Case History on Pipe Pile Installation-PDF

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The case history describes installation of 120 open-ended, 24-inch-diameter concrete-filled pipe piles supporting a 650-foot chimney at a Michigan power plant. Each pile was approximately 200 feet long, driven through loose sands and silts over stiff clay to Marshall sandstone. The design required a working capacity of 300 tons and an ultimate capacity of 600 tons.<br /><br />Analysis showed that the specified pipe piles and available driving energy might not overcome the soil resistance or transmit the force needed to reach bedrock. Wave-equation and static-soil analyses predicted an ultimate dynamic capacity of about 400 tons—below the design target. Jetting at the pile tip alone was insufficient, and was constrained by nearby structures. The long piles were also vulnerable to increased resistance from soil compaction and “freeze” during splicing delays.<br /><br />A successful installation method was developed using a 24-inch augered hole under slurry to a depth of 100 feet, reducing friction in the upper soils. A high-energy IHI-J44 hammer then drove the pile to sandstone. After driving, the pile was mechanically cleaned and redriven to the specified resistance; it was cleaned again, filled with a concrete plug, and completed with concrete. The pile tip was reinforced to allow cleaning and seating without damage. Actual driving records closely matched the theoretical predictions.<br /><br />A representative pile was load-tested to 700 tons using a hydraulic jack and reaction system. Its performance confirmed that the installation method achieved the required capacity. The authors emphasize that installation feasibility must be considered during design—especially for high-capacity piles—and that conventional settlement criteria may not adequately interpret their load-test results.

Keywords

concrete-filled pipe piles

high-capacity foundation

pile installation

wave-equation analysis

static-soil analysis

augered hole slurry

pile driving

load test

Michigan power plant

Marshall sandstone