普通钢筋混凝土梁的体外预应力加固

Strengthening Reinforced Concrete Beams by External Prestressing

体外预应力技术是加固既有钢筋混凝土结构最有效的方法之一， 可提高结构的承载能力和耐久性， 降低钢筋疲劳应力幅度。文中通过一座普通钢筋混凝土桥的加固设计实例， 介绍了普通钢筋混凝土梁体外预应力加固的适用范围、设计原则、计算方法及应注意的问题， 同时建立了加固时的预应力钢筋用量计算的简化公式。

External prestressing is one of the most effective methods for strengthening existing concrete structures.The durability of the existing structure can be improved and the stress in the reinforced steel under fatigue loading can be decreased by external prestressing.In this paper,the qualifications of application, of external prestressing and some design principles and methods are introduced through an illustrative design case of strengthening a RC railway bridge.At the same time,a simplified formula is given to calculate the amount of external tendons.