Flexural Strengthening For Reinforced Concrete T-Shaped Beam By Tightened Strands Position Change

Abstract

In this study, external strengthening of T-shape beams is investigated using a new profiling technique by drop downing the tendon from the flange to near the bottom of the beam, the investigation includes the effect of different turning point position of the tendon on: deflection, first crack load, service load, and maximum failure load. Totally 4 beams are casted with same dimensions of 2000mm length, 230mm and 50mm of flange width and depth, respectively; web width and height of 130mm and 170mm, respectively. All of them they have the same material properties, concrete 30MPa and main steel bars 510MPa. Three of the beams are strengthened by external tightened tendons of diameter 6mm and maximum stress of 1770MPa, with different turning points of the cable near beam’s bottom under prestressing of 140MPa, and other beam without strengthening as control beam. The results show for all the profiles increasing in first crack load between (30.8% to 61.5%), service load between (18.5% to 25%), and for maximum failure load, the improvement is between (40% to 50%) compared to the control beam.

Keywords

• tendons
• external strengthening
• t-shape beam
• pre-stressing