İnşaat Mühendisliği Bölümü Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.11779/1943
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Book Part Comparison of the Observed and Numerical Performance of a Seismic Isolated Hospital(International Association for Earthquake Engineering, 2024) Şadan, B.; Sahin, B.; Tüzün, C.; Demircioglu-Tumsa, M.B.; Erdik, M.; Demircioglu Tumsa, M.B.The southeastern region of Turkiye was struck by powerful earthquakes on February 6, 2023, with magnitudes measuring M7.7 and M7.6. These earthquakes resulted in significant damage, destruction, and loss of life, affecting both Türkiye and extending into northern Syria. Among the approximately 100 isolated buildings in Turkiye, 11 isolated hospitals were located in the impacted region. This paper presents a comprehensive assessment of the seismic performance of the seismically isolated Osmaniye State Hospital during the Kahramanmaras earthquakes. The evaluation comprises site observations and numerical analysis utilizing ground motion records obtained from the nearest accelerometers. Site observations involved monitoring the movements of the isolators located at the moats around the perimeter of the hospital. Using a borescope allowed for detailed internal inspection of the isolation bearings, facilitating close-up examination of the isolators and enabling the identification of movement scuff marks on the sliding surfaces. These observations were used to estimate the maximum isolation bearing movement and determine the residual displacement offset of the bearings. The observed displacements of the isolation system were compared with the design values to assess the performance of the seismically isolated structure. Discrepancies between the observed and designed displacements provide valuable insights into the actual behavior of the isolation system. A nonlinear time history analysis was conducted using ground motion records obtained from the nearest accelerometers to further analyze the seismic response. This numerical analysis allowed for the simulation of earthquake excitations and the evaluation of the dynamic behavior of the seismically isolated Osmaniye State Hospital. The combination of site observations and numerical analysis yielded important findings regarding the seismic performance of the seismically isolated Osmaniye State Hospital during the Kahramanmaras earthquakes. The comparison between observed and design displacements provided insights into the efficacy of the isolation system, while the numerical analysis further validated the structural response. These findings contribute to improving the design and implementation of seismically isolated structures. © 2024, International Association for Earthquake Engineering. All rights reserved.Book Part Numerical Analysis of Buildings in Golbasi During the 2023 Turkey-Syria Earthquake(International Association for Earthquake Engineering, 2024) Tobita, T.; Kunisawa, M.; Sendir Torisu, S.; Kiyota, T.; Tönük, G.; Çinicioğlu, O.; Shiga, M.; Torisu, S.On February 6, 2023, earthquakes of Mw 7.8 and Mw 7.5 occurred in south-eastern Turkey. In Golbasi, located on the East Anatolian Fault, severe damages such as building subsidence and tilting due to liquefaction were observed. In this study, settlement and tilting behavior due to liquefaction of relatively large structures in Golbasi, when adjacent to each other, were reproduced using effective stress analysis. The research results demonstrates that the differential subsidence behavior of adjacent buildings can be replicated. Furthermore, the interference of stresses within the soil beneath adjacent structures resulted in behaviors such as inward collapsing or conversely an outward leaning differential subsidence. This study also discusses the subsidence trends associated with varying distances between structures and varying in the embedment depth of shallow foundations. © 2024, International Association for Earthquake Engineering. All rights reserved.Book Part Japanese and Turkish Joint Detailed Survey of RC Buildings Damaged by the 2023 Turkey Earthquake(International Association for Earthquake Engineering, 2024) Tajiri, S.; Yazgan, U.; Maeda, M.; Liu, H.; Shegay, A.; Monical, J.; Andirir, G.The Architectural Institute of Japan formed an investigation team to survey the damage to buildings damaged by the February 2023 Turkey earthquakes. The investigation team was dispatched to the affected area from March 28 to April 4, 2023 and conducted field surveys jointly with a Turkish expert group. As part of this investigation, the authors conducted detailed surveys of damaged reinforced concrete buildings. The survey area covers five provinces where extensive building damage was confirmed: