Person: YAZICI, GÖKHAN
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Dr. Öğr. Üyesi
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YAZICI
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GÖKHAN
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Publication Metadata only Dynamic behavior and optimization of offshore gravity platforms(ASME-AMER SOC MECHANICAL ENG, THREE PARK AVE, NEW YORK, NY 10016-5990 USA, 2005-05) Mastanzade, Nıjat S.; YAZICI, GÖKHANThis paper presents the results of a dynamic investigation with the aim of determining both the optimal shape of an offshore gravity platform column and the required mass of the infill water The natural frequency formulation of the structure with the added infill water mass, E-r, was obtained by using Rayleigh's method. Pontyagin's maximum variational principle was used to define the shape of the column. An algorithm and a computer program were developed to obtain the numerical solution of, the problem. Finally, a scaled model of the gravity platform was built and tested, in order to verify the results obtained from the analytical research and to determine the mass of the. infill water.Publication Metadata only Case Study: Izmit Domestic and Industrial Water Supply Build-Operate-Transfer Project(ASCE-AMER SOC CIVIL ENGINEERS, 1801 ALEXANDER BELL DR, RESTON, VA 20191-4400 USA, 2004-06) Şentürk, H. A.; Kaplanoğlu, S. B.; YAZICI, GÖKHANThe "build, operate, and transfer model" (BOT) is a financing model, which is used in many developing countries to finance new infrastructure projects with private sector participation. The BOT method foresees the financing, designing, building, operating, and managing of the facility by the private sector and then its transfer free of charge, to the owner after a predetermined concession period. For interested parties, the history of BOT laws and projects in Turkey is presented as an Appendix. In this study, the Izmit Domestic and Industrial Water Supply Project, the biggest privately financed water Supply project procured under the BOT model in the world at the time and the first in Turkey will be introduced and the problems that arose during the implementation of the project, namely, the scope of the project, equity debt ratio, return on equity, principles of accounting, coordination of State departments, land access, determination of the optimum operation period, and the sale price of the water, will be presented and suggestions will be given on how to deal with these problems.Publication Metadata only Dynamic behaviour of seismically isolated cylindrical offshore storage tanks(AMER SOC MECHANICAL ENGINEERS, THREE PARK AVENUE, NEW YORK, NY 10016-5990 USA, 2005) Mastanzade, Nijat; YAZICI, GÖKHANCylindrical offshore storage tanks are mainly used to store critical liquids such as petroleum and LNG. Failure of these tanks after an earthquake not only results in high financial losses but can also create an environmental disaster as well. Seismic isolation technique has been utilized in this study to mitigate the damaging effects of lateral earthquake forces. In this study, seismic isolation is used in cylindrical offshore storage tanks. Seismic isolators are protected from the marine environment by a water-proof flexible membrane that allows the horizontal movement of the tank. The mathematical model takes the following into account: mass of the stored liquid, added mass of the water surrounding the tank, horizontal stiffness and damping of the isolation system. Internal forces due to the hydrostatic and hydrodynamic forces acting on the system during an earthquake have been calculated by using the shell-moment theory. The results of the analyses are compared for both the isolated and fixed-base tanks.Publication Metadata only Blast Response of Slabs in ReinforcedConcrete Buildings(2018-10) YAZICI, GÖKHAN; 140840This study presents the response of reinforced concrete slabs in building structures exposed to blast loads. The mid-span displacements, support rotations, and damage patterns were investigated for a varying charge mass located underneath the slab. Detonations were simulated using the airblast-loading functions available in the explicit solver of LS-Dyna. The reinforcements of the slab were modeled by using line elements inserted into the volumetric finite-element mesh of the concrete material. The effects of support conditions on the slab response were evaluated. Results from the numerical study showed that the slab failed first at the supports before the midspan region disintegrated due to rebar ruptures. Therefore, the strengthening of the support region plays a crucial role in the blast response of the slab. Suggestions for blast upgrading of reinforced concrete slabs were summarized.Publication Metadata only Snow induced collapse of hail protection canopies(Pergamon-Elsevier Science Ltd, The Boulevard, Langford Lane, Kidlington, Oxford Ox5 1Gb, England, 2017-09) Vatansever, Cüneyt; SEÇKİN, EDİP; YAZICI, GÖKHAN; 151093; 119077; 140840This paper addresses the snow induced collapse of hail protection canopies of a major car dealership in Istanbul, Turkey. Each of them with different plan dimensions has been built to provide an enclosed space of over 50,000 square meters for parking. The structural system of each hail protection canopy consists of successive steel frames spaced at 5.0 m intervals. Some of these canopies collapsed on January 1st, 2016. The rest has been saved thanks to the immediate intervention provided by