| Title |
Shear Strengthening Effect by Deviator Location in Externally Post-tensioning Reinforcement |
| Authors |
Lee, Swoo-Heon ; Shin, Kyung-Jae ; Lee, Hee-Du |
| DOI |
https://doi.org/10.5659/JAIK_SC.2018.34.6.3 |
| Keywords |
Post-tensioning ; Reinforced Concrete Beam ; Damage ; Shear Strengthening ; Steel Rod ; Externally Unbonded ; Deviator |
| Abstract |
This paper described the shear strengthening effect by deviator location in pre-damaged reinforced concrete (RC) beams strengthened with externally post-tensioning steel rods. Three reinforced concrete beams as control beam and eight post-tensioned beams using external steel rods were tested to fail in shear. The externally post-tensioning material was a steel rod of 22mm diameter, and it had a 655MPa yield strength and an 805MPa tensile strength. Specimens depend on multiple variables, such as the number of deviators, location of deviator, and load pattern. The pre-damaged loads up to about 2/3 of ultimate shear capacities were applied to specimens using displacement control and the diagonal shear crack just occurred at these loading levels. And then, the post-tensioning up to when a strain of steel rod reaches about 2000 was continuously applied to beam. A displacement control was changed to a load control during post-tensioning. The post-tensioning resulted in increase of load-carrying capacity and restoration of existing deflection. Also, it prevented the existing diagonal cracks from excessively growing. Two deviators effectively improved the load capacity when compared with in case of test which one deviator at mid-span installed. When deviators were located near region which the diagonal crack occurred on, the strengthening impact by post-tensioning was greater. |