Identification of Sudden Stiffness Change in the Acceleration Response of a Nonlinear Hysteretic Structure

Table 3

Identification results of the simulated structure subjected to the different earthquake excitation in different cases.

Case	Seismic excitation	k1 (N/m)	k2 (N/m)	ζ1 (%)	ζ2 (%)	Y (mm)	α	β	γ	n
S1	(a) El-Centro earthquake	102.45	102.73	1.86	2.06	46.46	0.09	0.55	0.52	2.06
	(b) Kobe earthquake	102.79	102.73	2.12	1.83	47.38	0.10	0.56	0.57	1.95
	(c) Northridge earthquake	103.01	102.58	1.96	1.98	49.60	0.10	0.61	0.61	1.97
S2	(a) El-Centro earthquake	103.15	102.46	2.09	2.16	44.13	0.11	0.47	—	2.01
	(b) Kobe earthquake	102.65	102.74	2.12	1.82	44.65	0.10	0.49	—	1.96
	(c) Northridge earthquake	101.46	103.09	2.38	2.09	45.19	0.10	0.46	—	2.07
S3	(a) El-Centro earthquake	102.86	102.70	2.03	2.24	44.70	—	0.48	—	2.01
	(b) Kobe earthquake	103.13	102.71	2.15	1.84	44.39	—	0.48	—	1.93
	(c) Northridge earthquake	102.72	103.01	2.28	2.05	44.71	—	0.46	—	1.97
S4	(a) El-Centro earthquake	103.06	102.55	2.08	2.17	47.78	0.11	0.55	0.61	—
	(b) Kobe earthquake	102.54	102.73	2.16	1.84	47.62	0.10	0.56	0.58	—
	(c) Northridge earthquake	102.94	102.65	2.16	2.01	46.23	0.10	0.52	0.56	—