GEOTECHICAL-OTO Crafts Ave-2022 June
J1843-23-01
June 24, 2022
City of Northampton
c/o Ms. Dorrie Brooks
Jones Whitsett Architects
308 Main Street
Greenfield, Massachusetts 01301
Re: Preliminary Geotechnical Engineering Recommendations
208 Main Street at Crafts Avenue
Northampton, Massachusetts
Dear Ms. Brooks:
O’Reilly, Talbot & Okun Associates, Inc. (OTO) is pleased to provide this letter report
summarizing our geotechnical engineering recommendations for the proposed building at
Crafts Avenue in Northampton, Massachusetts. A Site Locus is provided as Figure 1. A
Site Sketch is provided as Figure 2.
Our geotechnical recommendations are based upon subsurface conditions observed in
two soil borings. Our services consisted of the full-time observation of the borings, review
of the logs and soil samples, engineering analyses, and preparation of this report. This
report is subject to the attached limitations.
PROJECT DESCRIPTION
Existing Conditions
The Site is located off Crafts Avenue in Northampton, Massachusetts. It is bounded to the
north and west by commercial and municipal buildings, to the south by Roundhouse Plaza,
and to the east by Crafts Avenue. The location of the Site is shown on Figure 1. The
northern portion of the Site contains an existing parking area (upper lot) for Northampton
municipal offices. A separate parking area (lower lot) for the Northampton Building
Department is located in the southern portion of the Site.
Topography in both the upper lot and lower lot is generally flat, near elevation 148 and
128 feet, respectively 1. Topographic relief between the two parking lots is provided by a
pair of retaining walls, a shrub covered slope, and an integrated stairwell (portions of which
also act to retain soil). A landscaped slope is also present along the eastern portion of the
Site, between the upper lot and Crafts Ave. The existing parking lots, retaining walls, and
nearby buildings are shown on Figure 2.
1 Elevations were determined using the “Massachusetts Elevation Finder”, which is based upon Lidar data. Accessed via:
https://massgis.maps.arcgis.com/apps/webappviewer/index.html?id=3144242832214194945076cc18d78372
Preliminary Geotechnical Engineering Recommendations
208 Main Street at Crafts Ave
Northampton, Massachusetts
June 24, 2022
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Proposed Construction
Preliminary project plans call for the construction of a five-story, approximately
3,200 square foot (footprint) building. The approximate location of the building is shown
on Figure 2. The structure will be a multi-story structure. We anticipate that the building
will have a constant bottom floor level even with the existing ground surface in the lower
lot, near elevation 128 feet. Therefore, a cut of approximately 22 feet will be required to
establish the bottom floor subgrade in the northern part of the building.
The lower two levels will be steel framed and the upper three levels will be wood framed.
The existing retaining walls will be demolished to prepare the Site for construction, and
the proposed building will be built into the existing slope. Therefore, the lower-level walls
in the northern half of the building will effectively be basement walls and will need to be
designed to resist lateral earth pressures.
We expect structural loads to be supported on both isolated column and continuous strip
footings. Maximum unfactored structural loads, as currently estimated are on the order of
130 kips for column loads and approximately 13 kips per linear foot for bearing walls. The
recommendations provided in this report should be reviewed and revised as necessary if
finals load differ.
SUBSURFACE EXPLORATIONS AND TESTING
Subsurface investigations consisted of two soil borings performed within the footprint of
the proposed building. Boring CA-1 was performed in the upper lot to a depth of 34 feet,
and boring CA-2 was performed in the lower lot to a depth of 19 feet. Boring locations are
shown on Figure 2. The borings were performed on May 19, 2019, by Seaboard Drilling
of Chicopee, Massachusetts. Borings were performed using a Mobile B-53 truck mounted
drill rig and drive and wash (CA-1) or hollow stem (CA-2) drilling techniques. Boring logs
are attached.
Soil samples were collected continuously from the ground surface to a depth of four feet
below ground surface, at a depth of five feet, and every five feet thereafter. Soil samples
were collected using a two-inch diameter split spoon sampler, driven 24 inches with a
140-pound automatic hammer falling 30 inches (American Society for Testing and
Materials Test Method D1586 “Standard Test Method for Penetration Test and Split-Barrel
Sampling of Soils”). The number of blows required to drive the sampler each six inches
was recorded. The standard penetration resistance, or N-value, is the number of blows
required to drive the sampler the middle 12 inches. Soil properties, such as strength and
density, are related to the N-value. The field N-values are corrected to a standard 60%
hammer efficiency, known as N60, to account for differing hammer efficiencies for each
hammer type and drill rig. The N-values presented on the boring logs are field values,
which are not adjusted for hammer efficiency. However, the adjusted N60 values were
used in our engineering calculations and analysis.
An O’Reilly, Talbot & Okun Associates, Inc. (OTO) engineer observed and logged the
borings. Samples were classified according to a modified version of the Burmister Soil
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Northampton, Massachusetts
June 24, 2022
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Classification System. After drilling, bore holes were backfilled with soil cuttings and
patched with asphalt.
Field Strength Testing
Field strength testing was performed on selected samples of the silt and clay using pocket
torvane (E-285 Pocket Vane Shear Tester) and pocket penetrometer devices. These field
measurements are intended to provide a rough measure of the strength of fine-grained
soils. The pocket penetrometer provides a measure of the unconfined compressive
strength of soil by failing the clay by “punching”. The torvane device provides an estimate
of the undrained shear strength of fine-grained soils by failing the silt and/or clay in a
rotational shearing mode. Theoretically, the unconfined compressive strength is twice the
undrained shear strength. A total of five pocket penetrometer and torvane tests (each)
were completed in the field. Pocket torvane and pocket penetrometer results are
presented on the attached boring logs and discussed below.
Photo-Ionization Detector (PID) Screening
The headspace of each soil sample collected from the borings was screened using a
MiniRAE Lite Photo-Ionization Detector (PID). PID screening provides an assessment of
volatile organic content of the samples. PID readings are provided on the attached boring
logs and discussed below.
Grain Size Analysis
One composite soil sample, collected from cuttings in the upper five feet of boring CA-1,
was submitted for grain size analysis (sieve only) to Allied Testing Laboratories of
Springfield, Massachusetts. This test was performed to evaluate the suitability of on-Site
soils for use as engineered fill. Results are discussed below.
