Finite Element Analysis on Bonding Test of CFRP Bars inside Concrete Yeou-Fong Li1 and Ru-Jyun Cheng2 1Professor of the Department of Civil Engineering , NTUT, Taipei, Taiwan . 2 Master of the Department of Civil Engineering, NTUT, Taipei, Taiwan. Abstract :In this paper, the interface model was proposed and the finite element analysis was applied to numerical simulation the bonding test of CFRP bars inside concrete. Two parameters were used in this interface model. Interface shear modulus ( ) was obtained from the deformation compatibility between CFRP bars and inner concrete and the uniform stress distribution condition by the critical tensile strength of CFRP bonding test. Analytical results the isotropic condition. Critical shear stress ( ) of interface was calculated with the assumption of shows that the distribution of interface shear stress is uniform at the region near by loading location and the shear stress decreased gradually along the bar member. The shear stress was less impacted on the bar end. Comparison of the analytic and test results indicated that the analytical critical strength was conservative cause of the analytical variable stress distribution. Keywords： Bonding analysis, FRP bar, Finite Element Method (FEM) . The Procedure of Analysis Analysis Result Interface Model were proposed Applied The Interface Model to The Bonding Analysis Interface Model Conclusions The interface model can not only simulate the transmission of strength between CFRP bars and concrete but also the deboning mechanism. The proposed CFRP bonding interface model in this study is referable for components member behaviors analysis.