Sürdürülebilir Kalkınma Amaçları

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• MakaleYalnız künye2018/r/gumushane/16684
  Earthquake Performance of Reinforced-Concrete Shear-Wall Structure Using Nonlinear Methods

  Çavdar, Ozlem; Çavdar, Ahmet; Bayraktar, Ender

  In earthquake engineering, the performance-based design method is used to determine the expected performance level of structures under an earthquake effect. The level of performance is related to the damage situation that could occur in the structure after the earthquake. In performance-based structural design, it is predicted that more than one damage level can emerge under one earthquake effect. In this study, the seismic behavior of a reinforced-concrete shear-wall building that collapsed during the 2003 Bingol earthquake was investigated by nonlinear static analysis and nonlinear dynamic analysis. The selected reinforced-concrete shear-wall structure is located in Bingol, Turkey. Local code was considered for assessing a seismic performance evaluation of the selected reinforced-concrete shear-wall building. The performance goals of the reinforced-concrete shear-wall structure were evaluated by applying the pushover (incremental equivalent earthquake load) method and procedures of the code and nonlinear dynamic analysis. According to the code, the reinforced-concrete shear-wall building was not expected to satisfy life safety performance levels under a design earthquake. In this study, one collapsed building was selected in order to test the reliability and usability of performance analysis methods under different earthquakes.

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• MakaleYalnız künye2018/r/gumushane/16182
  Automated Model Updating of Historical Masonry Structures Based on Ambient Vibration Measurements

  Altunisik, Ahmet Can; Okur, Fatih Yesevi; Genç, Ali Fuat; Günaydin, Murat; Adanur, Suleyman

  Finite-element (FE) model updating is a very effective procedure for determining the uncertainty parameters in a structural model and minimize differences between experimentally and analytically identified dynamic characteristics. This procedure can be practiced with manual and global/local automatic model updating procedures. Automatic model updating is very popular because of its applicability to all kinds of engineering structures to minimize differences, and its damage localization and structural health monitoring. This paper considers a historical masonry bastion to obtain its dynamic characteristics numerically with the finite-element method and experimentally with ambient vibration tests (AVTs). Sensitivity analyses for the uncertainty parameters and manual and automated model updating to minimize differences are also performed. A castle bastion located in Trabzon, Turkey is selected as an application. The FE model of structure is developed in commercial software. The first three natural frequencies are obtained between 5 and 10Hz, and AVTs are performed under natural excitation using enhanced frequency domain decomposition (EFDD) and subspace structural identification (SSI) techniques. The first three natural frequencies are obtained between 4 and 7Hz. The comparison of analytically and experimentally identified dynamic characteristics shows a close agreement between mode shapes, but 26% difference in natural frequencies. To minimize the difference, the FE model of the bastion is updated using manual and global/local automated updating, changing its material properties of Young's modulus and material density. The maximum differences are reduced from 27 to 3% with manual updating, and to 0.02% with automated model updating.

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• MakaleYalnız künye2016/r/gumushane/16368
  Dynamic Characteristics of an Arch Dam Model before and after Strengthening with Consideration of Reservoir Water

  Altunisik, Ahmet Can; Günaydin, Murat; Sevim, Baris; Bayraktar, Alemdar; Adanur, Suleyman

  This technical note presents an investigation about the changing of dynamic characteristics of an arch dam model before and after strengthening considering reservoir water. To this end, an arch dam-reservoir-foundation model has been constructed in the laboratory. Ambient vibration tests have been performed on the damaged and strengthened arch dam models for empty and full reservoir to determine the effect of water on the dynamics characteristics. Enhanced frequency domain decomposition method has been used to extract the dynamic characteristics. Finally, the dynamic characteristics obtained from the damaged and strengthened dam models have been compared to with each other. Also, the natural frequencies for damaged and strengthened models are compared to detect the effect of strengthening application on the frequencies. Results indicate that the natural frequencies and damping ratios are changed with the full reservoir. However, mode shapes are not changed. Results also show that the natural frequencies of damaged dam considerably increase after strengthening applications.

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• MakaleYalnız künye2016/r/gumushane/15857
  Nonlinear Earthquake Performance Evaluation of a Structure Collapsed during the Van, Turkey, Earthquake on October 23, 2011

  Çavdar, Ozlem; Bayraktar, Alemdar

  The paper investigates the structural performance of a seven-story reinforced concrete (RC) building that collapsed during the Van (Turkey) earthquake on October 23, 2011, using nonlinear static and dynamic methods. The selected RC building has two blocks and was designed according to the Turkish Earthquake Code (TEC) in 1975. The site investigation included sections and steel detailing and soil and concrete properties taken after the earthquake. The pushover and nonlinear time history analyses of the building were completed using the existing plan and test and observation data. It is concluded that the building collapses both analysis types. (C) 2015 American Society of Civil Engineers.

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• MakaleYalnız künye2012/r/gumushane/16178
  Seismic Performance Assessment of Masonry Tile Domes through Nonlinear Finite-Element Analysis

  Atamturktur, S.; Sevim, B.

  This article discusses a combined analytical and experimental study on the nonlinear seismic performance of two Guastavino-style masonry domes located in the United States. The seismic performance of these masonry domes is simulated with nonlinear finite-element (FE) models. To support the assumptions and decisions established during the development of the FE models, the vibration response of the domes is measured on-site and systematically compared against the numerical model predictions. Linear FE models are developed that are in close agreement with the measured natural frequencies and in visual agreement with the measured mode shapes. Next, these linear models are extended into the nonlinear range by incorporating the Drucker-Prager damage criterion. Finally, nonlinear FE models are used to assess the performance of these two domes under seismic loadings obtained from the 1940 El Centro earthquake acceleration records. The predicted displacements and internal tensile stress levels are used to make inferences about the potential behavior of these two buildings under the selected earthquake load. DOI: 10.1061/(ASCE)CF.1943-5509.0000243. (C) 2012 American Society of Civil Engineers.

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