Civil Engineering / İnşaat Mühendisliği

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

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  • Article
    Citation - WoS: 1
    Citation - Scopus: 1
    Çelik Köprü I-kirişlerine Yanal Destek Sağlayan Trapez Sac Kalıpların Mukavemeti
    (Turkish Chamber of Civil Engineers, 2009) Eğilmez, Oğuz Özgür; Alkan, Deniz
    Trapez Sac Kalıplar (TSK) hem çelik bina hem de çelik köprü sektörlerinde beton döşemenin kalıp sistemi olarak sıklıkla kullanılmaktadırlar. TSK’ler her ne kadar bina inşaatlarında çelik I-kirişlere yanal destek sağlayıcı elemanlar olarak işlev görseler de, çelik köprü sektöründe trapez sac kalıplardan destek elemanları olarak yararlanılmasına izin verilmez. Ancak, önceki çalışmalar birleşim detayının geliştirilmesi durumunda TSK sisteminin kirişin yanal kararlılığına belirgin şekilde destek sağlayabildiğini göstermiştir. Bu makale halen devam etmekte olan ve TSK’lerin mukavemetinin incelendiği analitik bir çalışmanın ara sonuçlarını içermektedir. Geçmişte, TSK sistemleriyle desteklenen köprü kirişlerin genel burkulma davranışını irdeleyen basit sonlu elemanlar modelleri (SEM) kullanılmıştır. Bu çalışmada TSK’leri hem birbirlerine hem de kirişlere bağlayan vidalardaki kararlılık destek kuvvetlerini belilemek için kullanılan geliştirilmiş bir sonlu elemanlar modelinin sonuçlarına yer verilmiştir. Bu çözümleme sonuçları TSK’lerin içermesi gereken mukavemet ihtiyacını belirleyecek olan bir tasarım yönteminin geliştirilmesinde kullanılacaktır.
  • Conference Object
    Citation - Scopus: 1
    Strength Requirements of Permanent Metal Deck Forms Used for Lateral Bracing of Steel Bridge Girders
    (2006) Eğilmez, Oğuz Özgür; Helwig, T.A.; Herman, R.S.
    Permanent metal deck forms (PMDF) are often used in steel bridges to support the weight of the wet concrete during deck construction. Although the PMDF also has the potential to provide bracing to steel bridge girders during construction, the stiffness of the PMDF system as a lateral brace is drastically reduced by the eccentric support angle connection detail used to attach the forms to the girders. Laboratory tests have shown that a simple modification to the connection detail can substantially increase the stiffness of these PMDF systems and allow utilization of the PMDF for girder bracing. This paper presents results from a parametrical study conducted to determine stability and strength requirements for PMDF used to provide lateral bracing to steel bridge girders. Detailed FEA models were used to determine the stability bracing strength requirements for the fasteners that are used to connect the PMDF along the sidelaps of the sheets and to the girders. Design expressions are presented as well as an example demonstrating the use of the design equations.
  • Conference Object
    Improving the Ductility of Steel I-Beams Through the Use of Glass Fiber Reinforced Polymers
    (Curran Associates, 2010) Eğilmez, Oğuz Özgür; Alkan, Deniz; Özdemir, Timur
    Flange and web local buckling in beam plastic hinge regions of steel moment frames can prevent beam-column connections from achieving adequate plastic rotations under earthquake-induced forces. Reducing the flange-web slenderness ratios (FSR/WSR) of beams is the most effective way in mitigating local buckling as stipulated in the latest seismic design specifications. However, existing steel moment frame buildings with beams that lack the adequate slenderness ratios set forth for new buildings are vulnerable to local member buckling and thereby system-wise instability prior to reaching the required plastic rotation capacities specified for new buildings. This paper presents results from a research study investigating the cyclic behavior of steel I-beams modified by a welded haunch at the bottom flange and reinforced with glass fiber reinforced polymers at the plastic hinge region. Cantilever I-sections with a triangular haunch at the bottom flange and FSR higher then those stipulated in current design specifications were analyzed under reversed cyclic loading. Beam sections with different depth/width and flange/web slenderness ratios (FSR/WSR) were considered. The FEA results revealed that the GFRP reinforcement moderately improves the plastic local behavior of steel I-beams.
  • Conference Object
    Citation - Scopus: 1
    Stiffness and Strength of Shear Diaphragms Used for Stability Bracing of Slender Beams
    (Curran Associates, 2014) Eğilmez, Oğuz Özgür; Akbaba, Andaç; Vardaroğlu, Mustafa
    Light gage metal decking is often used in structures as concrete deck formwork, roof cladding or siding. In the steel building and bridge industries, decking acts like a shear diaphragm and provides continuous lateral bracing to the top flange of non-composite beams and girders that they are attached to. The building industry has long relied on the in-plane stiffness and strength of metal decking to brace steel beams during construction. Although the current AASHTO LRFD specifications do not allow bridge deck forms to be relied upon as a bracing source for steel bridge I-girders, recent studies have demonstrated that deck forms can significantly increase the buckling capacity of bridge girders by providing a relatively simple modification to the connection. Shear diaphragm bracing of steel I-beams have been studied in the past. These studies mainly focused on beams with stocky webs. The purpose of the study outlined in this paper is to enhance the understanding of both the stiffness and strength of shear diaphragms used to brace slender steel I-beams. The parameters that are investigated include diaphragm stiffness, sheet thickness, number of side-lap fasteners, flange width, and web slenderness ratio. Beams with web slenderness ratios of 100 to 160 and span/depth ratios of 10, 15, and 20 are considered. A simple finite element analytical (FEA) model is utilized in the study. The results indicate that web slenderness ratio does not have a major effect on fastener forces and the strength behavior of shear diaphragms is dependent on the number of side-lap fasteners. The findings of the study will be used to develop strength and stiffness requirements for shear diaphragms used to brace slender steel beams
  • Conference Object
    Citation - WoS: 9
    Cyclic Testing of Steel I-Beams Reinforced With Gfrp
    (Curran Associates, 2011) Eğilmez, Oğuz Özgür; Yormaz, Doruk
    Flange and web local buckling in beam plastic hinge regions of steel moment frames can prevent beam-column connections from achieving adequate plastic rotations under earthquake-induced forces. This threat is especially valid for existing steel moment frame buildings with beams that lack adequate flange/web slenderness ratios. As the use of fiber reinforced polymers (FRP) have increased in strengthening and repair of steel members in recent years, using FRPs in stabilizing local instabilities have also attracted attention. Previous computational studies have shown that longitudinally oriented glass FRP (GFRP) strips may serve to moderately brace beam flanges against the occurrence of local buckling during plastic hinging. An experimental study was conducted at Izmir Institute of Technology investigating the effects of GFRP reinforcement on local buckling behavior of existing steel I-beams with flange slenderness ratios (FSR) exceeding the slenderness limits set forth in current seismic design specifications and modified by a bottom flange triangular welded haunch. Four European HE400AA steel beams with a depth/width ratio of 1.26 and FSR of 11.4 were cyclically loaded up to 4% rotation in a cantilever beam test set-up. Both bare beams and beams with GFRP sheets were tested in order to investigate the contribution of GFRP sheets in mitigating local flange buckling. Different configurations of GFRP sheets were considered. The tests have shown that GFRP reinforcement can moderately mitigate inelastic flange local buckling.