l简介凹螺纹钢筋是日本高周波热炼株式会社开发的一种低碳热处理局强度予应力混凝土钢筋。强度可高达1422MPa，延伸率不低于5％，主要用于管桩的制造，还可用于江河桥梁，大跨度桥梁及高层建筑等。其形状特点为：3条（或6条）凹形槽呈螺旋状均布于钢筋的表面。这样，可在不降低 l INTRODUCTION Concave-screw rebar is a kind of low-carbon heat treatment strength prestressed concrete reinforcement developed by Japan High Frequency Thermal Processing Co., Ltd. The strength can be as high as 1422MPa, and the elongation is not less than 5%. It is mainly used for the manufacture of pipe piles, and it can also be used for river bridges, long-span bridges and high-rise buildings. Its shape is characterized by: 3 (or 6) concave grooves are spirally distributed on the surface of the steel bar. In this way, it can be reduced without lowering