Effects of deep excavation on seismic vulnerability of existing reinforced concrete framed structures

• Seismic vulnerability of existing R/C framed structures close to deep excavation.
• Evaluation of seismic damage indices and inter-story drifts.
• Viscous elasto-plastic with hardening model for pyroclastic sandy soil.
• Non-linear static and dynamic analyses considering soil–structure interaction.
• Excavation-induced effects on the propagation of seismic waves in the soil domain.

In this paper the effects of deep excavation on seismic vulnerability of existing buildings are investigated. It is well known that deep excavations induce significant changes both in stress and strain fields of the soil around them, causing a displacement field which can modify both the static and dynamic responses of existing buildings. A FEM model of a real case study, which takes into account geometry, non-linear soil behavior, live and dead loads, boundary conditions and soil–structure interaction, has been developed in order to estimate the soil displacements and their effects on seismic behavior of a reinforced concrete framed system close to deep excavation. Considering a significant accelerometric seismic input, the non-linear dynamic responses of the reinforced concrete framed structure, both in the pre and post-excavation configurations, have been evaluated and, then, compared to estimate the modification in seismic vulnerability, by means of different seismic damage indices and inter-story drifts.