What I usually see is either a geotechnical report referenced as available for inspection by bidders, or the boring logs and lab test results included as an attachment to the specs.
Owners have an obligation to share their knowledge of existing conditions with bidders, such as subsurface investigations, hazardous material surveys, etc. The literature is full of construction claim judgments against Owners who failed to do so. Sharing the geotechnical engineer’s opinions and design recommendations may or may not be a good idea, depending on the intended use of the information. I think it is normally best just to share all hard data and let the bidder be responsible for its interpretation.
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