SUBSURFACE CONDITIONS
The subsurface profile described below was interpreted based upon conditions
encountered in the soil borings. Subsurface conditions generally consisted of a surface
layer of pavement with granular base underlain by non-engineered fill, native fine-grained
soils, and bedrock.
Soil Conditions
Asphalt or Concrete Pavement: Each boring was performed in an existing paved parking
area. Four inches of asphalt with approximately six inches of granular base course was
present at boring location CA-1. The base consisted of medium to coarse sand with little
gravel and trace amounts of silt. Five to six inches of concrete was present at boring
location CA-2 with little to no granular base course.
Non-Engineered Fill: Approximately 15.5 feet and 5.5 feet of non-engineered fill was
encountered in borings CA-1 and CA-2, respectively. The fill generally consisted of loose
to medium dense, fine to coarse sand with varying amounts of gravel and debris (brick,
Preliminary Geotechnical Engineering Recommendations
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Northampton, Massachusetts
June 24, 2022
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concrete, wood, coal, ash). However, the bottom one to two feet of the fill contained
significant amounts (greater than 25% by volume) of debris at both boring locations. This
fill is not a suitable bearing layer. The fill extended to an approximate elevation of
132.5 feet in boring CA-1 and 122.5 feet in boring CA-2. Therefore, the base of the fill
appears to be above the bottom level subgrade in the northern part of the building and
about five feet below subgrade level in the southern portion.
Varved Silt and Clay: The fill layer was directly underlain by varved silt and clay.
Geologically, the Site is located near the western shore of former Lake Hitchcock, which
was a large post-glacial lake that formerly covered much of the Connecticut River Valley.
Sediments consisting of thin, interbedded lenses of silt and clay (collectively known as
varved clay) were deposited at the bottom of the lake.
Glacial Till: Glacial till appears to directly underlie the varved silt and clay level. Boring
CA-1 encountered refusal on what may be glacial till at a depth of approximately 34 feet
below ground surface (elevation 114 feet.) Boring CA-2 encountered glacial till at a depth
18 feet (elevation 110 feet). Glacial till is a very dense, heterogeneous mixture of silt, clay,
sand, and gravel that is generally present immediately above bedrock throughout New
England. Given its density, glacial till should be relatively incompressible under the
anticipated foundation loads and would be a good bearing surface to support the
anticipated building. However, since the top of the glacial till unit is about 15 feet below
the bottom level it is unlikely that it could be used as a bearing surface for a shallow
foundation system.
Bedrock: Auger refusal was encountered in both borings on what might be bedrock.
Refusal was encountered in boring CA-1 at a depth of 34.1 feet below ground surface
(elevation 113.9 feet) and in boring CA-2 at 19.2 feet elevation (elevation 108.8 feet).
Groundwater Conditions
Groundwater was encountered boring CA-2 at a depth of eight feet below ground surface,
corresponding to an approximate elevation of 120 feet, or about eight feet below the
anticipated bottom slab level. The depth to groundwater could not be determined in boring
CA-1 due to the method of drilling employed.
Results of Unconfined Compressive and Shear Strength Testing
The unconfined compressive strength of the clay stratum was estimated in the field using
a pocket penetrometer and the undrained shear strength was estimated using an E-285
Pocket Vane Shear Tester. These field measurements are intended to provide a rough
measure of the engineering properties of the fine-grained soils. Vane Shear
measurements of shear strength ranged from approximately 1,500 to 4,500 pounds per
square foot (psf) in the soft varved silt and clay portion. Pocket penetrometer
measurements of unconfined compression strength ranged from approximately 500 to
2,500 psf. Pocket vane shear and penetrometer test results are presented on the attached
boring logs.
Preliminary Geotechnical Engineering Recommendations
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Northampton, Massachusetts
June 24, 2022
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Environmental Field Screening
The headspace of each soil sample was screened using a photoionization detector (PID).
PID screening provides an assessment of volatile organic compounds (VOCs) of the
samples. PID readings taken from samples of native Site soils and the fill at boring location
CA-2 were generally below the instrument detection limits. However, PID readings taken
from samples of the non-engineered fill at boring location CA-1 ranged from 1.3 to 23 parts
per million (ppm). The 23 ppm reading is above typical background levels and indicative
of the presence of VOCs. This fill material may have originated at a former coal gasification
plant that was located near the Site. Therefore, the fill may be regulated under the
Massachusetts Contingency Plan (MCP). The owner should carry a contingency for further
testing, removal, and disposal costs associated with managing regulated soils. PID
readings are presented on the boring logs.
Grain Size Distribution
The sample collected from the upper five feet of boring CA-1 was classified as a fine gravel
and fine to coarse sand with trace amounts of coarse gravel and silt. This appears to be
suitable for use as Sand and Gravel and Granular Fill.
SIGNIFICANT GEOTECHNICAL ISSUES
The significant geotechnical issues for the proposed construction addressed in this report
include the following: the presence of non-engineered fill within the footprint of the
proposed building; foundation bearing capacity and settlement; seismic design
considerations; pavement design; and the suitability of on-Site materials for use as
engineered fill.
PRELIMINARY DESIGN RECOMMENDATIONS
The following recommendations are provided for the construction assumed in this report
and refer to the 9th Edition of the Massachusetts State Building Code (MSBC). We note
that the 9th Edition of the MSBC includes amendments to the 2015 International Building
Code (IBC).
Non-Engineered Fill and Demolition of Existing Structures
Non-engineered fill was encountered in the upper 5 to 16 feet with significant amounts of
debris (greater than 25% by volume) in the bottom portion of the fill layer. A description of
the fill soils is provided above. The non-engineered fill soils were likely placed to achieve
final grades during construction of the existing upper and lower parking lots. This fill is an
unsuitable bearing material for the proposed building due to the variability of the
composition and density of this material.
We recommend that the contractor remove the non-engineered fill from beneath the
footprint of the new building. We note that the fill appears to extend below proposed footing
and slab subgrade levels in the southern portion of the building. It may be possible to
reuse some of the excavated material, provided over-sized and deleterious materials
Preliminary Geotechnical Engineering Recommendations
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Northampton, Massachusetts
June 24, 2022
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(debris) are removed. Additional information regarding the reuse of on-Site granular
material is presented below.
