Dynamic Response of Embedded Machine Foundations

Two case studies are presented which describe the measured transient and steady-state dynamic response of two types of machine foundation systems. Each machine foundation was embedded and was undergoing rocking and sliding motion. Measurements made on these prototype systems are compared with values predicted from available theoretical and model studies, after introducing in situ dynamic soil properties. In the first case study, the motion of the embedded, air-compressor foundation was only slightly less than that predicted for an equivalent circular foundation resting on the surface. This close agreement was predicted very well by results of transient response tests on the actual foundations, which showed that the damped natural frequency and damping ratio were close to those of an equivalent surface foundation. In the second case study, the actual motion of the two embedded vacuum pump foundations was substantially less than that predicted for an equivalent surface foundation