STUDY OF DAMAGE EQUIVALENT FACTORS OF URBAN RAIL TRANSIT STEEL BRIDGE

To study the damage equivalent factors of urban rail transit steel bridge, the factors of Chinese urban rail transit steel bridge are analyzed based on the S-N curve and damage equivalent factor method in Eurocode. Six traffic types of urban rail transit applied to Chinese urban rail transit steel bridge are proposed, and three load diagrams, ZC, ZK and LM71, are selected as fatigue load models. According to the actual traffic volume of Chinese urban rail transit, a simplified calculation method using bi-linear S-N curve is proposed, which is compared with the methods using single slope S-N curve. Thus, damage equivalent factors of urban rail transit steel bridge are analyzed. To consider the characteristics of Chinese urban rail transit, an equivalent factor λ_v considering the maximum permitted vehicle speed is proposed. The results demonstrate that by taking diagram ZC as fatigue load model and considering influence of the maximum permitted vehicle speed, the damage equivalent factors based on the simplified bi-linear S-N calculation method can be reasonably applied to fatigue verification of Chinese urban rail transit steel bridge.