We understand that the existing staircase may be demolished to prepare the Site for the
new construction. Any foundation walls or slabs, or utilities that are located within the
footprint of the proposed building should be removed in their entirety. These excavations
may extend below the planned slab and footing levels. Any excavations resulting from the
removal of existing foundations and/or slabs, should be backfilled with compacted
engineered fill, consistent with the recommendations provided below and in the Earthwork
Considerations section.
Abandoned buried utilities containing asbestos (such as electrical conduit insulation or
transite pipe) are commonly found during construction excavations. Furthermore, former
structures (pipes, conduits, foundations walls) may contain or be covered with materials
containing asbestos. Such materials should be handled in accordance with MassDEP’s
asbestos regulations (310 CMR 7.15). We recommend that suspect materials be
managed appropriately and tested by a Department of Labor Standards (DLS) certified
asbestos inspector prior to disturbances.
Excavations resulting from the removal of non-engineered fill, foundations, slabs, and/or
other structures should be backfilled with compacted engineered fill. Recommendations
for backfill gradation and compaction requirements are provided below.
Foundation Recommendations
The proposed building can be founded on either a thick concrete mat or normal spread
footing foundation. The structural mat would cover the entire lower level, while spread
footings would be located under footings and load bearing walls. Both alternatives would
likely bear on 12-inches of compacted Crushed Stone over the native soils. A maximum
allowable bearing pressure of 2,000 pounds per square foot may be used for the design
of both foundation systems. Both systems have relative advantages and disadvantages.
The normal spread footing foundation system would involve less concrete and reinforcing
steel. The concrete mat would be more rigid which would limit the potential for differential
settlement. In addition, the installation of waterproofing would be easier for a mat
foundation system.
The varved silt and clay layer is soft and could compress under the anticipated building
loads, potentially causing the building to undergo unacceptable settlement. The actual
building loads are not unknown at this time, and we cannot provide a detailed estimate of
potential settlement. However, up to three inches of total differential settlement is possible
for a five-story building. We recommend that a rigorous settlement evaluation be
conducted during final design. We note that the soft soils present below subgrade level
could be improved using aggregate piers. The piers would likely extend to the base of the
soft varved silt and clay layer (at an elevation of about 110 feet).
Exterior footings (or the exterior edge of a mat foundation) should be embedded a
minimum of 48 inches below the lowest adjacent grade for frost protection. Interior footings
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Northampton, Massachusetts
June 24, 2022
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should bear at least two feet below the surrounding floor slab. Strip footings, beneath the
load bearing walls, should be at least 18 inches wide. Isolated column footings should be
at least 24 inches wide. All other applicable requirements of the Massachusetts State
Building Code (MSBC) should be followed.
The structural mat or spread footings should not be placed on frozen soils and should be
free of loose or disturbed materials. Any boulders or cobbles larger than four inches in
diameter should be removed from within one foot of the bottom of the footings and
replaced with Crushed Stone or Sand and Gravel fill. The foundation subgrades should
be densified immediately prior to placement of footing concrete with at least three passes
with a vibrating plate compactor. If pumping of the subgrade occurs, vibratory compaction
should be stopped, and OTO contacted to provide additional recommendations. If loose
materials are present in the excavations, they shall be recompacted to form a firm, dense
bearing surface.
Concrete Slabs
We recommend that concrete floor slabs bear on at least 12 inches of compacted Crushed
Stone to provide uniform support and a capillary moisture break. The subgrade should
also be free of large boulders or cobbles, if encountered. The engineered fill beneath the
concrete slabs should meet the grain size distribution characteristics outlined in Table 1.
The subgrade within the footprint of the proposed building should be stripped of topsoil,
asphalt, and any non-engineered fill. Prior to the placement of any engineered fill, we
recommend that the building footprint be thoroughly densified to treat any loose areas
present. If non-engineered fill, soft, or disturbed areas are present, these materials should
be removed and recompacted or replaced with compacted, Sand and Gravel or Crushed
Stone. Fill supporting slabs should be placed in accordance with the recommendations
presented on Sheet 1.
Groundwater and Surface Water Control
The near surface varved silt and clay present at the Site inhibits the vertical infiltration of
stormwater and may result in layers of perched groundwater during periods of wet
weather. Therefore, we recommend that the building include perimeter drainage to control
groundwater and surface water infiltration. The perimeter drainage system can consist of
perforated PVC pipe, installed in a Crushed Stone trench, and wrapped in a non-woven
geotextile fabric. Furthermore, we recommend that a Crushed Stone drainage layer be
included beneath the first-floor slab. The Crushed Stone drainage layer and perimeter
drain should be hydraulically connected to allow the water to flow away from the
foundation via gravity. A typical detail of the underdrain system is shown on Sheet 2.
Clean-outs should be provided in the sub-slab and/or perimeter drainage system, to allow
for future maintenance.
Since the bottom levels will be occupied, we recommend that water proofing be provided
below the slab, water-stops be included, and at a minimum, the basement walls be damp-
proofed. We recommend that complete (membrane) waterproofing be strongly considered
Preliminary Geotechnical Engineering Recommendations
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Northampton, Massachusetts
June 24, 2022
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by the architect. As we discussed above, the use of a mat foundation system simplifies
the installation of the waterproofing system.
It should be noted that temporary groundwater control may be required during construction
to provide for the installation of the mat/footings, drainage layers and utilities. It should be
possible to dewater excavations by trenching or using sump pumps. Furthermore, the
contractor should establish and maintain proper drainage of soils during construction.
The native Site soils are susceptible to moisture, due to the high percentage of fines within
the soil mass. If these soils become wet during construction, they will become soft and
easily disturbed.
Seismic Considerations
Earthquake loadings must be considered under requirements in Section 1613 and 1806
of the 9th Edition (October 2017) of the Massachusetts State Building Code (MSBC). The
9th Edition of the MSBC is based upon the International Building Code 2015 (IBC) with
Massachusetts amendments. Note that the IBC refers to ASCE-7 (2010), Minimum Design
Loads for Buildings and Other Structures.
Site Class and Earthquake Design Factors
Section 1613 of the IBC covers lateral forces imposed on structures from earthquake
shaking and requires that every structure be designed and constructed to resist the effects
of earthquake motions in accordance with ASCE-7. Lateral forces are dependent on the
type and properties of soils present beneath the Site, along with the geographic location.
