Analysis Of Influence Of Vehicle Overload On Fatigue Reliability Of RC Bridge

Reinforced concrete bridge is a common structural in road bridge and railway bridge, it have been widely applied in small span highway bridges due to its simple structure, easy to produce, cost economics, etc.. In China, due to the design standards is lagging behind, and the pursuit of maximizing the economic benefits of highway bridges lead to vehicle overloading phenomenon exists objectively. Engineering practice shows that:although an accidental overload not necessarily to cause significant structural damage to the bridge, but the effect of repeated overload will exacerbate fatigue damage type structure, increasing the risk of failure, shorten the life of bridge, improve maintenance costs. Therefore, the study overloading operator fatigue damage under the law of the bridge and safety assessment has important practical significance.First, the basic concept of structural reliability, common calculation method, the analysis method of fatigue problems and three fatigue Reliability Analysis Model have introduced in this article, for subsequent analysis and calculation of reinforced concrete bridges overloading effects of fatigue reliability provides a theoretical basis for the work. Then, Starting from the method of standard, analysis of the relationship between vehicle overloading and fatigue reliability, fatigue life. Finally, based on traditional model of cumulative fatigue damage and standard fatigue vehicles of British BS5400 then taking a typical 20m span reinforced concrete bridge as the engineering background, to study the overloaded vehicles effect on the fatigue reliability of reinforced concrete bridge and the time-variant law of the fatigue reliability is studied in detail with the consideration of vehicle overload and traffic growth and its fatigue life. The results show that the higher level of overload the detail fatigue reliability will more lower and the probability of fatigue failure will more greater; Taking vehicle overloaded with traffic growth will greatly shorten the fatigue life of the bridge, compared to only consider the vehicle overload, the details of the service post-fatigue reliability will dramatically reduce the risk of fatigue failure will increase significantly in period of bridge design reference and fatigue life will be greatly reduced.