Harbor Bay Business Park liquefaction during Loma Prieta earthquake-A critical state perspective

Part of the Harbor Bay Business Park, Alameda in California, showed evidence of liquefaction during the 1989 Loma Prieta earthquake, but this was accompanied by only small settlements and no significant damage to two recently constructed office buildings. Digital CPT records are available from a reasonably comprehensive postearthquake investigation. These, in combination with the large body of test data associated with the Park's development, have been used to assess the soil behavior at this site further. Using analysis based on critical state soil mechanics, it appears likely that the presence of underlying Bay Mud was an important factor, with the limited undrained strength of that stratum limiting the transmitted shear stresses to the overlying and liquefiable sand fill but without preventing its liquefaction. This inferred behavior is consistent with a system (i.e., favoring interaction between layers) response, which was also observed during the 2010-2011 Canterbury earthquake sequence.

Automated summary

Part of the Harbor Bay Business Park in Alameda, California showed evidence of liquefaction during the 1989 Loma Prieta earthquake, but the recently constructed office buildings were not significantly damaged. Analysis based on critical state soil mechanics suggests that the presence of underlying Bay Mud played an important role in limiting the transmitted shear stress but not preventing liquefaction of the overlying sand fill. This behavior is consistent with the interaction between layers observed during the Canterbury earthquake sequence.