考虑空间变量的氯盐环境下RC简支梁桥失效概率分析

发布时间：2018-05-05 22:02

本文选题：RC梁桥 + 空间变量　；参考：《土木工程学报》2014年12期

【摘要】：桥梁结构常规失效概率计算主要集中在关键截面,但在腐蚀环境下,蚀坑分布具有空间特征,关键截面可能随之发生变化。因此,基于一维随机场理论,考虑混凝土强度、混凝土表面氯离子浓度以及扩散系数等参数的空间分布特性,使用平方指数自相关函数,建立氯盐环境下RC简支梁桥的空间时变可靠度模型,计算腐蚀环境下的结构失效概率。通过将荷载场、材料场和腐蚀介质场离散为随机变量,合理选取的相关长度d和波动系数θ,结合空间均值法,计算了氯盐环境下简支RC梁桥服役期的随机失效概率。研究表明:考虑参数空间特征时的RC梁桥失效概率比不考虑空间分布特征时高18%,寿命期超载作用导致桥梁结构失效概率是正常运营条件下的6倍,因此需要严格管理车辆荷载,延长桥梁服役寿命。
[Abstract]:The conventional failure probability calculation of bridge structure is mainly focused on the critical section, but in the corrosion environment, the distribution of the corrosion pit has the spatial characteristics, and the key section may change with it. Therefore, based on one-dimensional random field theory, the spatial distribution characteristics of concrete strength, chloride concentration on concrete surface and diffusion coefficient are considered, and the square exponent autocorrelation function is used. The spatial time-varying reliability model of RC simply supported beam bridge under chloride environment is established and the failure probability of RC simply supported beam bridge under corrosion environment is calculated. By discretization of load field, material field and corrosion medium field into random variables, reasonable selection of correlation length d and fluctuation coefficient 胃, combined with space mean method, the random failure probability of simply supported RC beam bridge in chloride environment is calculated. The results show that the failure probability of RC beam bridge considering the spatial characteristics of parameters is 18 times higher than that of the bridge without spatial distribution, and the failure probability of bridge structure caused by overloading of life cycle is 6 times higher than that under normal operation condition, so it is necessary to strictly manage the vehicle load. Extend the service life of the bridge.
【作者单位】：长沙理工大学省部共建桥梁工程安全控制教育部重点实验室;
【基金】：国家自然科学基金(51178060,51378081) 交通运输部主干学科应用基础研究项目(2014319825160) 中国博士后科学基金(2014M552127) 国家重点基础研究发展计划(2015CB057700)
【分类号】：U441;U448.217

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