Φ７高强预应力钢丝管桩技术经济分析丰台桥梁厂钱树青丰台桥梁厂在１９６６年研制预应力混凝土管桩时，可以选择的预应力钢筋有两种：一是Φ１２热轧Ⅳ级螺纹钢；另一种为Φ５ｍｍ预应力高强钢丝。后者虽很适合作预应力筋，但当时镦头工艺没有解决，对法兰桩配筋也嫌麻烦... Φ7 high-strength prestressed steel pipe pile technical and economic analysis Fengtai Bridge Qianqin Qingfengtai bridge plant in the development of prestressed concrete pipe piles in 1966, there are two kinds of prestressed steel can be selected: First, Φ12 hot rolled Ⅳ grade rebar; The other is Φ5mm prestressed high-strength steel wire. Although the latter is suitable for prestressing tendons, but at the time did not solve the heading process, the flange pile reinforcement also find it troublesome ...