the employees allowing accumulated snow to slide off the roof. Following the incident, a site investigation has been conducted to inspect the structural failures and a numerical 3D model to represent the whole structure was developed using OpenSEES to understand the collapse mechanism of the hail protection canopies. In addition, the scope of the structural design calculations was examined to check for potential incorrect design assumptions. Consequently, site observations and analysis results indicate that the hail protection canopies collapsed due to a combination of erroneous design assumptions on snow load and the poor design and construction of structural members and their connections.Publication Metadata only Çelik Köprü Yarışmaları: Yapısal Çelik Eğitiminde Önemli bir Deneyim(2013) Coşkun, Erdal; SEÇKİN, EDİP; YAZICI, GÖKHAN; 140840Publication Metadata only Parametric Study of the Seismic Response of Base Isolated Liquid Storage Tanks with Lead-Core Elastomeric Bearings(Polish Acad Sciences Inst Physics, Al Lotnikow 32-46, Pl-02-668 Warsaw, Poland, 2014-02) YAZICI, GÖKHAN; 140840Field reports from past earthquakes indicate that liquid storage tanks are quite susceptible to earthquake related damages due to the sloshing motion of the contained liquid and that the failure of these structures can have catastrophic impacts on the environment in addition to significant financial losses. Recently, the use of seismic response modification strategies such as base isolation and energy dissipation systems have been extended to liquid storage tanks, particularly large liquified natural gas tanks, in order to protect them from the damaging effects of earthquakes. Base isolation involves the installation of horizontally flexible base isolation bearings under the liquid storage tanks to extend the vibration period of the structure and to provide an additional mechanism for energy dissipation. This paper investigates the effects of the variation of mechanical properties of lead-core elastomeric base isolation bearings on the dynamic response of liquid storage tanks through a comprehensive parametric study which was conducted with a script that uses the Mat lab state-space solvers. The paper begins by outlining the mechanical analogue system to be used for calculating the overturning moment and the base shear in tank wall as well as the free surface displacements for a cylindrical liquid storage tank subjected to horizontal base excitation. The nonlinear force-displacement characteristics of the bearings are modelled with the Bouc-Wen hysteresis model. Results of the parametric study show that base isolation can be effective at decreasing the base shear and that special attention must be paid to the increases in the sloshing displacements in determining the freeboard height.Publication Metadata only Sloshing Displacement Measurements Based on Morphological Image Analysis(2018-04) YAZICI, GÖKHAN; SAATÇI, ERTUĞRUL; 140840; 10488Sloshing of the contained liquid is an important issue, which needs to be dealt with in the design of moving liquid storage tanks, such as fuel tanks subjected to earthquakes. Numerical methods such as the finite element method or smoothed particle hydrodynamics are commonly used to analyze the sloshing response of liquids in the design of liquid storage containers. The analysis results obtained from numerical methods are usually validated through the comparison of free surface displacements obtained from laboratory tests conducted on scaled tank models. However, the equipment required for measurement can be quite costly and the setup of the measurement system for moving containers can be a tedious process. In order to simplify the measurement setup and reduce the associated cost, we propose a measurement system based on morphological image analysis using a stationary HD camera. In order to verify the validity of the proposed method a shaking table test was conducted on a transparent prismatic liquid tank subjected to a simulated earthquake base motion. The liquid tank was filled with colored water to facilitate image analysis. The video record of the experiment was processed by the proposed algorithm implemented in the MATLAB environment to measure the free surface displacements on the right wall of the tank. The free surface displacements obtained from the video record by automated image analysis were congruent with the manual measurements conducted on the individual video frames.Publication Metadata only SAR Design with IFC(Crc Press-Taylor & Francis Group, 6000 Broken Sound Parkway Nw, Ste 300, Boca Raton, Fl 33487-2742 Usa, 2009) TÜRKYILMAZ, EMRAH; YAZICI, GÖKHAN; TR140840; TR113480This paper reports a study where IFC based building models were utilized in the evaluation of "adaptability" issues of dwelling layouts in an educational context. The first part of the study discusses a workshop on the CAD implementation of the SAR design methodology, which was popularized in Netherlands in the post-WW2 era, to increase the adaptability of residential dwellings. The second part of the study focuses on the use of IFC based building models to automate the preparation of the SAR taxonomy explained in the workshop. The primary objective of using IFC in this study was to explore the potential use of this maturing technology in design research education.Publication Metadata only Steel Bridge Competitions A case of hands on structural steel education(2013) Coşkun, Erdal; SEÇKİN, EDİP; YAZICI, GÖKHAN; 119077; 140840; 141151