Abstract

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Title:: Fatigue Performance Monitoring and Assessment for Concrete Low-box Girder Bridge

Author(s):: GUAN Guo-dong; ZHAI Mu-sai; ZHANG Pei-jie ; WANG Chun-sheng; Xi’an Highway Research Institute

Keywords:: concrete low-box girder bridge; fatigue performance; service monitoring; traffic load; overload

Abstract:: Weigh-in-motion (WIM) system was adopted to monitor the fatigue loads of Yaoxian medium bridge in Shaanxi provincial road S305, and standard fatigue vehicle model for concrete bridges in Shaanxi province was determined based on recorded data. Dynamic strain monitoring technique was adopted to conduct continuous strain monitoring of key positions on concrete lowbox girder, acquiring the real stress spectrum under service situation. Moreover, the fatigue life assessment of structures was carried out by using Miner linear criterion and stress amplitudecycle number curve. The results show that the fatigue life of concrete lowbox birder is 5 120 years under the present traffic load, and the fatigue life decreases to 254 years when taking into consideration of fatigue corrosion. Under overload situation, when the ratio of overload vehicle belows 1%, the influence is little; when the ratio reaches 10%, the fatigue life of structures will decrease sharply with increasing of the overload ratio. Research achievement can provide technical support for the future management and maintenance of Yaoxian medium bridge, and provide reference for fatigue life assessment of other similar bridges.