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 unconfined 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.

Keywords
steel-confined RC column; acoustic emission; parametric analysis; damage evaluation; failure mechanism

Authorship

Fangzhu Du

School of Civil Engineering, Dalian University of Technology, Dalian 116024, China. E-mail: fangzhudu@mail.dlut.edu.cn, lidongsheng@dlut.edu.cn, wangyanlei@dlut.edu.cnDalian University of TechnologyChinaDalian, ChinaSchool of Civil Engineering, Dalian University of Technology, Dalian 116024, China. E-mail: fangzhudu@mail.dlut.edu.cn, lidongsheng@dlut.edu.cn, wangyanlei@dlut.edu.cn

State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian 116024, ChinaDalian University of TechnologyChinaDalian, ChinaState Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian 116024, China

Dongsheng Li ^**Corresponding author

Baohua Shan

Key Lab of Structures Dynamic Behavior and Control (Harbin Institute of Technology), Ministry of Education, Harbin 150090, China. E-mail: shanbaohua@hit.edu.cnMinistry of EducationChinaHarbin, ChinaKey Lab of Structures Dynamic Behavior and Control (Harbin Institute of Technology), Ministry of Education, Harbin 150090, China. E-mail: shanbaohua@hit.edu.cn

School of Civil Engineering, Harbin Institute of Technology, Harbin 150090, China.Harbin Institute of TechnologyChinaHarbin, ChinaSchool of Civil Engineering, Harbin Institute of Technology, Harbin 150090, China.

Yanlei Wang

*Corresponding author

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Figures | Tables

Figures (18)
Tables (6)

Material	Yield Strength (MPa)	Tensile Strength (MPa)	Elastic Modulus (GPa)	Thickness or Diameter (mm)	Elongation(%)
Steel tube	280	414	210	3	10.9
Rebar	420	590	205	16	17.5
Stirrup	400	525.4	206	8	18.3

Test Group	Specimen Number	Steel Tube	Longitudinal Rebar	Stirrups	Concrete	Axial Compression Ratio	Shear Span Ratio
QSS0	3	-	6Φ16	Φ8@100	C40	0.3	4
QSS3	3	3 mm	6Φ16	Φ8@100	C40	0.3	4

Sensor type	Peak response frequency/kHz	Threshold	Sampling rate	Sampling points	PDT/μs	HDT/μs	HLT/μs
R-15a	150	45 dB	1 MSPS	1024	300	800	1000

Unconfined group	Load/kN	Hysteresis energy (N*m)	Total AE hits	Confined group	Load/kN	Hysteresis energy	Total AE hits
QSS001	129.6	28935	846028	QSS301	160.2	79617	855610
QSS002	136.5	29371	901561	QSS302	173.8	79238	948138
QSS003	122.3	28214	829574	QSS303	154.1	78769	899737

Cycle	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15
QSS001	0.05	0.03	0.04	0.06	0.08	0.09	0.12	0.14	0.19	0.22	0.39	0.60	1.09	1.45	2.30
QSS002	0.03	0.02	0.04	0.05	0.07	0.09	0.10	0.13	0.16	0.20	0.37	0.54	0.86	1.31	1.76
QSS003	0.03	0.05	0.06	0.07	0.08	0.10	0.13	0.15	0.18	0.21	0.34	0.49	0.81	1.35	1.87
QSS301	0.02	0.04	0.07	0.08	0.09	0.10	0.13	0.14	0.17	0.20	0.21	0.22	0.25	0.26	0.28
QSS302	0.03	0.04	0.07	0.09	0.10	0.11	0.14	0.16	1.19	0.21	0.22	0.24	0.26	0.27	0.29
QSS303	0.02	0.03	0.05	0.07	0.09	0.10	0.12	0.14	0.16	0.18	0.20	0.22	0.23	0.24	0.26

Cycle	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15
QSS001	0.08	0.04	0.09	0.05	0.17	0.26	0.75	0.59	0.91	0.76	1.50	1.24	1.30	0.96	0.91
QSS002	0.09	0.07	0.14	0.11	0.22	0.29	0.67	0.61	0.89	1.43	1.31	1.18	0.93	0.82	0.76
QSS003	0.06	0.05	0.08	0.12	0.15	0.24	0.60	0.66	1.34	1.15	1.27	1.03	0.98	0.87	0.92
QSS301	0.22	0.13	0.37	0.26	0.39	0.60	0.68	0.79	1.19	0.86	0.95	0.88	1.57	0.50	0.71
QSS302	0.17	0.09	0.28	0.22	0.40	0.65	0.77	0.89	1.26	0.94	1.42	1.13	1.02	0.76	0.63
QSS303	0.14	0.08	0.31	0.19	0.43	0.67	0.80	1.05	1.33	0.92	1.26	0.95	0.87	0.64	0.79