Gaziantep, Hatay, Kahramanmaras, Adiyaman, and Malatya. The buildings surveyed were those that are useful for comparative analysis, and ones that allowed for relative ease of an on-site inspection. As a result, a total of 25 buildings were investigated, many of which were constructed after 2000, and the damage level ranged from slightly to severely damaged. In each building, the arrangement, dimensions, and damage grades of columns and walls on the floors that suffered the most damage were recorded, and their damage level was evaluated based on the Japanese and the Turkish post-earthquake damage assessment guidelines. In this paper, an overview of the results of this survey is reported. Based on the survey results, we report the results of an analysis of the structural features and seismic performance of the surveyed Turkish buildings compared to typical Japanese buildings. In addition, the causes of commonly observed damage characteristics in the surveyed buildings and the damage level determined by the Japanese and Turkish guidelines are discussed. © 2024, International Association for Earthquake Engineering. All rights reserved.Book Part Citation - Scopus: 1Modifications on Seismic Damage Assessment System of TCIP Based on Reparability(International Association for Earthquake Engineering, 2021) Ilki, A.; Halici, O.F.; Kupcu, E.; Cömert, M.; Demir, C.Evaluating the damage state of buildings has always been one of the major challenges that both engineers and authorities face after catastrophic earthquakes in seismic regions. After such events, considering the number of buildings in need of inspection and the insufficient number of qualified inspectors, the availability of a thorough but rapidly applicable damage assessment method is vitally important. An assessment system serving this purpose was developed for the Turkish Catastrophe Insurance Pool (TCIP, known as DASK in Turkey) at the beginning of the new millennia to evaluate the damages in reinforced concrete (RC) and masonry structures. The assessment system assigns a damage state (related with a damage modifier for the capacity loss) to each vertical structural member (columns and shear walls) based on the observed residual damages, such as crack width, concrete crushing, cover spalling and buckling of reinforcement. Beam damages are also taken into account in a similar way. After that, the weighted damage percentage (WDP) is calculated by taking into account the damage state and the cross-sectional area of each vertical member and the number of heavily damaged horizontal members. Since its development, this assessment method has been used by TCIP to decide the indemnities (and somehow future) of damaged structures to be either ‘repaired’ (partial indemnity) or ‘demolished’ (full indemnity) after earthquakes that took place in Turkey. In recent years, the number of scientific studies in regard to the concept of reparability of damaged structures, which is a determining parameter in buildings’ future decisions after seismic events, is increased. Consequently, TCIP initiated a research project to adjust the damage assessment method with the conclusions of up-to-date state-of-the-art scientific research. This paper presents the followed methodology and brief results of different phases of the project. In order to propose modifications for the current method, firstly, an experimental database was established focusing on the performance of damaged structural members. The database was used to validate/revise the member damage modifier parameters. Secondly, in order to define a reparability limit in terms of the building WDP value, a literature survey investigating the fundamental mechanical characteristics (such as stiffness, strength and ductility) that can be used to define the seismic behavior of damaged, and damaged-and-repaired structural members was performed. These mechanical characteristics were then used in a series of nonlinear structural analyses on typical buildings representing the common typologies of buildings in Turkey. The analyses covered the undamaged, damaged and damaged-and-repaired cases in order to determine the damage state/level where the cost of the repair applications become unfeasible or the seismic performance of the repaired structure deviates considerably from that of its undamaged state. Finally, by comparing the seismic performances of undamaged, and damaged-and-repaired cases together with the repair costs, new threshold values were proposed for WDP for different damage levels (and indemnity decisions). © The 17th World Conference on Earthquake Engineering.Conference Object Seismic Performance of Damaged Code-Conforming Rc Columns Repaired With Sustainable Structural Mortar(Elsevier B.V., 