一、前言在预应力混凝土桥梁设计中,预加力产生的弹性次内力和徐变次内力在预加力作用之中是相当重要的因素。根据线性徐变理论,把求徐变次内力问题,可化为求弹性次内力问题。因此,求预加力次内力问题,关键是求弹性次内力问题。目前,桥梁设计人员仍然是按力法原理,基于分段图乘法、解冗力方程组的方法来求解预加力产生的次内力较繁。本文提出一个关于影响线理论的定理,据此定理,并用等效荷载的概念,将预加力的作用换算成等效的荷载,并把此荷载在相应的影响线上加载,就可求得预加力产 I. Preface In the design of prestressed concrete bridges, the secondary internal forces and the secondary internal forces caused by pre-energizing force are very important factors in the pre-energizing effect. According to the theory of linear creep, the internal stress problem of seeking creep can be transformed into the problem of elastic secondary stress. Therefore, the key to seek the secondary internal forces of pre-stressing is to seek the secondary internal forces of elasticity. At present, bridge designers are still based on the principle of force method, based on piecewise block multiplication, solution of redundant force equations to solve the pre-stress generated by the sub-internal force more complicated. In this paper, we present a theorem about the theory of influence lines. Based on the theorem and the concept of equivalent load, the effect of pre-stressing is converted into an equivalent load and the load is loaded on the corresponding influence line. Pre-force production