氯離子侵蝕下預應力混凝土橋梁抗彎承載壽命函數(shù)
發(fā)布時間:2018-03-31 18:02
本文選題:壽命函數(shù) 切入點:氯離子 出處:《江蘇大學學報(自然科學版)》2015年02期
【摘要】:通過菲克第二定律和預應力鋼絲局部蝕坑模型,運用蒙特卡羅方法分析了預應力筋的開始銹蝕時間和剩余面積變化規(guī)律;利用預應力筋銹蝕計算結(jié)果,分析了抗力退化情況;結(jié)合跨中彎矩效應時變規(guī)律,運用蒙特卡羅方法分析了結(jié)構正截面抗彎承載可靠概率在壽命期內(nèi)的變化;利用威布爾型壽命函數(shù)擬合了可靠概率計算結(jié)果,二者顯示出較好的相合性;對主梁高度、保護層厚度、氯離子質(zhì)量濃度、擴散系數(shù)和腐蝕電流密度等對壽命函數(shù)的影響進行了參數(shù)分析.結(jié)果表明:增加梁高對耐久性能影響較小,保護層厚度對壽命函數(shù)影響較大,提高耐久性能應當針對環(huán)境氯離子質(zhì)量濃度、擴散系數(shù)和腐蝕電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.
【作者單位】: 同濟大學土木工程學院;
【基金】:國家重點基礎研究發(fā)展計劃(973)項目(2013CB036300) 江西省交通廳重大科研項目(2012C0002)
【分類號】:U441;U448.35
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