大跨度连续刚构桥悬臂施工期预应力损失及其对策探究安排

发布时间：2018-06-03 10:24

本文选题：预应力 + 损失　；参考：《公路工程》2017年05期

【摘要】：以重庆某高速公路跨沟大桥实际工程为研究对象,通过有限元分析方法,对连续刚构桥悬臂施工期预应力损失进行了研究。结果表明:随着混凝土加载龄期的增长,预应力钢筋各项预应力损失值逐渐减少,在实际施工过程中,加载龄期不可能无限延长,在进行大跨度预应力混凝土连续刚构桥的预应力筋损失值的控制时,需要确定合理加载龄期。通过施工期的有限元分析,加载龄期为7 d时较合适。在预应力损失所有项目中,占比重最大时摩擦损失,管道以及钢绞线成形质量间的摩擦是摩擦损失的主要起因。为了使施工的摩擦降到最低,就得控制管道成形质量以及合理的优化钢绞线穿束质量;预应力的损失可以通过合理的计算引申量来减少;另外为了减少预应力的损失还可以加强预张拉和持荷时间等。
[Abstract]:Taking the actual project of a highway crossing ditch bridge in Chongqing as the research object, the prestressing loss of cantilever of continuous rigid frame bridge during construction is studied by finite element analysis method. The results show that with the increase of the loading age of concrete, the prestressing loss value of prestressed bars decreases gradually, and in the actual construction process, it is impossible to prolong the loading age indefinitely. In order to control the loss of prestressed tendons of long-span prestressed concrete continuous rigid frame bridge, it is necessary to determine the reasonable loading age. Through the finite element analysis of the construction period, the loading age of 7 days is more suitable. Among all the items of prestress loss, friction loss is the main cause of friction loss when the proportion is the largest, and the friction between the forming quality of pipeline and steel strand is the main cause of friction loss. In order to reduce the friction of construction to the minimum, it is necessary to control the quality of pipeline forming and optimize the quality of steel strands, and the loss of prestress can be reduced by reasonable calculation of extension. In addition, in order to reduce the loss of prestress, pretension and load holding time can be strengthened.
【作者单位】：西安铁路职业技术学院土木工程系;长安大学理学院;
【基金】：中铁二十一局、中铁第一勘察设计院及西安铁路职业技术学院共同研究科研项目(XTZY15H01)
【分类号】：U445.4;U448.23

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