2024) Kolemenoglu, S.; Halici, O.F.; Demir, C.; Aydemir, C.; Aydemir, M.E.; Ilki, A.Examining the seismic performance of damaged reinforced concrete (RC) structures after repair applications is vital for an effective post-earthquake disaster management policy. However, the number of experimental studies investigating the seismic behavior of repaired RC members is insufficient, especially for structural members that have endured slight or moderate level damages. In this study, four identical large-scale code-conforming RC columns were tested under combined effects of axial load and reversed cyclic lateral displacements. The reference column was tested until failure, while the remaining three columns were first imposed to lateral displacements until the formation of damages at different levels, then repaired with structural repair mortar that contains recycled raw materials without removing axial load and tested again until failure. The primary objectives of the experimental program are to enhance the knowledge on the post-earthquake performance of damaged RC columns and to investigate the effects of repair applications after slight and moderate damage levels. This paper provides details on the effectiveness of the aforementioned repair technique on the seismic performance of code-complying RC columns damaged at different damage levels. © 2024 Elsevier B.V.. All rights reserved.Conference Object Citation - WoS: 2Citation - Scopus: 3An Overview on the Structural Monitoring, Assessment and Retrofitting of Historical Structures With a Focus on 13th Century Monuments(Springer international Publishing Ag, 2024) Ilki, Alper; Inci, Pinar; Halici, Omer F.; Demir, Cem; Comert, Mustafa; Kuran, FikretMonumental historical structures affirm natural and cultural identity and hence they should be transmitted to future generations. The protection and preservation of these structures against aging and natural hazards, particularly seismic actions, requires a comprehensive approach including diagnosis of the present condition of the structure and enhancement of structural capacity for disaster mitigation, if necessary. It is obvious that due to their historical values, any attempt towards the preservation of the monumental historical structures must be carried out with respect to the principles of integrity and authenticity. In this study, the structural performance assessment procedures, implementation of structural health monitoring systems and seismic strengthening strategies are discussed and described with reference to 13th-century monumental historical structures in Turkiye. The structural engineering aspects of recent activities for the restoration and preservation of the Great Mosque and Hospital of Divrigi (a world heritage listed structure) and Sivas Ulu Cami (Mosque) Minaret are briefly presented. In light of the structural analysis and monitoring results, recommendations for interventions to these monumental structures are outlined.Conference Object Citation - Scopus: 1Investigation Procedure for the Diagnosis of Historical Minarets: Inclined Minaret of Sivas Ulu Cami (mosque)(Springer, 2024) İnci, Pınar; Demir, Cem; Aldırmaz B.; Çoban S.; Halıcı, Ömer Faruk; Cömert M.; Kiraz F.; Comert, M.; Aldirmaz, B.; Ilki, A.; Coban, S.The inclined minaret of Sivas Ulu Cami (Mosque) from the 13th century Danishmend Period is one of the most invaluable architectural heritages in Turkey. The extent of inclination of the minaret towards the North-West direction, the seismicity of the region, and structural damages that occurred in time have emphasized the need for comprehensive structural and geotechnical investigations. Accordingly, a rehabilitation project is currently going on under the coordination of the General Directorate of Foundations of Turkey. Within the scope of the project, first, a series of field surveys have been conducted to obtain the current features of the minaret including the characteristics of the structural system, damages, deviation from the vertical axis, ground conditions and foundation details. In addition to that, a monitoring system including inclinometers, linear potentiometers and accelerometers has been mounted for tracking the evolution of deformations and damages in time under environmental influences and extracting the dynamic properties of the minaret. Findings from the field survey and monitoring system were used for constructing an analytical model of the structural system of the minaret. Then nonlinear time history analyses were conducted under various strong ground motion records to estimate the seismic performance of the minaret when subjected to earthquakes of different characteristics. The results showed that the tensile stresses that occurred due to seismic actions exceeded the tensile strength