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通过4根1∶5城市轻轨预应力混凝土轨道梁模型的500 d长期试验,对其时随性能进行较系统的研究与分析,重点考察混凝土种类、截面上下缘应力差等因素对轨道梁徐变变形、徐变应变、截面曲率、钢筋应力及预应力筋应变等的影响。基于龄期调整有效模量法,编制步进法时随有限元分析程序,实现轨道梁徐变变形的时随全过程分析。应用该程序对本文试验结果进行模拟分析,计算值与试验结果吻合良好。在试验研究、时随全过程分析及美国规范ACI 318—02的基础上,提出综合考虑混凝土种类、预应力筋张拉方式、钢筋配筋率及截面上下缘应力差的城市轻轨轨道梁徐变变形设计建议。研究成果为我国城市轻轨预应力混凝土轨道梁的工程设计与应用及有关规范的编制提供了依据和参考。
Based on 500 long-term tests of four 1: 5 urban light rail prestressed concrete track beam model, the properties of the prestressed concrete track beam were systematically studied and analyzed with emphasis on the influence of concrete types, the stress difference between the upper and lower edges of the cross section, Deformation, creep strain, cross-section curvature, steel stress and prestressing tendons and other effects. Based on the age-adjusted effective modulus method, the step-by-step method is followed with the finite element analysis program to analyze the whole process of the creep deformation of the track beam. The program is used to simulate the test results in this paper. The calculated values are in good agreement with the test results. Based on the analysis of the whole process and the American ACI 318-02, the creep of urban light rail track beam considering the concrete types, the prestressing tendon tensioning method, the ratio of reinforcing steel reinforcement and the stress difference between the upper and lower edges of the section is proposed. Deformation design recommendations. The research results provide the basis and reference for engineering design and application of China’s urban light rail prestressed concrete track girder and the preparation of relevant norms.