An objective of the structural health monitoring system is to identify the state of the structure and to detect its damagesafter a major event, such as the earthquake, to ensure the reliability and safety of structures. Innovative analysistechniques for the damage detection of structures have been extensively studied recently. However, practical andeffective damage identification techniques remain to be developed for nonlinear structures, in particular nonlinearhysteretic reinforced concrete (RC) structures. In this paper, in addition to the equivalent time-varying linear model, asmooth hysteretic model with stiffness and strength degradations and with the pinching effect is used to represent thedynamic characteristics of reinforced concrete (RC) frames. A system identification technique capable of detectingdamages in nonlinear structures, referred to as the adaptive quadratic sum-square error with unknown inputs (AQSSEUI)is used to track the degradation of the time-varying parameters of nonlinear RC frames. The performance of theAQSSE-UI technique is also demonstrated by the experimental data
An objective of the structural health monitoring system is to identify the state of the structure and to detect its damagesafter a major event, such as the earthquake, to ensure the reliability and safety of structures. Innovative analysistechniques for the damage detection of structures have been extensively studied recently. However, practical andeffective damage identification techniques remain to be developed for nonlinear structures, in particular nonlinearhysteretic reinforced concrete (RC) structures. In this paper, in addition to the equivalent time-varying linear model, asmooth hysteretic model with stiffness and strength degradations and with the pinching effect is used to represent thedynamic characteristics of reinforced concrete (RC) frames. A system identification technique capable of detectingdamages in nonlinear structures, referred to as the adaptive quadratic sum-square error with unknown inputs (AQSSEUI)is used to track the degradation of the time-varying parameters of nonlinear RC frames. The performance of theAQSSE-UI technique is also demonstrated by the experimental data