Gordie Howe International Bridge Foundations - Drilled Shaft Construction in Challenging Detroit Limestone-PPT Presentation

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The Gordie Howe International Bridge project required large-diameter drilled-shaft foundations in challenging Detroit River conditions. The site included former industrial land with contaminated fill, clay layers, glacial till, and weathered, fractured Dundee Limestone. Bedrock strength increased with depth, while deep artesian water and hydrogen sulfide added construction risks.<br /><br />The foundation scope included twelve 3.0 m diameter tower shafts, each about 37 m long, with 7 m rock sockets, plus back-stay and dock-wall shafts. Construction used an oscillator-installed casing system, cranes and grabs to excavate overburden, and conventional drilling tools for the limestone. Polymer slurry was cleaned and reused in a closed-loop system. Crews managed artesian water with full-length casing and a maintained slurry head, and cleaned shafts using buckets, fluid exchange, and airlifting. Heavy reinforcement cages—up to 140,000 lb and 132 ft long—required coordinated crane picks.<br /><br />Operational constraints included heavy oscillator loads near a bulkhead, cold weather, night work, safety concerns, and restrictions involving traffic, boats, trains, and trucking. Rock flour made shaft cleaning difficult, and hydrogen sulfide in rock fractures could lower pH and stain steel.<br /><br />A static load test used four 865 mm O-cells, with a maximum test load of 160 MN and a 24-hour hold. Testing and quality control also involved strain gauges, telltales, TIP, CSL, pressuremeters, and SQUID testing.<br /><br />Quality-control investigations addressed localized low-temperature readings in seven shafts, mainly near the river; CSL anomalies in the upper 10 m that improved over time and were checked with cores; reinforcement-cage congestion; and uncertainty in interpreting SQUID results, including possible probe rotation or resistance.

Keywords

Gordie Howe International Bridge

drilled-shaft foundations

Detroit River

Dundee Limestone

artesian water

polymer slurry

oscillator-installed casing

rock socket

static load test

quality control