In the light of the feature of urban bridges spanning lanes, a senise of simplified formulas besing on the displacementmethod to calculate the internal forces is derivated in this artide.

• 本文针对城市过街桥的特点，用位移法为基础推导出计算内力的一整套简便公式，概念清晰，运算简单，精度较高，便于手算，也便于电算。