Comparison of Characteristic of Fatigue Stresses in Steel Box-girders of Long Span Cable Bridges
Y. Wang, B. J. Wu, Z. X. Li
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College of Civil Engineering, Southeast University, Nanjing 210096, China
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History+
Received
Revised
Published
2008-04-08
2008-07-11
2009-02-25
Issue Date
2009-02-25
Abstract
The monitoring of fatigue stress is a key issue of structural health monitoring and safety assessment of long-span bridges. For a mass of data recorded by health monitoring system, daily data differ in thousands ways. Data in local period of time cannot reflect whole strain character and in different types of bridges such as a cable-stayed bridge and a suspension bridge, responses due to vehicle load and environment load are diverse. In order to acquire roundly actual running state and stress level, statistical analysis of vast data recorded is needed. This paper is aimed at investigating the feature of fatigue stress spectrum on the steel box-girders under service loading on the basis of strain history data recorded by structural health monitoring system installed on Runyang Suspension Bridge and Cable-stayed Bridge. The probability density function of fatigue damage increments of each bridge is simulated. The result of parameter estimation of half-year-samples shows that, relative accumulative damage increments are submitted to lognormal distribution in both bridges. In the same environment and vehicle loads, fatigue damage due to vehicle and temperature varying in suspension bridge is twice higher than that in cable-stayed bridge. Damage increments induced by strain history containing noise is twice higher than those after getting rid of noise, and damage increments coupling with temperature deformation goes beyond 30% of those without regard to temperature deformation. Therefore, controlling sternly impacts of noise and temperature deformation, and picking-up actual dynamic strain messages to evaluate fatigue state of long span cable bridges are needed.
Y. Wang;B. J. Wu;Z. X. Li.
Comparison of Characteristic of Fatigue Stresses in Steel Box-girders of Long Span Cable Bridges[J]. Journal of Vibration and Shock, 2009, 28(2): 86-91
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