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混凝土箱梁桥作为大中桥的主要桥型之一在中国应用广泛,具有诸多优点,但底板纵向裂缝是这种桥型最常见病害之一,对结构耐久性影响显著。该文采用数值方法,通过引入弥散裂缝模型和混凝土受拉软化模型研究了底板纵向裂缝的长度、深度和数量对箱梁整体受力性能的影响。结果表明:裂缝对所在跨的应力和挠度有一定的影响,而对其临跨影响不大;当纵向裂缝贯通箱梁时,对箱梁的受力性能影响较大;随着裂缝长度的增加,箱梁挠度持续增大;与裂缝的长度和深度相比,纵向裂缝的数量对箱梁的整体受力影响相对较小,但对底板的应力影响较大。
As one of the main bridge types of Dazhong Bridge, the concrete box girder bridge is widely used in China and has many advantages. However, the longitudinal cracks of the floor plate are one of the most common diseases of this bridge type, and have a significant impact on the structural durability. In this paper, the influence of the length, depth and number of the longitudinal cracks in the slab on the mechanical behavior of the box girder is investigated by introducing the numerical model and the model of the diffusion crack and the tension-softening of the concrete. The results show that the fractures have a certain influence on the stress and deflection across which they are located, but have little effect on the span of the span. When the longitudinal cracks penetrate the box girder, the influence on the mechanical properties of the box girder is greater. With the increase of the crack length , The deflection of the box girder continues to increase. Compared with the length and depth of the crack, the number of longitudinal cracks has a relatively small impact on the overall stress of the box girder, but has a greater impact on the stress of the floor slab.