Optimization of Project Schedule and Cost Using Available Steel Sections as Foundations for a Deep Seated Structure-Paper

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A 24 m-deep Car Dumper Vault (CDV) at a coastal bauxite project was initially designed on a partially compensated raft. Excavation was supported by three levels of sheet piles, but near the final depth the east-side slope failed, displacing the supports and disturbing the founding soils. The original foundation approach was therefore abandoned.<br /><br />The replacement design used 136 bored, cast-in-place concrete piles, 800 mm in diameter and socketed into bedrock. Installation was expected to take about two months and cost approximately US$600,000. Because the project was already delayed, the team sought a faster alternative.<br /><br />The owner had 15,000 tonnes of unused HP 360 × 133 steel sections in storage from an earlier project. Corrosion testing confirmed that the sections remained suitable for reuse. Engineers evaluated their structural and geotechnical capacity, checked drivability with trial piles, and verified the design through static load tests and driving records.<br /><br />The final design used 330 driven H-piles. Installation, including trial piles and load testing, was completed within 30 days. Because the steel sections were already available on site, the installation cost was about US$200,000—roughly US$400,000 less than the bored-pile option—and the schedule was shortened by about one month.<br /><br />The project demonstrates how reassessing available materials after a construction setback can produce a safe, practical foundation solution while reducing both cost and project duration.

Keywords

Car Dumper Vault

bauxite project

foundation redesign

sheet pile failure

bored cast-in-place piles

bedrock socketing

steel H-piles

reuse of materials

driven piles

cost and schedule savings