作　　者： ; ; ; ;

机构地区： 中交四航工程研究院有限公司

出　　处： 《混凝土》 2013年第11期61-64,共4页

摘　　要： 为实现精细化施工,需考虑后张法预应力混凝土大直径管桩分批张拉过程有关预应力损失。以某改进型混凝土管桩张拉全过程的预应力损失发展为例,对多钢束分批次张拉工序造成的预应力损失和控制应力进行理论推导,并对由混凝土收缩徐变、钢筋应力松弛和桩端边界引起的预应力损失进行了试验和对比分析。结果表明:前次张拉的预应力在紧邻的后次张拉影响下损失最大,之后损失变化量趋于平缓,分批次张拉预应力损失率与理论结果相符;该类桩型分批次张拉应力损失率最大约10%;改进型管桩中与时间相关的预应力损失和有效预应力传递长度较规范设计值偏小。 The prestress loss relative to time and location of prestress tendons needs to be considered for refinement construction in post-tensioned prestress concrete cylinder pile.As an example of prestress loss development of the modified large diameter post-tensioned concrete pile, the formulas of prestress loss and construction control tensile force were derived, and the prestress loss relative to time and location were be tested in every step of batch prestressing.Result indicated that batch prestress loss have the same radio as that deduced the-oretically, and former batch prestress suffers greatest loss caused by the proximate tension, and suffers little loss affected by subsequent tension.The loss is more than 10% of control tension value under batches prestress tension process in this type of piles.Prestress loss rela-tive to time and the pretress transfer length are much less than the value in design codes.

关 键 词： 后张法 预应力混凝土大管桩 分批张拉 预应力传递长度

领　　域： [建筑科学]