Ductile Iron Pile Foundation Solution for Interior Retrofit Projects-Paper

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The paper presents ductile iron piles (DIPs) as a foundation option for interior retrofits where access, headroom, vibration, cleanliness, and uninterrupted operations constrain construction. Modular pile sections are driven with an excavator-mounted hydraulic hammer and connected by bell-and-spigot joints, avoiding field splicing. DIPs can develop capacity through end-bearing or, when installed with grout, through bonding between the grout and surrounding soil.<br /><br />At a Hartford shipping facility, DIPs supported a new mezzanine in an active warehouse with limited overhead clearance and demanding compression and tension loads. End-bearing piles were driven to glacial till or rock. Load tests confirmed less than 0.2 inches of movement at 100 tons in compression and less than 0.25 inches at 25 tons in tension. Seventy-three production piles were installed in eight working days, with allowable capacities of 50 tons in compression and 15 tons in tension.<br /><br />At a Philadelphia facility, end-bearing piles were used in variable alluvial and residual soils. Testing showed that capacity depended on depth and termination conditions: piles bearing in lower alluvial deposits achieved about 45–47 tons allowable capacity, while deeper piles reaching stiff residual clay achieved 60–75 tons. The results enabled optimization of pile-cap layouts.<br /><br />The case studies demonstrate that DIPs can provide moderate-to-high capacities with low vibration and rapid installation in constrained, operational facilities. Site-specific load testing was important, particularly where piles terminated in soil rather than rock, to verify capacity and guide design.

Keywords

ductile iron piles

foundation retrofit

end-bearing piles

low vibration installation

modular pile sections

bell-and-spigot joints

load testing

warehouse mezzanine

glacial till

soil bearing capacity