温度对大型桥梁模态频率的影响研究  

Effects of Temperature on Modal Frequencies of Large Bridge

作　　者：张通 

机构地区：[1]三门峡市公路局,三门峡472000

出　　处：《武汉理工大学学报》2011年第7期94-100,共7页Journal of Wuhan University of Technology

基　　金：国家自然科学基金重点资助项目(50538020)

摘　　要：为了分析温度对大型桥梁模态频率的影响程度及规律,在桥梁的长期监测中,寻找一种直观、准确、具有可操作性的方法,以预测、滤除温度对模态频率的影响。以桥梁结构的温度及温差分布作为输入矢量,以模态频率作为输出矢量,建立了基于单截面温度分布和多截面温度分布的两个BP神经网络模型,进行拟合及预测效果的对比分析。结果发现,两模型均对模态频率进行了较好地预测、拟合,具有较强的泛化能力。基于多测面温度分布的神经网络模型,预测效果更好,平均相对偏差仅略大于千分之一。因此,温度分布、变化对桥梁模态频率有显著影响,BP神经网络模型能较好地拟合、预测频率随温度的变化,温度沿桥梁纵向分布的差异对模态频率的影响不可忽略。In order to analyze the effects and regularity of modal frequencies due to temperature changes,and find out a directive,accurate and operative method to predict and filter this effect in the long term monitoring of bridges,this paper designs two BP neutral network models,in which temperatures of bridge structure and frequencies are taken as input elements and output elements,respectively.The two models are respectively based on single section and multi section temperature distribution,to contrastively analyze their fitting and prediction effects.It is found that the two models all accurately predict and fit the modal frequencies and have better expanding performance.The better predict effect of the neutral network model can be obtained based on the multi section temperature distribution,the relative error is only more than 0.1%.The distribution and changes of temperature have obvious effects on modal frequencies of bridge.BP neutral network models can accurately fit and predict the changes of frequencies along with temperature changes.The influence on modal frequencies by the distinction of temperature longitudinal distribution along the bridge can not be ignored.

关 键 词：桥梁 温度 神经网络 模态频率 健康监测 

分 类 号：U446.2[建筑科学—桥梁与隧道工程]