Table 2: The first six calculated natural periods and frequencies before seismic strengthening.

Modes1st2nd3rd4th5th6th

DirectionLateralLateralLateralLateralTorsionalLateral
Period (sec)1.2291.2290.1910.1910.1000.077
Frequency (Hz)0.8130.8145.2245.2259.91012.888