Fatigue Crack Behavior at Rib-To-Deck Weld Bead in Orthotropic Steel Deck

Abstract

One of the typical fatigue cracks observed in orthotropic steel deck is a through-thickness crack which penetrates and propagates along the weld bead. Moreover, according to some reports of the fatigue crack observed in some bridges, the fatigue crack sometimes changes its direction suddenly, and propagates to the rib wall and the deck plate. Such fatigue damage can cause the sudden decrease of stiffness of longitudinal rib. However, the propagation mechanism of the crack has not been investigated clearly. In this study, numerical studies on the through-thickness crack at rib-to-deck weld bead in the orthotropic steel deck were carried out. Finite element model (FEM) of an orthotropic deck with different through-thickness crack at rib-to-deck weld bead was created. In order to identify the propagation behavior of the fatigue crack, stress intensity factors for three deformation modes were estimated by the FE analysis (FEA) and the displacement extrapolation method. Based on the maximum energy release rate (MERR) criterion, the equivalent stress intensity factor and the crack direction were evaluated. From the numerical results, the crack direction change was found to be originated by the Mode II and Mode III deformation near the crack tip due to the out-of-plane bending of the rib wall along the crack.

Fatigue Life Evaluation of Orthotropic Steel Deck of Steel Bridges Using Experimental and Numerical Methods

“…The fatigue load range for this test is from 10 kN to 131.6 kN. When the cyclic loading times reach 50,000 times, 250,000 times, 500,000 times, 750,000 times, 1,000,000 times, 1,250,000 times, 150,000 times, 750,000 times and 2,000,000 times the machine is stopped for a static load test, the strain values and displacement values are measured, and the model is checked [25][26][27].…”

Load Test and Fatigue Life Evaluation for Welded Details in Taizhou Yangtze River Bridge

“…The orthotropic steel box girder suffers from complicated forces, and has many types of joints and structural details. The steel deck has a large flexibility, which is susceptibe to fatigue cracking under high cyclic stresses by wheel loads [Fu, Zhang, Wang et al (2014); Ju and Tateishi (2014)], which are really hard to repair. In recent years, the fatigue failure of orthotropic steel bridge deck has become increasingly prominent, which has been a hot spot [Zhu, Li, Tian et al (2017); Zhang, Cui, Bu et al (2015); Zhang, Bu and Qiao (2017)].…”

Experimental Study of Fatigue Crack Behavior of Rib-To-Rib Butt Welded Connections in Orthotropic Steel Decks

“…Out-of-plane bending results in high local flexural stresses in the welded joints between the connection plate and trough rib, because the plate and trough rib thicknesses are relatively small. The topic of fatigue resistance of OSDs, ever since the phenomenon of fatigue resistance first appeared in bridges (de Freitas, Kolstein and Bijlaard, 2011;Ju and Tateishi, 2014;Liu, Wang and Liu, 2015), has been deeply and rigorously investigated. In OSDs, the most widely-used rib-to-deck welded connections are also most fatigue-sensitive locations due to direct wheel loading, and many researchers have focused on this topic.…”