What are the Special Considerations in Planning
The dimensions of the foundation should be such that for low-speed machines (operating speed less than 500 rpm) the natural frequency is high, and vice-versa. To obtain a high natural frequency, the foundation must have a large base area and a small self-weight. The foundation recommended in such cases is either of box or caisson type. To obtain a low natural frequency, the foundation must be fairly massive or should be supported on springs or other suitable materials.
The outline dimensions of the foundation (in-plan) are generally furnished by the machine manufacturers. The height of the foundation may be fixed tentatively on the basis of soil strata and the operating levels for the machinery.