Assembly Component Reinforced Method Research For Deck Throughfatigue Crack In Rib-to-deck Welded Joints Of Steel Bridge Deck

Rib-to-deck welded joints which are prone to fatigue cracks are important fatigue details of orthotropic steel bridge decks.Fatigue cracks initiation from weld toe and weld root which extending to the direction of deck plate thickness in this detail could cause serious impacts to normal service performance of orthotropic steel bridge decks once those fatigue cracks penetrate through the deck plate,and those through fatigue cracks are also difficult to reinforce.Taking the deck through fatigue cracks of rib-to-deck welded joints of orthotropic steel bridge decks as the research object,assembly component reinforced methods are given.The key issues related to the assembly component reinforced methods for deck through fatigue cracks are studied.The main research work is as follows:(1)Fatigue crack reinforcement methods for rib-to-deck welded joints of orthotropic steel bridge decks are reviewed,characteristics and deficiencies of those reinforcement methods are studied.Based on this,the ideas of assembly component reinforced methods which are used to reinforce deck through fatigue cracks are given.Compared with the previous reinforcement methods,this method can realize the reinforcement of deck through fatigue cracks of steel bridge deck without interruption or short interruption traffic.(2)For the weld toe deck through fatigue cracks,reversed U shape assembly component can achieve the reinforcement of the weld toe deck through fatigue cracks.The length of reversed U shape assembly component has limited influence on the weld toe deck through fatigue crack reinforcement effect,it will no longer improve reinforcement effect when each side of reversed U shape assembly component exceeds the fatigue crack length 150 mm.Increasing the thickness of reversed U shape assembly component can enhance the reinforcement effect of this method.According to different length of through fatigue cracks,appropriate thickness of reinforcement members should be selected for reinforcement.(3)For the weld root deck through fatigue cracks,the method of bolting reinforcement steel plates on the deck plate near the through fatigue cracks can be used to reinforcement those through fatigue cracks.Different thickness reinforcement steel plates can be used to reinforce weld root deck through fatigue cracks,and the reinforcement effect will be further improved with the increase of the thickness of reinforcement steel plates.The longitudinal length of the reinforcement steel plates has little effect on the reinforcement effect.