Seismic Stability Analysis of Pier G

M2C evaluated the seismic stability of sections of the Milpitas Station BART SVBX Project, in Milpitas, California and provided a one-dimensional site response analysis using FLAC to plot the free field spectral response and compare to the Target Spectra. Three pre-approved time histories were used in the 1D FLAC site response analyses and comprised the following:

• Prepared a 2D FLAC model to model soil and structure interaction behavior during simulated shaking.

• Captured the 2D FLAC model response at the free field as well as at the top of the structural wall and compare the calibrate the FLAC free field to the SHAKE, 1D FLAC results and target spectra used for structural design. The top of wall spectral response from 2D FLAC and any structural amplification relative to the target spectrum and free field will be evaluated and provided to the design team.

• Recorded acceleration, horizontal stresses and horizontal displacement histories along the box structure walls and document model performance. Estimate and provide racking displacements imposed on the box structure both during simulated shaking as well as permanent deformation at the end of shaking resulting.

• Prepared a report summarizing the results of the findings. Additionally, provide electronic files (in MS Excel format) including the results of the study.