THE IMPACT OF TALL BUILDINGS ON SEISMIC EARTH PRESSURES ACTING ON BASEMENT WALLS

Tall building construction in major cities has introduced new challenges in geotechnical earthquake engineering and design. The inertial forces from a tall superstructure may cause additional displacements and rotations in its basement, affecting the distribution and magnitude of seismic lateral earth pressures on basement walls. Nevertheless, existing analytical procedures for evaluating seismic lateral earth pressures on buried and not-buried earth retaining wall systems often neglect superstructure inertia and dynamic properties when assessing seismic lateral earth pressures on basement walls. This omission leads to uncertainties in the applicability and reliability of these procedures for tall building basements. Accordingly, in this study, we evaluate the impact of lateral resisting systems in tall superstructures on seismic earth pressures that are imposed on basement walls. We consider basements in dry sand and gravel through a parametric study that includes 156 2D nonlinear simulations of realistic scenarios. The findings reveal that inertial forces and dynamic lateral movements from a tall superstructure increase total lateral earth pressures on basement walls, particularly in the top two-thirds of their height, with an approximately trapezoidal distribution. The reliability of existing procedures depends on the building modal frequencies, input motion frequency content, and the stiffness of the structure-basement system in relation to the underlying soil. The results emphasize the importance of considering building dynamic properties and inertia when evaluating seismic earth pressures on basement walls to avoid unsafe estimations or overdesign.