大型梁式U形渡槽槽身结构动内力分析

采用有限元方法对变长度的大型梁式U形渡槽进行了模态分析和动力时程分析，得出了中长壳与长壳的槽身结构在横向及竖向地震作用下所产生的附加动内力的变化规律．在静力分析时，有限元解仅为传统方法解的l／3；在动力分析时，横向地震作用下的横向附加动弯矩值是有限元静力解的50％以上．因此当考虑了地震荷载时，采用传统方法所得到的内力结果是偏安全的，且安全系数至少为2．

Dynamic Internal Force Analysis of Large U-shaped Beam Aqueduct Structure

Time history response analysis finite element method and modal analysis finite element method are used to analyze large U-shaped beam aqueducts with different lengths in this paper. The earthquake responses of middle long shells and long shells with earthquake waves from transverse direction and vertical direction are stu- died and the regulations of the additive dynamic internal force were found. In the static analysis,the internal force result by finite element method is just one third of the result by the tratitional method.In the dynamic analysis,the transverse additional dynamic bending moment generated by the transverse earthquake is more than 50% of the static result by finite element method.That means when the dynamic loads are considered,the internal force result by the traditional method is safe and the safety factor is at least two.