客运专线大跨度PC连续箱梁桥收缩徐变研究

发布时间：2018-01-16 19:19

本文关键词：客运专线大跨度PC连续箱梁桥收缩徐变研究　出处：《中外公路》2015年06期 　论文类型：期刊论文

【摘要】：预应力混凝土连续箱梁桥的结构形式因其具有结构变形小、整体受力性能好等优点而被广泛应用,但是在桥梁运营阶段,梁体会因桥梁设计及施工过程中考虑收缩徐变不足而产生裂缝和不同程度的下挠现象。为了考虑混凝土收缩徐变对结构性能的影响规律,该文以青弋江客运专线预应力混凝土单箱三室连续梁桥为背景,通过有限元分析软件Midas/Civil对收缩徐变引起的主梁挠度、内力、钢束预应力损失进行对比分析。结果表明:混凝土收缩徐变引起主梁挠度增大,对中跨跨中附近影响尤其显著,考虑收缩徐变影响后主梁挠度变化曲线与实测值吻合度较好;混凝土收缩徐变导致主梁内力重分布,在成桥后前3年影响速率较大,以后逐渐趋于稳定;混凝土收缩徐变引起的钢束预应力损失,在跨中附近影响程度较大,在桥墩处影响程度较小;收缩徐变效应在成桥3年时已完成绝大部分。
[Abstract]:The structural form of prestressed concrete continuous box girder bridge is widely used because of its advantages of small deformation and good overall mechanical performance, but it is in the bridge operation stage. In order to consider the influence of concrete shrinkage and creep on the structural performance, the beam has experienced cracks and different degree of deflection due to the insufficient shrinkage and creep in the design and construction of the bridge. Based on the prestressed concrete single box three-room continuous beam bridge of Qingyijiang passenger dedicated Line, the deflection and internal force of the main beam caused by shrinkage and creep are analyzed by the finite element analysis software Midas/Civil. The results show that the deflection of the main beam increases due to the shrinkage and creep of concrete, especially in the middle span. After considering the effect of shrinkage and creep, the deflection curve of the main beam is in good agreement with the measured value. The shrinkage and creep of concrete lead to the redistribution of the internal force of the main beam, and the influence rate is larger three years before the completion of the bridge, and then it tends to be stable gradually. The prestressed loss of steel bundles caused by shrinkage and creep of concrete has a great influence near the middle span and a small influence on the piers. Most of the shrinkage and creep effects have been completed by the time of completion of the bridge for 3 years.
【作者单位】：江苏大学土木工程与力学学院;
【分类号】：U441;U445.7
【正文快照】： 随着中国经济和交通事业的迅猛发展,预应力混凝土连续箱梁桥以其结构刚度大、变形小、伸缩缝少、造型美观等优势而成为21世纪最具竞争力的桥型之一。由于受地形条件的约束,目前普遍采用分节段悬臂浇筑的施工方法,每个节段的完成包括混凝土的浇筑、预应力钢筋的张拉、挂篮的前

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