Abstract: The impact effect of the reinforced concrete rigid-frame arch bridge has a great effect on its safety and disease development． A reasonable impact coefficient plays a great role in the disease analysis and the reinforcement of rigid-frame arch bridges． The differences of bridge design specifications on the impact coefficient calculation method at different stages in China were discussed． The dynamic characteristics of a typical rigid-frame arch bridge were analyzed by using the calculation method of Three-Dimensional Finite Element． And a comparative analysis was made between the impact coefficients calculated respectively according to the 1985 version specification and the 2004 version specification． Then the difference between the impact effect measured and the impact effect calculated was analyzed according the measured data of a rigid-frame arch bridge’s dynamic loading test． The analysis shows that the impact coefficients calculated according to the 1985 version specification nearly matches the measured data; however，the impact coefficients calculated according to the 2004 version specification is able to conservatively cover the distribution of the impact coefficients in various situations．

Key words: bridge engineering, rigid-frame arch bridge, fundamental frequency, span, impact coefficients

摘要： 钢筋混凝土刚架拱桥的冲击效应对其病害发展和安全性有重要影响，合理的认识和确定冲击系数是进行刚架 拱桥病害成因分析及加固维修的重要前提。通过讨论我国不同时期桥梁设计规范对于刚架拱桥冲击系数计算方法 的差异性，建立了空间有限元模型分析了典型刚架拱桥的动力特性，分别按照“85”和“04”规范的计算原则分析比 较了其冲击系数的异同，结合刚架拱桥动载试验的实测数据分析了典型刚架拱桥实际冲击效应与规范计算结果的 差别。分析表明，按照“85”规范计算出的主拱冲击系数与实测正常行车下的冲击效应较为接近，按照“04”规范计 算的冲击系数能够偏保守的涵盖各种不同行车情况下实测冲击系数的分布。

关键词: 桥梁工程, 刚架拱桥, 基频, 跨径, 冲击系数