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APPROXIMATE THICKNESSES OF STRATIGRAPHIC UNITS PENETRATED
AND DEPTH TO AUGER REFUSAL AT B-1

STRATIGRAPHIC UNIT B-1 P-1
Topsoil Layer 0.2 ft. -
Fill Layer 2.8 ft. -
Old Topsoil Layer 0.25 ft. -
Subsoil Layer 0.75 ft. -
Sand and Gravel Layer 4.5 ft. -
Auger Refusal 8.5 8.5
Note:

1. Samples were not collected during the advancement of test probe P-1. This probe was
advanced to confirm the depth to auger refusal encountered at B-1.

Groundwater Conditions

Groundwater was not observed at test boring B-1 or test probe P-1. It should be noted, however,
that groundwater fluctuates with season and precipitation; therefore, groundwater might be
present are other times of the year.

GEOTECHNICAL ENGINEERING EVALUATION AND RECOMMENDATIONS

The organic topsoil, loose to medium dense fill, and buried organic layers are inadequate for
support of the signal mast arm foundation. These unsuitable soils were found to a depth of 4 feet
below the existing surface elevation. Directly beneath the fill and organic layer, dense to very
dense sand, gravel, and boulder soil deposits were to a depth of 8.5 feet, where bedrock or large
boulders were encountered.

Based upon results of the subsurface exploration program, the traffic signal mast arm may be
supported by a drilled pier or a spread footing type foundation system. The loose fill and organic
layers within 4 feet of the surface are unsuitable for support of either type of foundation;
therefore, these materials should be excavated within 3-feet clear of the drilled pier and replaced
with compacted structural fill material.

According to Note 4, Sheet No. TS-01_Rev2016 of the NHDOT Standard Plans, the maximum
design soil pressure is 1.5 tons per square foot (tsf) both horizontally and vertically for a spread
footing; and according to Note 3, Sheet No. TS-04_Rev2016 of the NHDOT Standard Plans, the
soil’s minimum angle of internal friction is 32 degrees for a drilled pier foundation.

The engineering properties of the soil layer encountered below 4.0 feet indicate that the sand and
gravel fill layer has dense relative density; and therefore, is adequate for support of a spread
footing or drilled pier type foundation. The fill and organic layer must be replaced with structural
fill material. Backfill material around the spread footing/pedestal type foundations should consist
of NHDOT Item 304.3 (Crushed Gravel) as detailed in the 2010 Edition of the NHDOT Standard
Specifications for Road and Bridge Construction. This material should be placed in 8-inch
maximum loose lifts and be compacted to at least 95 percent of the materials maximum dry
density as determined by ASTM Designation D-1557. Backfilling around the foundation with

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.

FINAL DESIGN CONSTRUCTION MONITORING

It is recommended that a qualified geotechnical engineer or his/her representative be retained to
provide engineering services during the excavation and foundation construction phases of the
project. This will become particularly important relative to the inspection and testing of backfill
materials and concrete used in construction of the foundation elements. This would allow for
design changes in the event that subsurface conditions differ from those anticipated prior to the
start of construction. The adequacy of compaction of all backfill material should be verified by
field density testing.

In the event that any changes in the nature, the design, or the location of the mast arms are
planned, the conclusions and recommendations contained in this report shall not be considered
valid unless the changes are reviewed and the conclusions of the report modified or verified in
writing by Miller Engineering & Testing, Inc.

Thank you for this opportunity to be of service on this project. Please call us if you have
questions or require additional information.

Sincerely,
MILLER ENGINEERING & TESTING, INC.

: A PA

9 FA fot i. Ah
Frank K. Miller, P.E.
Executive Vice President

Figure

DANIEL WEBSTER HIGHWAY

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Greenman-Pedersen, Inc,

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BORING LOCATION PLAN

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Attachment A

LIMITATIONS

Explorations

The analyses, recommendations and designs submitted in this report are based in part
upon the data obtained from subsurface explorations. The nature and extent of variations
between these explorations may not become evident until construction. If variations then
appear evident, it will be necessary to re-evaluate the recommendations of this report.

The generalized soil profile described in the text is intended to convey trends in
subsurface conditions. The boundaries between strata are approximate and idealized, and
have been developed by interpretation of widely spaced explorations and samples; actual
soil transitions are probably more gradual. For specific information, refer to the boring
logs.

Water level readings have been made in the drill holes at times and under conditions
stated on the boring logs. These data have been reviewed and interpretations have been
made in the text of this report. However, it must be noted that fluctuations in the level of
the groundwater may occur due to variations in rainfall, temperature, and other factors
differing from the time measurements were made.

Review

4,

It is recommended that this firm be retained to review final design plans and
specifications. In the event that any changes in the nature, design, or location of the
structures are planned, the conclusions and recommendations contained in this report
shall not be considered valid unless the changes are reviewed and conclusions of the
report modified or verified in writing by Miller Engineering & Testing, Inc.

Construction

It is recommended that this firm be retained to provide soils engineering services during
the excavations and foundation construction phases of the work. This is to observe
compliance with the design concepts, specifications, or recommendations and to allow
design changes in the event that subsurface conditions differ from those anticipated prior
to the start of construction.

Use of Report

6.

This report has been prepared for the exclusive use of the Greenman-Pedersen, Inc. for
the proposed DW Highway & Graham Drive Traffic Signal Mast Arm located in
Nashua, NH in accordance with generally accepted soil and foundation engineering
practices. No other warranty, expressed or implied, is made.

This soil and foundation engineering report has been prepared for this project by Miller
Engineering & Testing, Inc. This report was completed for design purposes and may be
limited in its scope to prepare an accurate bid. Contractors wishing a copy of the report
may secure it with the understanding that its scope is limited to design considerations
only.

