LOCALIZED TORSIONAL STRENGTHENING TECHNIQUE FOR RC BOX BEAMS WITH TRANSVERSE OPENINGS

Abstract

In the present study, experimental analysis was performed to investigate the effect of localized strengthening by steel plates on the torsional capacity of reinforced self-compacting concrete (SCC) box beams containing a transverse opening under pure torsional moments of seven hollow core beam specimens. The seven tested beam specimens were cast with the dimensions (1800x300x300mm) respectively, for the length, width, and depth; six of them including transverse openings of dimensions (100x100mm). The parameter studies were: with or without transverse opening, the position of the transverse opening was at (L/4) and (L/2) of the clear span length of the beams (from one side or two sides). The current strengthening technique used depends on: the localized steel plates fabricated to be fully bonded with SCC through using bolts as shear connectors. The experimental results show the ultimate torque decreased by (34.7%) and (45.3%) for the tested specimens which contained transverse openings respectively at a distance (L/4) and (L/2), in comparison to the control beam. By the opposite side, the ultimate torsion moments were increased by (34%) and (55.5%) for the tested specimens which contained transverse opening at a distance (L/4) and respectively strengthened by (one and two) face localized steel plates, relative to the reference specimens. Whereas, the maximum torsional moments were raised by about (20%) and (24%) for the tested specimens containing transverse opening at a distance (L/2) and strengthened by (one and two) face localized steel plates respectively, compared to the reference beam. , it concluded that torsional capacity has deteriorated because of the existing transverse opening, and it has been enhanced due to the contribution of the approved technique.