granular fill material would require that the excavation be sufficiently sloped to conform to
OSHA Guidelines Title 29 CFR Subpart P 1926.650. Considering the site constraints, a shoring
system may be required where an open excavation is impractical.
The following Table summarizes the required mast arm foundation sizes for spread footing and
drilled pier foundation alternatives:
Recommended Foundations Types
Test Location Spread Footing | Drilled Pier
Boring Foundation Foundation
No. Alternative Alternative (1)
Type 1C Spread | Type 2 drilled
DWH & Footing pier (3’-0
B-1 Graham Drive (9°-0”x7’-0”) diameter) and
NE Corner 2’-0” thick and (11’-0 deep)
6-4” deep
(1) Bedrock is likely to be encountered at 8.5 feet below the surface; thus, blasting
and/or hoe-ramming might be necessary to install the pier to the proper elevation. A
spread footing foundation is shallower; thus bedrock would not be encountered
during construction.
The foundation base soils should consist of firm and stable, naturally occurring dense Sand and
gravel deposits that are free of standing water. A Geotechnical Engineer from MET should
inspect the foundation base soils prior to the placement of steel reinforcement steel rebar to
verify these conditions are satisfied.
