Performance of Storage Tanks Supported by Shallow & Deep Foundations-Paper

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The paper reviews foundation performance for storage tanks, which are heavy, thin-shelled structures sensitive to both uniform and differential settlement. Excessive movement can damage tank floors, shells, and connected equipment, so design must meet stringent settlement limits set by standards such as API, EEMUA, and British guidance. Acceptance criteria vary with tank type and include limits on tilt and circumferential and radial settlement.

Three project examples demonstrate that foundation solutions should be selected according to subsurface conditions and project requirements:

- <strong>Bored cast-in-place piles, Vizag:</strong> Tanks on very soft ground and fill were supported on piles extending to competent weathered rock. Pile load tests supported the design.
- <strong>Vibro stone columns:</strong> For tanks on loose silty sand and sandy silt, stone columns improved bearing capacity, reduced settlement, and increased resistance to liquefaction. Plate load tests confirmed adequate performance.
- <strong>Vibro compaction, Singapore:</strong> Reclaimed loose-to-medium-dense sands beneath tanks were densified. Hydrotest settlements of 5–15 cm were within operating tolerances and consistent with design predictions.

The authors conclude that piles are not the only viable option for difficult ground. With thorough geotechnical assessment, ground improvement—such as stone columns or vibro compaction—can support shallow foundations while meeting performance requirements. Depending on soil conditions, these approaches may reduce cost and construction time compared with deep foundations. Field verification through pile or plate load tests and tank hydrotests is important to confirm performance.

Keywords

storage tanks

foundation performance

settlement criteria

ground improvement

bored cast-in-place piles

vibro stone columns

vibro compaction

soft ground

liquefaction resistance

hydrotest settlements