Papers by Keyword: Welded Bridge Members

Abstract: The crack growth behavior and the fatigue life of welded members with initial crack in bridges under traffic loading were investigated. Based on existed fatigue experiment results of welded members with initial crack and the fatigue experiment result of welded bridge member under constant stress cycle, the crack keeps semi-elliptical shape with variable ratio of a/c during crack propagation. The calculated method of the stress intensity factor necessary for welded bridge member crack propagation was discussed. The crack remained semi-elliptical shape with variable ratio of a/c during crack propagation. The fatigue crack propagation law suitable for welded steel bridge member fatigue crack propagation analysis was deduced based on the continuum damage mechanics and fracture mechanics. The proposed fatigue crack growth model was then applied to calculate the crack growth and the fatigue life of existed welded member with fatigue experimental result. The calculated and measured fatigue life was generally in good agreement, at suitable initial conditions of cracking, for welded member widely used in steel bridges.

Abstract: The behavior of crack growth with a view to fatigue damage accumulation on the tip of cracks is discussed. Fatigue life of welded components with initial crack in bridges under traffic loading is investigated. The study is presented in two parts. Firstly, a new model of fatigue crack growth for welded bridge member under traffic loading is presented. And the calculate method of the stress intensity factor necessary for evaluation of the fatigue life of welded bridge members with cracks is discussed. Based on the concept of continuum damage accumulated on the tip of fatigue cracks, the fatigue damage law suitable for steel bridge member under traffic loading is modified to consider the crack growth. The proposed fatigue crack growth can describe the relationship between the cracking count rate and the effective stress intensity factor. The proposed fatigue crack growth model is then applied to calculate the crack growth and the fatigue life of two types of welded components with fatigue experimental results. The stress intensity factors are modified by the factor of geometric shape for the welded components in order to reflect the influence of the welding type and geometry on the stress intensity factor. The calculated and measured fatigue lives are generally in good agreement, at some of the initial conditions of cracking, for a welded component widely used in steel bridges.