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Modification of an Existing Elevated Tabletop Compressor Foundation Disclosure Number: IPCOM000218854D
Publication Date: 2012-Jun-07
Document File: 1 page(s) / 32K

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The Prior Art Database

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by Jerry Ong


The modification of existing elevated structures supporting centrifugal rotating machinery (tabletops) may present additional problems not normally encountered in a new design. A case history of a revamp highlights special aspects of dynamic design and foundation performance evaluation and analysis.

An existing, three wall, four column concrete tabletop, supporting an in-line equipment train consisting of a motor, a gear, and two compressors was scheduled for a major alteration. Historical data of past problems and vibration measurements was compared with a dynamic analysis of the existing structure. Various configurations of a revised tabletop were tried. This sensitivity study showed the same problem evident in the existing structure analysis-- translational and torsional modes of vibration indicating high amplitude levels.

The final design conclusion to remove existing walls is an example of a classic dynamic principle--that strengthening or stiffening of a structure is not always the solution to a vibration problem, because of the inherent natural frequencies of a structure. In spite of a myriad of other problems associated with the modification, the tabletop and equipment have currently undergone startup smoothly without vibration problems. The successful evaluation of the existing foundation may be attributed to consideration of available performance information, prop...