In Plain English
Quick Answer
Drilling a hole in the ground to collect soil samples and determine what's underground before designing foundations.
Definition
Definition
A subsurface investigation technique where a drill rig advances a borehole into the ground to retrieve soil samples and perform in-situ tests at various depths. Soil borings are performed by geotechnical engineers to determine soil stratification, bearing capacity, groundwater conditions, and other properties needed for foundation design. The data is summarized in a geotechnical report with boring logs.
Context
Why It Matters in Bidding
Soil borings drive foundation design, which is one of the largest cost and risk variables on any project. If a geotechnical report is available at bid time, the estimator can scope excavation, dewatering, over-excavation, and deep foundations accurately; if borings are missing or limited, that uncertainty must be carried as a qualification or contingency rather than absorbed silently.
Example
Example
Before submitting a bid on a warehouse, the estimator reviews the boring logs in the geotechnical report, sees the water table sits two feet above footing elevation, and adds a dewatering and pumping line item the other bidders may have overlooked.
See Also
Related Terms
FAQ
Questions Contractors Ask
Who pays for soil borings on a construction project?
On most projects the owner commissions and pays for the geotechnical investigation during design, then shares the report with bidders. If borings are not provided, contractors should not assume favorable conditions; instead they qualify the bid based on available data and may price the investigation as an added scope if required.
How do soil borings affect my foundation estimate?
Boring logs reveal bearing capacity, soil layers, and groundwater, which determine whether you can use shallow spread footings or need piles, piers, or ground improvement. They also flag unsuitable soils requiring removal and replacement. Without this data, foundation pricing is a guess, so estimators rely on the logs to scope excavation and structural support.
What should I do if no geotechnical report is included in the bid documents?
Submit your bid with a written qualification stating it is based on assumed soil conditions and excludes unforeseen subsurface issues, rock, or groundwater. Carry a contingency where allowed, and request the report or borings during the RFI period so unknown conditions become a change-order item rather than your loss.
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