Fatigue behavior of orthotropic composite deck integrating steel and engineered cementitious composite

Orthotropic steel decks offer many advantages in bridges, but they are prone to fatigue damage. One of the effective approaches to increase the fatigue resistance is to enhance the stiffness through applying a concrete layer, forming a composite section with the steel deck. However, once the concrete is cracked, the composite action is compromised. To improve the fatigue resistance, this study proposes a composite deck using engineered cementitious composite (ECC) and large U-ribs through experimentation and simulations. Two full-scale composite decks were tested to investigate the fatigue resistance and failure process, and validate a finite element model that was used to elucidate the effect of ECC on the fatigue performance. The test results showed that the composite deck had sufficient fatigue resistance, and the analysis results showed that the ECC overlay reduced the stress range by 90% at the rib-to-deck and diaphragm welded joints and 54% at the rib-to-diaphragm welded joints. One interesting finding is that the proposed deck has a robust fatigue resistance even after damages were caused in the deck system. This study is expected to advance the knowledge of the effect of ECC on the fatigue resistance, understand the underlying mechanisms, and promote further research and potential applications of the proposed composite deck.