Özet:

IN modern buildings, transverse openings are often used in order to pass the pipes of health services, electrical cables or air conditioning ducts and other prepuce. The presence of these openings leads to a weakening of the beam so it must work to investigate the behavior of these beams in order to know how the presence of openings affects beam resistance. In this research, the behavior of reinforced concrete T-beams with circular openings exposed to pure torsional moment is studied. The experimental program involves testing of five beams with same dimensions and reinforcements. One of them is solid beam and used as reference for comparison with other beams with an opening and the other four T- beams containing circular openings of deferent dimension(100 and 150) and location(Lc/2 and Lc/3). Practical results show that the T-beam with circular openings of diameter (100mm) with different locations (Lc/2 and Lc/3), where Lc is the clear span of the beam, have an ultimate torsional capacity lower than that for solid beam by about (23% and 30%) respectively. The increase of the openings size causes a significant decrease in torsional capacity, where the beams with circular openings of diameter (150mm) with different locations (Lc/2 and Lc/3) have an ultimate torsional capacity lower than that for solid beam by about (56 % and 61%) respectively. Practical results show also that the presence of circular openings with diameter of 47% and 71% from the total depth increases the angle of twist significantly as compared with reference beam for the same applied torque level.

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