Appendix - GSA

• Bearings and distances for all property lines within the
limits of work.
• Official datum upon which elevations are based and the
benchmark on or adjacent to the site to be used as a
starting point.
• Official datum upon which horizontal control points
are based.
• If there are not already two benchmarks on the site,
establish two permanent benchmarks.
• Elevations of key datum points of all building
structures and improvements directly adjacent and
across the street from the project site during both wet
and dry season.
• Delineate location of any wetlands or floodplains,
underground streams or water sources.
Geotechnical Investigation
and Engineering Report
On most GSA projects geotechnical investigations will
take place at three separate stages: during site selection,
during building design, and during construction. The
requirements for geotechnical work during site selection
and during construction are described in other GSA
documents. The requirements for geotechnical work for
the building design are defined here. They apply whether
GSA contracts for geotechnical work separately or include
the geotechnical investigation in the scope of the A/E
services.
Purpose. The purpose of the geotechnical investigation
during building design is to determine the character and
physical properties of soil deposits and evaluate their
potential as foundations for the structure or as material
for earthwork construction. The type of structure to be
built and anticipated geologic and field conditions has a
significant bearing on the type of investigation to be
conducted.
The investigation must therefore be planned with
knowledge of the intended project size and anticipated
column loads, land utilization and a broad knowledge of
the geological history of the area.
The guidelines given here are not to be considered as
rigid. Planning of the exploration, sampling and testing
programs and close supervision must be vested in a
competent geotechnical engineer and/or engineering
geologist with experience in this type of work and
licensed to practice engineering in the jurisdiction where
the project is located.
Analysis of Existing Conditions. The report should
address the following:
• Description of terrain.
• Brief geological history.
• Brief seismic history.
• Surface drainage conditions.
• Groundwater conditions and associated design or
construction problems.
• Description of exploration and sampling methods and
outline of testing methods.
• Narrative of soil identification and classification, by
stratum.
• Narrative of difficulties and/or obstructions
encountered during previous explorations of existing
construction on or adjacent to the site.
• Description of laboratory test borings and results.
• Plot plan, drawn to scale, showing test borings or pits.
• Radon tests in areas of building location.
• Soils resistivity test, identifying resistivity of soil for
corrosion protection of underground metals and
electrical grounding design.
Revised March 2005 – PBS-P100
SUBMISSION REQUIREMENTS
Surveys and Geotechnical Reports – Geotechnical Investigation & Engineering Report
349
A.5