| Title |
Flexural Strengthening of Damaged Reinforced Concrete (RC) Beams using Externally Post-tensioning Steel Rods |
| Authors |
Lee, Swoo-Heon ; Lee, Hee-Du ; Lee, Chang-Soo ; Shin, Kyung-Jae |
| DOI |
https://doi.org/10.5659/JAIK_SC.2017.33.7.3 |
| Keywords |
Post-tensioning ; Reinforced Concrete Beam ; Damage ; Flexural Strengthening ; Steel Rod ; Externally Unbonded |
| Abstract |
An experimental work was undertaken to observe and assess the behavior of damaged reinforced concrete (RC) beams with external post-tensioning steel rods. Six simply supported beams ― two control beams and four comparable beams post-tensioned using externally steel rods ― were tested in three-point bending. The main parameters are the diameter of external post-tensioning rods (22mm and 28mm) and the ratio of tension steel reinforcement (=0.0106 and 0.0166). For the post-tensioned beams, V-shaped profiles were used with a deviator located at the bottom of mid-span, and the post-tensioning force was applied to beams in order to overcome the low load-carrying capacity and existing deflection. The post-tensioning force acting on the steel rods was applied by tightening nuts of anchorage and its value was monitored by attached strain gauges. The initial strain of about 2000 was chosen for post-tensioning force because it is about the maximum strain that two adult men can apply without struggle. Test results indicate that the externally post-tensioning increased the load-carrying capacity by about 40~101% and the flexural stiffness by about 27~43% compared to control beams. On the other hand, the larger steel reinforcements and external rods of the section disturbed the yielding of external rod at ultimate strength. |