Design and Construction Challenges of Lax Automated People Mover Large-Diameter CIDH Piles in an Active Airport-PPT Presentation

PPT Presentation

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The presentation describes the design and construction challenges of large-diameter cast-in-drilled-hole (CIDH) piles for the LAX Automated People Mover (APM), built within an active airport. The project includes a guideway and six stations, with piles installed close to existing parking structures, utilities, and a central outfall sewer. The APM is being delivered through a 30-year design-build-finance-operate-maintain contract.<br /><br />The project included more than 200 CIDH piles, 6 to 11 feet in diameter. Because of their size and capacity, pile load testing was required for selected piles. Testing compared dry and slurry-supported construction methods and measured end-bearing resistance and skin friction.<br /><br />Results showed that very dry sands and high-plasticity, over-consolidated clays developed less side resistance than predicted by standard AASHTO methods. Conversely, dense sands produced greater end-bearing resistance than AASHTO predictions, while stiff clays performed similarly to those predictions.<br /><br />Load testing supported the use of higher resistance factors and limited end-bearing resistance, with settlement capped at one inch. Ultimately, the piles were all less than 90 feet long and constructed using the dry method. The testing also enabled the project to avoid slurry use in the Central Terminal Area.

Keywords

LAX Automated People Mover

CIDH piles

large-diameter piles

pile load testing

dry construction method

slurry-supported construction

end-bearing resistance

skin friction

AASHTO methods

airport infrastructure