型钢开口肋-UHPC组合桥面板构造细节疲劳性能研究OA

Fatigue cracking of typical structural details can significantly cause fatigue resistance reduction of orthotropic steel bridge decks(OSDs)and shorten the service life.A hot-rolled section steel-ultra-high performance concrete(UHPC)lightweight composite bridge deck with open ribs(HSD),which was first used in the steel box girder of a long-span arch bridge,was taken as the research object.The refined three-dimensional finite element analysis models with mixed shell and solid elements for steel-box girder segment were established.Fatigue loading and theoretical analysis were conducted to explore the stress distributions and fatigue damage characteristics of typical fatigue-prone details,and to predict the fatigue life.The results indicate that rib-to-deck and rib-to-crossbeam welded joints are two types of critical structural details determining the fatigue performance of HSD.Each type of welded joints has multiple fatigue failure modes,and the stress distributions and fatigue performance of the welded joint corresponding to different failure modes have significant differences.Fatigue properties of the two types of welded joints are determined by the fatigue resistance of toe-deck failure and toe-crossbeam failure,respectively.When traffic growth is taken into account,the fatigue cumulative damage of each fatigue failure mode in the two welded joints increases significantly and exhibits representative nonlinear growth.By contrast,the rib-to-crossbeam welded joint has lower fatigue strength and a shorter fatigue life below the design life.This welded joint has a higher risk of fatigue cracking during the design service life.Therefore,the improvement of local structural details and more inspection and maintenance are needed to ensure the fatigue resistance and service safety of HSD.