体内外配束预应力混凝土箱梁的力学响应研究

Research on Mechanical Response of Pre-stressed Concrete Box Girder with Internal and External Tendons

对于体内外混合配束的预应力混凝土箱梁,根据层壳单元理论,结合混凝土关联流动法则、混凝土弥散裂缝模式及钢筋的双线性理想弹塑性本构,建立了箱梁结构的非线性有限元模型,并进行了数值分析。通过对称加载和偏载加载的典型加载分析可知,偏载会产生应力集中的现象,使得结构的极限荷载偏低,故在结构运营过程中应尽量避免出现偏载的加载方式。无论对称加载或偏载加载,体内外混合配束的预应力混凝土箱梁都经历了较为明显的4个发展阶段,即弹性受力阶段、非线性初始阶段、非线性发展阶段和高度非线性阶段。研究结论可供工程设计参考。

According to the theory of shell element,the law of correlative flow of concrete,the mode of concrete dispersion crack and the bilinear ideal elastic-plastic constitutive law of steel bar,the nonlinear finite element model of the box girder structure with internal and external mixed tendons for pre-stressed concrete box girder with internal and external beams was established and the numerical analysis was carried out.Through the analysis of the typical load of symmetrical load and unbalanced load,it can be seen that the unbalanced load can produce the phenomenon of stress concentration,which made the ultimate load of the structure lower,so the unbalanced load should be avoided as far as possible during the operation of the structure.Whether under symmetrical or eccentric loading,the pre-stressed concrete box girder with internal and external mixed tendons has undergone four distinct stages of developments,that was,elastic loading stage,nonlinear initial stage,non-linear development stage and highly non-linear stage.The conclusions can be used for reference in engineering design.