体外预应力梁的弧长法分析与二次效应评估

为跟踪体外预应力混凝土梁的软化段路径，建立了一种基于法平面弧长算法的有限元模型，可预测梁从开始加载直到失效的非线性响应.通过对计算和试验结果的比较验证了分析模型的可靠性.设计了3根设置不同转向块的体外预应力混凝土梁以及1根体内无黏结预应力混凝土对比梁，利用提出的分析模型对这些梁进行非线性全过程分析.分析结果表明，当梁没有配置转向块时，二次效应随着挠度的增加会越来越明显；通过在梁最大挠度处设置一个转向块，能基本消除二次效应的不利影响.

Arc-length method analysis and second-order effect evaluation of externally prestressed beams

To trace the softening path of externally prestressed concrete beams, a finite element model based on the normal plane arc-length algorithm was developed, which is capable of predicting the nonlinear response of the beams from zero loads up to ultimate loads. The reliability of the analytical model was verifled through comparison of computational and test results. Three externally prestressed concrete beams with different deviators and a comparable concrete beam prestressed with internal unbonded tendons were designed and then analyzed using the proposed analysis model. The analytical results demonstrate that the second-order effects become more and more significant with increasing deflection for beam without deviators, whereas theses effects can be minimized as long as one deviator is placed at the section of the maximum deflection of the beams.