This sub-section provides a basis for establishing the dynamic forces to be used by civil engineers in foundation design calculations. Soil mechanics, natural frequency calculations, bearing pressure, concrete strength, and other design factors are not covered here. Refer to the Civil and Structural Manual for such information. Foundations, anchor bolts, and grouting are discussed in the General Machinery Manual.
In addition to knowing the dimensions and weights of the machinery to be supported, engineers designing the foundation must know the magnitude, direction, and frequency of the dynamic forces that the machinery will exert on the foundation.
The importance of foundations to a compressor installation cannot be overemphasized. Foundations attenuate vibratory forces generated by the machinery, and reduce transmission of these forces to the surrounding plant and equipment. Foundations also keep the machinery in alignment.
To perform these essential functions throughout the life of the installation, the foundation must be sized to support the weight of the machinery while imposing a tolerable bearing pressure on the soil or structure. It must be properly designed so that the system, consisting of the foundation, soil, machinery, and piping, is not at or near a resonant condition. It is particularly important on offshore structures, which may be susceptible to resonance from the machinery vibration. The purchaser of the machinery is normally responsible for the design of the foundation.
The vendor or manufacturer of the machinery will seldom take this responsibility because his expertise is not in this field. It would not be in his best interest to accept the risks associated with the design. Additionally, the vendor does not have specific knowledge about the soil conditions at the site.