Sürdürülebilir Kalkınma Amaçları

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• MakaleYalnız künye2013/r/gumushane/15444
  Experimental analysis on FEM definition of backfill-rectangular tank-fluid system

  Cakir, Tufan; Livaoglu, Ramazan

  In the present study, the numerical and experimental investigations were performed on the backfill- exterior wall-fluid interaction systems in case of empty and full tanks. For this, firstly, the non-linear three dimensional (3D) finite element models were developed considering both backfill-wall and fluid-wall interactions, and modal analyses for these systems were carried out in order to acquire modal frequencies and mode shapes by means of ANSYS finite element structural analysis program. Secondly, a series of field tests were fulfilled to define their modal characteristics and to compare the results from proposed approximation in the selected structures. Finally, comparing the theoretical predictions from the finite element models to results from experimental measurements, a close agreement was found between theory and experiment. Thus, it can be easily stated that experimental verifications provide strong support for the finite element models and the proposed procedures themselves are the meritorious approximations to the real problem, and this makes the models appealing for use in further investigations.

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• MakaleYalnız künye2012/r/gumushane/15726
  Fast practical analytical model for analysis of backfill-rectangular tank-fluid interaction systems

  Cakir, Tufan; Livaoglu, Ramazan

  The paper describes a simple, efficient and reasonably accurate analytical model for analysis of backfill-rectangular tank-fluid interaction systems. The presented model uses Housner's two-mass approximation for fluid interaction and mass-spring-dashpot system for backfill interaction and accommodates a variety of features that may affect the behavior of rectangular tanks including fluid volume, backfill geometry, soil properties and flexible/rigid wall types. Unlike the conventional finite element and the finite difference models that require considerable effort and knowledge to prepare the input data, the proposed model requires only a few pieces of data to define the problem and control the analysis. A series of finite element simulations were also fulfilled on two real rectangular tanks subjected to backfill and fluid effects. A reasonably good accord was obtained comparing the analytical predictions to results from numerical simulations. Thus, it can be stated that the model may be used effectively to perform a broad suite of parametric studies at the design stage and also as a reliable tool for estimating the system behavior. The results obtained from parametric seismic analyses indicated that backfill interaction, wall flexibility and fluid interaction considerably affect the lateral displacements. The sloshing response, however, was not practically affected by the backfill interaction and the wall flexibility.

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• MakaleYalnız künye2011/r/gumushane/15899
  Effects of backfill on seismic behavior of rectangular tanks

  Livaoglu, Ramazan; Cakir, Tufan; Dogangun, Adem; Aytekin, Mustafa

  The reliability and/or stability of the lifeline structures against failure under seismic loads are of critical concern, and must be studied carefully. Therefore, the main objective of this paper is to demonstrate the commonly encountered backfill effects on the dynamic response of rectangular tanks. However, only the exterior wall of the tank which interacts with both the backfill and fluid is tackled, as each part of the structure shows considerable differences in terms of both the load bearing mechanisms and the geometrical and positional differences. Finite element analyses are employed, taking into consideration the fluid-wall-backfill interaction. The analyses are conducted to observe whether or not both backfill and wall behavior can be affected by variation of the internal friction angle. For that purpose, some comparisons are made on vertical displacements of the backfill, roof displacements, stress responses, etc., by means of internal friction angle variations of the backfill from 25 degrees to 40 degrees. Consequently, it is observed that the variations on maximum vertical displacements are affected considerably. In contrast, the maximum stress responses are affected partially. However, the inertial effects of the backfill show that pseudo-static approximations may be insufficient to understand the dynamic behavior of the backfill-wall-fluid system. (C) 2011 Elsevier Ltd. All rights reserved.

  İncele
• Proje2009/r/gumushane/19320
  Yerüstü ve ayaklı su depolarının deprem davranışlarının sıvı ve zemin etkileşimleri dikkate alınarak incelenmesi

  Livaoğlu, Ramazan; Dogangun, Adem

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• MakaleYalnız künye2008/r/gumushane/15832
  Investigation of seismic behavior of fluid-rectangular tank-soil/foundation systems in frequency domain

  Livaoglu, R.

  Main purpose of this study is to evaluate the dynamic behavior of fluid-rectangular tank-soil/foundation system with a simple and fast seismic analysis procedure. In this procedure, interaction effects are presented by Housner's two mass approximations for fluid and the cone model for soil/foundation system. This approach can determine; displacement at the height of the impulsive mass, the sloshing displacement and base forces for the soil/foundation system conditions including embedment and incompressible soil cases. Models and equations for proposed method were briefly explained for different tank-soil/foundation system combinations. By means of changing soil/foundation conditions, some comparisons are made on base forces and sloshing responses for the cases of embedment and no embedment. The results showed that the displacements and base shear forces generally decreased, with decreasing soil stiffness. However, embedment, wall flexibility, and soil-structure interaction (SSI) did not considerably affect the sloshing displacement.

