Finite Element Analysis of Crack Arrest Technology on Weld end of the Vertical Rib in the Steel Bridge

The finite element analysis of crack arrest technology was carried out on weld end of the vertical rib in the steel bridge. Three kinds of finite element models, namely stop-hole, CFRP (Carbon Fiber Reinforced Plastics) reinforcement and stop-hole + CFRP reinforcement were established. The stress distribution of the crack section was analyzed and then the effects of crack arrest technology under various working conditions on fatigue performance of this detail were studied. Besides, the crack propagation of the weld end after crack arrest processing was researched based on the crack models established according to the crack path on real bridges. The result shows that the stress concentration on the crack tip is got rid of by the stop-hole technology while a new stress concentration point is created on the hole edge where the new crack may initiate; the lateral width increasing of the CFRP has little influence on the decline of SIF(Strength Intensity Factor)K_I if the crack has been fully covered by the CFRP; at the early stage of crack propagation, the joint action of stop-hole and CFRP reinforcement technology can dramatically decline the stress concentration coefficient of the crack tip, but it shares the similar crack arrest effects with that by using only CFRP reinforcement technology at the later stage.