Reinforcement Effect of Steel Plates After Cracking on Both Sides of Diaphragm-to-Rib Welded Joint in Orthotropic Steel Decks

Bilateral cracking would occur at weld toes on both sides of diaphragm-to-rib welded joints in orthotropic steel decks, which severely affects the safety of bridges. Previous studies mainly focus on the crack maintenance on one side of DU, ignoring the situation of bilateral cracking. By conducting fatigue tests, the local stress characteristics of DU reinforced by steel plates on both sides were analyzed and the influence degree of adhesive quality, reinforcement methods and parameters on the reinforcement effect was clarified. The reasonable size and thickness of steel plates were recommended by numerical simulation. The results demonstrate that the interaction between cracks can be effectively reduced after simultaneously carrying out reinforcement on both side of DU. Although the stress transmission of steel plate reinforced with adhesive is better than that by bolts, the reinforcement effect is greatly affected by adhesive quality, while for the bolt connection, the local stress of the reinforced area will still maintain a safe level in a period of time after secondary cracking. The thickness of the steel plate is recommended to be 2 mm less than the diaphragm, and the reinforcement area shall be fully covering the cracks to achieve a better reinforcement effect.