Stress Analyses and Parametric Study on Full-Scale Fatigue Tests of Rib-to-Deck Welded Joints in Steel Orthotropic Decks

Abstract

Fatigue tests of full-scale orthotropic steel decks were recently conducted to evaluate the fatigue performance of rib-to-deck partial-joint-penetration (PJP) groove welded joints. The test results indicated that rib-to-deck joints are more prone to fatigue cracks in the deck plate than in the rib wall. A shallower weld penetration (for example, an 80% PJP) also appeared to have a slightly higher fatigue resistance than a deeper one (for example, a 100% weld penetration). These PJP welds were also more vulnerable to cracking initiated from the weld toe than from the weld root. Finite-element analyses of the test specimens, using the effective notch stress method, were performed to supplement the laboratory testing and provide additional information on the behavior of these welded joints. The analysis results showed a good correlation with the observed crack patterns. A parametric study also showed that the fatigue resistance of the PJP joint can be significantly influenced by the transverse loading location, deck plate thickness, and the weld penetration ratio. Increasing the deck plate thickness was effective in reducing the stresses, while the rib wall thickness had a little effect. A shallower weld penetration at the PJP joint appeared to have a positive effect in enhancing the fatigue resistance.