Capabilities and Limitations of Different Numerical Tools in Capturing Seismic Site Performance in a Layered Liquefiable Site

A centrifuge experiment was performed modeling seismic site performance under 1D horizontal earthquake shaking in a saturated and layered soil profile, including a loose layer of Ottawa sand. The results were used to evaluate the predictive capabilities of two classes of soil constitutive models (multi-yield and bounding surface) and two numerical platforms (OpenSees and FLAC) used by three different teams. The models were independently calibrated using the same set of monotonic and cyclic triaxial tests as well as the larger boundary value problem modeled in centrifuge. Despite differences in calibration methodologies and priorities among three modelers, the results showed that small element tests and centrifuge experiments do not always lead to the same calibrated soil parameters. Although current numerical platforms and constitutive models were capable of reproducing many aspects of seismic site response observed in centrifuge, they still need improvements to capture volumetric strains in free-field conditions.