Civil Engineering / İnşaat Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/13

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  • Research Project
    Tarihi yığma yapıların yapısal davranışlarının incelenmesinde izlenecek esasların belirlenmesi; Örnek çalışma: Urla Kamanlı camii
    (TÜBİTAK - Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, 2004) Aktaş, Engin; Teomete, Egemen
    Tarihi yapılar, binlerce yıllık kültürel birikimimizin en değerli parçalarmdandır. Onlarca medeniyete ev sahipliği yapmış Anadolu toprakları, bünyesinde sayısız tarihi yapı bulundurmaktadır. Bu yapıların yokolmasmı engellemek ve gelecek nesillere ulaşmasını sağlamak önemli bir insanlık vazifesidir. Yıllar tarihi yapılara oldukça hoyrat davranmış ve çoğunun üzerinde derin izler bırakmıştır. Bu yapıların bir kısmı restorasyon ve güçlendirmeye ihtiyaç duymaktadırlar. Hassas bir şekilde yaklaşılması gereken tarihi yapılar, herhangi bir müdahale öncesinde etraflıca gözlenip, analiz edilmelidir. Yapının problemleri iyi tanımlanmalıdır; yapının özgün durumu göz önüne alınarak, araştırma metodları planlanmalı ve uygulanmalıdır. Yapının tarihçe araştırması, röleve çıkartılması, malzeme ve yapısal testler, zemin analizi, uzun dönem gözlemler ve yapı analizi yapıya uygulanacak araştırma metodları arasında sayılabilir. Bu çalışmada örnek olarak seçilen, tarihi yığma yapı Urla Kamanlı Camii üzerinde araştırma metodlarmm uygulanması gösterilmiştir. Yapı analizleri için modellemede Sonlu Elemanlar Metodu seçilmiş, yapının test ve gözlemler sonucu elde edilen geometrik ve malzeme verileri bu modelde kullanılmıştır. Yığma yapıların sonlu elemanlar metodu ile modellenmesinde sıkça kullanılan mikro ve makro modellemeden, yapının büyüklüğü gözönüne alınarak makro modelleme tercih edilmiştir. Makro modellemede yığma sistem öğeleri, homojenize edilerek yığma davranışın modellenmesine gidilir. Toplanan verilerle, yapının sonlu elemanlar analizi, LUSAS adlı ticari bir program ile gerçekleştirilmiştir. Yapıya öz yük, sismik yükler ve olası oturma senaryoları için elastik lineer analizler uygulanmış ve yapıdaki sorunlu bölgeler irdelenmiştir. Ayrıca doğrusal olmayan analizler sayesinde ise yapının öz yük ve oturma senaryolarının beraberce etkittirilmesi ile yapıdaki mevcut durum açıklanmaya çalışılmıştır.
  • Research Project
    Moment aktaran mevcut çelik çerçeve kiriş kolon birleşimlerinin deprem davranışlarının cam elyaf takviyeli kompozit malzemeler kullanılarak geliştirilmesi
    (2010) Eğilmez, Oğuz Özgür; Dönmez, Cemalettin; Tanoğlu, Metin
    [No Abstract Available]
  • Conference Object
    Citation - Scopus: 3
    Seismic Performance of Cfrp Jacketed Sub-Standard Rc Columns Under High Axial Stress and Shear Demand
    (Springer, 2022) Demir, Merve Nur; Demir, Uğur; Demir, Cem; İlki, Alper
    In the last decades, lessons learnt from the major earthquakes, that occurred in many countries, brought revisions in prevailing seismic design codes. As a consequence of this phenomenon, the current building stock in Turkey is mainly comprised of reinforced concrete (RC) buildings which were designed according to different seismic design codes. The presented paper is a component of a comprehensive investigation which containing three variables i) high axial load ratio defined as axial load divided by the axial capacity, ii) high shear demand defined as the ratio of shear demand at flexural yielding to shear resistance and iii) low transverse reinforcement ratio owing to large spacing among steel reinforcements. Thus, a total of four full-scale square RC columns comprised of i) one column designed to comply with the former Turkish Seismic Design Code (TSDC, 1975) and ii) three columns which are not compliant to any design codes (referred as sub-standard), were tested under high axial load ratio, 0.4 for code-conforming and 0.75 for sub-standard columns, combined with reversed cyclic lateral loading. The columns were also designed to have high shear