近海盐雾区钢筋混凝土圆形截面构件承载力退化研究

谷音 李攀

摘要：基于半無限平板单元的平板扩散模型常常直接被用来预测钢筋混凝土圆柱开始腐蚀时间，而忽视截面形状对氯离子扩散的影响。采用考虑时变性及圆形形状特性的扩散方程，分析了近海盐雾区圆形截面形状对开始腐蚀时间的影响。分析结果表明，海岸线距离越远、半径越小，采用平板扩散模型高估开始腐蚀时间的现象越明显。提出腐蚀钢筋混凝土圆柱截面承载力计算模型，进一步探讨了半径对不同服役期近海盐雾区截面承载力退化率的影响。研究结果表明，随着半径的增大，钢筋腐蚀对截面承载力的影响变小。当混凝土圆柱暴露在重度盐雾区时，可直接采用平板扩散模型评估钢筋开始腐蚀时间。为了控制采用平板扩散模型所引起的退化率差值在5%内，当钢筋混凝土圆柱暴露在轻度盐雾区且半径小60 cm时，需考虑形状对开始腐蚀时间的影响，进一步评估圆柱截面不同服役期截面剩余承载力。

关键词： 钢筋混凝土;圆柱;氯离子腐蚀;承载力;盐雾区

中图分类号：TU375.3 文献标志码：A 文章编号：20966717（2020）04015311

收稿日期：20191014

基金项目：国家自然科学基金（51578157）;福建省科技计划引导性项目（2009Y004）

作者简介：谷音（1976 ），女，教授，博士生导师，主要从事桥梁防震减灾研究，Email： cinoa@fzu.edu.cn。

Received：20191014

Foundation items：National Natural Science Foundation of China （No. 51578157）; Leading Projects of Science and Technology Plan of Fujian Province（No.2009Y004）

Author brief： Gu Yin （1976 ）， professor， doctorial supervisor， main research interests： sesimic design of bridge， Email： cinoa@fzu.edu.cn.

Bearing capacity degradation of reinforced concrete circular members at coastal atmosphere zone

Gu Yin， Li Pan

（College of Civil Engineering， Fuzhou University， Fuzhou 350108， P. R. China）

Abstract： The slab diffusion model based on semiinfinite slab element is usually used to estimate the time to corrosion initiation of RC （reinforced concrete） circular column exposed to coastal atmosphere zone， which ignoring the effect of the circular acrosssection. The diffusion model considering the diffusion coefficient as timedependent variable and the effect of circular acrosssection shape， the influence of the shape of circular RC column exposed at coastal atmospheric zone on the corrosion initiation time is analyzed. The results show that with the coastline increasing and the radius decreasing the overestimation of the corrosion initiation time by using the slab diffusion model is the more obvious. A model for calculating the bearing capacity of corroded reinforced concrete columns is presented， the effect of the radius value on evaluating the degradation rate of bearing capacity of the column at coastal atmosphere zone under different service periods is further discussed. The research results show that the increase of radius result in the reduction of the influence of corrosion on bearing capacity. In the scenario of the RC column located at heavy salt fog zone， the slab diffusion model can be directly used to evaluate the corrosion time. However， in order to control the degradation rate difference value caused by using slab diffusion model within 5%， the effect of shape on corrosion initiation time should be considered when this column is exposed to the light salt fog zone and the radius is less 60cm. And the residual bearing capacity of RC circular column with different service periods is further evaluated.

Keywords：reinforced concrete; circular column; chlorine ion corrosion; the erosion by chlorine ion; bearing capacity; saltspray zone