Attachment B

TEST BORING LOG

Project: DWH- Graham Dr. Traffic Signal Sheet 1 of _!
Nashua, NH Boring No: B-1
MILLER ENGINEERING & TESTING, INC. —
espe ee Project No: 16.186.NH Location: See Plan
100 Sheffield Road - Manchester, NH 03103] — Date Start: 08-22-16
Ph. (603) 668-6016 - Fax: (603) 668-8641 pigs Eat 08-22-16 Approx. Surface Elev:
GROUNDWATER OBSERVATIONS
CASING SAMPLER Date Depth Casing At Stabilization Period
Type HSA SS 08-22-16 None Upon Completion
Size 2-1/4" ID 1-3/8" ID
Hammer 140 Ibs.
Fall 30"
SAMPLE BLOWS a
Depth/ | Cas Sampl Depth suai Sample Description s
Elev. | byft |StmPle ep Pen. | Rec. | 0-6" | 6-12" |12-18"|18-24"|Change : r Z.
No. Range
9 S-1 0.0-2.0 24 16 2 4 10 9 S-1: 2" of dark brown, gray, loose, very fine sand and silt
q with abundant roots (topsoil), underlain by brown, loose to
medium dense, fine sand, little silt, trace fine gravel (FILL)
27 8-2 2.0-3.0 12 10 5 3 S-2: Brown, loose, fine sand, little silt, trace fine gravel
J] (FILL)
S2A 3.0-4.0 12 10 4 6 S-2A: 3" layer of dark brown, loose, very fine sand and silt
4 (old topsoil layer), underlain by orange-brown, rusty-
brown, fine sand and silt (subsoil)
‘ 8-3 4.0-6.0 24 13 13 24 36 59 S-3: Brown, very dense, fine to coarse sand and fine to
q medium subrounded gravel, broken rock fragments (small
boulders)
| Auger and Spoon Refusal at 8.5"
6
8 —_
BORING TERMINATED AT 8.5 ft ()
105
125
Driller: R. Marcoux COHESIVE CONSISTENCY (Blows/Foot) COHESIONLESS (Blows/Foot) PROPORTIONS USED
Helper: M. White 0-2 VERY SOFT 0-4 VERY LOOSE TRACE: 0-10%
Inspector: D. Ray 2-4 SOFT 4-10 LOOSE LITTLE: 10-20%
4-8 MEDIUM STIFF 10-30 MEDIUM DENSE SOME: 20-35%
8-15 STIFF 30-50 DENSE AND: 35-50%
15-30 HARD 50+ VERY DENSE

NOTES: (1) Moved approximately 6' north of boring B-1 and attempted probe P-1 to confirm refusal depth.

REMARKS: THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY BETWEEN SOIL TYPES. TRANSITION MAY BE GRADUAL.
WATER LEVEL READINGS HAVE BEEN MADE IN THE DRILL HOLES AT TIMES AND UNDER CONDITIONS STATED ON THE BORING LOGS.

FLUCTUATIONS IN THE LEVEL QF THE GROUNDWATER MAY OCCUR DUE TO OTHER FACTORS THAN THOSE PRESENT AT THE TIME MEASUREMENTS WERE MADE

TEST BORING LOG

Project: DWH- Graham Dr. Traffic Signal Sheet 1 of _!
Nashua, NH Boring No: P-1
MILLER ENGINEERING & TESTING, INC. —§—$—
a ere i Project No: 16.186.NH Location: See Plan
5
100 Sheffield Road - Manchester, NH 03103} Date Start: 08-22-16
Ph. (603) 668-6016 - Fax: (603) 668-8641 Date End: 08-22-16 Approx. Surface Elev:
GROUNDWATER OBSERVATIONS
CASING SAMPLER Date Depth Casing At Stabilization Period
Type HSA SS 08-22-16 None Upon Completion
Size 2-1/4" ID 1-3/8" ID
Hammer 140 Ibs.
Fall 30"
Depth’ | C SAMPLE BLOWS Strat. e
ep ‘as rata . 2
Elev. | bi/ft (S4™ple Depth Pen. | Rec. | 0-6" | 6-12" |12-18"|18-24"|Change Sample Description 5
No. Range
8 - 0.0-8.5 102 -: No sample collection. Drilled P-1 to a depth of 8.5' and
7 encountered auger refusal.
24
444
6 —_-
34
BORING TERMINATED AT 8.5 ft
105
2 4
Driller: R. Marcoux COHESIVE CONSISTENCY (Blows/Foot) COHESIONLESS (Blows/F oot) PROPORTIONS USED
Helper: M. White 0-2 VERY SOFT 0-4 VERY LOOSE TRACE; 0-10%
Inspector: D. Ray 2-4 SOFT 4-10 LOOSE LITTLE: 10-20%
4-8 MEDIUM STIFF 10-30 MEDIUM DENSE SOME: 20-35%
8-15 STIFF 30-50 DENSE AND: 35-50%
15-30 HARD 30+ VERY DENSE
NOTES:
REMARKS: THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY BETWEEN SOIL TYPES. TRANSITION MAY BE GRADUAL.
WATER LEVEL READINGS HAVE BEEN MADE IN THE DRILL HOLES AT TIMES AND UNDER CONDITIONS STATED ON THE BORING LOGS.
FLUCTUATIONS IN THE LEVEL QF THE GROUNDWATER MAY DUE TO OTHER FACTORS THAN THOSE PRESENT AT THE TIME ME, EMENTS WERE MADE,