Although there are many literatures about effects of temperature on bridge structures' frequencies and related statistical methods,few studies reflect dynamic performance and time-varying frequency characteristics of bridge structures under the combined action of multi-environmental factors.Adopting the co-integration theory with the ability to quantify the long term balance relationship among multiple non-stationary sequences,a 3-span RC bridge model under natural environment were monitored and analyzed continuously,a model for long-term balance of temperature-humidity-frequency based on the co-integration theory was established to study the comprehensive effects of temperature and humidity on the bridge's frequencies.The results demonstrated that the established model has a better fitting precision and a predictive ability,it can fully reflect essential characteristics of influences of temperature and humidity on bridge frequencies;based on this co-integration model,the bridge frequency modification model considering effects of multienvironmental factors is proposed to effectively eliminate effects of temperature and humidity on bridge frequencies,and accurately reveal bridge's dynamic feature variation due to structures' internal causes,it can provide effective information for bridge damage diagnosis and safety assessment.%环境温度和湿度效应及其变化导致工程结构的模态参数有明显的波动和时变特性;目前关于温度对桥梁频率影响和相关量化统计方法并不能完全反映多环境因素综合作用下的结构动力性能和时变频率特性.利用协整理论能够量化多个非平稳序列之间长期均衡关系的能力,对自然环境下三跨混凝土桥梁模型的长期监测及数据分析,建立了基于协整理论的“温度—湿度—频率”长期均衡模型,研究了温度和湿度对结构频率的综合影响.结果表明该模型具有较好的拟合精度和预测能力,能充分反应环境温度和湿度对结构频率影响的本质特征;基于该协整模型,进一步提出了考虑多环境因素影响的桥梁频率修正模型,有效剔除环境温度和湿度对频率的影响,准确展现结构内因引起的动态特性改变,为桥梁损伤诊断和安全评估提供有效信息.
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