大直径无粘结预应力钢套筒混凝土涵管的试验研究

Experiment Study on Concrete Culvert Pipe with Unbonded Prestress Steel Sleeve of Large Diameter

通过试验,对无粘结预应力张拉施工中混凝土内钢绞线的应力、预应力损失和混凝土管壁中的应力分布,以及充水条件下混凝土管壁中的应力分布等问题进行了研究。试验结果表明,一端张拉时,预应力筋单圈布置管的预应力损失小于双圈布置管;预应力张拉完毕后,混凝土管环向形成闭合的压应力环,有效地提高了混凝土涵管的抗裂能力;张拉后管壁的抗拉强度远大于1.0MPa水压所产生的拉应力。

Through two prototype check bar, the prestress of steel strand in the concrete during unbonded prestress stretch-draw construction, prestress loss and prestress distribute in the concrete tube wall, as well as the prestress distribute in the concrete tube wall in full water are all researched. Result shows that, when one end being stretched, prestress loss of single circle prestressing tendon arrangement pipe is smaller than two circle tendon arrangement; after pulling construction, concrete pipe form close pressure loop, which can increase anti-crack performance of concrete culvert pipe; tensile strength more bigger than stress produced by 1,OMP hydraulic pressure.