Nonlinear Resonance Analysis of Slender Portal Frames under Base Excitation

Table 2

Natural vibration frequencies of the arched-roof frame.

(m)	Natural vibration frequency (rad/s)
	1st mode	2nd mode	3rd mode	4th mode
1.0	21.02	51.73	122.60	167.05
3.0	17.81	48.51	97.77	151.60
5.0	13.20	40.79	74.02	113.41