Effect of Shallow Rocking Foundation on Seismic Energy Dissipation Capacity and Self-centering Ability of RC Framed Buildings
摘要
Seismic design concepts highlight the importance of shallow rocking foundations as an efficient method for dissipating energy during intense seismic events. However, a viable methodology to design such foundations is yet to be established. Therefore, this study investigates the impact of various soil types on the ability of reinforced concrete (RC) frame buildings with shear walls supported by rocking foundations to self-center and dissipate seismic energy. For the analytical investigation, a simplified and regular plan of the RC building and foundation is designed and detailed according to the relevant Indian standards. To demonstrate the advantages of rocking foundations, this study compares the seismic responses of RC buildings with different levels of foundation rocking to those of conventionally designed foundations by conducting nonlinear dynamic time history analyses. Rocking foundation reduces the seismic force demands of the RC buildings, as indicated by the foundation rotation-overturning moment hysteretic responses. This is because rocking foundation causes more significant foundation rotation at the base of the foundation than the conventionally designed ones. Consequently, there is an observed increase in energy dissipation due to the effective utilization of the nonlinearity of the foundation. Further, rocking foundation exhibits better self-centering ability than conventional footings for very strong ground motion record.