Foundation

Module from the Storage Tank Engineering Curriculum curriculum.

Module 7 - Foundation and Settlement · Learning Objectives · 1. Design ringwall foundation for large tanks (> 50 ft diameter) · 2. Select crushed stone/gravel pad for small tanks with asphalt/oiled sand top · 3. Include undertank leak detection (double bottom or liner) · 4. Apply cathodic protection with MMO or magnesium anodes · 5. Apply API 653 App B settlement measurement and evaluation · Foundation Types

Type	Tank Size	Soil Bearing Req	Cost	Settlement Tolerance	Notes
Granular pad on grade	< 50 ft D	1500-2500 psf	Low	High (but uniform)	Small tanks
Crushed stone ringwall	50-150 ft D	2500-4000 psf	Medium	Low-moderate	Most refinery
Reinforced concrete ring	> 150 ft D or soft	3000-6000 psf	High	Low	Crude tanks
Pile-supported slab	Very soft soil	> 6000 psf pile	Highest	Very low	Coastal, marshy

Source: Storage_Tank_Engineering_Curriculum_v1.xlsx · Sheet: Foundation

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