SummaryIn operational modal analysis (OMA), only structural responses are typically available. In this context, bias and variance (uncertainty) errors may exist in modal estimates (especially damping estimates), resulting in inaccurate determination of the modal properties of large‐scale structures under harsh excitations. To this end, a hybrid OMA framework based on the modal decoupling, the natural excitation technique, the random decrement technique (RDT), and improved eigensystem realization algorithm (ERA) with the automated stabilization diagram is presented to perform high‐accuracy modal estimates with uncertainty quantification for large‐scale structures under normal and severe ambient excitations. The accuracy and effectiveness of the hybrid framework for identifying the modal parameters are validated by numerical simulation study of a framework structural model. Furthermore, the hybrid framework is applied to analyze recorded acceleration responses of a supertall building with 600‐m height under normal excitations and typhoon condition to verify its applicability in field measurements. The numerical simulation and field measurement studies demonstrate that the hybrid framework can not only perform precise modal estimations with uncertainty quantification through a single ambient vibration measurement but also effectively reveal the variations of modal properties of supertall structures under harsh excitations from multiple perspectives. This paper aims to enhance the reliability and accuracy of modal estimation for engineering structures and further provide insight into the variations of dynamic properties of large‐scale civil structures under severe excitations.

中文翻译：

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通过混合操作模态分析框架对大型土木结构进行不确定性量化的模态识别

摘要在运行模态分析 (OMA) 中，通常仅提供结构响应。在这种情况下，模态估计（尤其是阻尼估计）中可能存在偏差和方差（不确定性）误差，导致在恶劣激励下无法准确确定大型结构的模态特性。为此，提出了一种基于模态解耦、自然激励技术、随机递减技术（RDT）和带有自动稳定图的改进特征系统实现算法（ERA）的混合OMA框架，以执行高精度模态估计正常和严重环境激励下大型结构的不确定性量化。通过框架结构模型的数值模拟研究，验证了混合框架识别模态参数的准确性和有效性。此外，该混合框架还用于分析记录的600米高超高建筑在正常激励和台风条件下的加速度响应，以验证其在现场测量中的适用性。数值模拟和现场测量研究表明，混合框架不仅可以通过单次环境振动测量进行不确定性量化的精确模态估计，而且可以从多个角度有效揭示超高层结构在恶劣激励下模态特性的变化。本文旨在提高工程结构模态估计的可靠性和准确性，并进一步深入了解大型土木结构在剧烈激励下的动力特性变化。