An Innovative Substructure Damage Identification Approach for Shear Structures Based on ARMAX Models

Shear structures are used to model tall buildings which play important roles in supporting people's living and working in large cities. These buildings will be gradually deteriorated with the material aging and environmental corrosions. In this paper, an innovative substructure approach is proposed to locate and quantify damages in any storeys of a shear structure with only using three accelerometers. A multiple partition technology is used to extract physical parameters such as stiffness and damping of single inter-storey connection from an independent substructure only containing one storey cut out from the whole structure. By doing this multiple division, damages happened in multi storeys can be identified separately which is a big progress compared to previous researches that mainly consider one damaged storey in whole structure. As in the previous researches, an autoregressive-moving average with exogenous inputs (ARMAX) model is introduced to extract the modal information of each lower substructure and to encapsulate the complex input information on the boundaries of substructure, which can effectively reduce the number of sensors and the calculation process. A damage indicator combining both the information of ARMAX model parameters and model residuals is utilized to enhance the damage identification robustness, where the Kolmogorov-Smirnov (K-S) statistic test is used to evaluate the difference between ARMAX model residuals of tested substructure and of referenced substructure. Simulation of a 10-storey shear structure and an experiment of a 5-storey shear structure have been conducted to verify the effectiveness of the proposed approach, which demonstrate that the innovative approach can accurately identify the structural damages in multi storeys even with large environmental noise disturbance.