Effectiveness of elliptical rolling rods for base isolation

Elliptical rolling rods between the base and foundation of a structure provide a new base isolation system. Herein, the effectiveness of elliptical rolling rods for isolating a multistory building against earthquake forces is investigated. A theoretical formulation for obtaining seismic response of a multistory building supported on elliptical rolling rods is developed. Due to the nonlinear force-deformation behavior of elliptical rolling rods, the seismic response of the system is obtained using an iterative numerical integration technique. The effectiveness of elliptical rolling rods is studied by comparing the response between isolated and corresponding fixed base systems for different eccentricities of the rods. It is shown that elliptical rolling rods are quite effective in reducing the seismic response of the system without undergoing large base displacements.