  İncele
• MakaleYalnız künye2008/r/gumushane/15827
  Investigation of dynamic response of masonry minaret structures

  Dogangun, Adem; Acar, Ramazan; Sezen, Halil; Livaoglu, Ramazan

  Almost all historical minarets in Turkey were constructed using cut stone, masonry blocks or combination of these two materials. The structural and geometrical properties of each masonry minaret, or slender tower structure, depend on many factors including the structural knowledge and applications at the time of construction, experience of the architect or engineer, seismicity of the region, and availability of construction materials in that area. Recent earthquakes in Turkey have shown that most masonry minarets in high seismic regions are vulnerable to structural damage and collapse. In this study, in order to investigate the dynamic behavior of historical unreinforced masonry minarets, three representative minarets with 20, 25, and 30 m height were modeled and analyzed using two ground motions recorded during the 1999 Kocaeli and Duzce, Turkey earthquakes. The modal analyses of the models have shown that the structural periods and the overall structural response are influenced by the minaret height and spectral characteristics of the input motion. The dynamic displacement and axial stress time histories are computed at the critical points on the minarets. During recent earthquakes, most minaret failures occurred above the base of the structure. Consistent with the observed response, the largest stresses were calculated at the same location.

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• MakaleYalnız künye2008/r/gumushane/14931
  Dynamic analysis and seismic performance evaluation of above-ground liquid-containing tanks

  Sezen, Halil; Livaoglu, Ramazan; Dogangun, Adem

  A large number of industrial facilities were damaged during the 1999 Mw 7.4 Kocaeli, Turkey earthquake. One of those industrial facilities, Habas plant located within 10 km of the fault trace, provides liquefied gases to commercial plants and medical facilities. Two of the three tanks at the Habas facility collapsed during the earthquake. The main objectives of this paper were to evaluate the seismic performance of tanks and investigate the parameters influencing the dynamic behaviour. Simplified and finite element dynamic analyses of the tanks are carried out including the effect of liquefied gas-structure interaction using a ground motion recorded at a nearby site. The vulnerabilities of the structural system, the observed performance, and damage pattern are discussed by comparing the dynamic analysis results with the strength and deformation capacity of the support columns. The dynamic analysis results from a simplified three-mass model and a finite element model confirmed that the axial and lateral strength of the columns supporting the two nearly full tanks were not sufficient to resist the demand imposed during the earthquake. Consistent with the observed structural performance, an elastic response is predicted for the columns supporting the undamaged 25% full identical tank.

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• MakaleYalnız künye2007/r/gumushane/14930
  Effect of foundation embedment on seismic behavior of elevated tanks considering fluid-structure-soil interaction

  Livaoglu, R.; Dogangun, A.

  This paper investigates the effects of foundation embedment on the seismic behavior of fluid-elevated tank-foundation-soil system with a structural frame supporting the fluid containing tank. Six different soil types defined in the well-known seismic codes were considered. Both the sloshing effects of the fluid and soil-structure interaction of the elevated tanks located on these six different soils were included in the analyses. Fluid-elevated tank-foundation-soil systems were modeled with the finite element (FE) technique. The fluid-structure interaction was taken into account using Lagrangian fluid FE approximation implemented in the general purpose structural analysis computer program, ANSYS. FE model with viscous boundary was used to include elevated tank-foundation-soil interaction effects. The models were analyzed for the foundations with and without embedment. It was found that the tank roof displacements were affected significantly by the embedment in soft soil, however, this effect was smaller for stiff soil types. Except for soft soil types, embedment did not affect the other response parameters, such as sloshing displacement, of the systems considered in this study.

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• MakaleYalnız künye2007/r/gumushane/14090
  Traditional Turkish masonry monumental structures and their Earthquake response

  Doğangün, Adem; Sezen, Halil; Tuluk, Ö. İskender; Livaoğlu, Ramazan; Acar, Ramazan

  Many historical and new masonry minarets were damaged or collapsed during the 1999 earthquakes in Kocaeli and Duzce, Turkey. These and other recent earthquakes not only caused loss of property but also loss of many lives. The structural failures and resulting casualties have led to discussion and investigation of potential reasons for poor seismic performance of masonry minarets. The primary goal of this study is to review the construction practices for historical and new masonry minarets in Turkey and to discuss the seismic damage observed in those structures. The architectural and structural properties of contemporary and historical Ottoman minarets and their components are presented. For example, a very old special technique for reinforcing and linking adjacent stone blocks with iron pieces in the vertical and horizontal directions is discussed. The structural damage examples are used to better understand the reasons for the observed failure mechanisms. It is concluded that the transition region between the square minaret boot and cylindrical body was most vulnerable to damage, and the iron clamps used in historical minarets effectively prevented structural damage.

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• MakaleYalnız künye2006/r/gumushane/15816
  Traditional wooden buildings and their damages during earthquakes in Turkey

  Doǧangün, Adem; Tuluk, Ö.Iskender; Livaoǧlu, Ramazan; Acar, Ramazan

  Wood is one of the oldest structural materials used in structures in many parts of the World. Woodframe buildings were also commonly constructed in Turkey until approximately 1960. After that, as reinforced concrete and masonry buildings have been preferred, wooden buildings have almost been forgotten. But, in 1999, Kocaeli and Duzce earthquakes reminded traditional buildings. Since reinforced concrete buildings presented high level of damage and traditional buildings relatively performed well during these earthquakes. In this study, types of traditional wooden buildings used in Turkey are mainly introduced and their damages in earthquakes are discussed. Damaged and undamaged wooden building photos are illustrated. Some structural weaknesses are highlighted by the earthquake damages including cracking and falling of plaster, failure of mortar, loosening or failing of connections, large lateral displacements, dislodgement of the masonry infill, loosening or failing of connections and failure of connections to foundation.

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