预应力混凝土连续梁的非线性分析

The Nonlinear Analysis of Pre-stressed Concrete Beams

采用分层法对预应力混凝土梁进行了非线性有限元分析，利用计算机数值计算方法，模拟预应力混凝土多跨连续梁的加载试验全过程，分析预应力混凝土梁的非线性特性，通过各层单元引入对应材料的非线性模型，并采用离散裂缝模型，能较正确地模拟预应力混凝土梁从弹性状态到极限状态的受力特性，算例表明该方法既能使混凝土非线性分析的结构模型得到简化，又能较好地预测预应力混凝土梁的开裂荷载、极限荷载、正截面裂缝开展、荷载挠度曲线关系和钢筋及混凝土的应力变化过程，计算结果与试验结果吻合较好。

The nonlinear analysis of pre-stressed concrete beams has been made by using layered finite element method in this paper. The proposed numerical method can be used to simulate the all stages of loading experiment of multii-span continuous beams and to analyze the nonlinear behavior of pre-stressed concrete beams. The material nonlinearity is introduced through the stress-strain relationships for the constituent materials in each layer and the de-velopment of crack is simulated by the smeared crack model, the behavior of a continuous pre-stressed concrete beam over the entire range from elastic stage to ultimate stage can be reflected. The examples prove that the proposed ap-proach can significantly simplify the structural model required for a nonlinear analysis of concrete structures and can predict the cracking load, the ultimate load, the development of crack on critical sections, load-deflection relation-ship and the total change in stress in the tendon and concrete. Calculations are in good agreement with experimental results.