环境温湿度对钢筋混凝土主拱圈应力重分布的影响研究

Study on Influence of Environmental Temperature and Humidity on Stress Redistribution of Main Reinforced Concrete Arch Ring

摘要:

针对现有规范中的不足，对比研究了变化温湿度收缩徐变模型和《公路钢筋混凝土及预应力混凝土桥涵设计规范》中的恒定温湿度收缩徐变模型下主拱圈截面应力重分布，建立空间实体单元模型与梁单元模型，并研究了普通钢筋对主拱圈截面应力重分布的影响。结果表明：变化温湿度模型结果更加精确。随着收缩徐变的进行，主拱圈截面上、下缘应力逐渐减小，当考虑普通钢筋时，截面应力进一步减小，考虑普通钢筋时主拱圈截面应力最大下降7.6%，表明普通钢筋对截面应力重分布有显著影响。从多尺度的角度对比梁单元模型和实体单元模型应力的空间分布，由于宽桥空间效应更加明显，普通的梁单元模型已经不能满足验算的精度要求，所以宽桥应采取梁格模型甚至实体单元分析来保证结果的精度。

Abstract:

According to the shortcomings of the existing codes, a comparative study is made on the stress redistribution of the main arch ring section under the varying temperature and humidity shrinkage creep model and the constant temperature and humidity shrinkage creep model in Code for Design of Highway Reinforced Concrete and Prestressed Concrete Bridges and Culverts. The spatial solid element model and the beam element model are established to study the influence of common steel bar on the stress redistribution of the main arch section. The results show that the result of the varying temperature and humidity model is more accurate. With the progress of shrinkage and creep, the stress on the upper and lower edge of the main arch ring section gradually decreases. When the common steel bar is considered, the section stress further decreases, and when the common steel bar is considered, the maximum stress of the main arch ring section decreases by 7.6%. It shows that the common steel bar has a significant effect on the stress redistribution of the section. Comparing the spatial distribution of stress between the beam element model and the solid element model from a multi-scale point of view, the spatial effect is more obvious because of wide bridge. The ordinary beam element model can no longer meet the accuracy requirements of checking calculation. Therefore, the grillage model or even the solid element analysis should be adopted for the wide bridge to ensure its accuracy of the results.