of the brick masonry at the region of the transition segment and the cylindrical body (top level of the boot).Conference Object Numerical Seismic Performance Investigation of Aac Infill Walls With Flat-Truss Bed-Joint Reinforcement(National Technical University of Athens, 2023) İlki, Alper; Halıcı, Ömer FarukAutoclaved Aerated Concrete (AAC) is a lightweight, energy-efficient and easy-to-transport material. As a result, AAC walls are becoming increasingly common as an infill solution in earthquake-prone areas such as Turkey, Italy, and Greece. Although infills are considered as secondary components in seismic design, they are extremely vulnerable to damage during earthquakes along both in-plane (IP) and out-of-plane (OOP) directions. Previous post-earthquake site examinations revealed that the failure of infill walls can result in serious injuries and casualties. Furthermore, huge economic losses as well as disruption in the functionality of essential buildings that are supposed to be operational after earthquakes may adversely affect the daily life in the earthquake-affected regions. One of the potential methods for increasing the seismic resilience of infill walls is use of bed-joint reinforcement between infill courses. In this paper, the general approaches in the establishment of the numerical finite element model for infill walls with and without bed-joint reinforcement are presented. The developed model was evaluated according to the previous full-scale experimental test results from strength and damage propagation point of view. The model will be used to investigate the response of infills with various bed-joint reinforcement amounts and height-to-length ratios to generalize the seismic performance improvements obtained by the use of flat-truss reinforcement both in the IP and OOP directions.Conference Object Site Characterization for Site Response Analysis in Performance Based Approach(Sipringer, 2022) Tönük, Gökçe; Ansal, AtillaThe local seismic hazard analysis would yield probabilistic uniform hazard acceleration response spectrum on the engineering bedrock outcrop. Thus, site-specific response analyses need to produce a probabilistic uniform hazard acceleration response spectrum on the ground surface. A possible performance based approach for this purpose requires a probabilistic estimation of soil stratification and engineering properties of encountered soil layers in the soil profile. The major uncertainties in site-specific response analysis arise from the variabilities of (a) local seismic hazard assessment, (b) selection and scaling of the hazard compatible input earthquake time histories, (c) soil stratification and engineering properties of encountered soil and rock layers, and (d) method of site response analysis. Even though the uncertainties related to first two items have primary importance on the outcome of the site-specific response analyses, the discussion in this article focuses on the observed variability and level of uncertainty in site conditions, related to soil stratification, thickness and type of encountered soil layers and their engineering properties, depth of ground water table and bedrock and properties of the engineering bedrock. Thus, one option may be conducting site response analyses for large number of soil profiles produced by Monte Carlo simulations for the investigated site to assess probabilistic performance based design acceleration spectra and acceleration time histories calculated on the ground surface based on 1D, 2D, or 3D site response analysis with respect to different performance levels.Book Part Citation - Scopus: 27The Modified Post-Earthquake Damage Assessment Methodology for Tcip (tcip-Dam(Springer, 2021) Cömert, Mustafa; Ilki, Alper; Halıcı, Ömer Faruk; Demir, CemPost-Earthquake damage assessment has always been one of the major challenges that both engineers and authorities face after disastrous earthquakes all around the world. Considering the number of buildings in need of inspection and the insufficient number of qualified inspectors, the availability of a thorough, quantitative and rapidly applicable damage assessment methodology is vitally important after such events. At the beginning of the new millennia, an assessment system satisfying these needs was developed for the Turkish Catastrophe Insurance Pool (TCIP, known as DASK in Turkey) to evaluate the damages in reinforced concrete (RC) and masonry structures. Since its enforcement, this assessment method has been successfully used after several earthquakes that took place in Turkey, such as 2011 Van Earthquake, 2011 Kutahya Earthquake, 2019 Istanbul Earthquake and 2020 Elazig Earthquake to decide the future of damaged structures to be either ‘repaired’ or ‘demolished’.