Fatigue Reliability Design Principle Research Of Prestressed-RPC High-speed Railroad Bridge

With the development of Bridge Engineering, it is gradually focused on the fatigue of bridge. RPC(Reactive Powder Concrete) has the property of high-strength, high-toughness and high-durability. Recently, the new material is beginning to be used in bridge construction. Although it is widely researched in RPC's anti-fatigue property, but there is little research about the RPC structures.Base on reliability principle, this paper summarized the productions on fatigue property research of the new material and researched the principle of RPC structure's fatigue design. The content of this paper is as follow:(1) Tested the distribution of RPC's fatigue life and fatigue strength, they are obey the normal distribution.(2) Referred to relative criterions, ascertained the basic fatigue parameters of RPC and steel. The parameters contain RPC's and steel's fatigue strength median, standard value, design value, reduction factor and coefficient of variation of fatigue strength.(3) Referred to relative criterions, ascertained the High-speed railway fatigue train and established the relative standard moment ratio spectrum. Compared the the relative standard moment ratio spectrum between High-speed railway and normal railway.(4) Analyzed the cross-section mechanical behavior of RPC bending structures. Based on reliability principle, proposed equivalent repeated stress partial factor principle of RPC structure. This principle can test reliability of fatigue capacity limit state. Proposed the optimal ratio between equivalent repeated stress and fatigue strength.(5) Based on the above conclusion, tested the middle-span cross-section reliability of fatigue capacity limit state of a 32m prestressed RPC T-shape beam with low height. Calculated the reliability index and partial factor. Proposed the target reliability index of High-speed railway and normal railway.