Fatigue of rib-to-deck joints repaired by adhesively bonded patches: Tests and models

Rib-to-deck joints in orthotropic steel decks of bridges are known to be prone to fatigue cracks. Repairing such cracks allows for prolonging the life of the infrastructure, provided that structural safety is guaranteed. The fatigue performance of rib-to-deck joints repaired by adhesively bonded patches is experimentally and numerically studied. Two repair schemes, one including bonding patches on the top of the deck and the other one involving bonding patches between the bottom of the deck and the U-rib, are considered. The patch material, patch size, and load levels are varied. The experiments show that specimens repaired with large patch sizes and high Young's modulus have a longer residual fatigue life than similar specimens with small patch sizes and low Young's modulus. Specimens subjected to low load levels demonstrate better bonding behavior during the test than similar specimens subjected to high load levels. The residual fatigue life of the rib-to-deck joints before and after repair are derived from the tests. A finite element analysis reveals that a thicker patch gives a greater reduction of stress but debonding becomes more likely at the edge of the patch. This study provides guidance to the design and application of adhesively bonded patches in repairing rib-to-deck joints in orthotropic steel decks.