氯盐环境下预应力混凝土梁桥氯离子扩散效应及其空间概率分析  

Effect of Chlorides Diffusion and Its Spatial Probability Analysis of Prestressed Concrete Bridge Under Chloride Environment

作　　者：彭建新[1,2] 吴婷婷[1] 胡守旺[1] 张建仁[1] 邵旭东[3] 

机构地区：[1]长沙理工大学桥梁工程安全控制省部共建教育部重点实验室,湖南长沙410114 [2]里海大学土木与环境工程系,宾夕法尼亚伯利恒pa18015 [3]湖南大学桥梁工程研究所,湖南长沙410082

出　　处：《中国公路学报》2016年第4期50-58,共9页China Journal of Highway and Transport

基　　金：国家重点基础研究发展计划("九七三"计划)项目(2015CB057701);国家自然科学基金项目(51178060;51378081);交通运输部主干学科应用基础研究项目(2014319825160);湖南省教育厅优秀青年项目(15B015);广东省交通运输厅科技计划项目(科技-2014-02-016);桥梁结构安全控制湖南省工程实验室开放基金项目(14KD12);桥梁结构安全控制和耐久性评估的理论研究及工程应用团队建设项目(15YTD07);湖南省研究生创新省级项目(CX2015B344)

摘　　要：为了研究压应力状态下氯离子侵蚀规律,首先修正考虑环境温度、湿度、荷载效应、混凝土与氯离子结合效应以及混凝土自身劣化效应影响的氯离子扩散模型,接着进行压应力状态下试块的氯离子扩散试验,并将修正模型计算值与试验值进行对比来验证其适用性,最后考虑环境、材料参数的空间变异性,建立预应力混凝土梁桥开始腐蚀的空间可靠度模型,对一座服役5年的梁桥进行开始腐蚀概率预测。研究结果表明:提出的氯离子扩散修正模型预测值与试验和实桥实测值均吻合较好;不考虑空间变异性时,实桥考虑劣化效应的100年时的开始腐蚀概率是不考虑时的1.72倍,不考虑荷载效应的比考虑的高1.88%,混凝土与氯离子结合效应R1=0.89的开始腐蚀概率较R1=0.77和R1=0.85分别增加了2.71%和0.80%;考虑空间变异性并考虑劣化效应的要提高10.63%,考虑荷载效应和不考虑荷载效应分别提高10.58%和11.14%,当R1取0.77,0.85,0.89时分别提高10.76%、10.90%、9.43%。In order to investigate the chloride ions diffusion law in concrete under compressive stress condition,a modified chloride ion diffusion model was presented which took account of ambient temperature and humidity,load effect,binding effect of chloride ion and concrete,and deteriorating effect of concrete.Then an experiment of the chloride diffusion under pressure tress state was conducted and values calculated by the modified model and the test values werecompared to verify the applicability of the modified model.A spatial time-dependent reliability model of corrosion initiation for prestressed concrete bridge was established considering spatial variability of environmental and material parameters,and the probability of corrosion initiation was predicted for a bridge served for 5 years.The results show that the prediction value calculated by the modified model agrees well with experimental value and measured value.when considering spatial variability,the probability of corrosion initiation of the bridge in 100 years which considers deteriorating effect of concrete is 1.72 times than that without considering it,the probability of corrosion initiation which does not consider load effect is 1.88% higher than that considering it,and the probabilities of corrosion initiation are 2.71% and 0.80% higher than those under R1=0.77 and R1=0.85 respectively when the binding effect of concrete and chloride ion R1 equals to 0.89;when considering spatial variability,the probability of corrosion initiation which considers deteriorating effect of concrete increases 10.63%,the probabilities of corrosion initiation which considers and does not consider load effect increase 10.58% and 11.14% and the probabilities increase 10.76%,10.90%,9.43% when R1=0.77,0.85,0.89.

关 键 词：桥梁工程 氯离子扩散 修正模型 空间变异性 腐蚀概率 

分 类 号：U443.35[建筑科学—桥梁与隧道工程]