近海鹽霧區(qū)鋼筋混凝土圓形截面構(gòu)件承載力退化研究

谷音 李攀

摘要：基于半無限平板單元的平板擴(kuò)散模型常常直接被用來預(yù)測鋼筋混凝土圓柱開始腐蝕時(shí)間，而忽視截面形狀對(duì)氯離子擴(kuò)散的影響。采用考慮時(shí)變性及圓形形狀特性的擴(kuò)散方程，分析了近海鹽霧區(qū)圓形截面形狀對(duì)開始腐蝕時(shí)間的影響。分析結(jié)果表明，海岸線距離越遠(yuǎn)、半徑越小，采用平板擴(kuò)散模型高估開始腐蝕時(shí)間的現(xiàn)象越明顯。提出腐蝕鋼筋混凝土圓柱截面承載力計(jì)算模型，進(jìn)一步探討了半徑對(duì)不同服役期近海鹽霧區(qū)截面承載力退化率的影響。研究結(jié)果表明，隨著半徑的增大，鋼筋腐蝕對(duì)截面承載力的影響變小。當(dāng)混凝土圓柱暴露在重度鹽霧區(qū)時(shí)，可直接采用平板擴(kuò)散模型評(píng)估鋼筋開始腐蝕時(shí)間。為了控制采用平板擴(kuò)散模型所引起的退化率差值在5%內(nèi)，當(dāng)鋼筋混凝土圓柱暴露在輕度鹽霧區(qū)且半徑小60 cm時(shí)，需考慮形狀對(duì)開始腐蝕時(shí)間的影響，進(jìn)一步評(píng)估圓柱截面不同服役期截面剩余承載力。

關(guān)鍵詞： 鋼筋混凝土;圓柱;氯離子腐蝕;承載力;鹽霧區(qū)

中圖分類號(hào)：TU375.3 文獻(xiàn)標(biāo)志碼：A 文章編號(hào)：20966717（2020）04015311

收稿日期：20191014

基金項(xiàng)目：國家自然科學(xué)基金（51578157）;福建省科技計(jì)劃引導(dǎo)性項(xiàng)目（2009Y004）

作者簡介：谷音（1976 ），女，教授，博士生導(dǎo)師，主要從事橋梁防震減災(zāi)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