رسائل ماجيستير
English
2012
Shear Behavior of Reinforced Concrete T-Beams With Openings in Flange and Strengthened by CFRP Laminates
رشا عبد الرضا غني الجزائري, مصطفى بلاسم داود
كلية الهندسة-جامعة بابل · العراق
In the construction of modern buildings, a network of pipes and ducts is necessary to accommodate essential services like water supply, sewage, air-conditioning, electricity, telephone, and computer network. Passing these services vertically required creating openings in Flanges of T-beams after or before construction. In the present research, an experimental and theoretical investigation carried for the shear strength of reinforced concrete T-beams with openings in flange and strengthened by CFRP Laminates. The experimental program consists of seven tested beams (length 1700mm * depth 250mm) one of which were constructed without any openings (reference beam TB), second, third and fourth beams (TB-1, TB-2 and TB-3) were constructed with openings (circles openings with diameter 50mm) in different locations, the others (TBS-1,TBS-2 and TBS-3)beams were constructed with openings and strengthened by CFRP sheets. The variables investigated in this work included the number, location of openings and the effected of strengthening by CFRP sheets. All beams had been tested as a simply supported span and subjected to two-point loading.Experimental results show that the presence of flange openings reduce the shear capacity about (12%) for beam containing one opening and about (18%-20%) for beams containing two openings in comparison with reference beam. And the results indicated that the use of CFRP sheet to upgrade the reinforced concrete T- beams with flange openings has significant effect on overall behavior such as the ultimate load, crack width and deflection. The ultimate load capacity of the strengthened beams was increased about (70-80) % in comparison with beams
containing openings. Also, the use of CFRP as externally strengthening system decreases the width crack, but, it cannot change the formation of the inclined crack, drilling the flange of the RC beams to wrap the CFRP strips and inclining them by 45° were the most effective and significant factors for strengthening RC beams. All the tested beams failed due to diagonal shear failure. In the other hand, three dimensional finite element analysis was used to investigate the performance of the reinforced concrete T- beams. ANSYS computer program (version 11) was utilized through this study. Full bond was assumed between the CFRP and concrete surface and between the steel reinforcement and concrete. Brick element SOLID65 and SOLID45 was used to represent concrete element and steel plate, respectively. While LINK8 and SHELL 41 were used to represent steel reinforcement and CFRP sheets respectively. The comparison between the experimental and theoretical results showed reasonable agreement and asserted the validity of the numerical analysis and methodology developed in this study.