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后张法预应力梁制孔的方法有预埋铁皮管及抽芯法两种。在抽芯法中多使用有弹性的管材内加衬棒以防止管材压扁。采用这些方法,不论在质量上、经济上、材料供应上、施工操作上,存在一定的缺点: 1.预埋铁皮管:需用大量铁皮,不经济,弯道部分制作与安装,均很困难,且大梁容易产生裂缝。 2.使用有弹性管材内加衬棒抽芯法:在抽拨过程中是靠管材拉细,管皮与混凝土剥离后拔出,这样管材就必须有足够的弹力与强度(现在虽有弹簧钢丝管及钢丝网胶管能满足弹力与强度的要求,但生产数量不多,采购不易,单价也高)。另外由于衬棒不能与管
Post-tensioning method of prestressed beam hole with embedded metal pipe and core pulling two. In the core pulling method, the use of flexible pipe lined with more to prevent pipe flattening. Adopting these methods, there are some shortcomings in terms of quality, economy, material supply and construction operation. 1. It is very difficult to pre-cover the metal pipe: a large amount of metal is needed, and the production and installation are not economical and the corners are difficult , And the girders prone to cracks. 2. The use of flexible pipe liner lining core pulling method: In the pumping process is by pipe thinning, pipe skin and concrete stripped and pulled out, so that the pipe must have sufficient elasticity and strength (although now the spring wire Tube and steel mesh hose to meet the elastic and strength requirements, but the production of small quantities, procurement is not easy, the unit price is also high). In addition due to the liner can not be with the tube