Civil Engineering / İnşaat Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/13
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Article Efficiency of Shear Studs Manufactured From Threaded Bars on the Punching Behavior of Flat Slabs(Golden Light Publishing, 2023) Saatçi, Selçuk; Saatcı, Selçuk; Yaşayanlar, YoncaPunching resistance in flat slab systems in reinforced concrete structures is often provided with drop panels or shear reinforcement around columns. Shear studs are effectively used in these structures as shear reinforcement. However, factory-made shear studs may not be available in all locations and small quantities for small projects. Therefore, cheap shear studs that can be manufactured from widely available materials in small quantities can be very useful in certain cases. In this study, shear studs manufactured from threaded bars, widely available in hardware stores, are used for providing punching resistance to flat slabs. Stud heads were formed with T-section nuts. Four slab specimens, two with shear studs and two without, were cast and tested under concentrated loads at their mid-point. The slabs had 2150×2150×150 mm dimensions and they were cast with two different longitudinal reinforcement ratios. Test results showed that manufactured shear studs significantly increased the load and deformation capacities of the slabs. Slabs with shear studs were able to show up to three times higher bending deformations and they were able to sustain up to 50% higher loads. The study has shown that these studs can be effectively used for punching strengthening purposes in flat plate systems or in other cases where punching resistance is needed.Article Citation - WoS: 10Citation - Scopus: 11Numerical Investigation on the Behavior of Reinforced Concrete Slabs Strengthened With Carbon Fiber Textile Reinforcement Under Impact Loads(Elsevier, 2022) Batarlar, Baturay; Saatcı, SelçukIn this study, impact load performance of reinforced concrete members strengthened with carbon fiber textile reinforcement (CFTR) was investigated through numerical simulations. In the first phase of the study, a finite element model was set up to model reinforced concrete slabs of 1500 × 1500 × 200 mm in dimensions, strengthened with CFTR and subjected to multiple impact loads, using software LS-DYNA. This model was validated against experimental data available in the literature and basic modeling parameters, such as material model selection, mesh size, and erosion parameters for better accuracy were determined. In the second phase of the study, a numerical parametric study was conducted using the validated model to reveal the effects of steel and textile reinforcement ratio, slab thickness, striker mass, size, and velocity on the behavior of steel-reinforced concrete slabs strengthened using CFTR. As a result of the study, it was found that CFTR was effective in limiting the peak and residual displacements in reinforced concrete slabs subjected to multiple impacts at the middle. Among 220 mm thick specimens, for the same steel reinforcement ratio, a higher CFTR ratio resulted in lower peak and residual displacement levels after the third impact. On the other hand, when 8 mm diameter steel reinforcement was varied from 100 mm to 200 mm spacing, it was found that steel reinforcement ratio was the dominant factor on the impact behavior over the CFTR ratio. CFTR strengthening was particularly more effective when the members displayed a global response instead of a local one, such as low-velocity high-mass impact loading or in the cases where the striker had a larger diameter. Similarly, thickness was also found to be a major factor on the effectiveness of CFTR. When thickness of the slab was varied from 50 mm to 300 mm, CFTR's effect was found to be more pronounced for thinner slabs in preventing perforation and limiting peak and residual displacements. However, for 200 and 300 mm thick slabs, CFTR did not have a significant effect since local punching behavior was dominant in these slabs and CFTR was not effective in this shear mechanism.Article Çelik Fiber İlaveli Etriyesiz Betonarme Kirişlerin Eğilme Etkisi Altındaki Davranışlarının Doğrusal Olayan Sonlu Elemanlar Analizi ile Belirlenmesi(Pamukkale Üniversitesi, 2018) Tayfur, Sena; Saatcı, Selçuk; Saatçi, Selçuk; Alver, NinelÇelik fiber katkılı betonarme elemanların kullanımı son yıllarda artmakla birlikte bu elemanların yapısal davranışlarının modellenmesinde mevcut analitik yöntemler yetersiz kalmakta ve doğrusal olmayan sonlu elemanlar yöntemi gibi sayısal yöntemlere ihtiyaç duyulmaktadır. Bu çalışmada üç noktalı statik yükleme altında davranışı deneysel olarak belirlenmiş çelik fiber katkılı iki kiriş ile çelik fiber katkısı olmayan bir kiriş Değiştirilmiş Basınç Alanı Teorisi'ne dayanan bir doğrusal olmayan sonlu elemanlar yöntemi ile analiz edilmiş ve sonuçlar irdelenmiştir Kullanılan yöntemde çatlamış betonda çatlak yüzeyleri arasında çelik fiberlerin ilettiği çekme gerilmelerinin modellenmesinde Basitleştirilmiş Kapsamlı Gömülme Modeli seçilmiştir. Analiz sonuçları deney sonuçlarıyla karşılaştırıldığında kullanılan sonlu elemanlar yönteminin kirişlerin eğilme kapasitelerini ve oluşan ana çatlakları yüksek hassasiyetle belirlediği, ancak kirişlerin deplasman kapasitelerini olduğundan çok daha düşük bulduğu görülmüştür. Modelin ana çatlakları doğru tespit etmekle birlikte oluşan çok sayıda küçük çatlakları doğru tespit edememesi ve bunun sonucu olarak ana çatlaklarda donatı kopmasının olduğundan erken gerçekleşmesi sonucu kirişin düşük deplasmanlarda göçtüğü değerlendirilmiştir. Daha hassas çözümler için çelik fiber katkısının modellenmesinde daha gelişmiş modellere ihtiyaç olduğu görülmüştür.