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预应力混凝土斜拉桥加固后的动力特性评价是结构加固后评价的重要内容之一。基于三主梁模式,建立了天津永和大桥的动力分析有限元模型。结合该桥原竣工时的实测结果,验证了动力分析模型的精度,以此为基准计算模型,考虑包括主跨合龙段置换并加固、桥面铺装翻新、换索及调索等加固措施对结构刚度和质量的影响,又计算了大桥加固后的结构自振频率和模态,对比分析了加固前后的动力特性变化。结果表明,大桥加固后的结构动力特性符合漂浮体系PC斜拉桥的特点,振型并未发生明显的变化,但加固后的结构自振频率略有降低。分析方法可供同类型桥梁加固后评价参考。
The evaluation of dynamic characteristics of prestressed concrete cable-stayed bridge after reinforcement is one of the important contents of structural reinforcement evaluation. Based on the three main girder mode, the dynamic analysis finite element model of Tianjin Yonghe Bridge was established. The accuracy of the dynamic analysis model is verified with the actual measured results at the completion of the bridge. Based on this, the model is calculated and the reinforcement measures including the replacement and reinforcement of the main span and the closure of the bridge deck, Stiffness and quality of the structure. The natural frequency and modal of the structure after the reinforcement of the bridge are calculated. The dynamic characteristics before and after reinforcement are compared and analyzed. The results show that the structural dynamic characteristics of the bridge after reinforcement are in accordance with the characteristics of the PC cable-stayed bridge with floating system. There is no obvious change in the vibration modes, but the natural frequency of the reinforced structure slightly decreases. Analysis method for the same type of bridge after reinforcement evaluation reference.