Per Table 1604.11, the maximum considered earthquake spectral response acceleration
at short periods (Ss) and at 1-sec (S1) was determined to be 0.171 and 0.066, respectively,
for Northampton, Massachusetts.
Soil properties are represented through Site Classification. Procedures for the Site-
specific determination of Site Classification are provided in Chapter 20 of ASCE-7. At this
Site, we evaluated Site Classification using one of the parameters allowed, Standard
Penetration Resistance (N-value). The Site Class was determined to be Class D based
upon soil data collected. Furthermore, the Site coefficients Fa and Fv were determined
according to Tables 1613.3.3(1) and 1613.3.3(2) of the IBC (2015), using both the Ss and
S1 values and the Site Class. For this Site, Fa and Fv were determined to be 1.6 and 2.4,
respectively.
Retaining and basement walls should be designed to resist dynamic lateral earth forces
in accordance with Section 1610.2 of the MSBC. The seismic earth forces as defined in
Section 1610.2 should be applied as an inverted triangle over the height of the wall and
added to the static lateral pressures. For purposes of the calculation, a total unit weight of
125 pounds per cubic foot should be used for the backfill against the retaining wall.
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Northampton, Massachusetts
June 24, 2022
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Liquefaction
Section 1806.4 relates to the liquefaction potential of the underlying soils. The liquefaction
potential was evaluated for saturated Site soils, using Figure 1806.4c of the MSBC.
However, based upon the observed density and composition of the native Site soils, it is
unlikely that liquefaction-induced settlement would occur under the design earthquake. In
addition, loose granular layers below the maximum depth explored are not anticipated.
Lateral Earth Pressures
Static lateral earth pressures will be imposed on basement and retaining walls. These
walls should be designed for unbalanced loading conditions. We anticipate that the walls
will be structurally braced, and not free to deflect, and recommend that an equivalent fluid
pressure of 55 pounds per cubic foot (pcf) be used. In addition, basement walls should
not be backfilled until the first-floor slab is installed. If basement walls are unbraced, they
need to be designed to resist overturning, sliding, and bearing capacity failure. For
unbraced walls, we recommend an equivalent fluid pressure of 35 pcf. A coefficient of
friction of 0.34 is recommended to evaluate frictional resistance to sliding along the base
of the wall and footings. These values apply to unsaturated soil conditions.
The soil against the outside of basement and retaining walls should not be over-
compacted, since this would greatly increase lateral loads against the walls. The
recommended degree of compaction for engineered fill and compaction means and
methods are presented on Sheet 1. We note that these are general guidelines and if it is
determined that a location falls into two or more categories, as presented in Table 1-1, the
design team should be notified to determine appropriate compaction efforts and/or
methods.
Exterior Slabs
Exterior concrete slabs, such as those at entryways and sidewalks adjacent to the building
should be designed to mitigate differential frost movement between adjacent slabs,
doorways, and pavements. To address this concern, we recommend that concrete slabs
at entryways be underlain by four feet of non-frost susceptible Sand and Gravel fill. Where
exterior slabs butt against hard surfaces, we recommend that for the area beyond the
edges of the slab, the bottom of Sand and Gravel fill should transition gradually upward at
a slope of 3H:1V or flatter (zone of influence). A typical detail showing an entryway fill area
is shown on Sheet 2.
Earthwork Considerations
We anticipate that earthwork for this project will include the following: removal and
replacement of non-engineered fill; excavations for footings; placement of compacted
engineered fill beneath the building, floor slab, and pavements (as needed); and the
treatment of the existing soils to address any localized loose areas that may be present.
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Northampton, Massachusetts
June 24, 2022
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Engineered Fill Recommendations
Three types of engineered fill types are recommended:
• Sand and Gravel for use immediately below sidewalks and as backfill following
demolition of structures and removal of non-engineered fill
• Crushed Stone for use immediately below footings and floor slabs, and in drainage
systems
• Granular Fill for use as miscellaneous fill
Grain size distribution requirements are presented in Table 1. On-Site soils may be
suitable for reuse as engineered fill (Sand and Gravel and Granular Fill), if free from
deleterious and/or oversized material. If the contractor elects to use the on-Site material
as fill, we recommend that a representative sample be collected, and a grain size
distribution analysis is performed to obtain approval by the engineer. Please note that the
Sand and Gravel specification is approximately that for Mass Highway M1.03.0, Type B
Gravel Borrow.
Table 1
Grain Size Distribution Requirements
Size
Sand and
Gravel Granular Fill Crushed
Stone
Percent Finer by Weight
3 inch 100 100 ---
1 inch --- --- 100
¾ inch --- --- 90-100
½ inch 50-85 --- 10-50
⅜ inch --- --- 0-20
No. 4 40-75 --- 0-5
No. 10 --- 30-90 ---
No. 40 10-35 10-70 ---
No. 200 0-10 0-15 ---
Compaction Recommendations
Fill, debris, topsoil, and organic soils should be removed from beneath the building
footprint and should not be reused as fill beneath structures. As was discussed above,
debris fill may be present below proposed footing elevations in the southern portion of the
proposed building. To avoid point loads any cobbles or boulders larger than four inches in
diameter, encountered at the subgrade should also be removed. The resulting excavations
should be backfilled with compacted Sand and Gravel or Crushed Stone fill.
Prior to the placement of any engineered fill, we recommend that the entire building
footprint be thoroughly proof compacted. Proof compaction should be accomplished by a
minimum of six passes with a 6,000-pound vibratory roller. To facilitate compaction, the
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Northampton, Massachusetts
June 24, 2022
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moisture content of the on-Site material should be maintained at or near the optimum
moisture content as determined by ASTM D1557.
Compacted fill should be placed in lifts ranging in thickness between 6 and 12 inches
depending on the size and type of equipment. Recommended degrees of compaction and
compaction means and methods are presented on Sheet 1.
Compaction within five feet of foundation or retaining walls should be performed using a
hand-operated roller or vibratory plate compactor. Placement and compaction of
engineered fill should proceed on both sides of foundation (frost) walls so that the
difference in top of fill on either side does not exceed two feet. Retaining walls should be
designed for unbalanced loading conditions and the engineered fill within ten feet of the
wall should be compacted using hand-operated plate or drum rollers weighing 250 pounds
or less.
