Advanced Steel Construction

Vol. 11, No. 3, pp. 383-394 (2015)


FATIGUE LIFE EVALUATION FOR CRACKED LONG-SPAN CONTINUOUS PC BRIDGES

 

Xin Ruan1, Hai-ying Ma2,* and Xue-fei Shi1
1 Department of Bridge Engineering, Email:
This email address is being protected from spambots. You need JavaScript enabled to view it. Tongji University, Shanghai, China.
2 ATLSS Center, Lehigh University, PA, USA
*(Corresponding author: E-mail:
This email address is being protected from spambots. You need JavaScript enabled to view it.)

 

DOI : 10.18057/IJASC.2015.11.3.11

 

ABSTRACT:

Long span pre-stressed concrete box girder bridges are widely constructed in China. Some typical deficiencies, such as unacceptable deflections and cracks in the concrete, often occur in those bridges with increasing service time. The deficiencies change the distribution of internal forces in the girders, which induces new problems, such as fatigue of reinforcements in the girders. In this paper, a fatigue life evaluation for a cracked long-span continuous PC bridges was conducted, which integrated weigh-in-motion (WIM) data and non-destructive examination (NDE) techniques. WIM data was used to investigate properties of vehicle load. The FE models of the cracked structure were developed to analyse the behaviour due to cracks. Various fatigue truck loads were considered in the models. Fatigue life evaluation based on real WIM data was developed to obtain the fatigue stress ranges due to the presence of cracks. Based on the analysis, the service life of the bridge was assessed before and after cracking at critical locations. A pre-stressed concrete box girder bridge, with three spans: 65m+100m+65m, was taken as an example to introduce the method. The present study provides better understandings of the post-cracking behaviour of long span continuous PC bridges. The outcome of this research can be efficiently utilized to reduce the risk of failure and achieve better management of the bridges.

 

Keywords:Continuous PC Bridge, Crack, Vehicular load, Fatigue life evaluation, Weight-in-motion, Stress range

 

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