Shaking Table Test for Evaluating the Seismic Performance of Steel Frame Retrofitted by Buckling-Restrained Braces

Table 4

Natural frequency and damping ratio of the specimen.

Number of the white noise	1	2	3	4	5	6	7	8	9	10
Pure frame f (Hz)	10.06	10.04	10	9.98	9.92	9.83	9.733	9.64	9.57	9.48
BRB frame f (Hz)	23.12	23.08	23.01	23.01	22.86	22.79	22.76	22.71	22.64	22.49
Pure frame ξ (%)	2.06	2.13	2.19	2.35	2.44	2.55	2.68	2.77	2.84	2.92
BRB frame ξ (%)	2.78	2.91	2.97	3.13	3.22	3.29	3.34	3.57	3.72	3.86