ENTIRE RANGE ANALYSIS OF EXTERNALLY PRESTRESSED CONCRETE BEAMS BASED ON COMPOSITE ELEMENTS

Evaluation is made to the research actuality and numerical simulation method of externally prestressed concrete structure. Composite element can comprehensively consider crack and plasticity of concrete. A kind of externally prestressed element is proposed，in which friction and considering slippage of external steel at deviators is ignored, leading to a more accurate simulation of deflection and stress. With those two kinds of elements, entire range of 3 test beams from third-point load to failure are analysized. Load(Q)-deflection(f) curves and deflection(f)-stress increment of externally prestressed steel(σ) curves are discussed, while physical meaning of turning point on the curves is identified, and new suggestion is given to the problem that how to make sure ultimate stress increment of externally prestressed steel. Through contrastive analysis of calculated value and test data, it is proven feasible and correct to use composite element and externally prestressed element together to analyze externally prestressed concrete structure, while providing support and experience to the numerical simulation in bridge structure.