İnşaat Mühendisliği Bölümü Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.11779/1943

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Start date: 2020Subject: search.filters.subject.Seismic

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  • Book Part
    Citation - Scopus: 1
    Modifications on Seismic Damage Assessment System of TCIP Based on Reparability
    (International Association for Earthquake Engineering, 2021) Halıcı, Ömer Faruk; Halici, O.F.; Kupcu, E.; Cömert, M.; Demir, C.; 01. MEF University; 02.04. Department of Civil Engineering; 02. Faculty of Engineering
    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.; Halıcı, Ömer Faruk; Demir, C.; Aydemir, C.; Aydemir, M.E.; Ilki, A.; 02.04. Department of Civil Engineering; 02. Faculty of Engineering; 01. MEF University
    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: 2
    Citation - Scopus: 3
    An 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; Halıcı, Ömer Faruk; Halici, Omer F.; Demir, Cem; Comert, Mustafa; Kuran, Fikret; 02.04. Department of Civil Engineering; 02. Faculty of Engineering; 01. MEF University
    Monumental 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: 1
    Investigation Procedure for the Diagnosis of Historical Minarets: Inclined Minaret of Sivas Ulu Cami (mosque)
    (Springer, 2024) İnci, Pınar; Halıcı, Ömer Faruk; Aldırmaz B.; Çoban S.; Halıcı, Ömer Faruk; Cömert M.; Kiraz F.; Comert, M.; Aldirmaz, B.; Ilki, A.; Coban, S.; 02.04. Department of Civil Engineering; 02. Faculty of Engineering; 01. MEF University
    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
    Citation - WoS: 7
    Citation - Scopus: 5
    State of the Art in Application of Seismic Isolation and Energy Dissipation in Turkey
    (Springer International Publishing Ag, 2023) Şadan, Bahadır; Şadan, Bahadır; 02.04. Department of Civil Engineering; 02. Faculty of Engineering; 01. MEF University
    This paper summarizes the passive structural control system applications and other related developments in Turkey, emphasizing the period between 2019 and 2022. The country hosts state-of-the-art seismic isolation applications, relatively greater in size, and use more isolators in each project (415 isolators per building on average) compared to the other seismic isolation projects worldwide. Construction of the world's largest seismic isolated building, Istanbul Basaksehir Pine and Sakura City Hospital, covering more than 1 million square meters of area and employing more than 2000 seismic isolators, was completed and has been in service since May 2020. 1915 Canakkale Bridge, constructed in memory of the great war of Canakkale during World War I, is now the world's longest suspension bridge with a 2023m main span length. Eight massive hydraulic dampers were used at the main deck and 48 at the approach viaducts in combination with 72 seismic isolators. Construction of a residential building complex in Istanbul consisting of 16 isolated blocks covering more than 170,000 m(2) area and having 454 seismic isolators is coming to an end very soon. Historical Nusretiye Clock Tower in Istanbul was relocated a few meters over seismic isolators. Historical Goztepe Railway Station in Istanbul was retrofitted to accommodate an additional railway line using seismic isolation technology. Seismic codes for buildings and bridges now include rules for the seismically isolated design of structures. Additionally, all seismic isolation designs must be peer-reviewed by law. A new seismic isolator testing facility was established in Eskisehir to respond to the demand for the large number of isolators that need to be tested.
  • Conference Object
    Structural Assessment of the 13th Century Great Mosque and Hospital of Divrigi: a World Heritage Listed Structure
    (12th International Conference on Structural Analysis of Historical Constructions (SAHC 2021), 2021) İlki, Alper; Halıcı, Ömer Faruk; Berlucchi, Nicola; Demir, Cem; Şanver, Ali Naki; Hurata, Ali; Cömert, Mustafa; Halıcı, Ömer Faruk; Kuran, Fikret; 02.04. Department of Civil Engineering; 02. Faculty of Engineering; 01. MEF University
    The Great Mosque and Hospital of Divrigi is located in the central eastern partof Turkey, in Divrigi, Sivas. The historical facility consists of a monumental mosque anda two-story hospital, which are adjacent to each other. The structure dates back to13th century Mengujekids period and has been listed by the UNESCO as a World Heritagesince 1985. Great Mosque and Hospital of Divrigi is particularly notable for its monumentalstone portals that are decorated with three-dimensional ornaments carved fromstone. The structural system of the monument consists of multi-leaf stone masonrywalls and stone piers that support the roof structure which consists of stone and brickarches and vaults. The structure is located about 90 km away from the North AnatolianFault Line, that has been causing several destructive earthquakes. Consequently, thestructure is prone to destructive seismic activities. In this study, after a briefintroduction on the structural system and current condition of the structure, thestructural performance of the Great Mosque and Hospital of Divrigi is investigatedthrough site observations and structural analyses. For this purpose, linear and nonlinear 3Dfinite element models of the structure are developed and the structure is examined under theeffects of vertical loads and seismic actions. In the light of the analyses results,recommendations for potential interventions are outlined for further preservation of thestructure.