Earthquake input and state estimation for buildings using absolute floor accelerations

Taher Sdiq Anwar; Li Jian; Fang Huazhen

摘要

After earthquakes, structural response such as interstory drift is critical for accurate structural assessment for buildings. Typically, direct integration of absolute floor accelerations does not yield reliable floor displacements due to the long-period drifts caused by noise, a widely acknowledged challenge. In this case, model-based estimation strategies can be employed, which often require the ground input for better accuracy. However, in many cases the ground input may not be available for lack of instrumentation or even be unmeasurable due to soil-structure interaction, hence needs to be estimated. Earthquake input estimation in this case is particularly challenging due to the lack of direct feedthrough term, leading to low observability of system input. As a result, input estimation is sensitive to modeling error, measurement noise, and incomplete measurements. To address this challenge, a hybrid strategy is proposed to estimate earthquake input, states, and acceleration response at unmeasured floors using limited absolute floor acceleration measurements. First, the earthquake input is estimated through a maximum a posteriori (MAP) estimation method, and then the estimated input is combined with Kalman filter to further estimate states and unmeasured responses. A comprehensive assessment was performed through a series of numerical and experimental tests including a comparative study with a popular online model-based method. While the online method demonstrated certain sensitivity to modeling error and measurement noise due to weak observability, the proposed strategy showed robustness and accuracy under realistic and challenging conditions. Further verification is also performed using a real-world building structure that experienced earthquake events.

机译：地震后，诸如壁垒漂移等结构反应对于建筑物的准确结构评估至关重要。通常，由于噪声引起的长期漂移，直接整合绝对地板加速度不会产生可靠的地板位移，这是一种广泛认可的挑战。在这种情况下，可以采用基于模型的估计策略，这通常需要接地输入以获得更好的准确性。然而，在许多情况下，由于土壤结构相互作用，接地输入可能无法缺乏仪器甚至不可估量，因此需要估计。由于缺乏直接馈通术语，在这种情况下，地震输入估计尤其具有挑战性，导致系统输入的可观察性低。结果，输入估计对建模误差，测量噪声和不完整的测量敏感。为了解决这一挑战，建议使用有限的绝对地板加速度测量来估计未测量的地板的地震投入，各国和加速度响应的混合策略。首先，通过最大后验（MAP）估计方法估计地震输入，然后将估计的输入与卡尔曼滤波器组合以进一步估计状态和未测量的响应。通过一系列数值和实验测试进行全面评估，包括具有流行基于在线模型的方法的比较研究。虽然在线方法由于可观察性较弱而展示了对建模误差和测量噪声的某些敏感性，但拟议的策略在现实和具有挑战性的条件下表现出稳健性和准确性。还使用经历地震事件的真实建筑结构进行进一步的验证。

Earthquake input and state estimation for buildings using absolute floor accelerations

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