单环预应力作用下混凝土压力管道受力分析研究

以弹性地基梁理论为基础，提出了无限长、半无限长和有限长预应力混凝土压力管道在单环预应力作用下的内力理论计算公式，并将计算结果与三维有限元分析结果进行了对比。得到了预应力筋束最大间距的计算方法，以保证压力管道各横断面能够建立相同均匀的预压应力；提出了预应力筋束分步张拉施工与荷载控制方法，以减小管壁混凝土的轴向次弯矩。研究结果对避免预应力张拉施工阶段在管壁混凝土内表面出现环形裂缝及合理进行预应力筋束布设等具有一定工程应用价值。

Theoretical analysis of prestressed concrete penstock under uni-ring-like prestress

Based on the elastic footing beam theory, the mechanical analytic solution of prestressed concrete penstock under the uni-ring-like axial loads is put forward, and the analysis is carried out to compare the results of theory calculating and finite element analysis. The formula is proposed to calculate the maximum distance of prestressed strands for ensuring the uniform distribution of prestressing along the penstock. The methods are suggested to determine the tensile steps and the tensile forces of prestressed strands for decreasing the secondary bending moment along the axial of the penstock. This research result is valuable to rational design of prestressed strands and can avoid the ring-like cracks of the inner concrete of the penstock.