A Monster Load Test of a Super Pile; Case History of the New Burnside Bridge Drilled Shaft Load Test Program-PPT Presentation

PPT Presentation

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The Burnside Bridge replacement project in Portland, Oregon, includes a pre-construction load test to verify the design and constructability of large-diameter drilled-shaft foundations for the new earthquake-resilient bridge.<br /><br />The test shaft was 10 feet in diameter and 130 feet long, with ten levels of strain gauges. Twelve 34-inch Osterberg cells, arranged in two levels, provided a test capacity of up to 102,000 kips. The shaft was constructed using full-length temporary casing, an oscillator, grab excavation, polymer fluid, airlifting, cage splicing, and tremie concrete placement.<br /><br />Quality-control measures included checks of shaft verticality, base cleanliness, concrete, and shaft integrity. The cased shaft’s centerline offset was 4 inches over 136 feet, and the base cleanliness inspection met the stated criteria.<br /><br />The load test mobilized a maximum shaft resistance of 68,652 kips (306 MN). Results measured side and base resistance across the site’s overburden and Troutdale formations, providing information for final foundation design.<br /><br />The presentation concludes that early load testing, industry input during program development, and a robust construction plan were key to the successful test. Although the test did not set a world record, it supplied valuable design and construction data for the new Burnside Bridge and represented a significant investment in Portland’s future.

Keywords

Burnside Bridge

Portland Oregon

load test

drilled-shaft foundation

earthquake-resilient bridge

Osterberg cells

shaft resistance

foundation design

quality control

construction testing