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【目的】研究混凝土自锚式悬索桥超宽加劲梁在施工过程中的应力分布规律,为超宽加劲梁的设计与施工提供一定的理论依据。【方法】采用剪力柔性梁格法,通过Midas/Civil建立空间有限元梁格模型,对自锚式悬索桥加劲梁受力性能进行分析。【结果】在施工过程中,加劲梁横截面各腹板处顶、底板中纵向应力的分布存在较大的不均匀性,预应力张拉工况中,加劲梁外侧边腹板处压应力最大;体系转化工况中,中腹板处压应力增量最大。体系转换过程中加劲梁顶、底板的应力变化规律不同,顶板中的压应力值在体系转换完成后达到最大,底板最大压应力值则出现在体系转换过程中。施加二期恒载,对吊索进行被动张拉,能够有效地减少主动张拉吊索过程产生的顶、底板应力差值。【结论】主缆轴力与预应力作用是造成加劲梁内应力分布不均的主要原因,通过调整预应力钢束的数量及位置,能够使加劲梁内应力分布更均匀。
【Objective】 The stress distribution law of the ultra-wide stiffening girder of concrete self-anchored suspension bridge during construction is studied to provide some theoretical basis for the design and construction of the ultra-wide stiffening girder. 【Method】 The finite element model of the beam was established by Midas / Civil using the flexible shear-beam method, and the mechanical behavior of the stiffening girder of the self-anchored suspension bridge was analyzed. 【Result】 In the process of construction, the distribution of longitudinal stress in the top and bottom plates of the cross-section of the stiffening girder has a large non-uniform distribution. In the prestressed tensioning condition, the compressive stress Maximum; system transformation conditions, the maximum increase in the stress at the web. In the process of system transformation, the stress variation law of the top and bottom of stiffened girder is different. The compressive stress value in the top plate reaches the maximum after the system conversion, and the maximum compressive stress value of the bottom plate appears in the system conversion process. Applying the second stage dead load and passive pulling the sling can effectively reduce the stress difference between the roof and the floor caused by the active tensioning sling. 【Conclusion】 The main cable axial force and prestressing effect are the main causes of uneven stress distribution in the stiffening girder. By adjusting the number and position of the prestressing steel strands, the stress distribution in the stiffening girder can be more uniform.