Abstract: To calculate the increasing coefficient of internal forces for continuous box girder bridges the calculating model with two spring bearings is established．The analytical results of an example by this model coincided satisfactory with those by the traditional method,and it simplified the calculation process to a certain extent with the latter．

Key words: continuous box girder bridge, increasing coeficient of internal force, equivalent span of simple supported beam , calculating model with two spring bearings, modified excentral pressure method

摘要： 提出了具有一对弹簧支承的计算模型，用来计算连续箱梁桥的内力增大系数．用本模型所得到的一个算例 的分析结果与按传统方法的分析值吻合甚好，并且它比后者在计算过程上得到了一定程度的简化．

关键词: 连续箱梁桥：内力增大系数：等代简支跨, 双弹簧支承计算模型, 修正偏心压力法．