Real-Time Dynamic Model Updating of a Hysteretic Structural System

Linear model updating techniques have been successfully applied in structural health monitoring (SHM) for assessing structural conditions. However, civil structures generally exhibit nonlinear hysteretic behavior under damaging loading conditions. Updating nonlinear models is necessary to represent a structure's deteriorating behaviors. Here, an approach is proposed to update a hysteretic model in real time. An experimental study is conducted to demonstrate the use of this nonlinear updating technique on a lab-sized shear building. A recently proposed modified Bouc-Wen model is used. A numerical study is performed to demonstrate the capabilities of the model updating technique in identifying the nonlinear model. The need for deionizing filters is also emphasized. The experimental study considers quasistatic cyclic tests to characterize the nonlinear behavior of the structure, and two shake table tests for demonstrating the proposed approach in the prediction of future responses. Comparison of the error indexes shows that the real-time updated model can be used to predict the response of the tested building structure during strong motion inputs. The real-time testbed developed in this study has the potential to enable rapid structural diagnosis and prognosis, and will facilitate many other engineering applications, such as rapid risk assessment and structural control design.