A calculation method of thermal fatigue stress spectrum for flat steel girder box based on measurement data
Received:May 03, 2016  Revised:September 07, 2016
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DOI:10.7511/jslx201704011
KeyWord:bridge engineering  steel box girder  GEV model  LHS  temperature gradient fatigue stress spectrum
           
AuthorInstitution
张海萍 长沙理工大学 土木与建筑学院, 长沙
刘扬 长沙理工大学 土木与建筑学院, 长沙
邓扬 长沙理工大学 土木与建筑学院, 长沙
江楠 长沙理工大学 土木与建筑学院, 长沙
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Abstract:
      In order to analyze the thermal fatigue stress spectrum of a flat steel box girder,Nan-Xi Yangtze River bridge was taken as the research object.The temperature data of a steel box girder were collected from a structural health monitoring system (SHMS).Then,the daily temperature maximum values and minimum values were obtained.The seasonal temperature extreme value probability distribution was described by generalized extreme value (GEV) model and the GEV model for a design reference period was established.The method of Latin hypercube sampling (LHS) was introduced in this paper to sample temperature data.Hence,temperature time-history curve in the design reference period by combining temperature extreme sampling and sine function model was obtained.The equation of linear regression between temperature gradient and stress effect was obtained by a finite element analysis.The temperature fatigue stress spectrum of an observation point on the steel box girder can also be obtained based on temperature time-history curve and linear regression model.Research shows that the temperature samples produced by simulation agree with the feature of seasonal temperature change and the correlation between simulation sampling probability model and measured data probability model is good.The thermal fatigue stress spectrum can be used in fatigue life design of steel box girders.