一、前言近十年来,我国桥梁建筑预应力混凝土技术的发展突飞猛进,特别是自1986年来,随着国内多种钢绞线束锚固体系先后研制成功并投入使用后,这一技术跨进了新的发展阶段。目前,国内兴建的大跨度预应力混凝土桥梁的预应力索已多数用钢绞线束代替钢丝束,设计的单索索力成十倍增加(按:以24—(?)5mm 钢丝束与55—(?)12.7mm 的同强 I. Introduction In the recent ten years, the development of bridge prestressed concrete technology in our country has progressed by leaps and bounds. Especially since 1986, with the successful development and application of various kinds of steel strand anchorage systems in China, this technology has stepped into a new development stage. At present, most prestressed cables for long-span prestressed concrete bridges built in China have mostly replaced the steel wire bundles with steel wire strands, and the designed single-wire cable force has ten times the increase (according to the requirements of 24- (?) 5mm steel wire bundles and 55- ?) 12.7mm with the strong