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一、前言随着我国预应力混凝土结构的发展,不断变化的建筑业中大跨度重荷载的预应力混凝土构件,对预应力钢筋的品种、强度质量要求也越来越高。而我国现有的预应力粗钢筋品种少,强度低(强度最高的Ⅳ级粗钢筋屈服强度仅550MPa)远不能适应需要。近年来从国外引进的高强精轧螺纹钢,是在整根钢筋上轧有螺纹,不带纵肋的大直径、高强度、高轧制精度的直条钢筋。现我国引进研制的75/90、95/110级两种高强度精轧螺纹钢筋,已经过国家冶金部技术鉴定,在国内已进入试用阶段。精轧螺纹钢以连接器连接,
I. INTRODUCTION With the development of prestressed concrete structures in China, the prestressed concrete components with large-span and heavy loads in the ever-changing construction industry have increasingly higher requirements on the varieties and strength of prestressed steel bars. However, China’s existing prestressed coarse steel bar has few varieties and its strength is low (the strength of the IV-class thick steel bar with the highest strength is only 550 MPa) far from meeting the needs. In recent years, the high-strength finish rolling rebar imported from abroad is a straight bar with large diameter, high strength, and high rolling precision, which is threaded on the entire steel bar without longitudinal ribs. The two kinds of high-strength finish rolled rebars, 75/90, 95/110, which were introduced and developed in China, have passed the technical appraisal of the Ministry of Metallurgical Industry and have entered the trial stage in China. Finished rebars are connected by connectors.