| 摘要 |
PURPOSE:To prevent explosion of prestressed concrete in an emergency by a method wherein tendons to be arranged in prestressed concrete are covered with covering layers that lose covering function at a specified level of the temperature. CONSTITUTION:The structure of a tendon is made by covering the exterior of the tendon 1 with thermoplastic resin 3. The tendon 1 is formed in a cord-like shape by intertwisting a number of high strength fiber materials and by intertwisting further a plurality of intertwisted fibers. The exterior of the cord- like tendon 1 is covered with a covering film 3 made of hard rubber or the like that loses covering function approximately at 100 deg.C. Then, reinforcements 9 are arranged in a prestressed concrete board 7 and the tendons 1 are arranged between the reinforcements. In the case where the temperature of the prestressed concrete 7 rises to a high level in the case of fire, the covering film 3 of the tendon 1 softens, deteriorating the strength in bonding to the concrete, and thereby explosion of the concrete can be avoided. |
