体外预应力混凝土结构体外筋极限应力分析

Analysis of Tendons Ultimate Stress at Ultimate Status on Externally Prestressed Concrete Structures

体外预应力混凝土结构是后张无粘结预应力结构,体外预应力筋和梁体在受力过程中变形不协调,预应力筋极限应力的确定一般需要通过结构的总变形求得.在试验基础上,利用无粘结预应力混凝土结构预应力筋极限应力的计算公式,对体外预应力梁进行计算,通过与试验结果对比,发现运用现行主要规范或规程中体内无粘结筋的计算方法计算体外预应力结构体外筋的极限应力,都存在较大误差,如何合理地进行体外预应力筋极限应力的计算应进行深入研究.

External prestressed concrete structure is one of the posttensioned unbonded prestressed structures, in which the deformation of external tendons is not compatible with that of beams , so ultimate stress of tendons only can be calculated depended on the total deformation of structures. Adopting formulas on ultimate stress of tendons in unbonded prestressed concrete structure, some calculations and compared calculation results with test ones were done. It＇s found that the formulas specialized in internal unbonded prestressed concrete code are not suitable for calculation of ultimate stress of external tendon due to great inaccuracy. So further study of ultimate stress of external tendon needs to be carried out.