In a machine-foundation soil system, the frequency and amplitude have to be controlled by suitable means such as by balancing of dynamic loads or using suitable foundation. The dynamic forces can be transmitted to the soil through the foundation by appropriate selection of foundation mass or by using damping. This paper is the outcome of a research study conducted recently to investigate dynamic response of circular foundation in sandy soils. The paper concentrates on dynamic behavior for circular foundation with cap-anchor made of reinforced cement concrete. The influence of increase of base diameter of cap-anchor foundation on resonant frequency and amplitude for various eccentricities ranging from 0° to 42° were studied. Significant increases in 6equency with different eccentricities were observed with increase in base diameter of the cap-anchor foundation from 0% to 40%. On the other hand, reduction of amplitude at resonance was recorded with the increase of base diameter at various eccentricities. Increase in resonant frequency (η) was observed as 27% whereas percentage increase in amplitude reduction (Ψ) was recorded 64% with embedment ratio of 30% only. It was found that the increase of base diameter of the circular foundation with cap-anchor can control vibration and is capable of withstanding higher dynamic forces when compared to simple foundation or non-circular/vertical foundation with cap-anchor
