| 引用本文: | 熊文,魏乐永,张学峰,王伟立,叶见曙.大跨度缆索支承桥梁基础冲刷动力识别方法[J].哈尔滨工业大学学报,2019,51(3):92.DOI:10.11918/j.issn.0367-6234.201711053 |
| XIONG Wen,WEI Leyong,ZHANG Xuefeng,WANG Weili,YE Jianshu.Dynamic-based bridge scour identification of super-span cable-supported bridges[J].Journal of Harbin Institute of Technology,2019,51(3):92.DOI:10.11918/j.issn.0367-6234.201711053 |
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| 摘要: |
| 为快速评估运营阶段桥梁基础冲刷状态,提出一种基于实测模态与模型更新的冲刷动力识别方法,并在杭州湾大桥桥塔冲刷检测中进行应用. 分别于2013年、2016年对杭州湾大桥上部结构进行了两次环境振动下的加速度数据采集工作,并进行模态分析,得到两次测试所对应的结构自振频率与振型. 同时利用有限元分析软件采用鱼骨模型进行上部结构数值建模,采用土弹簧进行下部结构桩土效应的模拟. 首先利用冲刷非敏感模态的实测自振频率对数值模型中的桩侧等效弹簧刚度进行模型更新,直至得到与实际相符的桩土边界条件. 进而利用冲刷敏感模态自振频率的实测变化值,对有限元模型中的基础冲刷深度进行模型更新,直至数值模拟变化值与实测变化值相一致,从而定量识别出3 a内基础冲刷深度的发展. 最后,利用水下地形测量数据完成对该冲刷识别方法准确性的验证. 研究结果表明:该方法利用桥梁上部结构实测模态变化进行下部结构基础冲刷模型的更新是可行的,基础冲刷深度的识别是准确的,可解决长期以来需要水下作业才能完成桥梁基础冲刷检测的技术难题. |
| 关键词: 桥梁工程 基础冲刷 模态变化 振动测试 变化分析 模型更新 |
| DOI：10.11918/j.issn.0367-6234.201711053 |
| 分类号:U442.5+9 |
| 文献标识码:A |
| 基金项目:江苏省自然科学基金(BK20161417)； 浙江省公路科技计划(2018H10)； 中央高校基本科研业务费专项资金(2242016R30023) |
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| Dynamic-based bridge scour identification of super-span cable-supported bridges |
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XIONG Wen1,WEI Leyong2,ZHANG Xuefeng3,WANG Weili1,YE Jianshu1
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(1. Department of Bridge Engineering, School of Transportation, Southeast University, 210096 Nanjing, China; 2. CCCC Highway Consultants Co., Ltd., 100088 Beijing, China; 3. Research Institute of Highway Ministry of Transport, 100088 Beijing, China)
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| Abstract: |
| In order to quickly assess bridge scour during operation period, a dynamic-based identification method was proposed based on the measured vibration modes and model updating technique, and was applied to the pylon scour detection of the Hangzhou Bay Bridge. Two field measurements were conducted in 2013 and 2016 respectively to record the acceleration data of the superstructure of the Hangzhou Bay Bridge under ambient vibration. A modal analysis was carried out to obtain the natural frequencies and modes of vibration for each measurement. The superstructure was numerically simulated by a fish-bone finite element model and the pile-soil effect of the substructure was simulated by soil springs. The stiffness of equivalent springs around piles in the simulation model was firstly updated based on the measured natural frequencies of the scour-insensitive modes. Until the simulated natural frequencies corresponded to the measurement, the stiffness of the springs in the simulation could be seen as the identification of the real pile-soil effect of the bridge. Then, the scour depth in the simulation model was updated based on the variation of the measured natural frequencies of the scour-sensitive modes. Until the simulated and the measured variations of the natural frequencies were the same, the scour depth in the simulation model could be regarded as the identification of the real situation of the foundation during the three years. The identification accuracy was finally verified by the results of underwater terrain map around the foundation of the bridge. Results show that it is feasible to update the foundation scour by tracing the measured modal variation of the superstructure to identify a correct scour depth. This method can resolve the long-term difficulty of the traditional scour detection because it does not need underwater operation. |
| Key words: bridge engineering foundation scour modal variation vibration test variation analysis model updating |
