Development for New Performance of Structural Concrete Members by Using Fiber Reinforced Plastics

研究了FRP筋作为预应力混凝土电杆筋的适用性。预应力混凝土的开裂荷载、变形和破坏荷载可以用传统的预应力混凝土理论来预测。通过调整配筋量和预应力，破坏模式变为延性，FRP筋不断裂。传统理论也预测了徐变和干缩引起的预应力降低。虽然松弛量取决于FRP的类型，但通过使用每个值，传统的方程可能是适用的。平行捻绳（PLR）是一种由平行排列的纤维包裹在聚合物护套中的柔性绳状材料。研究了芳纶纤维PLR作为体外拉索的预应力钢筋混凝土梁的强度和变形性能。通过体外索加固裂缝发生后的钢筋混凝土梁，提高了梁的刚度和强度。由于拉索的应力由考虑梁塑性承载力的方程控制，破坏模式可以是延性的而不发生拉索断裂。在低温下的静力性能方面，虽然强度比常温下有所提高，但由于极限变形变小，塑性降低。低温疲劳强度试验结果表明，其主要失效形式为钢筋断裂。S-N曲线变为线性，JSCE方程高估了强度。

The applicability of FRP rods for tendons of pre-tension type PC poles has been investigated. The cracking load, deformation and failure load are capable to be predicted by the traditional theory of the prestressed concrete. Adjusting the amount of reinforcement and prestress, the failure mode becomes ductile without the break of FRP rods. The reduction of prestress by creep and drying shrinkage is also predicted by traditional theories. Though the amount of relaxation depends on the type of FRP,by using each value traditional equation may be applicable.Parallel lay rope (PLR) is a flexible rope-like material consists of a parallel array of fibers encased in a polymeric sheath. The strength and the deformation behavior of prestressed reinforced concrete beams with aramid fiber PLR as external cables were investigated. By strengthening the reinforced concrete beam after occurrence of cracks by external cables, stiffness and strength of the beam increase. As the stress of cables are controlled by the equation considering the plastic capacity of beam, the failure mode can be ductile without the break of cables. As for the static behavior under low temperature, though the strength increases compared with normal temperature, the ductility decreases because the ultimate deformation becomes small. As for the fatigue strength under low temperature, the failure mode is the break of reinforcements. The S-N curve becomes linear and the equation of JSCE overestimates the strength.