Equivalent Viscous Damping Ratio Model for Flexure Critical Reinforced Concrete Columns

Table 2

Statistical results of the EVD ratio predicted by various models to those derived from experimental data.

Model	Equation of equivalent damping ratio		Mean	Covariance
Rosenblueth [9]		= 0.05	1.579	0.238
		= 0.10	1.373	0.258
Gülkan and Sozen [15]			0.592	0.272
Iwan [16]			0.571	0.298
Kowalsky [12]		= 0.05	0.823	0.266
		= 0.10	0.642	0.286
Hwang [28]			0.901	0.245
Kwan and Billington [17]			0.839	0.244
Iwan and Guyader [29]			0.519	0.252
Cheng and Ye [30]			0.778	0.264
Proposed	Equation (16a)–(16c)		1.025	0.202

Note. is the ratio of postyield stiffness to yield stiffness of the envelop curve of the structures and members.