Sloping and Earth Support
In areas of excavations, soil may become unstable when excavations extend deeper than
four feet. Any groundwater or surface water runoff encountered during the excavations will
need to be controlled be controlled via trenching and sumps to keep the excavation stable
and dry. Sloping may be necessary to protect personnel, adjacent buildings, and to
provide stability. The soils encountered in the upper 10 feet are estimated to be Type C
soils for slope stability purposes. The maximum allowable slope for excavations of Class C
soils is 1.5H:1V (34°). We recommend that a geotechnical engineer be on-Site to observe
actual soil conditions during the construction, if appropriate. We note that protective
systems for any excavation exceeding 20 feet in depth must be designed by a registered
professional engineer. All excavations should conform to current OSHA requirements.
Based upon the preliminary building location it does not appear that it will be necessary to
protect any of the adjacent buildings. However, a temporary earth support system may be
required along Crafts Avenue. in the northeastern portion of the Site. The design and
engineering of the temporary earth support systems should be the responsibility of the
contractor. Prior to construction, we recommend that the contractor evaluate the need for
a temporary earth support system to protect the existing building, foundation, and
personnel during construction.
FINAL DESIGN AND CONSTRUCTION PHASE SERVICES
It is recommended that O’Reilly, Talbot & Okun Associates, Inc. (OTO) be retained during
final design to further evaluate:
• Building settlement
• Foundation type (mat vs. spread footing foundation)
• The need for under slab drainage and/or waterproofing
• Temporary earth system requirements
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Northampton, Massachusetts
June 24, 2022
12 O:\J1800\1843 Jones Whitsett Architects Inc\23-01 208 Main Street at Crafts Avenue, Northampton -
Geotech\Report\OTO Crafts Ave Geotech Report 2022 June.docx
During final design, we should also be retained to prepare and/or review appropriate
specification sections and drawings, if necessary. During construction phases, we
recommend that OTO be retained to provide engineering support and to document
subgrade conditions and preparation.
We appreciated the opportunity to be of service on this project. If you have any questions,
please do not hesitate to contact the undersigned.
Sincerely yours,
O'Reilly, Talbot & Okun Associates, Inc.
Dustin A. Humphrey, P.E. Michael J. Talbot, P.E.
Project Manager Principal
Attachments: Limitations, Site Locus, Site Sketch, Sheets, Boring Logs, Laboratory Data
LIMITATIONS
1. The observations presented in this report were made under the conditions described
herein. The conclusions presented in this report were based solely upon the services
described in the report and not on scientific tasks or procedures beyond the scope of
the project or the time and budgetary constraints imposed by the client. The work
described in this report was carried out in accordance with the Statement of Terms and
Conditions attached to our proposal.
2. The analysis and recommendations submitted in this report are based in part upon the
data obtained from widely spaced subsurface explorations. The nature and extent of
variations between these explorations may not become evident until construction. If
variations then appear evident, it may be necessary to reevaluate the
recommendations of this report.
3. 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 interpretations of widely spaced explorations and
samples; actual soil transitions are probably more erratic. For specific information, refer
to the boring logs.
4. In the event that any changes in the nature, design or location of the proposed
structures are planned, the conclusions and recommendations contained in this report
shall not be considered valid unless the changes are reviewed and conclusions of this
report modified or verified in writing by O'Reilly, Talbot & Okun Associates Inc. It is
recommended that we be retained to provide a general review of final plans and
specifications.
5. Our report was prepared for the exclusive benefit of our client. Reliance upon the
report and its conclusions is not made to third parties or future property owners.
PROJECT No.
FIGURE No.
293 Bridge Street, Suite 500 Springfield, MA 01103 413.788.6222
O'Reilly, Talbot & Okun
E N G I N E E R I N G A S S O C I A T E S
www.OTO-ENV.com
208 MAIN STREET AT CRAFTS AVE
NORTHAMPTON, MASSACHUSETTS
SITE LOCUSO:\J1800\1843 Jones Whitsett Architects Inc\23-01 208 Main Street at Crafts Avenue, Northampton - Geotech\Boring Logs, Figures, Calculations\WorkingJ1843-23-01
1
Topographic Map Quadrant:
EASTHAMPTON, MA
Map Version: 1964
Current As Of: 1979
Date: MAY 2022
1:25,000 SCALE NATIONAL GEODETIC VERTICAL DATUM 1929 10 FOOT CONTOUR INTERVAL
0 1000
FEET
0 0.5 1.0
MILES
0 0.5 1
KILOMETERS
SITE
PROJECT NO.
FIGURE NO.293 Bridge Street, Suite 500 Springfield, MA 01103 413.788.6222O'Reilly, Talbot & OkunE N G I N E E R I N G A S S O C I A T E Swww.OTO-ENV.com208 MAIN AT CRAFTS AVENORTHAMPTON, MASSACHUSETTSSITE SKETCHO:\J1800\1843 Jones Whitsett Architects Inc\23-01 208 Main Street at Crafts Avenue, Northampton - Geotech\Boring Logs, Figures, CalculationsJ1843-23-01
2
DESIGNED BY: DAH
DRAWN BY: JE
CHECKED BY: DAH
DATE: 06/10/2022
REV. DATE:
LEGEND:
APPROXIMATE SOIL BORING LOCATION PERFORMED BY
SEABOARD DRILLING ON 5/19/2022, OBSERVED BY OTO
NOTES:
1. BASE MAP GENERATED BY REFERRING TO MASS MAPPER
(MASS GIS), ACCESSED ON JUNE 10, 2022
2. SAMPLE LOCATIONS ARE SHOWN ACCORDING TO TAPED
MEASUREMENTS TAKEN FROM EXISTING SITE FEATURES
3. ALL DATA IS TO BE CONSIDERED ACCURATE ONLY TO THE
DEGREE IMPLIED BY THE METHODS USED IN THE
DEVELOPMENT OF THIS PLAN
CA-1
220 MAIN ST
210 MAIN ST
210 MAIN ST
UPPER
PARKING
LOT
MAIN STREET
CRAFTS AVENUECA-2
LOWER PARKING LOT SCALE IN FEET
1" = 50'
0'25'50'100'
EXISTING RETAINING
WALL/STAIRCASE
APPROXIMATE FOOTPRINT
OF PROPOSED BUILDING
PROJECT No.
