Selecting Moduli Reduction and Damping Curves Based on Cone Penetration Test Soil Behaviour Type

A ground response analysis is performed to evaluate site-specific seismic ground motions. The seismic cone penetration test can be used to obtain shear wave velocity profiles and estimate unit weight profiles for ground response analyses. These analyses also require selection of normalized moduli reduction curves and damping curves. These are often selected from published curves for different soil types including gravels, sands, and clays with different plasticity indices. In this paper we examined if the cone penetration test soil behaviour type index, IC, could be used to inform the selection of published normalized moduli and damping curves. We compiled a set of published curves and cone penetration test (CPT) results in known soil units. We observed that the soil-behaviour-type index from the CPT could be correlated to the shape parameters for normalized moduli and damping reduction curves. The CPT penetration resistance can also be used to estimate the friction angle and limiting shear stress. CPT results can be used to add support to the selected parameters for ground response analyses.