Dynamic analysis and fatigue assessment of bridge decks subjected to traffic and corrosion effects
Date
2013
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Abstract
Fatigue damage has become one of the most common degradation mechanisms of highway bridge decks, which is primarily caused by passing traffic. The increase of heavy traffic over recent years, especially those overweight trucks, further worsens the situation. In the mean time, highway bridges are subjected to various aggressive environmental conditions leading to serious corrosion problems. Corrosion problem, faced by millions of reinforced concrete structures worldwide, can cause deterioration of the reinforcing steel bars, cracks and spalling on the bridge deck surface. As the bridge deck surface deteriorates over time, the road surface roughness profile will vary accordingly. The varying surface roughness profiles over time will generate increased dynamic loads on the bridge decks through dynamic interaction between surface roughness, vehicles of stochastic traffic and bridge structures. The increased dynamic loads, coupled by the reinforcement deterioration of bridge deck due to corrosion, will further cause accelerated response and fatigue accumulations on the bridge deck. Such a nonlinear time-progressive process continues over time throughout the lifespan of the bridge deck, which has not been systematically characterized or studied. The present study aims to characterize the coupling effects between the time-varying dynamic loads from stochastic traffic, deterioration bridge decks due to corrosion, and bridge performance. To tackle such a problem, firstly, a hybrid FEM-based analytical strategy is developed for the bridge and stochastic traffic system considering the time-dependent corrosion process. Secondly, scenario-based numerical studies are conducted for the typical combinations of traffic, corrosion-induced reinforcement deterioration and associated surface profile variations. Finally, based on the numerical findings, the fatigue damage of the bridge deck over time is analyzed and the remaining life of the prototype bridge decks is assessed under the joint effect of corrosion and stochastic traffic.