An experimental study on AEKF method for health monitoring of base-isolated structures

Abstract

Recently, an adaptive extended Kalman filter (AEKF) approach has been proposed for the damage identification and tracking of structures. Simulation and experimental studies have demonstrated that this AEKF approach is capable of tracking the damages for linear structures. In this paper, an experimental study is conducted and presented to verify the capability of the adaptive extended Kalman filter (AEKF) approach for identifying and tracking the damages in nonlinear structures. A base-isolated building model, consisting of a scaled building model mounted on a rubber-bearing isolation system, has been tested experimentally in the laboratory. The non-linear behavior of the base isolators is modeled by the Bouc-Wen model. To simulate the structural damages during the test, an innovative device, referred to as the stiffness element device (SED), is proposed to reduce the stiffness of either the upper story of the structure or the base isolator. Two earthquake excitations have been used to drive the test model, including the El Centro and Kobe earthquakes. Various damage scenarios have been simulated and tested. Measured acceleration response data and the AEKF approach are used to track the variation of the stiffness during the test. The tracking results for the stiffness variations correlate well with that of the referenced values. It is concluded that the AEKF approach is capable of tracking the variation of structural parameters leading to the detection of structural damages.