SSIFootingStiffness Description None References NIST (2012). Soil-structure interaction for building structures Formulae get_footing_router get_effective_profile_depth get_average_top_depth get_average_bottom_depth get_average_effective_shear_velocity get_dimensionless_frequency get_embedment_factor get_static_stiffness get_dynamic_stiffness_modifier get_radiation_damping_ratio get_stiffness get_dashpot_coefficient