SHEET No.
293 Bridge Street, Suite 500 Springfield, MA 01103 413.788.6222
O'Reilly, Talbot & Okun
E N G I N E E R I N G A S S O C I A T E S
www.OTO-ENV.com
Westfield Intermodal Transit Center
Elm and Arnold Streets
Westfield, Massachusetts
N
O’Reilly, Talbot & Okun
[ A S S O C I A T E S ]
ENGINEERING
SITE
C 2003 National Geographic Holdings, Inc.
Topographic Map Quadrant: West Springfield, MA
Map Version: 1977
Current as of: 1979
Table 1-1
Degree of Compaction Recommendations
Location Minimum
Compaction
Below Structures (Foundations and Slabs) 95%
Below Pavements/Sidewalks/Exterior Slabs 95%
Against Basement Walls/Retaining Walls 92%
Utility Trenches 95%
General Landscaped Areas 90%
Notes.
1. Percentage of the maximum dry density as determined by Modified Proctor ASTM D1557, Method C.
2. When location falls into two or more categories, the engineer should be notified to determine appropriate
compaction efforts and/or methods.
3. Crushed stone should be compacted in lifts of 12 inches to form a dense matrix using either traditional
compaction methods (vibratory plate and/or roller) or tamping with an excavator bucket in deep
excavations. It is generally not necessary to perform laboratory or field density testing on crushed stone.
Table 1-2
General Guidelines for Compaction Means and Methods
Compaction Method
Maximum
Stone Size
(Inches
Diameter)
Maximum Lift
Thickness (Inches)
Minimum Number
of Passes
Below Structures
& Pavement
Non-
Critical
Areas
Below Structures
& Pavement
Non-
Critical
Areas
Hand-operated
Vibratory Plate
and confined spaces
3 6 8 6 4
Hand-operated vibratory
drum roller
(less than 1000 pounds)
3 6 8 6 4
Hand-operated vibratory
drum roller
(at least 1,000 pounds)
6 8 10 6 4
Light vibratory drum roller
(minimum 3000 pounds) 6 10 14 6 4
Heavy vibratory drum
roller (minimum 6000
pounds)
6 12 18 6 4
Note: The contractor should reduce or stop drum vibration if pumping of the subgrade is observed.
GENERAL COMPACTION GUIDELINESO:\J1800\1843 Jones Whitsett Architects Inc\23-01 208 Main Street at Crafts Avenue, Northampton - Geotech\Boring Logs, Figures, Calculations\WorkingDESIGNED BY: ALS
DRAWN BY: DAH
CHECKED BY: MJT
DATE: 11/09/2016
REV. DATE: 5/24/2022
J1843-23-01
1
208 MAIN STREET AT CRAFTS AVE
NORTHAMPTON, MASSACHUSETTS
PROJECT No.
SHEET No.
293 Bridge Street, Suite 500 Springfield, MA 01103 413.788.6222
O'Reilly, Talbot & Okun
E N G I N E E R I N G A S S O C I A T E S
www.OTO-ENV.com TYPICAL FOUNDATION SECTIONO:\J1800\1843 Jones Whitsett Architects Inc\23-01 208 Main Street at Crafts Avenue, Northampton - Geotech\Boring Logs, Figures, Calculations\WorkingDESIGNED BY: ALS
DRAWN BY: DAH
CHECKED BY: MJT
DATE: 11/9/2016
REV. DATE: 5/24/2022
J1843-23-01
2
NOTES:
1. NOT FOR CONSTRUCTION, FOR ILLUSTRATION PURPOSES ONLY
2. FOR ADDITIONAL INFORMATION, REFER TO OTO's GEOTECHNICAL REPORT DATED JUNE 2022
3. UNPAVED AREAS SHALL INCLUDE LOAM CAP AND SHOULD BE GRADED TO DIRECT SURFACE FLOW AWAY FROM BUILDING
4. PERMEABLE BACKFILL SHALL BE USED IN AREAS WITH UNDERDRAIN SYSTEMS
BASE/SUBBASE
TYPICAL FOUNDATION SECTION
SLAB ON GRADE FOOTING WITH ENTRANCE SLAB
1
3
FLOOR SLAB
PREPARED SUBGRADE
SAND AND
GRAVEL FILLGRANULAR
FILL
SAND AND GRAVEL
SEE NOTES 3 AND 4
PERIMETER
DRAINAGE
SYSTEM TO BE
DESIGNED BY
OTHERS
CRUSHED STONE UPON
NON-WOVEN GEOTEXTILE
FABRIC (AS NEEDED)CRUSHED STONE TRENCH
PERFORATED PIPE
4' (MIN)
NON-WOVEN
GEOTEXTILE
FABRIC
PAVEMENT SECTIONENTRANCE SLAB
SLOPING PER
OSHA STANDARDS
208 MAIN STREET AT CRAFTS AVE
NORTHAMPTON, MASSACHUSETTS
FIRST FLOOR SLAB
TYPICAL FOUNDATION SECTION
BASEMENT FOUNDATION WITH GROUND LEVEL ENTRANCE SLAB
SAND AND
GRAVEL FILL
FLOOR SLAB
PREPARED SUBGRADE
BASEMENT
LEVEL
ENTRANCE SLAB
SLOPING PER
OSHA STANDARDS
BASE/SUBBASE
SEE NOTES 3 AND 44' (MIN)
1
3
PAVEMENT SECTION
WATERPROOFING
BARRIER
WATERPROOFING/
VAPOR BARRIER
CRUSHED STONE UPON
NON-WOVEN GEOTEXTILE
FABRIC (AS NEEDED)CRUSHED STONE TRENCH
PERFORATED PIPE
NON-WOVEN
GEOTEXTILE FABRIC
BLOWS/FOOT
(SPT N-Value)
0-4 Very soft
4-10 Soft
10-30 Medium Stiff
30-50 Stiff
>50 Very stiff
Hard
MATERIAL FRACTION SMALLEST
Coarse DIAMETER
Fine None SILT
Coarse 1/4" (pencil)Clayey SILT
Medium 1/8"SILT & CLAY
Fine 1/16"CLAY & SILT
SILT/CLAY see adjacent table 1/32"Silty CLAY
COBBLES 1/64"CLAY
BOULDERS
TERM % OF TOTAL
and 35-50%
some 20-35%
little 10-20%
trace 1-10%
PID: Soil screened for volatile organic compounds (VOCs) using a photoionization detector (PID) referenced to benzene in air. Readings in
parts per million by volume.
