Reciprocating Compressor Foundations to be Designed for Dynamic Loads

This being a very specialized area of foundation design the help of a subject matter expert was taken for the same. Again, this was done on a tight schedule as there was no slack between the arrival of the compressor packages and the completion of the foundations. The compressors are Acid Gas Compressor (4 nos) and Stabilizer Overhead Compressor (3 nos).

They are skid mounted units with air-cooled heat exchangers next to each of these skids. The foundation for the compressors and the air-cooled heat exchangers is connected. However, the dynamic analysis has been performed only for the compressor foundations.

Analysis covers the compressor foundation system, consisting of a raft foundation supporting compressor and auxiliary equipment mounted on a skid.

Detailed STAAD-based structural model was developed, where the foundation raft was represented using iso-parametric plate elements and the soil–structure interaction was simulated using elastic spring supports in all three translational directions as per geotechnical recommendations.

Dynamic loads for operating and other design scenarios are applied in the STAAD model of the compressor foundation based on vendor inputs, with unbalanced loads and couples simulated as time-history functions mathematically varying with time.

Time history analysis is performed to verify Structural response for unbalanced loads and peak vibration levels are compared with permissible limits for the extreme nodes.