Seismic Analysis of the Transportation Portal by the Combined Asymptotic Method

Table 1

The comparison of the natural frequencies, Hz.

RB standing alone		RB + TP, two basements fixed		RB + TP, one basement fixed		Comments about modes
No.	Frequency	No.	Frequency	No.	Frequency
				1	3.16𝐸−4	“Rigid” motion of portal
				2	4.48𝐸−4	“Rigid” motion of portal
				3	8.78𝐸−4	“Rigid” motion of portal
				4	1.67𝐸−3	“Rigid” motion of portal
		1	2.4132			Lumped masses on the top of portal move along Oy
1	4.0445	2	4.0445	5	4.0445	RB moves in the Ozy plane
2	4.0747	3	4.0647	6	4.0593	RB moves in the Ozx plane
3	9.2132	6	9.2057	12	9.2137	Torsion of RB around Oz
4	10.093	7	10.092	14	10.092	Vertical movement of RB