| Title |
Strengthening Depth Effect in Externally Post-tensioning Shear Strengthening of Pre-cracked Reinforced Concrete Beam |
| Authors |
Lee, Swoo-Heon ; Shin, Kyung-Jae ; Lee, Hee-Du |
| DOI |
https://doi.org/10.5659/JAIK_SC.2018.34.11.19 |
| Keywords |
Reinforced Concrete Beam ; Externally Post-tensioning ; Shear Strengthening ; Strengthening Depth ; Pre-cracked |
| Abstract |
This paper presents the shear strengthening effect of externally post-tensioning (EPT) method using high-strength steel rod in pre-cracked reinforced concrete (RC) beams. Three- and four-point bending tests were performed on a total of 8 specimens by adjusting the strengthening depths in the deviator position of EPT. The effective strengthening depths were 435, 535, and 610mm. The pre-loading up to about 2/3 of ultimate load capacity measured in unstrengthened RC beam were applied in the beam to be post-tensioned. The EPT method was then applied to the pre-damaged RC beams and re-loading was added until the end of the test. EPT restored deflections of 3 mm or more, which account for about 40% of deflection when the pre-loading was applied. The shear strengthening increases more than 3 times and 36~107% in terms of the stiffness and load-carrying capacity compared to unstrengthening RC beams. The increased load-carrying capacities of the post-tensioned beam with strengthening depths of 435 and 535mm are almost the same as 36~61%, and those of 610 mm are 84~107%, which shows the greatest shear strengthening effect. |