中文摘要：

采用混凝土和钢筋的增量型温度-应力耦合本构模型,在充分考虑高温下无黏结预应力筋总变形协调条件和其对梁单元有限元列式影响的基础上,将无黏结预应力筋内力与未知结点位移共同作为待求列矢,推导高温下无黏结预应力混凝土受弯构件非线性有限元全过程分析的增量有限元格式,建立其高温下非线性有限元计算模型,并提出其非线性有限元平衡方程组的求解方法,编制NAUPCLF非线性有限元程序,并对进行的高温试验及有关试验资料完成实例计算。结果表明,计算数值基本能反映其高温下变形及预应力筋应力的变化规律,计算理论较充分地表现了无黏结预应力混凝土受弯构件的无黏结特性及高温受力特点,可为建立高温下无黏结预应力混凝土受弯构件的耐火极限计算方法、进一步深入研究预应力混凝土结构的抗火性能和完善其基于抗火特性的设计方法提供手段和参考。

英文摘要：

Based on the incremental temperature-stress coupling constitutive models and the general deformation compatibility of the unboded prestressed tendons,the nonlinear finite element calculation formula take the unknown nodal displacements and the tensile forces in the unbonded tendons as the unsolved column matrix.The incremental format of the nonlinear finite element method and the calculation model for analysis of unbonded prestressed concrete flexural members at high temperature are presented.The solution approach was proposed,and a FORTRAN program developed.The experimental calculations reflect the patterns of deformation and stress of prestressed tendons at high temperature.