As part of advance construction work, geotechnical exploration is being undertaken throughout the US and Canadian project footprints to help prepare for full construction of the Gordie Howe International Bridge.
What is the purpose?
Geotechnical sampling is critical to confirm design assumptions by providing engineers with the information they need to design foundations and other structures. This type of boring informs the design team on the soil bearing pressure, the active soil load, the location of the groundwater table and the characteristics of each layer of soil.
How are samples taken?
Work typically involves a drill rig and one support vehicle for transferring personnel and field supplies. A crew typically consists of three or four workers including an operator, support staff and field engineer.
The geotechnical crew performs a combination of pounding and drilling into the earth until they reach bedrock. From there they drive a casing an additional 20 to 40 feet deeper to assess the quality of bedrock. Pulling one core sample can take two-to-three days. Samples are sent back to the designer for analysis and incorporation of the data into design. The core sample holes are filled after the sample is taken.
A number of geotechnical crews are currently in the field working to gather approximately 1000 geotechnical samples across the project sites.