Abstract: The author proposes that the partially prestressed highway bridges be designed according to the degree of prestresing. In this paper, the design method and its merits are explained. The calculations for the projects in the "Standard Design Drawings JT/GQB 025-75" has been made. Based on this, the influence of the degree of prestressing upon the steel requirement and the relations between the degree of prestressing and the crack width have been analyzed. The crack control by hypothetical tensile stress is too conservative and unsuitable for lower degree of prestressing. Therefore, the recommendation for design of PRC bridges by means of hypothetical tensile stress is improper.

摘要： 本文建议按预应力度设计预应力公路桥梁,对按预应力度设计预应力梁的方法作了介绍,指出了它的优点。文中按"公路桥涵标准图JT/GQB 025-75"的截面进行了计算,对预应力度对用钢量的影响以及与裂缝宽度的关系做了分析,得到用名义拉应力控制裂缝过分保守,不适用于低预应力度的情况,故不宜推荐作为设计部分预应力桥梁的基本方法的初步结论。