Browsing by Author "Alsdudi, Mohammed"

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Determination of Optimum Cfrp Composite Amount in Strengthening Reinforced Concrete Beams With Inadequate Shear Strength
(2020) Alsdudi, Mohammed; Arslan, Musa Hakan; Özkılıç, Yasin; Yazman, Şakir; Aksoylu, Ceyhun; Gemi, Lokman
Kesme Dayanımı Yetersiz Betonarme Kirişlerin Güçlendirilmesinde Optimum Lifli Polimer Miktarının Belirlenmesi
(Konya Teknik Üniversitesi, 2021) Alsdudi, Mohammed; Arslan, Musa Hakan; Gemi, Lokman
Bu çalışmada kesme kapasitesi yetersiz denge altı dikdörtgen kesitli betonarme kirişlerin kesme açıklıkları boyunca dıştan CFRP ile güçlendirilmesi sonucunda düşey yük altında değişen davranışı deneysel olarak incelenmiştir. Çalışmada yapım yönetmeliklerinde yer alan normlara göre kiriş davranışını gerek dayanım gerekse süneklik açısından ideal seviyeye getirecek olan CFRP'nin optimum şerit genişliği (wf) / şerit aralıkları (sf) oranı belirlenmiştir. Deneysel çalışmada, ½ ölçekli 8 adet 125 x 250 x 2500 mm boyutlarında betonarme kiriş numunesi hazırlanmıştır. Kirişlerde kesme kapasitesinin yetersiz olması için etriyeler Ø5 / 35 cm olacak şekilde seçilmiştir. Numunelerden bir tanesi güçlendirilmeden referans olarak test edilirken diğer numunelerin kesme açıklıkları boyunca artan CFRP (wf) / (sf) oranlarda güçlendirilerek testleri gerçekleşmiştir. Deneysel sonuçlarına göre (wf) / (sf) oranın 0.55'i geçmesi ile beraber kiriş davranışı kesme kırılması yerine eğilme kırılması gözlemlenmiştir. Bununla beraber kirişin yönetmelik normlarına göre yeterli kesme rezerv değerine ulaşabilmesi için (wf) / (sf) oranın 0.82'ye kadar çıkarılması gerektiği de görülmektedir. Çalışmada kullanılan CFRP'nin yönü ve gramajının güçlendirmede en önemli etkenlerden biri olduğu ve kullanılan 240 gr/m2 lik CFRP'nin kesme bölgelerinde betonun çatlaması ile beraber ani kopmalar yaşadığı görülmüştür. Yönetmeliklerde yer alan kapasite formüllerinde CFRP malzemesi ile ilgili gerek yön gerekse gramaj bilgilerinin bulunmaması ise bir eksiklik olarak düşünülmüştür.
Citation - WoS: 13
Citation - Scopus: 14
Numerical and Analytical Investigation of Parameters Influencing the Behavior of Shear Beams Strengthened by Cfrp Wrapping
(Techno-Press, 2023) Aksoylu, Ceyhun; Özkılıç, Yasin Onuralp; Yazman, Şakir; Alsdudi, Mohammed; Gemi, Lokman; Arslan, Musa Hakan
In this study, a parametric study was performed considering material properties of concrete, material properties of steel, the number of longitudinal reinforcement (reinforcement ratio), CFRP ply orientations, a number of layers as variables by using ABAQUS. Firstly, the parameters used in the Hashin failure criteria were verified using four coupon tests of CFRP. Secondly, the numerical models of the beams strengthened by CFRP were verified using five experimental data. Finally, eighty numerical models and eighty analytic calculations were developed to investigate the effects of the aforementioned variables. The results revealed that in the case of using fibrous polymer to prevent shear failure, the variables related to reinforced concrete significantly affected the behavior of specimens, whereas the variables related to CFRP composite have a slight effect on the behavior of the specimens. As a result of numerical analysis, while the increase in the longitudinal tensile and compression reinforcement, load bearing capacity increases between 23.6%-70.7% and 5.6%-12.2%, respectively. Increase in compressive strength (29 MPa to 35 MPa) leads to a slight increase in the load-carrying capacity of the specimens between 4.6% and 7.2%. However, the decrease in the compressive strength (29 MPa to 20 MPa) significantly affected (between 6.4% and 8.1% decrease observed) the behavior of the specimens. As the yield strength increases or decreases, the capacity of specimens increase approximately 27.1% or decrease 12.1%. The effects of CFRP ply orientation results have been obtained as a negligible well approximately 3.7% difference. An increasing number of CFRP layers leads to almost no effect (approximately 2.8%) on the behavior of the specimen. Finally, according to the numerical analysis, the ductility values obtained between 4.0 and 6.9 indicate that the beams have sufficient ductility capacity.
Citation - WoS: 45
Citation - Scopus: 47
Optimum Amount of Cfrp for Strengthening Shear Deficient Reinforced Concrete Beams
(Techno-Press, 2022) Gemi, Lokman; Alsdudi, Mohammed; Aksoylu, Ceyhun; Yazman, Şakir; Özkılıç, Yasin Onuralp; Arslan, Musa Hakan
The behavior of shear deficient under-balanced reinforced concrete beams with rectangular cross-sections, which were externally strengthened with CFRP composite along shear spans, was experimentally investigated under vertical load. One of the specimens represents a reference beam without CFRP strengthening and the other specimens have different width/strip spacing ratios (w(f)/s(f)). The optimum strip in terms of w(f)/s(f), which will bring the beam behavior to the ideal level in terms of strength and ductility, was determined according to the regulations. When the w(f)/s(f) ratio exceeds 0.55, the behavior of the beam shifted from shear failure to bending failure. However, it has been observed that the w(f)/s(f) ratio should be increased up to 0.82 in order for the beam to reach sufficient shear reserve value according to the codes. It is also observed that the direction and weight of the CFRP composite are one of the most critical factors and 240 gr/m(2) CFRP strips experienced sudden ruptures in the shear span after the cracking of the concrete. It is considered as a deficiency that the empirical shear capacity formulas given for the beams reinforced with CFRP in the regulations do not take into account both direction and weight of CFRP composites.