demand in the order of 0.62 and 0.80 for bare sub-standard according to ACI 318 (2019) and TBEC (2018) design codes as sometimes observed in existing sub-standard structures. In addition to that, the ratio of shear demand for the code-conforming column is calculated 0.43 and 0.50 as per design codes, respectively. Besides, the ratio of transverse reinforcement area to the minimum required transverse reinforcement area was 0.19 and 0.77 for sub-standard columns according to ACI 318 (2019) and TBEC (2018), respectively. For the code-conforming column, the aforementioned ratio was 0.57 and 1.32 for both design codes, in the same manner. One of the sub-standard columns was kept as a reference column while the other two of them have been externally jacketed with one layer or two layers of carbon fiber-reinforced polymer (CFRP) sheets. Test results pointed out that the confinement provided by CFRP jacketing has remarkably improved the performance of seismically-deficient RC columns subjected to high axial compression under high shear demand in terms of lateral load capacity and ductility. The experimental results were also supplemented with theoretical work to evaluate the effects of CFRP jacketing on the seismic behavior of sub-standard RC columns.
  • Conference Object
    Citation - WoS: 1
    Citation - Scopus: 2
    Seismic Performance of Substandard Rc Columns Retrofitted With Sprayed Gfrm
    (Springer, 2022) Kian, Nima; Demir, Uğur; Demir, Cem; Maraşlı, Muhammed; İlki, Alper
    There is a myriad amount of substandard reinforced concrete (RC) buildings in developing countries that do not comply with the requirements and instructions of the current building design codes. In particular, columns in these substandard buildings demonstrate unsatisfactory and undesired behavior against lateral loads, mainly due to low concrete compressive strength and poor reinforcement detailing. The problem is exacerbated when the axial load ratio (ratio of applied axial load to the axial load capacity) and/or the shear ratio (ratio of shear force corresponding to moment capacity (Ve) to the shear capacity (Vr)) is/are high, leading to brittle failure modes. In this study, three full-scale substandard RC columns subjected to high axial load ratio of 0.75 were tested under constant axial load combined with reversed cyclic lateral displacements. Shear ratio (Ve/Vr) of the substandard columns were 0.75 and 0.82 according to ACI 318-19 (ACI 318 (2019) Building Code Requirements for Structural Concrete. American Concrete Institute, Farmington Hills, MI, USA) and (Turkish Building Earthquake Code (Turkish Building Earthquake Code (TBEC) (2018) Disaster & Emergency Management Authority, Ankara, Turkey), respectively. According to the TBEC (Turkish Building Earthquake Code (TBEC) (2018) Disaster & Emergency Management Authority, Ankara, Turkey), columns had a high Ve/(fctmbd) ratio of 1.12, where, fctm, b, and d are the direct tensile strength of concrete, width of the cross-section, and effective depth of the section. The ratio of transverse reinforcement to minimum required transverse reinforcement according to the ACI 318-19 (ACI 318 (2019) Building Code Requirements for Structural Concrete. American Concrete Institute, Farmington Hills, MI, USA) and TBEC (Turkish Building Earthquake Code (TBEC) (2018) Disaster & Emergency Management Authority, Ankara, Turkey) was 0.19 and 0.77, respectively. Two of the columns were retrofitted with an innovative, cost-effective, and easily-applicable strengthening method, through external jacketing with sprayed glass fiber reinforced mortar (GFRM) of different characteristics. The remaining column was tested as the reference specimen to evaluate the efficiency of the strengthening method. The test results demonstrated the extremely poor performance of the reference substandard column as well as the remarkable lateral load capacity and ductility improvement provided by the adopted novel strengthening approach.