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建立了基于正交实验的响应面模型和精细有限元模型,并将其用于中华大桥的有限元模型修正,通过实测动力数据对修正后的有限元模型计算结果进行了验证。基于修正后的有限元模型,分析了预应力对预应力钢筋混凝土桥梁模态信息(频率和振型)的影响,以及单元类型对桥梁模态频率的影响。结果表明,修正后的有限元模型能够比较准确地反映桥梁实际结构的动力特性,基于响应面模型和遗传算法的修正方法可有效地用于大桥的健康监测和状态评估;预应力对预应力钢筋混凝土桥梁模态信息的影响较小,建模时可不予精确考虑;对于由多根预应力混凝土梁组成的桥梁体系,采用实体单元分析较好。
The response surface model and the finite element model based on orthogonal experiment were established and used to correct the finite element model of Zhonghua Bridge. The calculated results of the modified finite element model were verified by the measured dynamic data. Based on the modified finite element model, the influence of prestressing on the modal information (frequency and mode shape) of prestressed reinforced concrete bridges and the influence of element type on the modal frequency of bridge are analyzed. The results show that the modified finite element model can accurately reflect the dynamic characteristics of the actual bridge structure. The response method based on response surface model and genetic algorithm can effectively be used for the health monitoring and condition assessment of the bridge. Prestressing force The influence of modal information of concrete bridge is small, so it can not be considered accurately in modeling. For the bridge system composed of many prestressed concrete beams, the analysis by physical unit is better.