Browsing by Author "Yaman, Ismail Ozgur"

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Cfrp-Confined Concrete Columns Under Different Environmental Conditions
(Ice Publishing, 2013) Erdil, Baris; Akyuz, Ugurhan; Yaman, Ismail Ozgur
The behaviour of carbon fibre reinforced polymer-confined cylindrical and prismatic concrete specimens subjected to several different environmental conditions was investigated in four groups. The first group of specimens was used as a reference. In the second group, specimens were exposed to dry heating-cooling (H-C) cycles in the environmental test chamber (ETC), whereas specimens in the third group were kept in water while simultaneously being subjected to H-C cycles in the ETC. Finally, the last group of specimens was kept outside of the laboratory to determine the outdoor environmental effect. After the ageing phase, specimens were tested under monotonic uniaxial loading to determine the change in their mechanical properties. Cylindrical specimens were observed not to be significantly affected by H-C cycles with the exception of their ultimate strain, which decreased under outdoor conditions. As for the prismatic specimens, dry H-C cycles were found to reduce strength by up to 24% and strain by up to 33%. Wet H-C cycles and outdoor exposure were seen to decrease further the strength and ultimate strain of prismatic specimens.
Confinement Effectiveness of Cfrp in Axial Members Under Various Loading Conditions
(Trans Tech Publications Ltd, 2013) Erdil, Baris; Akyuz, Ugurhan; Yaman, Ismail Ozgur
In this study, parameters affecting the mechanical properties of FRP-confined cylindrical and prismatic concrete columns were studied via experimental data, which were collected after an extensive literature review. The parameters were summarized as unconfined concrete strength, FRP thickness, cylinder diameter, overlap length of FRP, sustained stress level, heating-cooling effect and corner radius in prismatic specimens. Considering these parameters the confinement effectiveness is established analytically in the light of ultimate strength values obtained from the test results available in the literature. No steel reinforcement is taken into account because the main aim is to capture the behavior of FRP-confinement only. The analytical results revealed that unconfined concrete strength, FRP thickness, cross-sectional dimension of the specimen are the main parameters controlling the confinement effectiveness in cylindrical specimens. In addition to these parameters corner radius and sustained stress level are found to be significant in prismatic specimens.