基于动力特性识别的桥墩冲刷状态分析

发布时间：2018-10-05 13:08

【摘要】：为提高桥墩冲刷深度监测的经济性与便利性,提出一种基于动力特征识别的桥墩冲刷状态分析理论。该理论首先基于结构自振频率与振型,对其合理筛选后转换得到能反映桥梁状态的结构柔度矩阵,基于该结构柔度矩阵得到反映关注方向结构刚度的"计算结构位移差",将其作为桥墩冲刷识别参数。进而利用参数分析得到该冲刷识别参数与不同桥墩冲刷深度之间的理论定量关联,同时利用桥梁检测时获得的结构实际动力特性和实际取值,以及预先得到的"计算结构位移差"与冲刷深度之间的关系进行反演计算,得到了桥墩冲刷此时的反演深度。最后以简支梁桥为示例,基于American Petroleum Institute(API)规范所推荐的计算公式建立多方向的桩土弹簧模型,利用逐步移除相应弹簧单元模拟桥墩冲刷行为,演示了所提出的基于动力特性识别的桥墩冲刷状态分析理论的具体应用方法与步骤,并给出该方法的应用前提。研究结果表明:反演得到的桥墩冲刷深度具备一定的准确性,而多桥墩之间的耦合性可利用拟合公式进行修正;该方法可借助常规桥检项目对桥墩冲刷状态进行定性及定量分析,具备计算逻辑严密准确、监测设备便利经济的优点,在动力特征准确识别的基础上,可准确预测桥墩冲刷深度。
[Abstract]:In order to improve the economy and convenience of scour depth monitoring of bridge piers, a theory of analysis of pier scour state based on dynamic feature recognition is proposed. Firstly, based on the natural vibration frequency and mode shape of the structure, the flexibility matrix of the bridge can be obtained by the reasonable selection and conversion. Based on the flexibility matrix of the structure, the "calculation of structural displacement difference", which reflects the directional stiffness of the bridge, is obtained and used as the identification parameter of the bridge pier scour. Furthermore, the theoretical quantitative correlation between the scour identification parameters and the scour depth of different piers is obtained by using the parameter analysis. At the same time, the actual dynamic characteristics and the actual values of the structures obtained during the bridge detection are used. And the relationship between the calculated structural displacement difference and the scour depth is obtained in advance, and the inversion depth of the bridge pier erosion is obtained. Finally, taking simply supported beam bridge as an example, a multi-direction pile-soil spring model is established based on the formula recommended by American Petroleum Institute (API) Code, and the scour behavior of pier is simulated by removing the corresponding spring element step by step. The application method and steps of the theory of scour state analysis based on dynamic characteristic identification are demonstrated, and the application premise of this method is given. The results show that the depth of erosion of bridge piers obtained by inversion has certain accuracy, and the coupling between multiple piers can be modified by fitting formula. This method can be used for qualitative and quantitative analysis of the scour state of bridge piers with the help of conventional bridge inspection projects. It has the advantages of strict and accurate calculation logic, convenient economic monitoring equipment, and on the basis of accurate identification of dynamic characteristics, The erosion depth of bridge piers can be accurately predicted.
【作者单位】：东南大学交通学院;同济大学桥梁工程系;
【基金】：江苏省自然科学基金项目(BK20161417) 交通运输部建设科技项目(2013 318 223 380,2014 318 J14 250) 中央高校基本科研业务费专项资金项目(2242016R30023)
【分类号】：U442.32

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