The effect of opening size and location on the performance of reinforced concrete t-beams under pure torque

الملخص EN

In modern buildings, transverse openings are often used in order to pass the pipes ofhealth services, electrical cables or air conditioning ducts and other prepuce.

Thepresence of these openings leads to a weakening of the beam so it must work toinvestigate the behavior of these beams in order to know how the presence of openingsaffects beam resistance.

In this research, the behavior of reinforced concrete T-beamswith circular openings exposed to pure torsional moment is studied.

The experimentalprogram involves testing of five beams with same dimensions and reinforcements.

Oneof them is solid beam and used as reference for comparison with other beams with anopening and the other four T- beams containing circular openings of deferentdimension(100 and 150) and location(Lc/2 and Lc/3).

Practical results show that the Tbeam with circular openings of diameter (100mm) with different locations (Lc/2 andLc/3), where Lc is the clear span of the beam, have an ultimate torsional capacity lowerthan that for solid beam by about (23% and 30% ) respectively.

The increase of theopenings size causes a significant decrease in torsional capacity, where the beams withcircular openings of diameter (150mm) with different locations (Lc/2 and Lc/3) have anultimate torsional capacity lower than that for solid beam by about (56 % and 61% )respectively.

Practical results show also that the presence of circular openings withdiameter of 47% and 71% from the total depth increases the angle of twist significantlyas compared with reference beam for the same applied torque level.