Abstract: The prestressed concrete continuous rigid frame straight beam model and the bending beam model were established by the finite element software MIDAS /Civil，with the same span and variable cross-section single cell box． The deformation， the reaction force and stress behaviours were analyzed under the influence of dead load and live load and at the operation stage of bridge． At the same time，the modelling method that may cause differences in the final results was considered， so the grillage method was adopted to do the modelling analysis for the curved girder． The obtained results are regarded as important reference to verify the accuracy of data，which finds out the differences of the curved girder bridge and straight girder bridge in the force and deformation． Therefore，the mechanical characteristics of the curved girder bridge are analyzed more accurately．

Key words: continuous rigid frame bridge, bending beam, deformation, internal forces, finite element analysis

摘要： 采用有限元软件MIDAS/Civil建立了相同跨度的预应力混凝土变截面单箱单室连续刚构直梁模型和弯梁模 型，分析了在恒载、活载作用下和成桥运营阶段直梁桥和弯梁桥的变形、反力和内力特征;考虑建模方法对最终结果 可能造成的差异，对弯梁模型还采用梁格法进行建模分析，并将所得结果作为重要参考以验证结果的准确性，得到 弯梁桥和直梁桥在受力和变形上的差异，从而更准确的分析弯梁桥的受力。

关键词: 连续刚构桥, 弯梁, 变形, 内力, 有限元分析