Fatigue performance of a simply-supported T-beam UHPC bridge deck variable section joint structure

Abstract

A UHPC bridge deck joint structure is proposed herein in order to meet the requirements for the rapid construction of a multi-span concrete simply-supported T-beam bridge and long-term stress resistance of the bridge deck joint structure. Particular consideration is paid to the reasonable selection of high-performance materials to ensure the durable service of the variable section joint, to reduce the joint stiffness to match the beam end deformation demand, and to improve the crack resistance. To study the long-term mechanical properties and reliability of the beam structure in engineering application, full-scale segmental models of the bridge deck joint are constructed using either ultra-high performance concrete (UHPC) or steel fiber reinforced concrete (SFRC), and the two models are compared via material performance testing and fatigue testing. The test results show that the UHPC specimen does not crack under the full fatigue loading condition, and both specimens were subjected to a total of 2.84 million fatigue loading cycles without failure. The residual joint strength of the UHPC specimen is shown to be 1.8 times that of the SFRC specimen. The comprehensive test results and stress behavior analysis demonstrate that the UHPC variable section joint bridge deck structure can meet the long-term stress requirements.