Failure behavior monitoring and evaluation of steel–confined reinforced concrete columns by acoustic emission under quasi-static loading

The mechanical behavior and failure evolution of steel-confined and uncon-fined reinforced concrete (RC) columns are investigated under quasi-static loading through acoustic emission (AE) signal. The excellent hysteresis response, lighter damage characteristics and delayed catastrophe of steel– confined RC columns are verified. Characteristic AE parameters were obtained during the test process, AE monitoring results indicated that the progressive deformation of the test specimens occurred in three stages representing different damage conditions. Extended AE features, including damage severity, modified cumulative signal strength ratio, sentry function, and b-value are calculated to evaluate the damage growth, failure mechanism, and estimate the critical points. The synthesis analysis of multi-indicators mutual verify, overcome the disadvantages of using single-indicator evaluation, and successfully be used to determine the complex damage properties, identify damage statuses, and provide critical warning information for steel–confined RC columns.