Foundation Natural Frequency

I’m designing a pump foundation and need to see to it that the pump’s operating speed is 33% removed from the foundation’s natural frequency. The preliminary design of the foundation is a simple block of concrete, about 10.3’ x 4.3’ x 5’ deep. How to determine the natural frequency? Are soil properties involved?


Depends on how sensitive the piece of equipment is, really. Typically for a typical industrial motor/pump application, I will design the foundation 3x the weight of the motor.

Alternatively, if you are designing a foundation for a generator (high $$ equipment) you may want to consider the soil properties as well. A good reference book would be Design of Structures and Foundations for Vibrating Machines by Arya, O’neil and Pincus.

Above is a snippet.

Another source of info can be found here: