无粘结力筋与体外力筋预应力混凝土桥梁的发展历程与现状

A Historical Review and the State of the Art of the Application of Unbonded and External Tendons in Prestressed Concrete Bridges

回顾了预应力混凝土桥梁发展史上最早出现的无粘结体外力筋预应力结构，在经历了一个相当沉寂的时期以后，又充满活力，向前发展的历程。比较了有粘结与无粘结力筋两种预应力混凝土结构的优缺点。对当前的无粘结力筋预应力混凝土结构，在设计计算与构造细节方面的特殊问题，进行了讨论。最后列举了从３０年代到９０年代，一些有代表性的体外力筋桥梁的概况，以便对这类桥梁从设计构思到施工实践有更好的了解。

A brief review is given to the history of application of unbonded and external tendons in prestressed concrete bridges, from the first P. C. bridge built in 1937, through a period of stagnation for several decades, then coming to a time of development full of vigor and vitality. A comparison is made between two kinds of prestressed concrete structures with bonded and unbonded tendons with regard to their advantages and drawbacks. Some special problems in the design and detailing of the up to date P. C. sturctures with unbonded tendons are discussed. Finally, are given essential features of some representative bridges built with unbonded and external tendons from the middle thirties to the late nineties of the twentieth century, in order to help study such kind of stuctures from design concept to construction practice.