We use the finite element method to analyze the impact of the longitudinal and lateral position changes of vehicle load on shear lag effect of continuous box girder bridge, and get the research conclusions: (1) With the difference of the longitudinal and lateral position of the vehicle load, the distribution of shear lag is variously different, meanwhile different load models make the shear lag greatly different;(2)The fulcrum is the most sen-sitive section on the longitudinal position of the vehicle load, and the along edge in the web shear lag difference is the biggest, in the cross section it is small;(3)The top and the bottom of the box girder are greatly influenced by the changes of lateral loading position of vehicle load. Partial load makes the shear lag peak shift, and the bot-tom of the shear lag shows a decreasing trend. (4) In the design of multi cell box girder, the influence of differ-ent load models of shear lag effect should be fully considered.%采用有限元计算方法,分析汽车荷载纵向作用位置和横向作用位置变化对连续箱梁剪力滞效应的影响,结果表明:1) 连续箱梁桥剪力滞系数随着汽车荷载作用位置的变化而变化,并且这种变化差别较大;2) 对汽车荷载纵向作用位置最敏感截面为支点处截面,此处边腹板与中腹板剪力滞系数差别最大,在跨中截面处相差不大;3) 汽车荷载横向作用位置的变化对箱梁顶板和底板的剪力滞影响较大,偏载使得剪力滞系数峰值出现偏移,且底板的剪力滞系数呈现出逐渐减少的趋势.因此,在设计阶段,应充分考虑汽车荷载作用位置变化对薄壁箱梁剪力滞效应的影响.
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