Torvane: Undrained shear strength is estimated using an E285 Pocket Torvane (TV). Values in tons/ft2.
Penetrometer: Unconfined compressive strength is estimated using a Pocket Penetrometer (PP). Values in tons/ft2.
SUMMARY OF THE BURMISTER SOIL CLASSIFICATION SYSTEM (MODIFIED)
RELATIVE DENSITY (of non-plastic soils) OR CONSISTENCY (of plastic soils)
STANDARD PENETRATION TEST (SPT)
1/4" to 3/4"GRAVEL
15-30
>30
MATERIAL: (major constituent identified in CAPITAL letters)
COHESIONLESS SOILS COHESIVE SOILS
8-15
1/16" to 1/4"
Method: Samples were collected in accordance
with ASTM D1586, using a 2" diameter split
spoon sampler driven 24 inches. If samples were
collected using direct push methodology
(Geoprobe), SPTs were not performed and
relative density/consistency were not reported.
N-Value: The number of blows with a 140 lb.
hammer required to drive the sampler the middle
12 inches.
WOR: Weight Of Rod (depth dependent)
WOH: Weight Of Hammer (140 lbs.)
*Based upon uncorrected field N-values
RQD: Rock Quality Designation is determined by measuring total length of pieces of core 4" or greater and dividing by the total length of the
run, expressed as %. 100-90% excellent; 90-75% good; 75-50% fair; 50-25% poor; 25-0% very poor.
COMMON FIELD MEASUREMENTS
Wetted sample is rolled in hands to smallest possible
diameter before breaking.
Very High
Cannot distinguish individual particles
SAND
3" to 6" in diameter
> 6" in diameter
Note: Boulders and cobbles are observed in test pits and/or auger cuttings.
ORGANIC SILT: Typically gray to dark gray, often has strong H2S odor. May contain shells or shell fragments. Light weight.
Fibrous PEAT: Light weight, spongy, mostly visible organic matter, water squeezed readily from sample. Typically near top of layer.
Fine grained PEAT: Light weight, spongy, little visible organic matter, water squeezed from sample. Typically below fibrous peat.
DEBRIS: Detailed contents described in parentheses (wood, glass, ash, crushed brick, metal, etc.)
BEDROCK: Underlying rock beneath loose soil, can be weathered (easily crushed) or competent (difficult to crush).
Fill: Material used to raise ground, can be engineered or non-engineered.
Varved clay: Fine-grained, post-glacial lake sediments characterized by alternating layers
(or varves) of silt, sand and clay.
ADDITIONAL CONSTITUENTS
BORING LOGS
COMMON TERMS
Glacial till: Very dense/hard, heterogeneous mixture of sand, silt, clay, sub-angular gravel.
Deposited at base of glaciers, which covered all of New England.
IDENTITY
High
Non-plastic
Slight
PLASTICITY
Finest visible & distinguishable particles
3/4" to 3"
Low
Medium
GRAIN SIZE RANGE
1/64" to 1/16"
Dense
Very dense
COHESIVE SOILSCOHESIONLESS SOILS
BLOWS/FOOT CONSISTENCY(SPT N-Value)
<2
2-4
4-8
RELATIVE
DENSITY
Very loose
Loose
Medium dense
Page 1 of 2
34.1
148.0 Jeff
8 Joe
0 Roller Bit with Wash
N (2 3/8" O.D.)
FIRST (ft)N/A 2" O.D. Split Spoon
LAST (ft)--Automatic
TIME (hr)--140 lb / 30"
DEPTH (ft)ELEV.
10/24 S-1 PID = 0.2 ASPHALT 1
(0-2')BASE COURSE
FILL
19/24 S-2 PID = 5.5
(2-4')
16/24 S-3 PID = 7.5
(5-7')
12/24 S-4 PID = 1.3
(10-12')
2
18/24 S-5 PID = 23.0 15.5 132.5
(15-17')SILT AND CLAY
24/24 S-6 PID = 0.0
(20-22')TV = 0.75 3
PP = 0.50 4
0/24 S-7 --
(25-27')
1. Soil screened in field using MiniRAE Lite photoionization detector (PID) referenced to benzene in air. Readings in parts per million (PPM) by volume.
2. Auger grinding on wood at 13 feet below ground surface.
3. Undrained shear strength estimated in field using E285 Pocket Torvane (TV). Values in tons/ft2.
4. Unconfined compressive strength estimated in field using Pocket Penetrometer (PP). Values in tons/ft2.
5. Auger grinding at 34 feet below ground surface.
25'
1/1/2/2
CA-1
Remarks:PROJECT NO.
1843-23-01
LOG OF BORING
NO RECOVERY
2/1/2/2 Top 2.5": Very loose, gray, medium to coarse SAND, little gravel, trace silt, trace debris
(coal, ash; piece of 2" gray brown clay and silt; FILL)
Next 0.5": DEBRIS (100% light brown wood)
Bottom 15": Soft, blue to dark gray, varved SILT and CLAY, trace fine sand, trace medium
sand, trace debris (slag; 1" varves)
20'
1/1/2/2 Soft, gray brown to red brown, varved SILT and CLAY (1" varves)
10'
3/7/6/3 Top 8": Medium dense, brown gray, medium to coarse SAND, little gravel, little silt, trace fine
sand (FILL)
Bottom 4": Medium dense, light gray, fine to coarse SAND, trace gravel, trace silt, trace fine
sand (FILL)
15'
6/5/5/6
5/5/4/4
Medium dense, light gray, medium to coarse SAND, some gravel, trace silt, trace fine sand,
damp (FILL)
5'
HAMMER TYPE TYPE
Top 4": ASPHALT
Loose, brown, fine GRAVEL and fine to coarse SAND, trace silt, dry (BASE)
N/A
HAMMER WGT/DROP SIZE N/A
DEPTH (ft)/
SAMPLES
SAMPLES
SAMPLE DESCRIPTION
(MODIFIED BURMISTER)
REMARKS/
WELL
CONSTRUCTION
PENETR.
