• The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.

International Concrete Abstracts Portal


Title: How the Choice of Various SSI Models Influences the Seismic Response of Medium-Span Bridges

Author(s): Nathalie Roy

Publication: Web Session



Appears on pages(s):



Date: 3/28/2021

In the design stage, bridges are commonly modeled considering rigid foundations, thus neglecting the soil-structure interaction, which can have a significant impact on the evaluation of the base shear forces and superstructure displacements. This parametric study is about the influence of soil-structure interaction, using 3D models calibrated with ambient and forced-vibration tests, with different approaches for the energy dissipation and stiffness of the foundation soil. Superstructure displacements and base shears obtained with the rigid foundation model are compared with those obtained using linear soil-structure interaction models: (i) the simplified method proposed in the latest edition of the Canadian Highway Bridge Design Code (CSA S6-14); and (ii) the method proposed in the US National Earthquake Hazards Reduction Program (NEHRP-2012). The latter represents the foundation-structure interaction using a parallel damper and spring system, while the CSA S6-14 uses only a spring, without damping. The earthquake responses are calculated by time-history analyses for a case study bridge, using artificial accelerograms for different soil types. The influence of soil-structure interaction on displacements and shear forces is quantified. The decision to include soil-structure interaction into structural models, with various levels of complexity, can then be evaluated in the context of seismic design of highway bridges.