Abstract: Taking the frame beam of frame structurefully reinforced by external prestressing technology as the research object, force characteristics were analyzed and the corresponding mechanical models wereestablished. The principles of force balance, point oblique solution andmoment-curvature relation were appliedto infer the expression of cable internal force and the curve expression afterdeformation, the load-deflection curve equation of the beam,which were compared with the previous experimental results. The results show that the internal force of cable changes with the vertical position of cable node and there is a non-linear relationship between the internal force of cable and the axial force of the web member.In the elastic stage, when the boundary condition of the beam deflection curve equation approaches infinitely the state of simply supported beam (or embedded beam), the maximum value of the deflection curve equation is basically consistent with that of the deflection of the beam in the middle span in the existing literature. While there is a great difference between the theoretical and experimental values of the deflection curve in the plastic stage. The analysis results in the elastic stage can provide a theoretical reference for engineering practice.

Key words: concrete structure, structure reinforcement, external prestressing, full structure reinforcement, comparative analysis