Yazar "Ecemis, Ali Serdar" seçeneğine göre listele

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    Buildings Damages after Elazig, Turkey Earthquake on January 24, 2020
    (Springer, 2021) Dogan, Gamze; Ecemis, Ali Serdar; Korkmaz, Serra Zerrin; Arslan, Musa Hakan; Korkmaz, Hasan Husnu
    A 6.8-magnitude earthquake that occurred on January 24, 2020, has been effective in Turkey's eastern regions. The earthquake, with recorded peak ground acceleration (PGA) value of 0.292 g, caused the destruction or heavy damage of buildings, especially in the city center of Elazig province. The purpose of this paper was to share the results of detailed investigation in the earthquake-stricken area. Additionally, the causes of damages and failures observed in the buildings were compared to those that had occurred in previous earthquakes in Turkey. In this study, the damages observed in especially RC buildings as well as in masonry and rural buildings were summarized, the lessons learned were evaluated, and the results were interpreted with reference to Turkish earthquake codes. In the study, it was particularly emphasized why the building stock underwent such damage even though the buildings were exposed to earthquake acceleration well below the design acceleration values.
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    Excessive snow induced steel roof failures in Turkey
    (Pergamon-Elsevier Science Ltd, 2022) Korkmaz, Hasan Husnu; Dere, Yunus; Ozkilic, Yasin Onuralp; Bozkurt, Mehmet Bakir; Ecemis, Ali Serdar; Ozdoner, Nebi
    In January 2017, collapses of the numerous roofs were reported due to excessive snowfall in many provinces of Turkey. In this study, the reasons behind the collapses of the steel roofs of 19 factory buildings were investigated. The steel roofs supported by the precast reinforced concrete columns indicated a similar collapse pattern to each other under the unexpected heavy snow loading. The failure mechanisms of the roofs under the snow loading were simulated numerically. Nonlinear finite element models of a typical industrial building were developed and analyzed under an incremental vertical loading that is identical to snow loading. As a result of the analysis, the vertical load carrying capacity of the roof system and the snow load level causing the collapse of roof were determined. The resulting snow load was compared with the snow load values provided by the code specifications. In addition, the collapse mechanism of the steel roof system was analytically determined and compared with the collapse modes observed in the field and the causes of the failure were evaluated. The failure mechanism and the buckling modes obtained from analyses were found very similar to those observed during the site inspections. The main reasons of the roof failures may be attributed to excessive amount of snow caused by climate change and discrepancy of designed project and as-built project due to lack of building inspection control during the construction of the buildings.
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    School buildings performance in 7.7 Mw and 7.6 Mw catastrophic earthquakes in southeast of Turkey
    (Elsevier, 2023) Ozturk, Murat; Arslan, Musa Hakan; Dogan, Gamze; Ecemis, Ali Serdar; Arslan, Hatice Derya
    Although Turkey is located in one of the active earthquake belts of the world, the 7.7 and 7.6 magnitude earthquakes that occurred on February 6, 2023, 9 h apart, as rarely seen in the seismology literature, caused one of the biggest disasters in Turkey's history. In the earthquakes affecting an area of approximately 110,000 square kilometers, serious damage and collapse occurred in public buildings as well as other structures. There are more than 12,000 school buildings in the earthquake-affected area and this number constitutes an important part of public buildings. This article deals with the damage types and causes of various public school buildings that were exposed to the earthquakes in southern Turkey on February 6, 2023. The seismicity of the region and the effects of the 6 February earthquakes were discussed, and the response spectra of the different regions most affected by the earthquakes were compared with the design spectra defined in the codes. In addition, during the field investigation the damage types and causes of damage in school buildings were listed in sections and the observations made with performance based analytical studies were supported. From field reconnaissance, the importance of understanding the deficiencies of school buildings, which have social priority, in order to avoid tragic consequences in possible earthquakes has been revealed.
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    Seismic performance improvement of RC buildings with external steel frames
    (Techno-Press, 2021) Ecemis, Ali Serdar; Korkmaz, Hasan Husnu; Dere, Yunus
    In this study, in order to improve the seismic performance of existing reinforced concrete (RC) framed structures, various external attachment of corner steel frame configurations was considered as a user-friendly retrofitting method. The external steel frame is designed to contribute to the lateral stiffness and load carrying capacity of the existing RC structure. A six story building was taken into account. Four different external corner steel frame configurations were suggested in order to strengthen the building. The 3D models of the building with suggested retrofitting steel frames were developed within ABAQUS environment using solid finite elements and analyzed under horizontal loadings nonlinearly. Horizontal top displacement vs loading curves were obtained to determine the overall performance of the building. Contributions of steel and RC frames to the carried loads were computed individually. Load/capacity ratios for the ground floor columns were presented. In the study, 3D rendered images of the building with the suggested retrofits are created to better visualize the real effect of the retrofit on the final appearance of the fa?ade of the building. The analysis results have shown that the proposed external steel frame retrofit configurations increased the lateral load carrying capacity and lateral stiffness and can be used to improve the seismic performance of RC framed buildings.
