The effect of vertical excitation on the response of soil-structure systems allowed to uplift

The effects of vertical excitation on the response of soil-structure systems allowed to uplift are investigated. The super-structure is modeled as an equivalent single-degree of freedom system having bilinear behavior. The foundation is modeled as a rigid disk resting on distributed tensionless Winkler springs and dampers. The soil structure model is then analyzed using the open-source software OpenSees. The study is conducted parametrically through time history analysis for a wide range of systems subjected to a family of ground excitations. The importance of vertical excitation on the response of conventional building-type structures is studied by assuming a practical range for nondimensional parameters. The average of results shows that vertical component of earthquake excitations generally increases total displacement and ductility demand in super-structure of uplifting systems, compared with them under only horizontal component.