Laboratory Fatigue Evaluation of Replacement Orthotropic Deck for a Signature Bridge

Fatigue performance of the proposed replacement orthotropic deck for the upper level of a signature bridge was evaluated by full scale prototype testing. The proposed deck, comprising of trapezoidal ribs with full depth internal bulkheads and relatively shallow sub-floor beams with cutouts, was made integral with floor system and the stiffening truss that made the subfloor beam load bearing. Fatigue testing was conducted using hydraulic actuators loaded in sequence that simulated the passage of tandem axles. A finite element model of the deck was analyzed to understand the complex behavior of the deck and to develop design improvements based on Phase 1 studies. The refurbished deck was fatigue tested in Phase 2 to demonstrate its infinite life performance. The studies provided critical information on issues related to fabrication and deck installation, and facilitated a life cycle cost-effective design for more than 100 years' service life under site specific loading.