Steady‐State Vibration of Subway‐Soil‐Building System

The steady‐state vibration of a subway‐soil‐building system is determined using an appropriate finite element model. The vibration level in the podium block of the building is obtained for two different track support systems: direct fixation and a floating slab. A pair of unit harmonic loads is used to simulate the wheel loading from a single train. Because the subway consists of twin double boxes, different loading combinations are used to determine the maximum velocity response in the podium for the frequency range of interest. It is found that the vibration levels for the floating slab track system exceed those of the direct fixation track system in the low frequency range. However, in the high frequency range, the floating slab track system behaves as an effective vibration isolator.