Fatigue damage failure behavior of steel bridge pavement under cyclic loading

Aiming at SMA, GA and EP mixtures double-layer pavement structure adopted commonly in steel bridge pavement engineering, theoretical analysis and tests were conducted for fatigue damage characteristics of steel bridge surface and asphalt concrete pavement under cyclic vehicle loads. Based on the fatigue damage degree, fatigue damage failure behavior of steel bridge pavement and dynamic evolution mechanism of damage field, stress and strain ones in fatigue cracking process were studied, and calculation expressions for damage, stress and strain fields during fatigue failure were deduced. The fatigue life theoretical formula for steel bridge pavement was derived. Steel box girder bridge pavements of Runyang Yangtze River Bridge 2005, Nanjing Yangtze River Third Bridge 2005 and Sutong Yangtze River Bridge 2008 were taken as examples, fatigue tests and predictions using the fatigue life theory were conducted for composite girders under different pavement structure combination schemes. The actual examples' study results showed that the prediction model for steel bridge pavement fatigue damage failure behavior is reasonable and feasible; compared with SMA and GA, EP has higher intensity and stronger low-deformation ability, and it is more suitable to meet anti-fatigue design requirements of long-span steel bridge pavement; the anti-fatigue performances of double-layer EP and "upper layer EP +lower layer GA" are superior to those of other pavement structure schemes, and their fatigue life is 1-2 times longer than other's with the same thickness; double-layer EP is applied in pavements of the three bridges mentioned above, these bridges' pavements operate successfully for more than 10 years, and their follow-up observation results are good. © 2020, Editorial Office of Journal of Vibration and Shock. All right reserved.