RESIST.
(bl / 6 in)
REC.
(in)
TYPE/
NO.
FIELD
TEST
DATA
PROFILE
BORING
LOCATION Upper parking lot
SAMPLER ROCK CORING INFORMATION
ENGINEER/SCIENTIST Caren Irgang WATER LEVEL ROD TYPE HAMMER DROP 30"
FINISH DATE 5/19/2022 UNDISTURBED SAMPLES BIT TYPE HAMMER WGT 300 lb
LOG OF BORING
PROJECT 208 Main Street at Crafts Ave CONTRACTOR Seaboard Environmental Drilling
START DATE 5/19/2022 DISTURBED SAMPLES HELPER CASE DIAMETER 4"
JOB NUMBER 1843-23-01 FINAL DEPTH (ft)DRILLING EQUIPMENT B-53 Truck Mounted Rig
LOCATION Northampton, MA SURFACE ELEV (ft)FOREMAN CASING
CA-1
5/8/9/9 Medium dense, light gray, medium to coarse SAND, trace silt, trace fine sand, trace fine
gravel, damp (FILL)
Page 2 of 2
DEPTH (ft)ELEV.
13/24 S-8 PID = 0.1 SILT AND CLAY
(27-29')TV = 1.00 (Continued)
PP = 0.50
13/24 S-9 PID = 0.1
(30-32')TV = 1.25
PP = 0.25
0/0.5 S-10 --34.1 113.9 5
(34')
Loose, red brown, fine SAND and SILT, little medium sand, trace fine gravel, trace coarse
sand
3/3/3/3
50 for 0.5"NO RECOVERY (Fractured rock fragments in spoon)
LOG OF BORING
REC.
(in)
TYPE/
NO.
PROFILE
CA-1
Job No.1843-23-01
SAMPLES REMARKS/
WELL
CONSTRUCTION
DEPTH (ft)/
SAMPLES
SAMPLE DESCRIPTION
(MODIFIED BURMISTER)
PENETR.
RESIST.
(bl / 6 in)
FIELD
TEST
DATA
Medium stiff, red brown, varved SILT and CLAY (1" varves)
Auger refusal at 34.1'35'
30'
60'
55'
50'
45'
40'
1/2/4/4
Page 1 of 2
19.2
128.0 Jeff
6 Joe
0 Hollow Stem Auger
A (1 5/8" O.D.)
FIRST (ft)8.0 2" O.D. Split Spoon
LAST (ft)N/A Automatic
TIME (hr)N/A 140 lb / 30"
DEPTH (ft)ELEV.
14/24 S-1 PID = 0.0 CONCRETE 1
(0-2')FILL
13/24 S-2 PID = 0.0
(2-4')
2
4/24 S-3 PID = 0.0 5.5 122.5
(5-7')SILT AND CLAY
120.0≡
20/24 S-4 PID = 0.0
(10-12')TV = 2.25 3
PP = 1.25 4
12/24 S-5 PID = 0.0
(15-17')TV = 1.25
PP = 1.25
18.0 110.0
GLACIAL TILL 5
1/2 S-6 --
(19-19.2')19.2 108.8
Auger refusal at 19.2'
1. Soil screened in field using MiniRAE Lite photoionization detector (PID) referenced to benzene in air. Readings in parts per million (PPM) by volume.
2. From cuttings: Dark gray sand, gravel, and debris from 4 to 5 feet (end of non-engineered fill at 5 feet).
3. Undrained shear strength estimated in field using E285 Pocket Torvane (TV). Values in tons/ft2.
4. Unconfined compressive strength estimated in field using Pocket Penetrometer (PP). Values in tons/ft2.
5. Auger grinding at 18 feet below ground surface.
LOG OF BORING CA-2
PROJECT 208 Main Street at Crafts Ave CONTRACTOR Seaboard Environmental Drilling
Very dense, red brown, fine SAND and SILT, trace fine gravel (fractured rock fragments in
spoon; TILL)
START DATE 5/19/2022 DISTURBED SAMPLES HELPER CASE DIAMETER N/A
JOB NUMBER 1843-23-01 FINAL DEPTH (ft)DRILLING EQUIPMENT B-53 Truck Mounted Rig
LOCATION Northampton, MA SURFACE ELEV (ft)FOREMAN CASING
ENGINEER/SCIENTIST Caren Irgang WATER LEVEL ROD TYPE HAMMER DROP 30"
FINISH DATE 5/19/2022 UNDISTURBED SAMPLES BIT TYPE HAMMER WGT 140 lb
REMARKS/
WELL
CONSTRUCTION
PENETR.
RESIST.
(bl / 6 in)
REC.
(in)
TYPE/
NO.
FIELD
TEST
DATA
PROFILE
BORING
LOCATION Center area of lower parking lot
SAMPLER ROCK CORING INFORMATION
HAMMER TYPE TYPE N/A
HAMMER WGT/DROP SIZE N/A
4/5/3/3 Top 7": Loose, gray brown, DEBRIS (30% varved silt and clay pieces, 25% brick, 25%
concrete, 20% coal, ash), damp
Bottom 6": Loose, light to dark brown, fine to coarse SAND, some debris (brick, concrete),
little fine gravel, damp
3/4/8/7 5.5": CONCRETE
Medium dense, orange brown, fine to medium SAND, little gravel, little silt, little to some
debris (coal, ash), damp (gray with little silt at 4"; 2" layer of brown fine to medium sand at
6"; brown at 8"; FILL)
DEPTH (ft)/
SAMPLES
SAMPLES
SAMPLE DESCRIPTION
(MODIFIED BURMISTER)
5'
2/2/3/3 Loose, gray brown, varved CLAY and SILT, damp
10'
3/3/4/4 Medium stiff, gray brown, varved SILT and CLAY, wet (1/2"-1/4" varves, 1/4" silt and 1/8"
clay)
15'
2/2/2/3 Top 4": Medium stiff, gray brown, varved SILT and CLAY, wet
Bottom 8": Loose, red brown, fine SAND and SILT, trace fine gravel, wet (1/2"-1/4" varves,
1/4" silt and 1/8" clay)
20'
50 for 2"
25'
CA-2
Remarks:PROJECT NO.
1843-23-01
LOG OF BORING