete blocks. The pull-out tests were conducted with two different fiber lengths and five different fiber contents for each strand diameter. The steel fibers were observed to improve the pull-out resistance of strands by controlling the crack growth inside concrete blocks. (C) 2011 Elsevier Ltd. All rights reserved.