ABSTRACT
Ultra-High Performance Fiber Reinforced Cementitious composite material (UHPFRC) is an optimal choice for bridge engineering, with high tensile and compressive resistance, fine compactness, favorable fluidity, low fatigue loss, and creep coefficient. In this paper, the UHPFRC layer combined with cold connectors was developed on top of the orthotropic steel deck (OSD) as UHPFRC-OSD composite structure, expecting to reduce the stresses in critical fatigue details of OSD and improve the durability of pavement. The composite action between the UHPFRC layer and steel deck plate is realized by epoxy resin gluing of connectors on the steel plate or by epoxy glued at the interface between steel and UHPFRC, thus avoiding fatigue details of welding shear connectors used in the construction stage. Fatigue vulnerable welded details are avoided when the OSD plate is stiffened by the UHPFRC layer, leading to enhanced performance and longer fatigue duration. Based on material property test results, material laws of UHPFRC were determined in both compression and tension. Finite element model (FEM) was built for a full-scale UHPFRC-OSD composite bridge deck to analyze the stress level at fatigue vulnerable details and the improvement of local stiffness. Finite element analyses results showed that a thin UHPFRC layer combined with the cold connectors could effectively improve the local stiffness of the steel plate more than 8 times.
