基于超高性能混凝土组合桥面钢箱梁的混合梁钢与混凝土结合段受力性能仿真分析

对于某钢混凝土组合-混合连续箱梁桥，提出了跨中采用钢-超高性能混凝土（UHPC）组合梁、桥面板采用矮肋板的方案以减轻自重，钢-混结合段区域上表面再覆盖一层UHPC，从而形成超高性能混合梁。为重点研究钢-混结合段的受力性能，首先采用MIDAS/CIVIL桥梁专用有限元计算软件建立了连续箱梁桥的大尺度整体模型，以确定钢-混结合段的最不利受力工况及其具体的内力数值；随后采用ABAQUS建立了钢-混结合段的小尺度局部有限元模型进行精细化分析，以明确该区域钢、普通混凝土（NC）和UHPC的应力分布情况。计算表明该桥钢-混结合段的刚度能平稳过渡，钢、NC和UHPC的应力水平均较低，具有良好的安全储备，能够满足桥梁的受力要求。

Simulated Analysis on Mechanical Behavior of Steel-concrete Combined Segment of Composite Girder Based on Ultrahigh Performance Concrete Composite Deck Steel Box Girder

For a steel-concrete combined composite continuous box girder bridge, the scheme of using the steel-ultrahigh performance concrete (UHPC) composite beam in the middle of the span and using the low ribbed slab for the bridge deck is proposed to lighten the dead weight. A UHPC layer is covered on the surface of steel-concrete combined segment area so as to form the ultrahigh performance composite girder. In order to specially study the mechanical behavior of steel-concrete combined segment, the large-scale overall model of continuous box girder bridge is established by using the MIDAS/CIVIL bridge finite element calculation software to determine the most unfavorable stress conditions and the specific internal force numerical values of the steel - concrete combined segment. Then, ABAQUS is used to establish a small-scale local finite element model of the steel-concrete combined segment for the fine analysis so as to reveal the stress distribution of steel, ordinary concrete (NC) and UHPC in this area. The calculation results show that the stiffness of the steel-concrete combined segment of the bridge can be smoothly transited, the stress levels of steel, NC and UHPC are lower, which has the good safety reserves and can meet the stress requirements of the bridge.