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    Seismic performance improvement of RC buildings with external steel frames
    (Techno-Press, 2021) Ecemis, Ali Serdar; Korkmaz, Hasan Husnu; Dere, Yunus
    In this study, in order to improve the seismic performance of existing reinforced concrete (RC) framed structures, various external attachment of corner steel frame configurations was considered as a user-friendly retrofitting method. The external steel frame is designed to contribute to the lateral stiffness and load carrying capacity of the existing RC structure. A six story building was taken into account. Four different external corner steel frame configurations were suggested in order to strengthen the building. The 3D models of the building with suggested retrofitting steel frames were developed within ABAQUS environment using solid finite elements and analyzed under horizontal loadings nonlinearly. Horizontal top displacement vs loading curves were obtained to determine the overall performance of the building. Contributions of steel and RC frames to the carried loads were computed individually. Load/capacity ratios for the ground floor columns were presented. In the study, 3D rendered images of the building with the suggested retrofits are created to better visualize the real effect of the retrofit on the final appearance of the fa?ade of the building. The analysis results have shown that the proposed external steel frame retrofit configurations increased the lateral load carrying capacity and lateral stiffness and can be used to improve the seismic performance of RC framed buildings.
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    Strengthening of T-beams using external steel clamps and anchored steel plates
    (Techno-Press, 2023) Dere, Yunus; Ozkilic, Yasin Onuralp; Ecemis, Ali Serdar; Korkmaz, Hasan Husnu
    In order to strengthen the reinforced concrete T-beams having insufficient shear strength, several strengthening techniques are available in the literature. In this study, three different strengthening strategies were numerically studied. First one is affixing steel plates to the beam surfaces. Second one includes tightening external steel bars vertically similar to beam stirrups. The last one is simultaneous application of these two strengthening procedures which is particularly proposed in this work. Available experimental test series in the literature were handled in the study. Finite element (FE) models of reinforced concrete beam specimens having sufficient (Beam-1) and low shear capacity (Beam-2) were created within ABAQUS environment. Strengthened beams with different techniques were also modelled to reflect improved shear capacity. FE simulations made it possible to investigate parameters that were not examined during the previous experimental studies. The results of the analyses were then compared and found consistent with the experimentally obtained data. Experimental and FEM analysis results are in agreement between 1% (closest) and 6%. (maximum). Beam-2 was stregthened with 5 new porposed methods. The rate of increase in shear strength varies between 33% and 64%. It was found that, the strengthening techniques were fairly useful in improving the shear capacity of the considered girder. The model with the proposed strengthening alternative has accomplished a higher load carrying capacity, ductility and stiffness than all of the other models.
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    Strengthening of T-beams using external steel clamps and anchored steel plates
    (Techno-Press, 2023) Dere, Yunus; Ozkilic, Yasin Onuralp; Ecemis, Ali Serdar; Korkmaz, Hasan Husnu
    In order to strengthen the reinforced concrete T-beams having insufficient shear strength, several strengthening techniques are available in the literature. In this study, three different strengthening strategies were numerically studied. First one is affixing steel plates to the beam surfaces. Second one includes tightening external steel bars vertically similar to beam stirrups. The last one is simultaneous application of these two strengthening procedures which is particularly proposed in this work. Available experimental test series in the literature were handled in the study. Finite element (FE) models of reinforced concrete beam specimens having sufficient (Beam-1) and low shear capacity (Beam-2) were created within ABAQUS environment. Strengthened beams with different techniques were also modelled to reflect improved shear capacity. FE simulations made it possible to investigate parameters that were not examined during the previous experimental studies. The results of the analyses were then compared and found consistent with the experimentally obtained data. Experimental and FEM analysis results are in agreement between 1% (closest) and 6%. (maximum). Beam-2 was stregthened with 5 new porposed methods. The rate of increase in shear strength varies between 33% and 64%. It was found that, the strengthening techniques were fairly useful in improving the shear capacity of the considered girder. The model with the proposed strengthening alternative has accomplished a higher load carrying capacity, ductility and stiffness than all of the other models.