This paper shows the simplified equation to predict the ultimate moment capacity and corresponding rod stress in reinforced concrete beam with external post-tensioning rods. Because the stress of external post-tensioning rod depends on the beam deflection, the previous analytical model for post-tensioned beams requires a tedious iteration process. Also, the stress equations in ACI code or other researchers’ models are suitable only for internal tendons in concrete beams. In this study, given the lack of analytical approaches to predict the nominal stress of the external unbonded rod, a simple and robust equation has been proposed for externally post-tensioned concrete beams. It is concluded that the proposed equation predicted the stress of external steel rods in post-tensioned concrete beams reasonably well.

• 이수헌(정회원, 텍사스알링턴대학교 박사후연구원, 공학박사) | Lee, Swoo-Heon
• 강현구(정회원, 서울대학교 건축학과 교수, 공학박사) | Kang, Thomas H.-K. 교신저자
• 신경재(정회원, 경북대학교 건축학부 교수, 공학박사) | Shin, Kyung-Jae