氯离子侵蚀下预应力混凝土桥梁抗弯承载寿命函数

发布时间：2018-03-31 18:02

本文选题：寿命函数　切入点：氯离子　出处：《江苏大学学报(自然科学版)》2015年02期

【摘要】：通过菲克第二定律和预应力钢丝局部蚀坑模型,运用蒙特卡罗方法分析了预应力筋的开始锈蚀时间和剩余面积变化规律;利用预应力筋锈蚀计算结果,分析了抗力退化情况;结合跨中弯矩效应时变规律,运用蒙特卡罗方法分析了结构正截面抗弯承载可靠概率在寿命期内的变化;利用威布尔型寿命函数拟合了可靠概率计算结果,二者显示出较好的相合性;对主梁高度、保护层厚度、氯离子质量浓度、扩散系数和腐蚀电流密度等对寿命函数的影响进行了参数分析.结果表明:增加梁高对耐久性能影响较小,保护层厚度对寿命函数影响较大,提高耐久性能应当针对环境氯离子质量浓度、扩散系数和腐蚀电流密度等因素制定措施.
[Abstract]:By means of Fick's second law and local corrosion pit model of prestressed steel wire, the variation law of the beginning corrosion time and residual area of prestressing tendons is analyzed by using Monte Carlo method, and the degradation of resistance is analyzed by using the results of corrosion calculation of prestressing tendons. Combined with the time-varying rule of moment effect in span, the variation of reliability probability of normal section under bending load during life cycle is analyzed by Monte Carlo method, and the results of reliability probability calculation are fitted by Weibull life function. For the height of the main beam, the thickness of the protective layer, the mass concentration of chloride ion, The effects of diffusion coefficient and corrosion current density on the life function are analyzed. The results show that the increase of beam height has little effect on the durability performance, while the thickness of the protective layer has a greater effect on the life function. The improvement of durability should be based on the environmental chloride concentration, diffusion coefficient and corrosion current density.
【作者单位】：同济大学土木工程学院;
【基金】：国家重点基础研究发展计划(973)项目(2013CB036300) 江西省交通厅重大科研项目(2012C0002)
【分类号】：U441;U448.35

【相似文献】