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Dr. Öğr. Üyesi
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Now showing 1 - 3 of 3
  • Publication
    Seismic Collapse Performance of a Full-Scale Concrete Building with Lightly Reinforced Columns
    (Asce-Amer Soc Civil Engineers, 2021) Töre, Erkan; Demir, Cem; CÖMERT, MUSTAFA; İlki, Alper
    Brittle failure of lightly reinforced concrete columns is one of the primary reasons for partial or total collapse of substandard existing buildings subjected to earthquake loading. This study presents collapse performance of a full-scale building that was performed to gain insight into the seismic behavior and the collapse mechanisms of nonductile buildings with lightly reinforced concrete columns. The three-story building was tested under displacement-controlled quasi-static reversed cyclic loading followed by a lateral pushover loading up to realization of the total collapse. In addition to the poor reinforcement details, columns had high axial load-to-axial capacity ratios as also observed in many existing substandard buildings. During the test, severe structural damage was observed at 0.9% first-story drift ratio in the cyclic part of the lateral loading and the brittle total collapse of the building took place during the pushover loading at 1.45% first-story drift ratio. In this paper, after the introduction of the test campaign, the formation of structural damage and collapse mechanisms are discussed. In addition, an attempt to predict the behavior and performance of the test building is made by using a column model that considers flexural, slip, and shear deformations. Finally, the obtained analytical results are compared with the experimental observations and results.
  • Publication
    Seismic Retrofitting Of the 19(TH) Century Hirka-i Serif Mosque Using Textile Reinforced Mortar
    (Taylor & Francis Inc., 2022) Demir, C.; CÖMERT, MUSTAFA; KOÇAK, PINAR İNCİ; Dusak, S.; İlki, A.
    In this study, a novel retrofitting intervention on the Hirka-i Serif Mosque (constructed in 1851), which has a significant importance for Muslims due to its historical relic preservation unit keeping the cloak of the Prophet Muhammad, was illustrated. For this purpose, first the seismic performance of the mosque was investigated through site investigations and structural analyses. A 3D finite element model of the Mosque was established, and the structural system was analyzed under the combined effects of the vertical loads and seismic actions. Additionally, the existing damages observed on the walls and vaults were investigated thoroughly. By taking the existing damages and the analyses results into consideration, a rehabilitation and seismic retrofit scheme was proposed and applied by making use of innovative materials. Throughout the study, recommendations of the guideline for earthquake risk management of historical structures in Turkey (2017) has been considered.
  • Publication
    Metadata only
    Seismic Risk Assessment and Preliminary Intervention Cost-Benefit Analysis for the Building Stock of Istanbul
    (Springer International Publishing, 2022) Demir, Cem; CÖMERT, MUSTAFA; Aydoğdu, Hasan Hüseyin; İlki, Alper
    Past destructive earthquakes in highly seismic areas of the world have shown that the failure of earthquake-prone buildings endangers the lives of the inhabitants and may cause enormous financial losses. Management of the seismic risks through effective mitigation efforts requires the identification of risky buildings in our cities. However, this is a challenging task, since the building stock is generally too huge to be investigated by using detailed seismic assessment methods provided by current technical documents. On the other hand, available quick assessment methods such as street surveys may lead to remarkably erroneous estimations, particularly if the building stock is composed of substandard buildings constructed without proper engineering service and inspection. Thus, reliable rapid assessment methodologies are required for seismic risk identification and classification of buildings in big cities. In the scope of a recent campaign launched by the Istanbul Metropolitan Municipality (IMM), PERA2019 rapid assessment methodology has been employed on more than 20000 buildings from 33 different districts of Istanbul. In this study, firstly, the preliminary results obtained for those buildings by considering a Scenario-Based Earthquake case are summarized. Then, a preliminary cost-benefit analysis considering the pre-earthquake and post-earthquake intervention costs (such as retrofitting, reconstruction and structural and non-structural damage repairs) together with the secondary costs (such as interruptions on the use of damaged buildings) have been performed and discussed. The obtained results indicate that a synchronized effort orchestrating rapid assessment methodologies and intervention strategies may provide feasible and effective solutions for reduction of seismic risks in big cities like Istanbul.