Fatigue reliability assessment for bridge welded details using long-term monitoring data  

作　　者：DENG Yang DING YouLiang LI AiQun ZHOU GuangDong 

机构地区：[1]Key Laboratory of Concrete and Prestressed Concrete Structure of Ministry of Education, Southeast University, Nanjing 210096, China

出　　处：《Science China(Technological Sciences)》2011年第12期3371-3381,共11页中国科学（技术科学英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant Nos.50725828,50808041);Scientific Research Foundation of Graduate School of Southeast University (Grant No. YBJJ0923);Teaching and Research Foundation for Excellent Young Teacher of Southeast University

摘　　要：A reliability assessment method of fatigue life based on the long-term monitoring data is developed for welded details in steel box girder,and the application research is presented with examples of welded rib-to-deck details in Runyang Bridges. Firstly the fatigue damage limit-state function is established based on S-N curves and Miner's rule,and the probability distribution characteristics of the coefficients in the function are discussed in detail. The uncertainties in fatigue loading effects are mainly studied based on long-term monitoring data. In the traditional studies,only the uncertainty of equivalent stress range is considered in fatigue reliability assessment. However,stress cycle number is also treated as a random variable in this paper because we know traffic flow every day differs in a thousand ways. Then the optimization method is employed to calculate the fatigue reliability. After studying the changing law of the reliability indices with time and the effect of the randomness of stress cycle number on reliability,the effect of the traffic growth on the reliability is studied. This study shows that the uncertainty in the fatigue life of the welded details can be well studied based on structural health monitoring,so it is necessary to carry out long-term strain monitoring of the welded details for accurate fatigue reliability assessment during the whole service period.

关 键 词：steel box girder fatigue loading effects equivalent stress range stress cycle number fatigue reliability traffic growth 

分 类 号：U448.33[建筑科学—桥梁与隧道工程] O346.2[交通运输工程—道路与铁道工程]