超高性能混凝土（UHPC）与钢桥面板组合是增加桥面刚度、减少疲劳损伤的有效途径，同时还具有自重轻，韧性好等优点。但两者间的连接构造也会约束UHPC自由收缩，设置不当将增大桥面板次应力及开裂风险，影响长期性能。本项目基于前期研究提出具有收缩弱约束特点的自然养护UHPC后结合组合桥面板，首先在钢桥面上设置短焊钉群，浇筑除群钉孔外的UHPC，待自然养护下早期收缩基本完成后，再浇筑群钉孔完成组合。与预制装配不同，后结合无需大量设置桥面接缝。目前后结合UHPC组合桥面板的收缩抗裂及受力机理，计算原理等还有待总结。本项目通过桥面板长期静置收缩试验与数值模拟归纳后结合对桥面板收缩的影响规律；通过荷载试验及非线性参数化有限元分析揭示桥面板及连接构造的静力与疲劳受力机理；最后通过总结试验和有限元分析结果并结合力学推导明确桥面板受力计算原理。研究成果将为基于UHPC力学特性的桥面板长期性能提升提供理论支撑。

Combining ultra-high performance concrete(UHPC) to a steel deck is effective to increase the deck stiffness and reduce the fatigue damages with light self-weight and favorable toughness. But the connection between them may restrain the UHPC shrinkage, and hence increase the deck secondary stress and cracking risk. This is not good to the structural long term performance. Based on the proposer’s research findings, this research proposes a kind of post connection normally cured UHPC composite deck which has the low shrinkage constraint feature. The studs are arranged in groups on the steel deck as shear connectors. UHPC is cast at places without group studs at first for avoiding the shrinkage constraint in the early period, and the places with group studs are cast afterwards to achieve the composite action. This is different from a prefabricated composite deck which includes many slab connection details. So far, the shrinkage crack resistance and mechanical mechanism of the post connection UHPC composite deck is not clear enough, and the evaluation principal has not been established yet. This research will use long term standing shrinking tests and simulations to investigate the influence of post connection operation on the composite deck shrinkage response. Meanwhile, loading tests as well as nonlinear parametric FEM analysis will be utilized to understand the static and fatigue mechanism of the deck and the connection detail. Finally, the mechanical evaluation principal will be derived by the test and analysis results together with the theoretical deductions. The research outcomes will provide a theoretical support to the improvement of long term deck performance by the mechanical feature of UHPC.