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| Fatigue reliability assessment of simply supported bridges subject to impact of stochastic vehicle loads |
| Received:April 22, 2017 Revised:June 04, 2017 |
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| DOI：10.7511/jslx20170422001 |
| KeyWord:bridge engineering simply supported bridge vehicle-bridge coupled vibration fatigue reliability stochastic traffic flow road roughness condition traffic volume |
| Author | Institution |
| 罗媛 |
长沙理工大学 土木工程学院, 长沙 ;南方地区桥梁长期性能提升技术国家地方联合工程实验室, 长沙 |
| 颜东煌 |
长沙理工大学 土木工程学院, 长沙 |
| 袁明 |
长沙理工大学 土木工程学院, 长沙 |
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| Abstract: |
| In order to investigate the fatigue safety of simply supported bridges subject to dynamic impact of stochastic vehicles,a new approach was presented for fatigue stress spectrum simulation of bridges based on vehicle-bridge coupled vibration and stochastic traffic flow.The approach was subsequently applied to fatigue reliability assessment.Stochastic traffic flows were simulated based on highway bridge weigh-in-motion measurements.An interpolation response surface function of the equivalent fatigue stress range was approximated by a small size vehicle sample.Probabilistic model of the fatigue stress was built by the Gaussian mixture functions.The fatigue stress spectrum of a typical simply supported T-girder bridge with a span length of 25 m was simulated.The fatigue reliability of the bridge was estimated accounting for road surface degradation and traffic growth.Numerical results indicate that:the stress spectrum simulated by the stochastic traffic load model has the characteristic of a multi-peak distribution,and the fatigue stresses due to overloaded vehicles were included in the spectrum model.The amplification factor of the fatigue stresses is larger than the impact factor resulting from the impact effects of vehicles.As a result,for an average road surface case,the fatigue damage due to the vehicle impact will be underestimated by the impact factor evaluated according to the design specification.Road surface degradation and traffic growth significantly decrease the fatigue reliability of the bridge in service period.The impact effect of vehicle on the simply supported bridges due to road surface degradation cannot be neglected. |