Research Article
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 | 3.16 | “Rigid” motion of portal | | | | | 2 | 4.48 | “Rigid” motion of portal | | | | | 3 | 8.78 | “Rigid” motion of portal | | | | | 4 | 1.67 | “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 |
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