基于特征参量控制的渡槽预应力张拉顺序研究

为了得到合理预应力张拉顺序，提出利用特征参量指导预应力张拉的新途径。分别对矩形带肋和无肋渡槽及 U 形渡槽动力特性进行分析。结果表明：对于 U 形渡槽，竖向预应力和环向预应力明显降低结构整体刚度，但预应力效应并不改变振型出现的先后顺序；通过对矩形无肋渡槽6种预应力张拉顺序进行分析，得到合理的预应力张拉顺序为：先张拉40％纵向预应力，再张拉竖向预应力，然后张拉剩余的60％纵向预应力，最后张拉横向预应力。矩形无肋渡槽的这种张拉顺序不仅避免了竖向预应力对结构整体刚度的过大影响，而且能抵消结构早期由于自重产生的不利挠度。研究的渡槽预应力张拉顺序对构件力学性能改变的影响可降低到最小。

Research on Sequence of Prestressing Tension in Aqueduct Based on Characteristic Parameters

In order to obtain reasonable sequence of prestressing tension,we put forward a new way by using charac-teristic parameters to guide prestressing tension.Dynamic characteristics of rectangular aqueducts with rib and with-out rib,and U-shape aqueduct are respectively analyzed.The results show that,as for U-shape aqueduct,the vertical prestress and the circumferential prestress can obviously reduce the overall stiffness of the structure,but the pres-tressing effect does not change the order of mode of vibration.Through analyzing 6 kinds of sequence of prestressing tension for rectangular aqueduct without rib,we obtain a reasonable sequence:Firstly,prestress in the longitudinal direction is tensioned up to 40% of the maximum.Secondly,we tension the prestress in the vertical direction.Then, the rest of prestress in the longitudinal direction is tensioned.Finally,we tension the prestress in the transverse di-rection.This sequence of prestressing tension of rectangular aqueduct without rib can not only avoid the excessive influence of vertical prestress on the overall rigidity of the aqueduct,but also counteract the negative deflection due to gravity of the structure at early stage.Influence of this sequence of prestressing tension on mechanical properties of aqueduct is the smallest in comparison with other sequences.