超高性能混凝土（UHPC）加固桥面板界面约束机理研究

Research on Interface Constraint Mechanism of Bridge Deck Reinforced with Ultra-High Performance Concrete (UHPC)

摘要:

采用超高性能混凝土（UHPC）加固普通混凝土桥面板，结合面处存在较大的约束收缩作用。为研究约束机制，提出UHPC收缩时变公式，建立了UHPC-混凝土组合桥面板约束收缩有限元模型。数值模拟与试验数据具有较高的吻合度，验证了有限元分析的准确性。进一步通过有限元分析，研究了组合桥面板中应力应变的分布规律，以及不同因素对结合面约束作用的影响。结果表明：UHPC板中沿厚度方向越靠近交界面，普通混凝土的约束效应越强，收缩应变越小，约束应力越大；混凝土强度、尺寸效应、配筋率、UHPC板厚通过改变结构相对刚度，对交界面的相互约束产生影响。

Abstract:

The ultra-high performance concrete (UHPC) is used to reinforce the ordinary concrete bridge decks. There is a relatively large restrictive contraction effect at the joint surface. To study the contraction mechanism, the time-varying formula for UHPC shrinkage is proposed, and the finite element model of constrained shrinkage of UHPC-concrete composite bridge decks is established. The numerical simulation has a high degree of agreement with the experimental data, verifying the accuracy of the finite element analysis. The further finite element analysis is conducted to study the stress-strain distribution rule in the composite bridge decks and the influence of different factors on the restraint effect of the joint surface. The results show that in the UHPC decks, the closer to the interface along the thickness direction, the stronger the restraint effect of ordinary concrete, the smaller the shrinkage strain, and the greater the restraint stress. The concrete strength, size effect, reinforcement ratio and UHPC deck thickness affect the mutual constraints at the interface by changing the relative stiffness of the structure.