Evaluation of Seismic Vulnerability of Reinforced Concrete Buildings Adjacent to the Deep Excavations

In this study, the effect of deep excavation on the seismic response of RC moment resisting building systems has been studied. Deep excavation can cause significant changes in the stress and strain levels of soil environment and also changes in the propagation of seismic waves. This leads to permanent displacements in the foundation system. In this study, three RC building systems, i.e. 5, 10, and, 15 stories, were modelled considering the nonlinear behaviour of soil and structural material as well as the soil-structure interaction effect. Nonlinear dynamic responses of buildings were evaluated before and after excavation and also with a rigid base (without soil modelling) under the seven earthquake records. Analysis results indicate an increase in seismic demands and responses in the vicinity of the excavation. So for 15-storey buildings near the excavation, 35% increase in the base shear, 70% increase in maximum drift, 26% increase in the story shear force, and a 30% increase in the maximum story acceleration was observed. As a result, considering the effect of excavation on the seismic response of RC building systems is inevitable.