| 摘要 |
PURPOSE:To raise the impact strength of a prestressed concrete pile by a method in which a high-tensile steel wire having a specific carbon content value and a specific tensile strength value is spot-welded with a spiral iron bar under a fixed pressure and tempered to give a given rupture elongation value to the wire, and the wire is buried in concrete. CONSTITUTION:PC steel bars 1 having a 0.4 or less carong content and a 110kg/mm.<2> or more tensile strength are arranged at given intervals on a circumference, a spiral iron bar 2 is wound around the PC steel bars 1, the contact points of them are spot-welded under a fixed pressure, and the hardened layers formed in the PC steel bars 1 by the spot welding are tempered. In this case, the tempering process is so conducted that the rupture elongation of the PC steel bar 1 becomes 8.5% or more. Then, the iron bar cage thus formed is put in a formwork. The PC steel bar is tensioned, concrete is placed into the formwork and molded centrifugally, and after the concrete is hardened to a given strength, the concrete pile is removed from the formwork to obtain a prestressed concrete pile. |
